assignment of ecosystem

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Renuka Gupta

Module 1: Ecosystems: Concept, Structure and Functions – Part 1

1.1 The Earth System and its components

1.2 Ecology and Ecosystems

1.3 Concept of Ecosystem

1.4 Ecosystem Structure

1.5 Types of Ecosystem

1.6 Ecosystem Boundary

The earth’s life support system consists of four main components – the geosphere, the atmosphere, the hydrosphere, and the biosphere (Fig 1.1). These components are overlapping and interrelated with each other. A change in one is likely to result in change in one or more others. These components are briefly described in the following way:

• The Geosphere:

This part of earth system consists of rocks, minerals, and sediments. It includes thin outer crust, a thick molten mantle composed mostly of rocks, and intensely hot core. Its upper portion contains soil layers where organisms live, grow and reproduce and thus provides an important ecological habitat and basis of many forms of life. Various processes taking place on the surface of geosphere include erosion, weathering and transport as well as tectonic forces and volcanic activity, which result in the formation of landforms such as mountains, hills, etc.

• The Atmosphere:

The atmosphere is the gaseous layer surrounding the earth’s surface and held to its surface by gravity. Its inner layer, the troposphere, consists mostly of nitrogen (78% of the total volume), oxygen (21%), and others (1%). The others include carbon dioxide, methane and water vapours mainly, all of these are called as greenhouse gases which absorb and release energy to warm the lower atmosphere. This layer extends only about 17 km above sea level at the tropics and about 7 kms above the poles. The next layer, stratosphere, extends from 17 to 50 km above the earth surface. Its lower portion consists  of ozone layer which traps 95% of the ultraviolet radiations coming from sun, prevents them from reaching the earth surface and allows life to exist on the earth surface. The outer layers of atmosphere are called as thermosphere and exosphere. The atmosphere also absorbs water from the earth’s surface via the process of evaporation; it then acts to redistribute heat and moisture across the earth’s surface, thus giving rise to different weather conditions..

• The Hydrosphere:

      This part includes all the gaseous, liquid, and solid water of the earth system. The hydrosphere includes – earth’s oceans and seas, polar ice, glaciers, icebergs, lakes, rivers and streams, atmospheric moisture and ice crystals, areas of permafrost, moisture found in the soil (soil water) and within rocks (groundwater). It includes both saltwater and freshwater systems. The oceans, which cover about 71% of the globe, contain about 97% of the earth’s water. The glaciers and icebergs lock 2% of the total water on earth and remaining 1% is found as surface waters and ground waters. Water is essential for the existence and maintenance of life on earth. The earth’s temperature is highly influenced by the hydrosphere. In some classifications, the glaciers, icebergs, and ice-caps are also called as the cryosphere.

• The Biosphere:

This part includes all zones of earth where life is present. It includes all the plants, animals, and microorganisms present on earth. Much of the biosphere is contained within a shallow surface layer encompassing the lower part of the atmosphere, the surface of the geosphere and approximately the upper 100 metres of the oceans. All living organisms of biosphere are intimately related to the other three spheres – as most living organisms require gases from the atmosphere, water from the hydrosphere and nutrients and minerals from the geosphere. Human beings as part of the biosphere, interact with the entire earth system, its components and subcomponents which follow the fundamental principles of physics, chemistry, biology, and geology. These principles function in terms of processes and cycles, such as climate processes, biogeochemical cycles and hydrologic cycle. The ability for utilizing and altering all aspects of the earth system including natural resources directly or indirectly place human beings in seemingly inevitable competition with all other organisms. The consequences of this competition are revealed in the form of global warming, disturbances in biogeochemical cycles such as perturbation of the nitrogen cycle, regional changes in quality and quantity of fresh water, etc. The main components of the earth system are interconnected by two factors –

• a) the one-way flow of energy from the sun, through the living organisms in their feeding interactions, into the environment, and eventually to outer space as heat. As the solar energy interacts with carbon dioxide and other gases in the troposphere, it warms the earth surface and lower atmosphere by the process of greenhouse effect. The later makes the earth’s temperature sustainable for living organisms which would otherwise be too cold to support the life on earth.
• b) the cycling of the nutrients through parts of biosphere. The nutrients that cycle through the major biogeochemical cycles are carbon, oxygen, hydrogen, nitrogen, phosphorous and sulphur – all of which are essential for life. These biogeochemical cycles operate at global scale and involve all of the main components of earth system, thus materials are transferred continually between the geosphere, atmosphere, hydrosphere and biosphere.

                                The interactions in nature are studied in a branch of science termed as ‘Ecology’ . Have you ever pondered that why the forest area is covered by huge lush green trees and besides these, what more is present in a forest? Why there is a difference in forest types along the physical gradients? Why the plants and animals in a pond differ from an ocean? How the availability of water and temperature could mark a difference in vegetation of a desert and a tundra region? How the animals affect water and nutrient availability in the soil? How does fire affect the amount of food available in grasslands? All these questions find answers in the study of ecology and ecosystems. The term ‘Ecology’ was first coined by the German biologist Ernst Haeckel in 1869. Haeckel defined ecology as ‘the study of natural environment including the relations of organisms to one another   and to their surroundings.’ It is derived from two Greek words – “oikos” meaning home and “logos” meaning study. Thus literally, ecology is the study of life at home with main emphasis on pattern of relations between organisms and their surrounding environment. Clements (1916) considered ecology to be the “ science of communities.” Odum (1963) has defined ecology as the “study of the structure and function of nature.” It was broadly defined by Andrewarth (1961) as “Ecology is the scientific study of interactions that determine the distribution and abundance of organisms.” Modern ecologist Smith (1977) has defined it as “a multidisciplinary science which deals with organism  and its place to live and focuses on ecosystem.” In simple words, it deals with the intricate web of relationships between living organisms and their non-living surroundings. The surroundings consist of other living organisms and non-living environment such as water, air, soil, etc. Ecologists mainly focus on the distribution, life processes and adaptations among the organisms, which further are associated with the analysis of flow of energy and nutrients.

  Ecology can also be considered in terms of concept of levels of organization. The entire biological spectrum can at the best be divided into ten levels of organization including atom, cell, organ and organ system. The ecologists study interactions within and among six of these levels – organisms, populations, communities, ecosystems, biomes and the biosphere (Fig 1.2)

Ecology is divided into two branches depending upon whether an individual organism or a group of organisms is considered in the study:

• Autecology:

The study of an individual species in relation to its environment is known as autecology. It includes the study of its geographical distribution, taxonomic position, morphological characters, life cycle and behaviour with reference to ecological factors that might influence these activities. For example, the study of a particular fish, i.e. where it lives, what it eats, how many eggs it lays, etc.

• Synecology:

The study of group of organisms in relation to their environment is called as synecology. Here the unit of study is the group of species. For example, the study of aquatic flora and fauna in a particular river, i.e., the kinds of fishes and other animals living in it, types of plants found, the interrelationship between the plants and animals and with the physical factors of water, etc.

In nature, the living organisms (plants, animals and microorganisms) and nonliving environment (e.g. water, air, soil, etc.) are inseparably interrelated and interact with each other. No living organism can exist by itself, or without an environment. Every organism uses energy, nutrients and water from its surrounding environment in various life activities.

• The plants obtain the energy directly from the sun, and, in case of animals and microorganisms, energy is taken from other organisms through feeding on plants, predation, parasitism and/or decomposition.
• The terrestrial plants obtain water mainly from soil, while animals get it from free standing water in the environment or from their food.
• The plants obtain most of their nutrients from the soil or water, while animals get nutrients from plants or other organisms. Microorganisms are the most versatile, obtaining nutrients from soil, water, food, or other organisms.

As a result, the organisms interact with one another and with their environment in a number of ways. These fundamental interactions among organisms and their non-living/physico-chemical environment constitute an interrelating and interdependent ever-changing system known as an ecological system or ecosystem . The ecosystem has been considered as the basic functional unit of ecology and ecology as study of ecosystems.

The togetherness of organisms and environment has been expressed in history by different ecologists. However, the formal terminologies began to appear in different parts of the world in late 1800s. Karl Mobius, a German scientist, in 1877 gave the term ‘biocoenosis’ to a community of organisms in oyster reef; in 1887, S. A. Forbes, an American scientist, described lake as ‘microcosm’ and Russian ecologist, Sukachev in 1944, expanded it to ‘geobiocenosis’.

Although the roots of ecosystem concept can be traced in 19th century, it is largely a twentieth century construct. A. J. Lotka came up with the idea of ecosystem and wrote in his book (entitled Elements of Physical Biology (1925): “the organic and inorganic worlds function in a single system to such an extent that it is impossible to understand either part without understanding the whole.”

However, the term ‘Ecosystem’ was first coined in 1935 by the British ecologist Sir Arthur G. Tansley as part of a debate over the nature of biological communities: “Our natural human prejudices force us to consider the organisms as the most important parts of these systems, but certainly the inorganic “factors” are also parts – could be no systems without them, and there is a constant interchange of the most various kinds within each system, not only between the organisms but between the organic and the inorganic. These ecosystems, as we may call them, are of the most various kinds and sizes.” Tansley described the most fundamental nature of ecosystems – as a system in which biotic and abiotic components of environment are interrelated. The main focus is on the organisms in the definition and the nature of the “constant interchange of the most various kinds” is not made clear.

The great ecologist, E. P. Odum (1971) defined ecosystem as “Any unit that includes all of the organisms (i.e. the “community”) in a given area interacting with the physical environment so that a flow of energy leads to clearly defined trophic structure, biotic diversity, and material cycles (i.e. exchange of materials between living and nonliving parts) within the system is an ecological system or  ecosystem” Thus, Odum describes explicitly that ecosystem is a geographical unit and energy flow plays a central role in defining structural and functional features of the ecosystem.

    Allen and Hoekstra (1992) stated ecosystem as “The functional ecosystem is the conception where biota are explicitly linked to the abiotic world of their surroundings. Systems boundaries include the physical environment. Size is not the critical characteristic, rather the cycles and pathways of energy and matter in aggregate form the entire ecosystem.” They defined it as “functional ecosystem” and emphasized on the functional features such as nutrient cycling or trophic dynamics as much as what it contains or its size.

   Though there may be differences in the definitions given by different authors, all have three common characteristics – biotic component, abiotic environment and interactions between these two. The biotic component of ecosystem generally consists of communities of organisms, and abiotic component includes the physico-chemical environment surrounding them. Interactions may be numerous including food webs, trophic dynamics, nutrients cycling, flow of energy, etc. It has held a central position in modern ecology and environmental sciences. Modern ecology is now defined as “the study of structure and functions of ecosystems.” Now a day, most of the environmental management strategies include recognition of ecosystems as a way of ordering our perception of nature.

    Ecosystems differ greatly in their composition – in the number and kind of species, the type and relative proportions of non-living constituents, and in the degree of variations in time and space. A forest, a grassland, a pond, a coral reef, a part of any field and a laboratory culture can be some examples of ecosystem. The size of ecosystems varies tremendously. An ecosystem could be an entire rain forest, covering a large geographical area, or it could be a single tree inhabiting a large no. of birds and/or microorganisms in its leaf litter. It could be a termite’s gut, a lake or the biosphere as a whole with an entire intertwined environment of earth. The number of ecosystems on earth is countless and each ecosystem is distinct. All ecosystems have the following common characteristics as given by Smith (1966):

• The ecosystem is the major structural and functional unit of ecology.
• The structure of an ecosystem is related to its species diversity; the more complex ecosystems have high species diversity.
• The function of ecosystem is related to energy flow and material cycling through and within the system.
• The relative amount of energy needed to maintain an ecosystem depends on its structure. The more complex the structure, the lesser the energy it needs to maintain itself.
• Ecosystems mature by passing from less complex to more complex stages. Early stages of such succession have an excess of potential energy and a relatively high energy flow per unit biomass. Later (mature) stages have less energy accumulation and its flow through more diverse components.
• Both the environment and energy fixation in any given ecosystem are limited and cannot be exceeded without causing serious undesirable effects.
• Alterations in the environment represent selective pressures upon the population to which it must adjust. Organisms which are unable to adjust to the changed environment disappear ultimately.

         All ecosystems have a feeding hierarchy which starts with an energy source (e.g. the sun) and then followed by producers, consumers and decomposers. These components are dependent on one another. One of the important features is presence of grazing or detritus food chain and webs which become the lifeline of ecosystems. In grazing food chain and webs, green plants (i.e. producers) synthesize food from non-living nutrients with the help of the sunlight in the process of photosynthesis. Animals (i.e. consumers) consume plants and other animals to get the nutrients. When plants and animals die and decay or when animals excrete waste, bacteria and fungi (i.e. decomposers) feed on the dead or waste materials and release the nutrients back into water and/or soil for reuse by the producers. In a detritus food chain or web, the energy comes from dead organic matter (i.e. detritus) instead of green producers. One example of a detritus food web is the ecosystem of a deciduous forest floor.

Ecosystems are sustained by the presence of biodiversity. Each organism in an ecosystem has a purpose (i.e. niche), as a result, the loss of one species can alter both the size and stability of  ecosystems. In a whole, the ecosystems are open systems – depicting that things are entering and leaving the system, even though the general appearance and basic functions may remain constant for long periods of time.

The ecosystem is largely divided into two components – Abiotic and Biotic components. Ecosystem structure is created due to interaction between abiotic and biotic components, varying over space and time.

• Abiotic Components

The abiotic components of an ecosystem refer to the physical environment or the non-living factors. The organisms cannot live or survive without their abiotic components. They mainly include i) inorganic substances required by organisms such as carbon dioxide, water, nitrogen, calcium, phosphorus, etc. that are involved in material cycles. The amount of these inorganic substances present at any given time in ecosystem is called as standing state or standing quality of ecosystem. ii) organic compounds like proteins, carbohydrates, amino acids, lipids, humic substances and others are synthesized by the biotic counterpart of an ecosystem. They make biochemical structure of ecosystem.

• iii) climatic factors including mainly rain, light, temperature, humidity, wind and air and iv) edaphic and other factors such as minerals, soil, topography, pH, etc. greatly determine the functions, distribution, structure, behavior and inter-relationship of organisms in a habitat.
• Biotic Components

The biotic components of the ecosystems are the living organisms including plants, animals and microorganisms. Based on their nutritional requirement, i.e. how they get their food, they are categorized into three groups – i) Producers are mainly the green plants with chlorophyll which gives them the ability to use solar energy to manufacture their own food using simple inorganic abiotic substances, through the process of photosynthesis. They are also called as photoautotrophs (photo-light, auto-self, troph-nutrition). This group is mainly constituted by green plants, herbs, shrubs, trees, phytoplanktons, algae, mosses, etc. There are some chemosynthetic bacteria (sulphur bacteria) deap

beneath in the ocean which can synthesize their food in absence of sunlight, thus known as chemoautotrophs (chemo-chemical, auto-self, troph-nutrition). ii) Consumers lack chlorophyll, so they depend on producers for food. They are also known as heterotrophs. They mainly include herbivorous (feed on plants), carnivorous (feed on other animals), omnivorous (feed on both plants and animals) and detritivores organisms (feed on dead parts, waste, remains, etc. of plants and animals,). iii) Decomposers (saprotrophs) are the microorganisms, bacteria and fungi, which break down complex dead organic matter into simple inorganic forms, absorb some of the decomposition products, and release inorganic nutrients that are reused by the producers. All ecosystems have their own set of producers, consumers and decomposers which are specific to that ecosystem. The nutritional relationship among different biotic components of an ecosystem is shown in Fig 1.3.

Based on the kind of habitat, there are essentially two types of ecosystems: Aquatic and Terrestrial Ecosystem (Fig 1.4). Any other sub-ecosystem falls under one of these two types.

• Terrestrial Ecosystem

The ecosystems on land are called as terrestrial ecosystems. They are broadly classed into:

• a) Forest Ecosystem:

They are the ecosystems with an abundance of flora, or plants in relatively small space. A wide diversity of fauna can also be seen. A small change in this ecosystem could affect the whole balance and effectively bring down the whole ecosystem. They are further divided into:

Tropical rainforest: These contain more diverse biodiversity than ecosystems in any other region on earth. They receive a mean rainfall of 80 cm for every 400 inches annually. In these, warm, moisture-laden environments, dense evergreen vegetation comprising tall trees at different heights are present, with fauna species inhabiting the forest floor all the way up to canopy.

Tropical deciduous forest: In these ecosystems, shrubs and dense bushes are found along with a broad selection of trees. The trees are mainly which shed their leaves during dry season. The type of forest is found in quite a few parts of the world while a large variety of fauna and flora are found there.

Temperate evergreen forest: Those have a few numbers of trees as mosses and ferns make up for them. Trees have developed needle shaped leaves in order to minimize transpiration.

Temperate deciduous forest: The forest is located in the moist temperate places that have sufficient rainfall. Summers and winters are clearly defined and the trees shed the leaves during the winter.

Taiga: found just before the arctic regions, the taiga is defined by evergreen conifers. As the temperature is below zero for almost half a year, the remainder of the months, it buzzes with migratory birds and insects.

• b) Desert Ecosystems:

Desert ecosystems are located in regions that receive low precipitation, generally less than 25 cm per year. They occupy about 17 percent of land on earth. Some deserts contain sand dunes, while others feature mostly rock. Due to the extremely high temperature, low water availability and intense sunlight, vegetation is scarce or poorly developed, and any animal species, such as insects, reptiles and birds, must be highly adapted to the dry conditions. The vegetation is mainly shrubs, bushes, few grasses and rare trees. The stems and leaves of the plants are modified in order to conserve water as much as possible, for example, succulents such as the spiny leaved cacti.

• c) Grassland Ecosystems:

Grassland Ecosystems are typically found in both tropical and temperate regions of the world. They share the common climactic characteristic of semi-aridity. The area mainly comprises grasses with a little number of trees and shrubs. A lot of grazing animals, insectivores and herbivores inhabit the grasslands. The two main types of grasslands ecosystems are

Savanna: The tropical grasslands are dry seasonally and have few individual trees. They support a large number of predators and grazers.

Prairies: It is temperate grassland, completely devoid of large shrubs and trees. Prairies could be categorized as mixed grass, tall grass and short grass prairies.

• d) Mountain Ecosystem:

Mountain land provides a scattered and diverse array of habitats where a large number of animals and plants are found. At the higher altitudes, under harsh environment, only the treeless alpine vegetatio can survive. The animals have thick fur coats for prevention from cold and hibernation in the winter months. Lower slopes are commonly covered with coniferous forests.

• Aquatic Ecosystems:

Aquatic ecosystem is the ecosystem found in a body of water. It encompasses aquatic flora, fauna and water properties, as well. There are two main types of aquatic ecosystem – Marine and Freshwater Ecosystem.

• a) Marine Ecosystem

Marine ecosystems are the biggest ecosystems, which cover around 71% of earth’s surface and contain 97% of out planet’s water. Water in marine ecosystems contains high amounts of dissolved minerals and salts. Various marine ecosystems include oceanic (a relatively shallow part of oceans which lies on the continental shelf), profundal (deep or bottom water), benthic bottom substrates, inter-tidal (the place between low and high tides), estuaries, coral reefs, salt marshes, hydrothermal vents where chemosynthetic bacteria make up the food base. Many kinds of organisms live in marine ecosystems: the brown algae, corals, cephalopods, echinoderms, dinoflagellates, sharks, etc.

• b) Freshwater Ecosystem

Contrary to the Marine ecosystems, the freshwater ecosystem covers only 0.8% of Earth’s surface and contains 0.009% of the total water. Three basic kinds of freshwater ecosystems exist. i) Lentic – slow-moving or still water like pools, lakes or ponds ii) Lotic – fast-moving water such as streams and rivers iii) Wetlands – places in which the soil is inundated or saturated for some lengthy period of time.

Natural and Artificial Ecosystems

All above ecosystems are Natural ecosystems as these operate themselves under natural conditions without any major interference by man.Some ecosystems are maintained artificially by human beings where, by addition of energy and planned manipulations, natural balance is disturbed regularly. For example, croplands like maize,

wheat, rice-fields etc. where man tries to control the biotic community as well as the physico-chemical environment. These are called as Artificial or Man-engineered ecosystems.

The ecosystems appear distinct from each other with time and space, but functionally they are linked with each other. No ecosystem can exist alone. They are always in contact with the adjacent ecosystems. There exist no functional boundaries between them. Adjacent ecosystems interact with each other in order to make their structure and function. For example, various insects may be aquatic for certain parts of their life cycle and later on they become herbivorous of the vegetation on land. The adjacent aquatic and land ecosystem may have common organisms like birds. There is an exchange of inorganic nutrients between them. For example, sea birds bring the element phosphorus from sea to land (in the form of guano). The same element phosphorus as found in Himalayan region may be brought to land by the rivers.  The boundaries of ecosystem do overlap and this overlapping area is known as the transition zone. The transition zone is also known as the ecotone. It can be wide or narrow. The tropical rain forest and savannah along with the grasslands are also included under it. These areas have the plants and animals of both the ecosystems. (See box 1.1)

• The earth’s life support system consists of four main components – the geosphere, the atmosphere, the hydrosphere, and the biosphere. These components are overlapping and interrelated with each other. A change in one is likely to result in change in one or more others.
• Ecology is defined as the study of natural environment including the relations of organisms to one another and to their surroundings. It is derived from two Greek words – oikos meaning home and logos meaning study. Thus literally, ecology is the study of life at home with main emphasis on pattern of relations between organisms and their surrounding environment.
• The fundamental interactions among organisms and their non-living/physico-chemical environment constitute an interrelating and interdependent ever-changing system known as an ecological system or ecosystem. The ecosystem has been considered as the basic functional unit of ecology and ecology as study of ecosystems.
• The ecosystem is largely divided into two components – Abiotic and Biotic components. The abiotic components of an ecosystem refer to the physical environment or the non-living factors. The biotic components of the ecosystems are the living organisms including plants, animals and microorganisms.
• Two important processes flow of energy and material cycling keep the ecosystem functional.
• Based on the kind of habitat, there are essentially two types of ecosystems: Aquatic and Terrestrial Ecosystem. The aquatic ecosystem includes marine and freshwater ecosystems. While, terrestrial ecosystems are the forests, grassland, deserts, mountain and man-made ecosystems.
• The ecosystems appear distinct from each other with time and space, but functionally they are linked with each other. No ecosystem can exist alone. They are always in contact with the adjacent ecosystems. There exist no functional boundaries between them. Adjacent ecosystems interact with each other in order to make their structure and function.
• The boundaries of ecosystem do overlap and this overlapping area is known as the transition zone. The transition zone is also known as the ecotone.
• The mixed ecosystem characteristics result in greater density and biodiversity along the ecotones. This phenomenon is called the edge effect . The new species living along edges are unique and are called edge species .

• Allen and Hoekstra (1992). Toward a Unified Ecology . Columbia University Press, New York.
• Clements, F.E. (1916). Plant succession: an analysis of the development of vegetation. Washington,DC: Carnegie Institution of Washington.
• G. Andrewartha (1961). Introduction to the study of animal populations . University of Chicago Press.
• Odum E. P. (1971). Fundamentals of Ecology . W. B. Saunders Company, Philadelphia.
• Odum, E.P. (1963). Ecology. Modern Biology Series. Holt, Rinehart and Wintson, New York.
• Smith, R.L. (1966). Ecology and Field Biology . Harper and Row, New York.
• Tansley, A.G. (1935). The use and abuse of vegetational concepts and terms. Ecology, 16: 284-309.

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Ecosystem: It’s Structure and Functions (With Diagram)

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An organism is always in the state of perfect balance with the environment. The environment literally means the surroundings.

The environment refers to the things and conditions around the organisms which directly or indirectly influence the life and development of the organisms and their populations.

“Ecosystem is a complex in which habitat, plants and animals are considered as one interesting unit, the materials and energy of one passing in and out of the others” – Woodbury.

Organisms and environment are two non-separable factors. Organisms interact with each other and also with the physical conditions that are present in their habitats.

“The organisms and the physical features of the habitat form an ecological complex or more briefly an ecosystem.” (Clarke, 1954).

The concept of ecosystem was first put forth by A.G. Tansley (1935). Ecosystem is the major ecological unit. It has both structure and functions. The structure is related to species diversity. The more complex is the structure the greater is the diversity of the species in the ecosystem. The functions of ecosystem are related to the flow of energy and cycling of materials through structural components of the ecosystem.

According to Woodbury (1954), ecosystem is a complex in which habitat, plants and animals are considered as one interesting unit, the materials and energy of one passing in and out of the others.

According to E.P. Odum, the ecosystem is the basic functional unit of organisms and their environment interacting with each other and with their own components. An ecosystem may be conceived and studied in the habitats of various sizes, e.g., one square metre of grassland, a pool, a large lake, a large tract of forest, balanced aquarium, a certain area of river and ocean.

All the ecosystems of the earth are connected to one another, e.g., river ecosystem is connected with the ecosystem of ocean, and a small ecosystem of dead logs is a part of large ecosystem of a forest. A complete self-sufficient ecosystem is rarely found in nature but situations approaching self-sufficiency may occur.

Structure of Ecosystem:

The structure of an ecosystem is basically a description of the organisms and physical features of environment including the amount and distribution of nutrients in a particular habitat. It also provides information regarding the range of climatic conditions prevailing in the area.

From the structure point of view, all ecosystems consist of the following basic components:

1. Abiotic components

2. Biotic components

1. Abiotic Components:

Ecological relationships are manifested in physicochemical environment. Abiotic component of ecosystem includes basic inorganic elements and compounds, such as soil, water, oxygen, calcium carbonates, phosphates and a variety of organic compounds (by-products of organic activities or death).

It also includes such physical factors and ingredients as moisture, wind currents and solar radiation. Radiant energy of sun is the only significant energy source for any ecosystem. The amount of non-living components, such as carbon, phosphorus, nitrogen, etc. that are present at any given time is known as standing state or standing quantity.

2. Biotic Components :

The biotic components include all living organisms present in the environmental system.

From nutrition point of view, the biotic components can be grouped into two basic components:

(i) Autotrophic components, and

(ii) Heterotrophic components

The autotrophic components include all green plants which fix the radiant energy of sun and manufacture food from inorganic substances. The heterotrophic components include non-green plants and all animals which take food from autotrophs.

So biotic components of an ecosystem can be described under the following three heads:

1. Producers (Autotrophic components),

2. Consumers, and

3. Decomposers or reducers and transformers

The amount of biomass at any time in an ecosystem is known as standing crop which is usually expressed as fresh weight, dry weight or as free energy in terms of calories/metre.

Producers (Autotrophic elements):

The producers are the autotrophic elements—chiefly green plants. They use radiant energy of sun in photosynthetic process whereby carbon dioxide is assimilated and the light energy is converted into chemical energy. The chemical energy is actually locked up in the energy rich carbon compounds. Oxygen is evolved as by-product in the photosynthesis.

This is used in respiration by all living things. Algae and other hydrophytes of a pond, grasses of the field, trees of the forests are examples of producers. Chemosynthetic bacteria and carotenoid bearing purple bacteria that also assimilate CO 2 with the energy of sunlight but only in the presence of organic compounds also belong to this category.

The term producer is misleading one because in an energy context, producers produce carbohydrate and not energy. Since they convert or transduce the radiant energy into chemical form, E.J. Kormondy suggests better alternative terms ‘converters’ or ‘transducers’. Because of wide use the term producer is still retained.

Those living members of ecosystem which consume the food synthesized by producers are called consumers. Under this category are included all kinds of animals that are found in an ecosystem.

There are different classes or categories of consumers, such as:

(a) Consumers of the first order or primary consumers,

(b) Consumers of the second order or secondary consumers,

(c) Consumers of the third order or tertiary consumers, and

(d) Parasites, scavengers and saprobes.

(a) Primary consumers:

These are purely herbivorous animals that are dependent for their food on producers or green plants. Insects, rodents, rabbit, deer, cow, buffalo, goat are some of the common herbivores in the terrestrial ecosystem, and small crustaceans, molluscs, etc. in the aquatic habitat. Elton (1939) named herbivores of ecosystem as “key industry animals”. The herbivores serve as the chief food source for carnivores.

(b) Secondary consumers:

These are carnivores and omnivores. Carnivores are flesh eating animals and the omnivores are the animals that are adapted to consume herbivores as well as plants as their food. Examples of secondary consumers are sparrow, crow, fox, wolves, dogs, cats, snakes, etc.

(c) Tertiary consumers:

These are the top carnivores which prey upon other carnivores, omnivores and herbivores. Lions, tigers, hawk, vulture, etc. are considered as tertiary or top consumers.

(d) Besides different classes of consumers, the parasites, scavengers and saprobes are also included in the consumers. The parasitic plants and animals utilize the living tissues of different plants and animals. The scavengers and saprobes utilize dead remains of animals and plants as their food.

Decomposers and transformers:

Decomposers and transformers are the living components of the ecosystem and they are fungi and bacteria. Decomposers attack the dead remains of producers and consumers and degrade the complex organic substances into simpler compounds. The simple organic matters are then attacked by another kind of bacteria, the transformers which change these organic compounds into the inorganic forms that are suitable for reuse by producers or green plants. The decomposers and transformers play very important role in maintaining the dynamic nature of ecosystems.

Function of Ecosystem :

An ecosystem is a discrete structural, functional and life sustaining environmental system. The environmental system consists of biotic and abiotic components in a habitat. Biotic component of the ecosystem includes the living organisms; plants, animals and microbes whereas the abiotic component includes inorganic matter and energy.

Abiotic components provide the matrix for the synthesis and perpetuation of organic components (protoplasm). The synthesis and perpetuation processes involve energy exchange and this energy comes from the sun in the form of light or solar energy.

Thus, in any ecosystem we have the following functional components:

(i) Inorganic constituents (air, water and mineral salts)

(ii) Organisms (plants, animals and microbes), and

(iii) Energy input which enters from outside (the sun).

These three interact and form an environmental system. Inorganic constituents are synthesized into organic structures by the green plants (primary producers) through photosynthesis and the solar energy is utilized in the process. Green plants become the source of energy for renewals (herbivores) which, in turn become source of energy for the flesh eating animals (carnivores). Animals of all types grow and add organic matter to their body weight and their source of energy is complex organic compound taken as food.

They are known as secondary producers. All the living organisms whether plants or animals in an ecosystem have a definite life span after which they die. The dead organic remains of plants and animals provide food for saprophytic microbes, such as bacteria, fungi and many other animals. The saprobes ultimately decompose the organic structure and break the complex molecules and liberate the inorganic components into their environment.

These organisms are known as decomposers. During the process of decomposition of organic molecules, the energy which kept the inorganic components bound together in the form of organic molecules gets liberated and dissipated into the environment as heat energy. Thus in an ecosystem energy from the sun, the input is fixed by plants and transferred to animal components.

Nutrients are withdrawn from the substrate, deposited in the tissues of the plants and animals, cycled from one feeding group to another, released by decomposition to the soil, water and air and then recycled. The ecosystems operating in different habitats, such as deserts, forests, grasslands and seas are interdependent on one another. The energy and nutrients of one ecosystem may find their way into another so that ultimately all parts of the earth are interrelated, each comprising a part of the total system that keeps the biosphere functioning.

Thus the principal steps in the operation of ecosystem are as follows:

(1) Reception of radiant energy of sun,

(2) Manufacture of organic materials from inorganic ones by producers,

(3) Consumption of producers by consumers and further elaboration of consumed materials; and.

(4) After the death of producers and consumers, complex organic compounds are degraded and finally converted by decomposers and converters into such forms as are suitable for reutilization by producers.

The principal steps in the operation of ecosystem not only involve the production, growth and death of living components but also influence the abiotic aspects of habitat. It is now clear that there is transfer of both energy and nutrients from producers to consumers and finally to decomposers and transformers levels. In this transfer there is a progressive decrease of energy but nutrient component is not diminished and it shows cycling from abiotic to biotic and vice versa.

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ENCYCLOPEDIC ENTRY

An ecosystem is a geographic area where plants, animals and other organisms, as well as weather and landscapes, work together to form a bubble of life.

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An ecosystem is a geographic area where plants , animals and other organisms , as well as weather and landscape , work together to form a bubble of life. Ecosystems contain biotic or living parts, as well as a biotic factors , or nonliving parts. Biotic factors include plants, animals and other organisms. Abiotic factors include rocks , temperature and humidity . Every factor in an ecosystem depends on every other factor, either directly or indirectly. A change in the temperature of an ecosystem will often affect what plants will grow there, for instance. Animals that depend on plants for food and shelter will have to adapt to the changes, move to another ecosystem, or perish . Ecosystems can be very large or very small. Tide pools , the ponds left by the ocean as the tide goes out, are complete, tiny ecosystems. Tide pools contain seaweed , a kind of algae , which uses photosynthesis to create food. Herbivores such as abalone eat the seaweed. Carnivores such as sea stars eat other animals in the tide pool, such as clams or mussels . Tide pools depend on the changing level of ocean water. Some organisms, such as seaweed, thrive in an aquatic environment, when the tide is in and the pool is full. Other organisms, such as hermit crabs , cannot live underwater and depend on the shallow pools left by low tides. In this way, the biotic parts of the ecosystem depend on abiotic factors. The whole surface of Earth is a series of connected ecosystems. Ecosystems are often connected in a larger biome . Biomes are large sections of land, sea or atmosphere. Forests , ponds, reefs and tundra are all types of biomes, for example. They're organized very generally, based on the types of plants and animals that live in them. Within each forest, pond, reef or section of tundra, you'll find many different ecosystems. The biome of the Sahara Desert , for instance, includes a wide variety of ecosystems. The arid climate and hot weather characterize the biome. Within the Sahara are oasis ecosystems, which have date palm trees, freshwater , and animals such as crocodiles . The Sahara also has dune ecosystems, with the changing landscape determined by the wind . Organisms in these ecosystems, such as snakes or scorpions , must be able to survive in sand dunes for long periods of time. The Sahara even includes a marine environment, where the Atlantic Ocean creates cool fogs on the Northwest African coast. Shrubs and animals that feed on small trees, such as goats , live in this Sahara ecosystem. Even similar-sounding biomes could have completely different ecosystems. The biome of the Sahara Desert , for instance, is very different from the biome of the Gobi Desert in Mongolia and China. The Gobi is a cold desert, with frequent snowfall and freezing temperatures. Unlike the Sahara, the Gobi has ecosystems based not in sand, but kilometers of bare rock. Some grasses are able to grow in the cold, dry climate. As a result, these Gobi ecosystems have grazing animals such as gazelles and even takhi , an endangered species of wild horse. Even the cold desert ecosystems of the Gobi are distinct from the freezing desert ecosystems of Antarctica. Antarcticas thick ice sheet covers a continent made almost entirely of dry, bare rock. Only a few mosses grow in this desert ecosystem, supporting only a few birds, such as skuas . Threats to Ecosystems For thousands of years, people have interacted with ecosystems. Many cultures developed around nearby ecosystems. Many Native American tribes of North Americas Great Plains developed a complex lifestyle based on the native plants and animals of plains ecosystems, for instance. Bison , a large grazing animal native to the Great Plains, became the most important biotic factor in the cultures of many Indigenous peoples of the Great Plains, such as the Lakota or Kiowa . Bison are sometimes mistakenly called buffalo. These tribes used buffalo hides for shelter and clothing, buffalo meat for food, and buffalo horn for tools. The tallgrass prairie of the Great Plains supported bison herds , which tribes followed throughout the year.

As human populations have grown, however, people have overtaken many ecosystems. The tallgrass prairie of the Great Plains, for instance, became farmland . As the ecosystem shrunk, fewer bison could survive. Today, a few herds survive in protected ecosystems such as Yellowstone National Park. In the tropical rainforest ecosystems surrounding the Amazon River in South America, a similar situation is taking place. The Amazon rainforest includes hundreds of ecosystems, including canopies, understories and forest floors. These ecosystems support vast food webs . Canopies are ecosystems at the top of the rainforest , where tall, thin trees such as figs grow in search of sunlight. Canopy ecosystems also include other plants, called epiphytes , which grow directly on branches. Understory ecosystems exist under the canopy. They are darker and more humid than canopies. Animals such as monkeys live in understory ecosystems, eating fruits from trees as well as smaller animals like beetles. Forest floor ecosystems support a wide variety of flowers , which are fed on by insects like butterflies. Butterflies, in turn, provide food for animals such as spiders in forest floor ecosystems. Human activity threatens all these rainforest ecosystems in the Amazon. Thousands of acres of land are cleared for farmland, housing and industry . Countries of the Amazon rain forest, such as Brazil, Venezuela and Ecuador, are underdeveloped. Cutting down trees to make room for crops such as soy and corn benefits many poor farmers. These resources give them a reliable source of income and food. Children may be able to attend school and families are able to afford better health care . However, the destruction of rainforest ecosystems has its costs. Many modern medicines have been developed from rainforest plants. Curare , a muscle relaxant, and quinine , used to treat malaria , are just two of these medicines. Many scientists worry that destroying the rainforest ecosystem may prevent more medicines from being developed. The rainforest ecosystems also make poor farmland. Unlike the rich soils of the Great Plains, where people destroyed the tallgrass prairie ecosystem, Amazon rain forest soil is thin and has few nutrients . Only a few seasons of crops may grow before all the nutrients are absorbed. The farmer or agribusiness must move on to the next patch of land, leaving an empty ecosystem behind. Rebounding Ecosystems Ecosystems can recover from destruction, however. The delicate coral reef ecosystems in the South Pacific are at risk due to rising ocean temperatures and decreased salinity . Corals bleach, or lose their bright colors, in water that is too warm. They die in water that isnt salty enough. Without the reef structure, the ecosystem collapses. Organisms such as algae, plants such as seagrass , and animals such as fish, snakes and shrimp disappear. Most coral reef ecosystems will bounce back from collapse. As ocean temperature cools and retains more salt, the brightly colored corals return. Slowly, they build reefs. Algae, plants and animals also return. Individual people, cultures and governments are working to preserve ecosystems that are important to them. The government of Ecuador, for instance, recognizes ecosystem rights in the countrys constitution . The so-called Rights of Nature says Nature or Pachamama [Earth], where life is reproduced and exists, has the right to exist, persist , maintain and regenerate its vital cycles, structure, functions and its processes in evolution . Every person, people, community or nationality will be able to demand the recognitions of rights for nature before the public bodies. Ecuador is home not only to rainforest ecosystems, but also river ecosystems and the remarkable ecosystems on the Galapagos Islands .

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46.1 Ecology of Ecosystems

Learning objectives.

By the end of this section, you will be able to do the following:

• Describe the basic ecosystem types
• Explain the methods that ecologists use to study ecosystem structure and dynamics
• Identify the different methods of ecosystem modeling
• Differentiate between food chains and food webs and recognize the importance of each

Life in an ecosystem is often about competition for limited resources, a characteristic of the theory of natural selection. Competition in communities (all living things within specific habitats) is observed both within species and among different species. The resources for which organisms compete include organic material, sunlight, and mineral nutrients, which provide the energy for living processes and the matter to make up organisms’ physical structures. Other critical factors influencing community dynamics are the components of its physical and geographic environment: a habitat’s latitude, amount of rainfall, topography (elevation), and available species. These are all important environmental variables that determine which organisms can exist within a particular area.

An ecosystem is a community of living organisms and their interactions with their abiotic (nonliving) environment. Ecosystems can be small, such as the tide pools found near the rocky shores of many oceans, or large, such as the Amazon Rainforest in Brazil ( Figure 46.2 ).

There are three broad categories of ecosystems based on their general environment: freshwater, ocean water, and terrestrial. Within these broad categories are individual ecosystem types based on the organisms present and the type of environmental habitat.

Ocean ecosystems are the most common, comprising over 70 percent of the Earth's surface and consisting of three basic types: shallow ocean, deep ocean water, and deep ocean surfaces (the low depth areas of the deep oceans). The shallow ocean ecosystems include extremely biodiverse coral reef ecosystems, and the deep ocean surface is known for its large numbers of plankton and krill (small crustaceans) that support it. These two environments are especially important to aerobic respirators worldwide as the phytoplankton perform 40 percent of all photosynthesis on Earth. Although not as diverse as the other two, deep ocean ecosystems contain a wide variety of marine organisms. Such ecosystems exist even at the bottom of the ocean where light is unable to penetrate through the water.

Freshwater ecosystems are the rarest, occurring on only 1.8 percent of the Earth's surface. Lakes, rivers, streams, and springs comprise these systems. They are quite diverse, and they support a variety of fish, amphibians, reptiles, insects, phytoplankton, fungi, and bacteria.

Terrestrial ecosystems, also known for their diversity, are grouped into large categories called biomes, such as tropical rain forests, savannas, deserts, coniferous forests, deciduous forests, and tundra. Grouping these ecosystems into just a few biome categories obscures the great diversity of the individual ecosystems within them. For example, there is great variation in desert vegetation: the saguaro cacti and other plant life in the Sonoran Desert, in the United States, are relatively abundant compared to the desolate rocky desert of Boa Vista, an island off the coast of Western Africa ( Figure 46.3 ).

Ecosystems are complex with many interacting parts. They are routinely exposed to various disturbances, or changes in the environment that effect their compositions: yearly variations in rainfall and temperature and the slower processes of plant growth, which may take several years. Many of these disturbances result from natural processes. For example, when lightning causes a forest fire and destroys part of a forest ecosystem, the ground is eventually populated by grasses, then by bushes and shrubs, and later by mature trees, restoring the forest to its former state. The impact of environmental disturbances caused by human activities is as important as the changes wrought by natural processes. Human agricultural practices, air pollution, acid rain, global deforestation, overfishing, eutrophication, oil spills, and waste dumping on land and into the ocean are all issues of concern to conservationists.

Equilibrium is the steady state of an ecosystem where all organisms are in balance with their environment and with each other. In ecology, two parameters are used to measure changes in ecosystems: resistance and resilience. Resistance is the ability of an ecosystem to remain at equilibrium in spite of disturbances. Resilience is the speed at which an ecosystem recovers equilibrium after being disturbed. Ecosystem resistance and resilience are especially important when considering human impact. The nature of an ecosystem may change to such a degree that it can lose its resilience entirely. This process can lead to the complete destruction or irreversible altering of the ecosystem.

Food Chains and Food Webs

The term “food chain” is sometimes used metaphorically to describe human social situations. Individuals who are considered successful are seen as being at the top of the food chain, consuming all others for their benefit, whereas the less successful are seen as being at the bottom.

The scientific understanding of a food chain is more precise than in its everyday usage. In ecology, a food chain is a linear sequence of organisms through which nutrients and energy pass: primary producers, primary consumers, and higher-level consumers are used to describe ecosystem structure and dynamics. There is a single path through the chain. Each organism in a food chain occupies what is called a trophic level . Depending on their role as producers or consumers, species or groups of species can be assigned to various trophic levels.

In many ecosystems, the bottom of the food chain consists of photosynthetic organisms (plants and/or phytoplankton), which are called primary producers . The organisms that consume the primary producers are herbivores: the primary consumers . Secondary consumers are usually carnivores that eat the primary consumers. Tertiary consumers are carnivores that eat other carnivores. Higher-level consumers feed on the next lower trophic levels, and so on, up to the organisms at the top of the food chain: the apex consumers . In the Lake Ontario food chain shown in Figure 46.4 , the Chinook salmon is the apex consumer at the top of this food chain.

One major factor that limits the length of food chains is energy. Energy is lost as heat between each trophic level due to the second law of thermodynamics. Thus, after a limited number of trophic energy transfers, the amount of energy remaining in the food chain may not be great enough to support viable populations at yet a higher trophic level.

The loss of energy between trophic levels is illustrated by the pioneering studies of Howard T. Odum in the Silver Springs, Florida, ecosystem in the 1940s ( Figure 46.5 ). The primary producers generated 20,819 kcal/m 2 /yr (kilocalories per square meter per year), the primary consumers generated 3368 kcal/m 2 /yr, the secondary consumers generated 383 kcal/m 2 /yr, and the tertiary consumers only generated 21 kcal/m 2 /yr. Thus, there is little energy remaining for another level of consumers in this ecosystem.

There is one problem when using food chains to accurately describe most ecosystems. Even when all organisms are grouped into appropriate trophic levels, some of these organisms can feed on species from more than one trophic level; likewise, some of these organisms can be eaten by species from multiple trophic levels. In other words, the linear model of ecosystems, the food chain, is not completely descriptive of ecosystem structure. A holistic model—which accounts for all the interactions between different species and their complex interconnected relationships with each other and with the environment—is a more accurate and descriptive model for ecosystems. A food web is a graphic representation of a holistic, nonlinear web of primary producers, primary consumers, and higher-level consumers used to describe ecosystem structure and dynamics ( Figure 46.6 ).

A comparison of the two types of structural ecosystem models shows strength in both. Food chains are more flexible for analytical modeling, are easier to follow, and are easier to experiment with, whereas food web models more accurately represent ecosystem structure and dynamics, and data can be directly used as input for simulation modeling.

Link to Learning

Head to this online interactive simulator to investigate food web function. In the Interactive Labs box, under underline Food Web end underline , click Step 1 . Read the instructions first, and then click Step 2 for additional instructions. When you are ready to create a simulation, in the upper-right corner of the Interactive Labs box, click OPEN SIMULATOR .

Two general types of food webs are often shown interacting within a single ecosystem. A grazing food web (such as the Lake Ontario food web in Figure 46.6 ) has plants or other photosynthetic organisms at its base, followed by herbivores and various carnivores. A detrital food web consists of a base of organisms that feed on decaying organic matter (dead organisms), called decomposers or detritivores. These organisms are usually bacteria or fungi that recycle organic material back into the biotic part of the ecosystem as they themselves are consumed by other organisms. As all ecosystems require a method to recycle material from dead organisms, most grazing food webs have an associated detrital food web. For example, in a meadow ecosystem, plants may support a grazing food web of different organisms, primary and other levels of consumers, while at the same time supporting a detrital food web of bacteria, fungi, and detrivorous invertebrates feeding off dead plants and animals.

Evolution Connection

Three-spined stickleback.

It is well established by the theory of natural selection that changes in the environment play a major role in the evolution of species within an ecosystem. However, little is known about how the evolution of species within an ecosystem can alter the ecosystem environment. In 2009, Dr. Luke Harmon, from the University of Idaho, published a paper that for the first time showed that the evolution of organisms into subspecies can have direct effects on their ecosystem environment. 1

The three-spined stickleback ( Gasterosteus aculeatus ) is a freshwater fish that evolved from a saltwater fish to live in freshwater lakes about 10,000 years ago, which is considered a recent development in evolutionary time ( Figure 46.7 ). Over the last 10,000 years, these freshwater fish then became isolated from each other in different lakes. Depending on which lake population was studied, findings showed that these sticklebacks then either remained as one species or evolved into two species. The divergence of species was made possible by their use of different areas of the pond for feeding called micro niches.

Dr. Harmon and his team created artificial pond microcosms in 250-gallon tanks and added muck from freshwater ponds as a source of zooplankton and other invertebrates to sustain the fish. In different experimental tanks they introduced one species of stickleback from either a single-species or double-species lake.

Over time, the team observed that some of the tanks bloomed with algae while others did not. This puzzled the scientists, and they decided to measure the water's dissolved organic carbon (DOC), which consists of mostly large molecules of decaying organic matter that give pond-water its slightly brownish color. It turned out that the water from the tanks with two-species fish contained larger particles of DOC (and hence darker water) than water with single-species fish. This increase in DOC blocked the sunlight and prevented algal blooming. Conversely, the water from the single-species tank contained smaller DOC particles, allowing more sunlight penetration to fuel the algal blooms.

This change in the environment, which is due to the different feeding habits of the stickleback species in each lake type, probably has a great impact on the survival of other species in these ecosystems, especially other photosynthetic organisms. Thus, the study shows that, at least in these ecosystems, the environment and the evolution of populations have reciprocal effects that may now be factored into simulation models.

Research into Ecosystem Dynamics: Ecosystem Experimentation and Modeling

The study of the changes in ecosystem structure caused by changes in the environment (disturbances) or by internal forces is called ecosystem dynamics . Ecosystems are characterized using a variety of research methodologies. Some ecologists study ecosystems using controlled experimental systems, while some study entire ecosystems in their natural state, and others use both approaches.

A holistic ecosystem model attempts to quantify the composition, interaction, and dynamics of entire ecosystems; it is the most representative of the ecosystem in its natural state. A food web is an example of a holistic ecosystem model. However, this type of study is limited by time and expense, as well as the fact that it is neither feasible nor ethical to do experiments on large natural ecosystems. It is difficult to quantify all different species in an ecosystem and the dynamics in their habitat, especially when studying large habitats such as the Amazon Rainforest.

For these reasons, scientists study ecosystems under more controlled conditions. Experimental systems usually involve either partitioning a part of a natural ecosystem that can be used for experiments, termed a mesocosm , or by recreating an ecosystem entirely in an indoor or outdoor laboratory environment, which is referred to as a microcosm . A major limitation to these approaches is that removing individual organisms from their natural ecosystem or altering a natural ecosystem through partitioning may change the dynamics of the ecosystem. These changes are often due to differences in species numbers and diversity and also to environment alterations caused by partitioning (mesocosm) or recreating (microcosm) the natural habitat. Thus, these types of experiments are not totally predictive of changes that would occur in the ecosystem from which they were gathered.

As both of these approaches have their limitations, some ecologists suggest that results from these experimental systems should be used only in conjunction with holistic ecosystem studies to obtain the most representative data about ecosystem structure, function, and dynamics.

Scientists use the data generated by these experimental studies to develop ecosystem models that demonstrate the structure and dynamics of ecosystems. They use three basic types of ecosystem modeling in research and ecosystem management: a conceptual model, an analytical model, and a simulation model. A conceptual model is an ecosystem model that consists of flow charts to show interactions of different compartments of the living and nonliving components of the ecosystem. A conceptual model describes ecosystem structure and dynamics and shows how environmental disturbances affect the ecosystem; however, its ability to predict the effects of these disturbances is limited. Analytical and simulation models, in contrast, are mathematical methods of describing ecosystems that are indeed capable of predicting the effects of potential environmental changes without direct experimentation, although with some limitations as to accuracy. An analytical model is an ecosystem model that is created using simple mathematical formulas to predict the effects of environmental disturbances on ecosystem structure and dynamics. A simulation model is an ecosystem model that is created using complex computer algorithms to holistically model ecosystems and to predict the effects of environmental disturbances on ecosystem structure and dynamics. Ideally, these models are accurate enough to determine which components of the ecosystem are particularly sensitive to disturbances, and they can serve as a guide to ecosystem managers (such as conservation ecologists or fisheries biologists) in the practical maintenance of ecosystem health.

Conceptual Models

Conceptual models are useful for describing ecosystem structure and dynamics and for demonstrating the relationships between different organisms in a community and their environment. Conceptual models are usually depicted graphically as flow charts. The organisms and their resources are grouped into specific compartments with arrows showing the relationship and transfer of energy or nutrients between them. Thus, these diagrams are sometimes called compartment models.

To model the cycling of mineral nutrients, organic and inorganic nutrients are subdivided into those that are bioavailable (ready to be incorporated into biological macromolecules) and those that are not. For example, in a terrestrial ecosystem near a deposit of coal, carbon will be available to the plants of this ecosystem as carbon dioxide gas in a short-term period, not from the carbon-rich coal itself. However, over a longer period, microorganisms capable of digesting coal will incorporate its carbon or release it as natural gas (methane, CH 4 ), changing this unavailable organic source into an available one. This conversion is greatly accelerated by the combustion of fossil fuels by humans, which releases large amounts of carbon dioxide into the atmosphere. This is thought to be a major factor in the rise of the atmospheric carbon dioxide levels in the industrial age. The carbon dioxide released from burning fossil fuels is produced faster than photosynthetic organisms can use it. This process is intensified by the reduction of photosynthetic trees because of worldwide deforestation. Most scientists agree that high atmospheric carbon dioxide is a major cause of global climate change.

Conceptual models are also used to show the flow of energy through particular ecosystems. Figure 46.8 is based on Howard T. Odum’s classical study of the Silver Springs, Florida, holistic ecosystem in the mid-twentieth century. 2 This study shows the energy content and transfer between various ecosystem compartments.

Visual Connection

Why do you think the value for gross productivity of the primary producers is the same as the value for total heat and respiration (20,810 kcal/m 2 /yr)?

Analytical and Simulation Models

The major limitation of conceptual models is their inability to predict the consequences of changes in ecosystem species and/or environment. Ecosystems are dynamic entities and subject to a variety of abiotic and biotic disturbances caused by natural forces and/or human activity. Ecosystems altered from their initial equilibrium state can often recover from such disturbances and return to a state of equilibrium. As most ecosystems are subject to periodic disturbances and are often in a state of change, they are usually either moving toward or away from their equilibrium state. There are many of these equilibrium states among the various components of an ecosystem, which affects the ecosystem overall. Furthermore, as humans have the ability to greatly and rapidly alter the species content and habitat of an ecosystem, the need for predictive models that enable understanding of how ecosystems respond to these changes becomes more crucial.

Analytical models often use simple, linear components of ecosystems, such as food chains, and are known to be complex mathematically; therefore, they require a significant amount of mathematical knowledge and expertise. Although analytical models have great potential, their simplification of complex ecosystems is thought to limit their accuracy. Simulation models that use computer programs are better able to deal with the complexities of ecosystem structure.

A recent development in simulation modeling uses supercomputers to create and run individual-based simulations, which accounts for the behavior of individual organisms and their effects on the ecosystem as a whole. These simulations are considered to be the most accurate and predictive of the complex responses of ecosystems to disturbances.

Visit The Darwin Project to view a variety of ecosystem models, including simulations that model predator-prey relationships to learn more.

• 1 Nature (Vol. 458, April 1, 2009)
• 2 Howard T. Odum, “Trophic Structure and Productivity of Silver Springs, Florida,” Ecological Monographs 27, no. 1 (1957): 47–112.

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What is an Ecosystem?

An ecosystem is the basic functional unit of an environment where organisms interact with each other (living and nonliving), both necessary for the maintenance of life on earth. It includes plants, animals, microorganisms, and all other living things along with their nonliving environment, which includes soil, land, air, water, dust, and other parts of nature. 

If ecology has to be studied in detail, the basic unit starts from the Ecosystem. The study of the Ecosystem deals with how organisms living together interact with each other and how energy flows through the chain of organisms in the Ecosystem. It also studies how an organism lives in a relationship that is harmful or benefitted by one another to live in a sustainable manner. 

It is seen in nature that the Ecosystem can be as large or  small. It depends on the number of abiotic components available in the environment. The ecosystem in the north or south poles does not have much flora and fauna as compared to a tropical climate like a forest due to the extreme climate the animals are subjected to. Only organisms that are resistant to such an environment will be able to make up the Ecosystem. Overall, it is understood that different ecosystems combined would make up the biosphere.

Types of Ecosystem

In ecology, ecosystems are classified into different types based on the region or on the basis of the environment like land or water. It can also be grouped based on the amount of energy the Ecosystem consumes.

 Classification in basic ecosystem are :

1. Terrestrial Ecosystem

2. Aquatic Ecosystem

All other types will fall on either of these ecosystems and hence can be subcategorized into different types. 

Terrestrial Ecosystem

These ecosystems can only be found on land. Different landforms will have different ecosystems based on the climate, temperature, types of organisms residing, the food chain, energy flow, and other factors. This Ecosystem has a relative scarcity of water percentage than the aquatic Ecosystem, and also there is better availability of sunlight as the major source of energy. Types of terrestrial ecosystems are: 

Forest Ecosystem: These ecosystems are a densely packed environment of various flora and fauna. It has the highest number of organisms living per square km. It is important to conserve this ecosystem as many rare species of the earth are found here. Most of the oxygen in the world is supplied by the forests.

Desert Ecosystem: Deserts are defined as ecosystems that receive rainfall of less than 25cm indicating extreme climate. Even in harsh temperatures, there are organisms that have resistance towards high temperatures and plants that require very little water to survive, having modified their leaves and stem to conserve water. Camels, rattlesnakes, and cacti are a few examples. 

Mountain Ecosystem: Mountains are regions of high altitude above sea level with scattered vegetation. It also has an extreme climate, and animals of these regions have developed thick fur on the skin to survive the cold climate.

Grassland Ecosystem: It mainly includes shrubs, herbs, and few trees which are not as dense as the forests. These basically include grazing animals, insectivores, herbivores. The temperatures are not too extreme in these ecosystems. There are two main forms: The savannas and prairies. The savannas are the tropical grasslands. It dries seasonally with many predators and grazers. The prairies are temperate grassland, which lack large shrubs and trees.

Aquatic Ecosystem

The aquatic ecosystem consists mainly of animals and organisms that stay in the water bodies, such as lakes, oceans and seas. Amphibians, fish, sea creatures all come under this ecosystem. Since water is in abundance, organisms survive using the oxygen dissolved in water. This ecosystem is much larger than the terrestrial ecosystem as it acquires a greater part of the earth. The two types of aquatic ecosystems are: 

Marine Ecosystem: It includes all the oceans and seas and constitutes about 71% of the earth’s surface. About 97% of the water on earth falls under this category. Sharks, whales, dolphins, seals, walrus, and many more come under this ecosystem.

Freshwater Ecosystem: It includes all the rivers, lakes, ponds, and water bodies that are not salted. This accounts for 0.8% of earth’s water and 0.009% of total water present on earth. There are three types of this ecosystem lotic system where the water is fast-moving, e.g., rivers. The lentic system where the water remains stagnant, e.g., ponds and lakes. The wetlands where the soil remains saturated for most of the time period.

Structure of the Ecosystem

The structure of an ecosystem refers to the explanation of living beings and the physical features of the environment in which the organisms live. 

Components of the Ecosystem 

The ecosystem has two components associated with it mentioned below: 

1. Abiotic component 

2. Biotic component

Abiotic Component

This basically involves inorganic minerals, calcium, phosphorus & iron. It also includes soil, water, land & solar radiation. It is further divided into climatic factors and edaphic factors which include rain, light, temperature, and wind, soil, pH, minerals, and topography.

Biotic Component

The biotic component consists of all the living organisms in the ecosystem. It can be classified as Autotrophic organisms that produce their own food and heterotrophic organisms which depend on other organisms for food. This classification is based on nutritional requirements of the organism. 

Producers: These are the organisms in the ecosystem that generate the food and energy with the help of sunlight, oxygen, and all other abiotic components. The main producers of the ecosystem are the plants.

Consumers: These are the organisms that take their nutrition from the food that is made by the producers. 

Primary Consumers: These organisms feed directly from the producers. They are herbivorous animals like deer, rabbit, cow, buffalo, and giraffes.

Secondary Consumers: These organisms feed on the primary consumers for their nutrition. These are carnivorous and omnivorous animals like crows, dogs, cats, snakes.

Tertiary Consumers: These organisms feed on secondary consumers. These are only carnivores where they only consume meat usually by preying on prey. Eg., lion, tiger, cheetah

Quaternary Consumers: These organisms feed on the tertiary consumers for their nutrition. Eg; Eagle, which consumes a snake that consumes a frog that consumes a fly.

Decomposers

These organisms break down dead matter and gain their nutrition, and the decomposed material returns back to the land, which will again be utilized by the producers to produce more food.

The Function of the Ecosystem 

The primary function of any ecosystem is the exchange of energy from one life form to others, which eventually runs in a circle and sustains the entire life of the planet. Without the ecosystems maintaining balance, there would not have been any life form existing on earth.

Important Ecological Concepts

The study of the Ecosystem involves understanding energy flow in the Ecosystem, the various relationships between two organisms, following commensalism, parasitism, mutualism, predation, and various symbiotic relationships exist in an ecosystem. Biogeochemical cycles and limiting factor complexes, the evolution of ecosystems, and the science of population in ecosystems are various important ecological concepts that come under the study of ecology.

 Ecosystem

Ecosystem can be defined as the main functional unit that exists in an environment where there is an intersection between all the organisms that are living in the environment which is required for balancing life on earth. Ecosystems are large in structure and have hundreds of animals and plants which live in a balance or it can be something small too. In harsh areas like the North and South poles, ecosystems are simpler in structure and have very few organisms which dwell in such areas. The ecosystems have all the components like plants, animals, microbes and many other living beings which live with non-living components like soil, land, water, air and other components of nature. When we study ecology, we start with studying the ecosystem which deals with the relationships between animals and how the transfer of energy occurs between these animals. We also learn about food chains and food webs. Ecosystems can be either small or large depending on the biotic and abiotic components present in the system. Ecosystems of harsh climate are usually smaller as there are lesser species and abiotic components too whereas the ecosystems of tropical climate will comparatively have a larger number of flora and fauna. We must remember that all the different types of ecosystems form the biosphere.

Some organisms are found in multiple and different ecosystems around the earth which share different relationships with other or similar organisms. There are ecosystems which help species mutually benefit each other be it in getting shelter, protection or food. This relationship is called mutualism. To learn more about the ecosystem, log in or sign up to Vedantu where you can download free notes and revision notes too.

FAQs on Ecosystem

1. Explain the types of terrestrial ecosystems?

The types of terrestrial ecosystem are as follows:

Forest ecosystem: This ecosystem consists of plants, animals and microbes which live together along with other abiotic components of the environment. This ecosystem helps in the maintenance of the earth’s temperature and acts as a large carbon sink.

Grassland ecosystem: In this ecosystem, grasses and herbs are largely present and thus the name. For example, Savannah grasslands and temperate grasslands.

Tundra ecosystem: Such an ecosystem does not have trees and are found mostly in the colder climates or areas where there is a low rainfall. This ecosystem is mostly covered by snow throughout the year. For example, the Arctic or mountain tops.

Desert ecosystem: This ecosystem is made of sand and has very low rainfall. Here, the days are very hot and nights are cold.

2.  Explain the types of aquatic ecosystems?

There are mainly two types of aquatic ecosystem:

Freshwater ecosystem: This is an aquatic ecosystem which includes ponds, rivers, lakes, wetlands and streams. They do not have any salt content as compared to the marine ecosystem. 

Marine ecosystem: This ecosystem is found in the oceans and seas. They have a high amount of salt content and are saline in nature. When compared to freshwater ecosystems, they have a greater biodiversity due to the presence of a larger amount of species.

3. What are the biotic components in the ecosystem?

The biotic components in the ecosystem are as follows:

Producers are the main components of the plants and are also called the autotrophs. They produce food by the process of photosynthesis and all the other components of the ecosystem are directly or indirectly dependent on them.

The second components are the consumers which are also called the heterotrophs that depend on the producers for food. They can be primary, secondary and tertiary. The primary consumers feed on the plants and are called herbivores. The secondary consumers depend on the primary consumers and can be either carnivore or omnivore. Lastly, the tertiary consumers depend on the secondary consumers for food. They can be omnivores. There are quaternary consumers in some food chains too which may not have any natural predators.

Decomposers are the components that depend on the dead and decay matter of all the other components. They can be fungi or bacteria. They are crucial for recycling energy and nutrients in the environment.

4. What are the abiotic components of an ecosystem?

The abiotic components are the non-living components of the ecosystem and they are crucial for the survival of the living beings as it helps in maintaining a proper balance in the environment. The nonliving or abiotic components are elements like water, air, soil, minerals, sunlight, temperature, wind, altitude and many more. We can understand the importance of abiotic factors when we consider the process of photosynthesis which requires sunlight by the plants.

5. Give some of the functions related to the ecosystem?

The functions of the ecosystem are as follows:

Ecosystems regulate all the processes that are required for the support and stabilization of the organisms and systems that are present in the environment.

It is important for recycling the necessary nutrients between the living and non-living beings.

It is required for maintaining balance between trophic levels present in the ecosystem.

For cycling the minerals through the biosphere.

The abiotic components allow the synthesis of organic components with some energy exchange.

Biology • Class 12

B.1 Ecosystem Interactions & Dynamics

How do ecosystems work, and how can understanding them help us protect them?

Unit Summary

In this unit, students investigate the 30 by 30 initiative, a proposal to protect 30% of US lands and waters by 2030, and the reasons humans engage in conservation. Students use the Serengeti National Park as a case study to figure out ecosystem and conservation principles and apply those understandings to conservation dilemmas in the US.

Through investigations with complex data sets and hands-on simulations, students figure out how limiting factors impact carrying capacity, how group behavior impacts survival, and how biodiversity supports ecosystem resilience. By engaging with real-world conservation dilemmas and exploring various interest-holder perspectives, students identify the trade-offs humans make as they manage natural resources to support human society as well as the natural systems we live in.

Simulations

Unit B.1 L8 – SageModeler Starting Template

Unit B.1 L4b – Data Excursion 2: Annual Rainfall and Wildebeest Occupancy

Unit B.1 L4a – Data Excursion 1: 30 Year Average Rainfall

Unit examples, additional unit information, next generation science standards addressed in this unit.

Performance Expectations

The unit builds toward the following NGSS Performance Expectations (PE):

• HS-LS2-1  Use mathematical and/or computational representations to support explanations of factors that affect carrying capacity of ecosystems at different scales.
• HS-LS2-2  Use mathematical representations to support and revise explanations based on evidence about factors affecting biodiversity and populations in ecosystems of different scales.
• HS-LS2-6  Evaluate the claims, evidence, and reasoning that the complex interactions in ecosystems maintain relatively consistent numbers and types of organisms in stable conditions, but changing conditions may result in a new ecosystem.
• HS-LS2-7  Design, evaluate, and refine a solution for reducing the impacts of human activities on the environment and biodiversity.
• HS-LS2-8  Evaluate the evidence for the role of group behavior on individual and species’ chances to survive and reproduce.
• HS-ESS3-3  Create a computational simulation to illustrate the relationships among management of natural resources, the sustainability of human populations, and biodiversity.
• HS-ETS1-3†  Evaluate a solution to a complex real-world problem based on prioritized criteria and trade-offs that account for a range of constraints, including cost, safety, reliability, and aesthetics as well as possible social, cultural, and environmental impacts.

† This performance expectation is developed across multiple courses.

Disciplinary Core Ideas

LS2.A: Interdependent Relationships in Ecosystems

• Ecosystems have carrying capacities, which are limits to the numbers of organisms and populations they can support. These limits result from such factors as the availability of living and nonliving resources and from such challenges such as predation, competition, and disease. Organisms would have the capacity to produce populations of great size were it not for the fact that environments and resources are finite. This fundamental tension affects the abundance (number of individuals) of species in any given ecosystem.

LS2.C: Ecosystem Dynamics, Functioning, and Resilience

• A complex set of interactions within an ecosystem can keep its numbers and types of organisms relatively constant over long periods of time under stable conditions. If a modest biological or physical disturbance to an ecosystem occurs, it may return to its more or less original status (i.e., the ecosystem is resilient), as opposed to becoming a very different ecosystem. Extreme fluctuations in conditions or the size of any population, however, can challenge the functioning of ecosystems in terms of resources and habitat availability.
• Moreover, anthropogenic changes (induced by human activity) in the environment—including habitat destruction, pollution, introduction of invasive species, overexploitation, and climate change —can disrupt an ecosystem and threaten the survival of some species.

LS2.D: Social Interactions and Group Behavior

• Group behavior has evolved because membership can increase the chances of survival for individuals and their genetic relatives.

LS4.D: Biodiversity and Humans

• Biodiversity is increased by the formation of new species (speciation) and decreased by the loss of species (extinction). (secondary)
• Humans depend on the living world for the resources and other benefits provided by biodiversity. But human activity is also having adverse impacts on biodiversity through overpopulation, overexploitation, habitat destruction, pollution, introduction of invasive species, and climate change . Thus sustaining biodiversity so that ecosystem functioning and productivity are maintained is essential to supporting and enhancing life on Earth. Sustaining biodiversity also aids humanity by preserving landscapes of recreational or inspirational value. 

ESS3.C: Biodiversity and Humans

• The sustainability of human societies and the biodiversity that supports them requires responsible management of natural resources.

ETS1.B: Developing Possible Solutions

• When evaluating solutions it is important to take into account a range of constraints including cost, safety, reliability and aesthetics and to consider social, cultural and environmental impacts.

Science & Engineering Practices

This unit intentionally develops students’ engagement in these practice elements:

• 2.3 Develop, revise, and/or use a model based on evidence to illustrate and/or predict the relationships between systems or between components of a system. 
• 2.4 Develop and/or use multiple types of models to provide mechanistic accounts and/or predict phenomena, and move flexibly between model types based on merits and limitations. 
• 2.5 Develop a complex model that allows for manipulation and testing of a proposed process or system.
• 2.6 Develop and/or use a model (including mathematical and computational) to generate data to support explanations, predict phenomena, analyze systems, and/or solve problems.
• 5.2 Use mathematical, computational, and/or algorithmic representations of phenomena or design solutions to describe and/or support claims and/or explanations. 
• 6.5 Design , evaluate, and/or refine a solution to a complex real-world problem, based on scientific knowledge, student-generated sources of evidence, prioritized criteria, and trade off considerations.

The following practices are also key to the sensemaking in this unit:

• 1.1 Ask questions that arise from careful observation of phenomena, or unexpected results, to clarify and/or seek additional information.
• 4.1 Analyze data using tools, technologies, and/or models (e.g., computational, mathematical) in order to make valid and reliable scientific claims or determine an optimal design solution . 
• 8.1 Critically read scientific literature adapted for classroom use to determine the central ideas or conclusions and/or to obtain scientific and/or technical information to summarize complex evidence, concepts, processes, or information presented in a text by paraphrasing them in simpler but still accurate terms.
• 8.2 Compare, integrate and evaluate sources of information presented in different media or formats (e.g., visually, quantitatively) as well as in words in order to address a scientific question or solve a problem.
• 8.5 Gather, read, and evaluate scientific and/or technical information from multiple authoritative sources, assessing the evidence and usefulness of each source.

Crosscutting Concepts

This unit intentionally develops students’ engagement in these crosscutting concept elements:

• 7.1 Much of science deals with constructing explanations of how things change and how they remain stable.  
• 7.2 Change and rates of change can be quantified and modeled over very short or very long periods of time. Some system changes are irreversible. 
• 7.4 Systems can be designed for greater or lesser stability.
• 4.1 Systems can be designed to do specific tasks.  
• 4.2 When investigating or describing a system, the boundaries and initial conditions of the system need to be defined and their inputs and outputs analyzed and described using models.
• 4.4 Models can be used to predict the behavior of a system, but these predictions have limited precision and reliability due to the assumptions and approximations inherent in models.

The following crosscutting concepts are also key to the sensemaking in this unit:

• 1.4 Mathematical representations are needed to identify some patterns.  
• 1.5 Empirical evidence is needed to identify patterns.
• 2.2 Cause and effect relationships can be suggested and predicted for complex natural and human designed systems by examining what is known about smaller scale mechanisms within the system. 
• 3.1 The significance of a phenomenon is dependent on the scale, proportion, and quantity at which it occurs. 

Connections to the Nature of Science

Which elements of the Nature of Science (NOS) are developed in the unit?

• Science knowledge is based on empirical evidence. (NOS-SEP)
• Science arguments are strengthened by multiple lines of evidence supporting a single explanation. (NOS-SEP)
• Many decisions are not made using science alone, but rely on social and cultural contexts to resolve issues. (NOS-CCC)
• Science is both a body of knowledge that represents a current understanding of natural systems and the processes used to refine, elaborate, revise, and extend this knowledge. (NOS-CCC)

How are they developed?

• Students engage with empirical evidence in the form of scientific articles, data, and images throughout the unit.
• Students gather multiple types of evidence (e.g. historical data,  kinesthetic modeling, simulation-based data, data generated from agent based models, etc.) to support their ideas.
• Students hear from a variety of perspectives as they consider whether the proposed solutions would have a positive impact.
• Students use their understandings gained from exploring the Serengeti as both an ecosystem and successful conservation plan to evaluate the success of the conservation plan for their conservation profile.

Unit Placement Information

What is the anchoring phenomenon and why was it chosen?

In the anchoring phenomenon, students explore conservation in the context of the 30 by 30 Initiative which aims to conserve 30 percent of US lands and waters by 2030. Students learn about the initiative and brainstorm criteria that people use when deciding to protect lands and waters. Students draw on their own experiences and investigate four different conservation profiles in the US. They develop initial models to explain the system and why humans wanted to protect it. They generate questions that they need to answer to be able to fully explain their models. Students also notice unique and common features in each case and are motivated to learn more about how ecosystems work and how we can use what we learn to protect them.

This phenomenon gives students a real world context for thinking about ecosystems and their protection while at the same time helping them recognize that often, what we learn about one ecosystem can be applied to another. This motivates the class to investigate a single case together, the Serengeti. The Serengeti was chosen as the focus of the majority of the lessons because it has been studied extensively for over 70 years and many long term, comprehensive data sets are available for students to investigate. In addition, the Serengeti phenomenon generated high student interest across racial and gender identities in a national survey.

Where does this unit fall within the OpenSciEd Scope and Sequence?

This unit is the first in the OpenSciEd High School Biology course sequence.

How is the unit structured?

The unit is organized into three lesson sets. Lesson Set 1 (Lessons 1-6) focuses on the populations within an ecosystem and the different factors that affect them. It ends with a transfer task about African wild dogs. Lesson Set 2 (Lessons 7-8) helps students begin to unravel the complexity of ecosystems as they discover the importance of keystone species in terms of ecosystem stability and resilience. Lesson Set 3 (Lessons 9-11) helps students use their understanding of ecosystems to evaluate their conservation in systems in the US. This unit culminates with a transfer task where they apply all of their understandings to the American Prairie and its conservation.

What modifications will I need to make if this unit is taught out of sequence?

This is the first unit of the High School Biology Course in the OpenSciEd Scope and Sequence. Given this placement, several modifications would need to be made if teaching this unit later in the year course. These include the following adjustments:

• As the first unit of the year, the lessons devote more time to developing and supporting classroom agreements. If the unit were to be taught later in the year, classroom community would need to be addressed elsewhere. 
• The unit introduces students to a key assessment routine, transfer tasks, that are a key part of the OpenSciEd program’s assessment system. In this unit, students are introduced to the routine and its purpose. Their engagement with this first transfer task is scaffolded through collaborative group work, peer and teacher feedback. Students also get to know the rubric structure for the task to increase their agency in the assessment process. If taught out of order, students would need to be introduced to transfer tasks in the first unit in which they experienced them.
• Developing and using models is a key practice in this unit and the OpenSciEd program. This unit introduces students to the practice of developing models by first including components and interactions in Lesson 1. In subsequent lessons students explain the interactions in their models as mechanisms. Finally, students use their models to predict outcomes. If taught out of order, students would benefit from a scaffolded approach to developing their modeling practice.

How do I shorten or condense the unit if needed? How can I extend the unit if needed?

The following are example options to shorten or condense parts of the unit without eliminating important sensemaking for students:

• Lesson 2: Read the History of Serengeti aloud as a class instead of reading in small groups and then discussing again as a class.
• Lesson 10: Instead of having each group present their conservation profiles and plans to the class, a gallery walk of the presentations may help to streamline this portion of the lesson.

To extend or enhance the unit, consider the following:

• Video of how they moved African wild dogs https://www.youtube.com/watch?v=S1m00A6koE0
• Images of the pups born in Liwonde after relocation https://www.facebook.com/watch/?v=605291120734360
• Updates on Liwonde National Park https://www.africanparks.org/the-parks/liwonde
• Lesson 7: Have students write algorithms for multiple agents.
• Lesson 8: Create additional Serengeti Component Articles for components your students’ mention but are not already included in the lesson.
• Lesson 8: Engage the whole class in the citizen science project, Snapshot Serengeti. Found at https://www.snapshotserengeti.org/.

Unit Acknowledgements

Unit Development Team

• Kate Henson, Revision Unit Lead, University of Colorado Boulder
• Will Lindsay , Field Test Unit Lead, University of Colorado Boulder
• Clarissa Deverel-Rico, Writer, University of Colorado Boulder
• Sara Krauskopf, Writer, University of Colorado Boulder
• DeAnna Lee-Rivers, Writer, University of Colorado Boulder
• Simon Raphael Mduma, Consultant Expert, Wildlife Biologist
• Celeste Moreno, Writer, University of Colorado Boulder
• Jamie Deutch Noll, Writer, BSCS Science Learning
• Kathryn Ribay, Writer, San Jose State University
• Jessica Schwarz, Consultant Expert, Roaring Fork Schools
• Anthony R.E. Sinclair, Consultant Expert, University of British Columbia 
• Wayne Wright, Writer, University of Colorado Boulder

We appreciate the support of two of our partners – ECA Science Kit Services and BSCS Science Learning – who provided kits for OpenSciEd facilitators and teachers in classrooms as part of the OpenSciEd field test.

Production Team

University of Colorado Boulder

• Madison Hammer, Production Manager
• Amanda Howard, Copy Editor
• Erin Howe, Project Manager

Unit External Evaluation

NextGenScience’s Science Peer Review Panel

An integral component of OpenSciEd’s development process is external validation of alignment to the Next Generation Science Standards by NextGenScience’s Science Peer Review Panel using the  EQuIP Rubric for Science . We are proud that this unit has earned the highest score available and has been awarded the  NGSS Design Badge . You can find additional information and read this unit’s review on the nextgenscience.org  website.

Unit standards

This unit builds toward the following NGSS Performance Expectations (PEs) as described in the OpenSciEd Scope & Sequence:

Reference to kit materials

The OpenSciEd units are designed for hands-on learning and therefore materials are necessary to teach the unit. These materials can be purchased as science kits or assembled using the kit material list.

NGSS Design Badge Awarded: Mar 12, 2023 Awarded To: OpenSciEd Unit B.1: Ecosystems: Interactions, Energy, Dynamics VERIFY

Licensed under OpenSciEd's Creative Commons NonCommercial Plus 4.0 International License

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• Biology LibreTexts - Introduction to Ecology
• Open Library Publishing Platform - Environmental Science - Ecology
• CORE - Ecology and the Environment
• National Center for Biotechnology Information - Ecology and Ecosystems
• Khan Academy - Ecology introduction
• The Ecological Society of America - What is Ecology?
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• Table Of Contents

ecology , study of the relationships between organisms and their environment . Some of the most pressing problems in human affairs—expanding populations, food scarcities, environmental pollution including global warming , extinctions of plant and animal species , and all the attendant sociological and political problems—are to a great degree ecological.

The word ecology was coined by the German zoologist Ernst Haeckel , who applied the term oekologie to the “relation of the animal both to its organic as well as its inorganic environment.” The word comes from the Greek oikos , meaning “household,” “home,” or “place to live.” Thus, ecology deals with the organism and its environment. The concept of environment includes both other organisms and physical surroundings. It involves relationships between individuals within a population and between individuals of different populations. These interactions between individuals, between populations, and between organisms and their environment form ecological systems, or ecosystem s. Ecology has been defined variously as “the study of the interrelationships of organisms with their environment and each other,” as “the economy of nature,” and as “the biology of ecosystems.”

Ecology had no firm beginnings. It evolved from the natural history of the ancient Greeks, particularly Theophrastus , a friend and associate of Aristotle . Theophrastus first described the interrelationships between organisms and between organisms and their nonliving environment. Later foundations for modern ecology were laid in the early work of plant and animal physiologists.

In the early and mid-1900s two groups of botanists, one in Europe and the other in the United States , studied plant communities from two different points of view. The European botanists concerned themselves with the study of the composition , structure, and distribution of plant communities. The American botanists studied the development of plant communities, or succession ( see community ecology: Ecological succession ). Both plant and animal ecology developed separately until American biologists emphasized the interrelation of both plant and animal communities as a biotic whole.

During the same period, interest in population dynamics developed. The study of population dynamics received special impetus in the early 19th century, after the English economist Thomas Malthus called attention to the conflict between expanding populations and the capability of Earth to supply food. In the 1920s the American zoologist Raymond Pearl , the American chemist and statistician Alfred J. Lotka, and the Italian mathematician Vito Volterra developed mathematical foundations for the study of populations, and these studies led to experiments on the interaction of predators and prey , competitive relationships between species, and the regulation of populations. Investigations of the influence of behaviour on populations were stimulated by the recognition in 1920 of territoriality in nesting birds. Concepts of instinctive and aggressive behaviour were developed by the Austrian zoologist Konrad Lorenz and the Dutch-born British zoologist Nikolaas Tinbergen , and the role of social behaviour in the regulation of populations was explored by the British zoologist Vero Wynne-Edwards. ( See population ecology .)

(Read Thomas Malthus’s 1824 Britannica essay on population.)

While some ecologists were studying the dynamics of communities and populations, others were concerned with energy budgets. In 1920 August Thienemann, a German freshwater biologist, introduced the concept of trophic, or feeding, levels ( see trophic level ), by which the energy of food is transferred through a series of organisms, from green plants (the producers) up to several levels of animals (the consumers). An English animal ecologist, Charles Elton (1927), further developed this approach with the concept of ecological niche s and pyramids of numbers. In the 1930s, American freshwater biologists Edward Birge and Chancey Juday, in measuring the energy budgets of lakes, developed the idea of primary productivity , the rate at which food energy is generated, or fixed, by photosynthesis . In 1942 Raymond L. Lindeman of the United States developed the trophic-dynamic concept of ecology, which details the flow of energy through the ecosystem. Quantified field studies of energy flow through ecosystems were further developed by the brothers Eugene Odum and Howard Odum of the United States; similar early work on the cycling of nutrients was done by J.D. Ovington of England and Australia. ( See community ecology: Trophic pyramids and the flow of energy ; biosphere: The flow of energy and nutrient cycling .)

The study of both energy flow and nutrient cycling was stimulated by the development of new materials and techniques—radioisotope tracers, microcalorimetry, computer science , and applied mathematics—that enabled ecologists to label, track, and measure the movement of particular nutrients and energy through ecosystems. These modern methods ( see below Methods in ecology ) encouraged a new stage in the development of ecology— systems ecology , which is concerned with the structure and function of ecosystems.

FREE K-12 standards-aligned STEM

curriculum for educators everywhere!

Find more at TeachEngineering.org .

• TeachEngineering
• Environments and Ecosystems

Lesson Environments and Ecosystems

Grade Level: 4 (3-5)

Time Required: 15 minutes

Lesson Dependency: None

Subject Areas: Biology, Life Science, Science and Technology

NGSS Performance Expectations:

• Print lesson and its associated curriculum

Curriculum in this Unit Units serve as guides to a particular content or subject area. Nested under units are lessons (in purple) and hands-on activities (in blue). Note that not all lessons and activities will exist under a unit, and instead may exist as "standalone" curriculum.

• Population Density: How Much Space Do You Have?
• Biodomes Engineering Design Project: Lessons 2-6
• Got Energy? Spinning a Food Web
• Plant Cycles: Photosynthesis & Transpiration
• Biomimicry: Natural Designs

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Engineering connection, learning objectives, worksheets and attachments, more curriculum like this, introduction/motivation, associated activities, lesson closure, vocabulary/definitions, additional multimedia support, user comments & tips.

Engineers adapt designs for housing, cities and many types of buildings to specific environments and ecosystems. They use their environment, knowledge of the biosphere and the concept of ecosystems to inform their designs and shape the human-built environment. Engineers and scientists use biodomes to study ecosystems and model how living and nonliving things interact in those natural environments. They also collaborate to use this information to predict the availability of water for communities.

After this lesson, students should be able to:

• Have a working knowledge of the various types of environments and ecosystems.
• Have a working knowledge of vocabulary related to environments and ecosystems.
• Define the biosphere and discuss its components.
• Identify how engineers can use their knowledge of environments, the biosphere and ecosystems.

Educational Standards Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards. All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN) , a project of D2L (www.achievementstandards.org). In the ASN, standards are hierarchically structured: first by source; e.g. , by state; within source by type; e.g. , science or mathematics; within type by subtype, then by grade, etc .

Ngss: next generation science standards - science.

International Technology and Engineering Educators Association - Technology

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Do you agree with this alignment? Thanks for your feedback!

State Standards

Colorado - science.

What are environments and ecosystems and why do we need to understand them? An environment is the surrounding area in which an organism lives, including the air, water, food and energy required for that organism to survive. An ecosystem includes all the living organisms and the nonliving things in an area that are linked together through the flow of nutrients and energy. On our planet, there are many different environments where organisms can live. There are mountains, valleys, trees, snow, and water environments, as well as hot and cold climate environments. (Conduct a class discussion [see the Pre-Lesson Assessment activities described in the Assessment section] to explore with students various types of environments and ecosystems [such as tropical rain forest, tundra, etc.] and their characteristics [climates, plants, animals, soils, weather, etc.]). (Optional: Consider showing students the attached PowerPoint presentation, Environments & Ecosystems Visual Aids .)

Animals, plants and other organisms have different physical characteristics that make them more adapted to a particular environment. However, different types of organisms can live together in similar environments. Birds have hollow bones (making them lighter) and feathers that help them to fly. Large animals need support and bone structure to walk; as a result, they have backbones and legs. Still, both of these animals might live in a forest.

Some physical characteristics make an organism less adapted for other environments. For example, whales have blubber so they can withstand cold temperatures and other mammals have thick fur, which protects them from the cold. Because of these characteristics, these animals would not survive very well in a hot desert environment. Also, some animals can adapt to changes in their environment by changing their physical characteristics or changing their surroundings. What are some things that protect us from the climate and/or weather that we experience? (Possible answers: Warm clothing homes/buildings with heating or air conditioning; homes/buildings that can withstand wind, snow, rain or other more severe weather conditions such as earthquakes or hurricanes.) Engineers help us design most of the things you just named! All organisms have a place in this world and are adapted to a specific niche or role within their environment.

Let's imagine that we are traveling through different environments on a mission to collect information about the plants, animals, weather and climate. All of these things make up the Earth's biosphere , which contains both living and nonliving components, such as air, soil, water and sunlight. The biosphere is the portion of the Earth where life is found. It is made up of all the different environments and ecosystems. Some examples of environments found in the biosphere include tropical rain forests, deserts, other forest types (such as deciduous or coniferous), grassland prairie and arctic climates.

Do you know what a biodome is? It is something that people make to model a particular environment and the community of organisms that live there. Engineers and scientists use biodomes to study ecosystems and model how living and nonliving things interact in those natural environments. Can you think of other reasons why studying the environment, climates and ecosystems, might be important to an engineer? (Possible answers: To learn how to better design structures to withstand hurricanes, earthquakes or tsunamis, as well as snow loads, flood prevention, etc.)

In this unit, we are going to become engineers who create model ecosystems. We will design and create our own biodomes and watch what happens to the living and nonliving things we place in them. We will have to learn as much as possible about the environment, though, so we can design and build successful biodomes!

Lesson Background and Concepts for Teachers

Two very different environments exist on our planet: land and water. The organisms that live in these environments have very similar requirements but may respond to them differently. Organisms that live on land must develop a way to combat gravity. They need legs or wings if they want to move. A tree develops a way to get water to move upwards (against gravity). Organisms in water take advantage of water properties to support their body, so they tend to be more hydro-dynamically designed

Compared to many animals and plants, humans are not very physically adapted to the environments in which they live. We comfortably tolerate only a small temperature range, between 63 and 99° Fahrenheit. As a result, we tend to adapt our environment to our needs rather than doing much adapting ourselves. Certain factors such as population call for further adaptaion, have students explore these factors in the hands-on design activity, Population Density: How Much Space Do You Have?

Engineers use their understanding of environments and ecosystems and their respective climates/weather types to design buildings, to inform the layout of communities, and to, in a large part, make the environments in which we live adapted to our needs. See Table 1 for examples of animals and plants that can be found in various environments. Engineers and scientists also collaborate to use this information to predict availability of water for communities.

• Population Density: How Much Space Do You Have? - Students learn how population affects the availability of resources and consider why population density information is useful to engineers.

Can you define the biosphere and what it contains? (Answer: The biosphere is the part of the Earth's atmosphere that is capable of supporting life and includes both living and nonliving things. It includes plants, animals, weather and climate.) What are some examples of environments found in the biosphere (Possible answers: Tropical rainforests, deserts, other forest types [such as deciduous or coniferous], grassland prairie and arctic climates.) How does an understanding of the different ecosystems help engineers to design our towns and cities, and shape the environment? (Answer: Engineers use information about environments and ecosystems to design homes and buildings that are comfortable for us to live and work.)

abiotic: Nonliving, for example, sunlight or rocks.

biodome: A human-made, closed environment containing plants and animals existing in equilibrium.

biome: An area with a certain set of ecological characteristics, including a specific climate, plants and animals living in it.

biosphere: The part of the Earth's atmosphere that is capable of supporting life and includes both living and nonliving things.

biotic: Pertaining to life or living organisms.

characteristic: A distinguishing feature or quality.

climate: The average weather, usually over a 30-year time period, for a particular region and time period. Climate is not the same as weather; it is the average pattern of weather for a particular region. Weather describes the short-term state of the atmosphere. Climatic elements include precipitation, temperature, humidity, sunshine, wind velocity, phenomena such as fog, frost and hailstorms.

ecosystem: A functional unit consisting of all the living organisms (plants, animals and microbes) in a given area, and all the nonliving physical and chemical factors of their environment, linked together through nutrient cycling and energy flow. An ecosystem can be of any size — a log, pond, field, forest or the Earth's biosphere — but it always functions as a whole unit.

engineer: A person who applies scientific and mathematical principles to creative and practical ends such as the design, manufacture and operation of efficient and economical structures, machines, processes and systems.

environment: The surroundings in which an organism lives, including air, water, land, natural resources, flora, fauna, humans, and their interrelationships. (Examples: Tundra, coniferous forest, deciduous forest, grassland prairie, mountains and rain forest.)

equilibrium: A stable condition of being in balance.

habitat: The natural home of a plant or animal.

homeostasis: Equilibrium of an internal environment.

model: (verb) To simulate, make or construct something to help visualize or learn about something else (as the living human body, a process or an ecosystem) that cannot be directly observed or experimented upon. (noun) A representation of something, sometimes on a smaller scale.

niche: A unique ecological role that an organism plays in an ecosystem.

Pre-Lesson Assessment

Pre-Unit Quiz : To conduct an overall pre/post assessment of the Biodomes curricular unit (six lessons, with associated activities), administer the Pre-Unit Quiz to the class before beginning any discussion on Biodomes. Then, after completion of lesson 6, administer the same (post-unit) quiz to the same students and compare pre- to post- scores. In addition, this short quiz is suitable to administer to a control group of students who have not completed the unit, to comparatively test the impact of the curricular unit on learning.

Group Discussion : As a class, have the students engage in open discussion. Solicit, integrate and summarize student responses, writing their ideas on the classroom board. All ideas should be respectfully heard. Take an uncritical position and discourage criticism of ideas. Have students raise their hands to respond. Ask the students:

• What different types of environments can you think of? (See Table 1 examples.)
• (For each environment) What is the climate like? What kind of weather might occur? (Dry or humid? Sunny or foggy? Hot or cold? Snowstorms or tornados?)
• (For each environment) What types of plants and animals live there? (See Table 1 examples.)

Picture Discussion : Using books or the internet, show students photographs of different types of environments. In an informal class discussion, have students identify:

• What types of animals and plants might be present in each environment?
• What resources would be present for people?
• How would those resources need to be conserved in order for people to survive?

Post-Introduction Assessment

Writing and Drawing/Drafting Reflection : Ask students to write a paragraph in their science journal or on a sheet of paper that describes themselves and where they live. They should include a description of their environment, habitat and community, and consider themselves as part of a population. Add a drawing or drafting component by having students place themselves in an environment of their choice and design a living space to protect themselves from the conditions of that environment. Remind students that engineers sometimes create these types of designs.

Group Discussion : Solicit, integrate and summarize student responses.

• Have students discuss and identify biotic and abiotic factors in the biosphere. This includes living and nonliving things, animals and plants, as well as the air, soil, rocks and sunlight.
• Pick an environment that is different from where the students live (for example, a rain forest, desert or arctic tundra.) Ask students to describe how their lives might be different if they lived in this new environment. Then, ask them to explain how they, as an engineer, would design a home for this environment. (For example, would you want thick walls in a tropical environment or in a desert?)
• Have students discuss why engineers and scientists might study different environments and ecosystems, as well as the extreme weather conditions that exist within different climates, such as floods, hurricanes, earthquakes, volcanoes or tsunamis.

Lesson Summary Assessment

Using Evidence: Ask students to write a paragraph using evidence to support the explanation that traits can be influenced by the environment. They can use what was taught in the lesson or do outside research as evidence.

Option 1 - Worksheet to Class Poster : Use the Environments and Ecosystems Worksheet as an exploratory activity for students to chart the various plants, animals and soil that are present in different ecosystems. Have students complete the worksheets individually and then share their information with the class to create one large ecosystem chart on a poster-sized sheet to hang in the classroom. See Table 1 for possible worksheet answers.

Option 2 - Worksheet to Class Chart: Have students complete the Environments and Ecosystems Worksheet as an individual investigation project, using books or the internet. Then, ask them to share their discoveries by providing them with sticky notes to record what they discovered about the different environments, encouraging them to use the vocabulary learned in their research. Have them post their responses on a poster chart divided into columns for each type of ecosystem. Once all notes are posted, read aloud some of the sticky notes, or have students come up and select notes to share with the class. Refer to the completed environments and ecosystems chart during subsequent lessons in this unit.

Lesson Extension Activities

Climates Research Project : As an individual exploratory research project, have students research the climates that are present in different environments and ecosystems. After selecting an environment type, research to find out its climate, rainfall, temperature and extreme conditions. Ask them to consider how they, as engineers, might take the climate into consideration for the design of homes or structures in the environment they are researching.

Use the internet to find additional resources that describe the characteristics of our planet's many ecosystems. Start with the following websites:

Discovery Channel Online

Ecosystems: http://library.thinkquest.org/11353/ecosystems.htm

Hawaiian Ecosystems at Risk Project (HEAR)

National Geographic

Sustainable Ecosystems Institute

U.S. Environmental Protection Agency (EPA) Student Center: http://www.epa.gov/students

U.S. Fish and Wildlife Service

In this multi-day activity, students explore environments, ecosystems, energy flow and organism interactions by creating a scale model biodome, following the steps of the engineering design process.

As students learn about the creation of biodomes, they are introduced to the steps of the engineering design process, including guidelines for brainstorming. They learn how engineers are involved in the design and construction of biodomes and use brainstorming to come up with ideas for possible biod...

Students learn about energy and nutrient flow in various biosphere climates and environments. They learn about herbivores, carnivores, omnivores, food chains and food webs, seeing the interdependence between producers, consumers and decomposers. This lesson is part of a series of six lessons in whic...

Students learn about population density within environments and ecosystems. They determine the density of a population and think about why population density and distribution information is useful to engineers for city planning and design as well as for resource allocation.

Bush, Mark B. Ecology of a Changing Planet . Second Edition. Saddle River, NJ: Prentice Hall, 2000.

Dictionary.com. Lexico Publishing Group, LLC. Accessed October 9, 2006.

Environmental Health Center Glossary. Updated September 27, 2005. National Safety Council. http://www.nsc.org/Pages/Home.aspx Accessed October 9, 2006.

Glossary of Terms. Public Entity Environment Management System Resource Center, Peer Center. http://www.peercenter.net/about/glossary.cfm Accessed October 9, 2006.

Weather and Climate Terminology, Glossary Data Lookup and Reference Service. Weather Guide, NetCent Communication. http://weather.ncbuy.com/glossary.html?action=LETTER&term=C Accessed October 9, 2006.

Contributors

Supporting program, acknowledgements.

The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.

Last modified: August 27, 2019

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What is Ecosystem? Definition, Structure, Types, and Functions

The ecosystem term was first coined by an ecologist Arthur Tansley in 1935. The ecosystem is a balance or equilibrium between living and non-living factors of the ecosystem where they tend to interact with each other. All living things, including plants, animals, and microorganisms, depend on non-living substances to survive and maintain the equilibrium of the natural environment.

This relationship between the living and nonliving elements is studied by the study of ecosystems. In this article, we will discuss ecosystem structure, function, and types of ecosystems.

Table of Content

What is an Ecosystem?

Structure of ecosystem, functions of ecosystem, types of ecosystem, functional units of ecosystem, ecosystem diversity, concepts of ecosystem.

Ecosystem Definition: An ecosystem can be defined as a unit of ecological studies that includes all the interactions between living organisms with their surrounding non-living environment.

In the word “ecosystem”, “eco” means environment, and “system,” refers to connected processes or elements. Ecosystems are made up of both biotic (or alive) and abiotic (or nonliving) components. It is a biological community where living and non-living components of the planet interact with each other. Ecosystem varies in the size and number of organisms they consist of. When the ecosystem is land-based it is called a terrestrial ecosystem and when it is water-based it is called an aquatic ecosystem.

The structure of an ecosystem is made of two main components: biotic and abiotic components. The biotic component interacts with the abiotic components to maintain the flow of energy. The energy is distributed in the environment. The ecosystem includes 2 main components for a working ecosystem:

• Biotic Component
• Abiotic Component

Also Read: Ecosystem and Its Component

Biotic Components

Plants, animals, microorganisms, aquatic plants, and all other living creatures are the biotic components of the ecosystem. These biotic components can be classified into:

• Producers: All autotrophs like plants, phytoplankton, etc. that can produce their food using sources like sun, water, carbon dioxide, or any other chemical elements belong to this category.
• Primary consumers: All herbivores that directly depend on plants, such as cows, goats, rabbits, and sheep, are considered primary consumers.
• Secondary consumers: All that depend on primary consumers for food are considered secondary consumers. The secondary consumer can be omnivores or carnivores . 
• Tertiary consumers: All animals that depend on secondary-level organisms for their food are known as tertiary consumers. 
• Quaternary consumer : Those animals that depend on the tertiary level organism for their food and are known as the quaternary consumer. This level is present in some food chains only.
• Decomposers: All microorganisms, such as bacteria and fungi , that depend on decaying and dead matter for food fall under this category. It contributes to environmental cleanup and ecosystem nutrient recycling. These nutrients support plant development and subsequently ecosystem maintenance.

Abiotic Components

It involves all the non-living things present in the environment. Some of the abiotic components are sun, soil, water, minerals, climate, rocks, temperature, and humidity. These components’ functioning together enables the ecosystem’s energy and nutrition cycles. The sun’s rays are the primary energy source. An ecosystem’s temperature changes have an impact on the types of plants that may flourish there. The availability of nutrients and soil nature determines the type and abundance of vegetation in an area. All the abiotic factors are essential factors that determine the number and type of organisms present in a region.

Following are some of the functions of the ecosystem ;

• It regulates different life processes.
• The various components of an ecosystem are designed in a manner to support the life systems.
• It regulates various types of nutrient cycles.
• It maintains the balance of energy flow between various levels of the ecosystem.
• It regulates the cycling of nutrients between abiotic and biotic factors.

An ecosystem can be small or large. There are 2 types of ecosystem :

Aquatic Ecosystem

Terrestrial ecosystem.

Oceans, rivers, seas, lakes, springs, and other water bodies are aquatic biomes. The bulk of the earth’s surface is covered by the water. Two-thirds of the earth’s surface is made up of oceans, seas, the intertidal zone, reefs, the seabed, and rock pools. This ecosystem includes plants, fishes, amphibians, coral reefs, huge sea creatures, and insects.

There are 2 types of aquatic ecosystem:

• Freshwater Ecosystem
• Marine Ecosystem

Freshwater Ecosystems

A freshwater ecosystem has low salinity levels, providing a good environment for a variety of plants and animals. The sizes of freshwater resources range from small ponds to very large rivers. Freshwater resources vary from one another in terms of how they travel. While some freshwater bodies are constantly moving, like rivers, others remain still, like ponds.

Freshwater Ecosystem Types: Based on the region, the three main categories of the freshwater environment are the lotic, lentic, and wetland freshwater ecosystems.

• Lotic: In a lotic freshwater ecosystem, the water bodies travel in one direction. Numerous rivers and streams start at their sources and meet rivers or oceans at their mouths as they travel toward their destinations. 
• Lentic: All non-flowing (still) waterways, such as ponds, swamps, bogs, lagoons, and lakes are lentic ecosystems. Due to the saturation of the underlying land, water will temporarily remain on the earth’s surface. They are closed structures that keep the water still. Because every lentic system has multiple areas with different biological environments, animals, and plants in that system behave and adapt in different ways. 
• Wetlands: Wetlands contain water and are home to vascular plants. Wetland environments are more often known as marshes, swamps, and bogs. Because soil and water are so close together, wetlands are highly productive. The plant species found in wetlands are referred to as hydrophytes since they have adapted to the area’s moist and humid climate. Wetland ecosystems contain hydrophyte plants such as cattails, pond lilies, and sedges. Various amphibians, reptiles, birds, shrimp, shellfish, and other animal species find refuge in wetlands.

Living creatures that live in Freshwater Ecosystems: Fishes, amphibians, reptiles, mosquitoes, dragonflies, bees, wasps, water spiders, ducks, geese, etc.

Marine Ecosystems

Aquatic environments with high levels of dissolved salt are marine ecosystems. These comprise the deep ocean, the open ocean, and the coastal marine ecosystems. Each of these has unique biological and physical properties. The ecosystem’s exposure to the sun, the amount of oxygen and nutrients that are dissolved in the water, the distance from land, the depth, and the temperature are all significant abiotic factors. Marine ecosystems have unique biotic and abiotic characteristics. 

A terrestrial ecosystem refers to an ecosystem of diverse land surfaces. Forests, deserts, grasslands, tundra, and coastal regions are all examples of terrestrial ecosystems. These terrestrial ecosystems are climate-dependent. 

• Forests: A type of terrestrial ecosystems that is covered in trees, creating several canopy layers. A variety of animal species live in dense tree covers and tropical rainforests. Forests are home to about 300 million different plant and animal species. A forest is a type of ecosystem that includes tropical rainforests, plantation forests, and temperate deciduous forests.
• Grasslands: It has a dry environment that permits relatively little vegetation. Primarily, different species of grasses, are what define the grassland ecosystem. In this environment, grass and herbs predominate. The ecosystem of grasslands is significant to the animal kingdom. 
• Tundra: Tundra has extreme environmental conditions like that of the polar region. The location is typically windy, blanketed in snow, and devoid of trees. Its environment is constantly covered in absolutely frozen dirt. Small ponds are formed when the snow melts. Some lichens can flourish in such ponds. 
• Deserts: Deserts are unproductive land surfaces with extreme temperature swings and inadequately maintained species. One of the driest land regions on the globe. A desert receives an extremely small amount of rainfall. Because of this, there is less vegetation. The desert ecosystem’s plants and animals have learned the skill of surviving extreme environments.

The ecosystem’s function is to maintain its various parts working together. It is a natural process of a transfer of energy in different biotic and abiotic elements of the world. Ecosystems maintain all the important ecological processes, including nutrient cycling. Ecosystems have different functional units those are:

• Production: Any ecosystem must have a consistent supply of solar energy to survive and function. Primary production is influenced by the types of plants that live there. Green leaves act as food preparators, while roots draw nutrients from the soil. Herbivores consume the plants, which then provide food for carnivores.  
• Decomposition: Decomposition is the breakdown of complex organic matter by decomposers into inorganic components such as carbon dioxide, water, and nutrients. The decomposers break down garbage and dead organic material. The primary decomposers in many ecosystems are fungi and bacteria.
• Energy flow: Radiant energy from the sun is the primary source of energy in all ecosystems. The ecosystem’s autotrophic, or self-sustaining, creatures utilize the energy of the sun. Plants use the sun’s energy to change carbon dioxide and water into simple, energizing carbohydrates. The more complex chemical substances, like proteins, lipids, and starches are produced by autotrophs.  Energy goes unidirectionally from the sun to producers, herbivores, and carnivores. Decomposers convert the dead autotrophs and heterotrophs into nutrients, which are energy sources for plants.
• Nutrient cycling: Chemical substances known as nutrients are substances that organisms need for growth and the maintenance of life. A vast range of chemical compounds is created when bio-elements interact. The organisms catch them, concentrate and combine them in different ways in their cells, and release them during metabolism and death.

Ecosystem diversity refers to the variety of different habitats and communities found in a particular area, along with the various interactions between them. These ecosystems include forests, grasslands, deserts, rivers, and oceans, each supporting a unique array of plants, animals, and microorganisms. The diverse range of ecosystems contributes to the overall health and stability of the environment, providing essential services like air and water purification, soil fertility, and climate regulation. Ecosystem diversity is crucial for maintaining biodiversity, as it ensures the survival of a wide range of species and helps ecosystems adapt to environmental changes. Protecting and conserving ecosystem diversity is essential for preserving the delicate balance of nature and ensuring the well-being of both wildlife and humans.

These are the important concepts under the ecosystem. Those are:

Food Chain and Food Webs

The cycle of energy starts with solar energy. The chain of energy transfer from one level to the topmost level is known as the food chain. Plants absorb solar energy and synthesize their food. Later on, herbivores feed on the plants for energy. Similarly, carnivores and omnivores feed on them for energy. 

The interconnected food chain is known as the food web . In nature mostly food webs are common instead of the food chain.

Also Read: Difference Btetween Food Webs and Food Chain

Ecological Pyramids

These are the graphical representations of the number, energy, and biomass of the trophic level of an ecosystem. Charles Elton postulated the ecological pyramid in 1927. The base of the ecological pyramid denotes the producers of that particular ecosystem. Then it is followed by the consumers and the top decomposers. 

Energy Flow in Ecosystem

The flow of energy in the ecosystem is always in one direction or unidirectional. Even though producers tend to absorb 100% sun’s light energy in their capacity, they only pass on 10% of that energy to the next trophic level and then only 10% of that energy is passed into the next level.

Biogeochemical Cycle

It is also known as the nutrient cycle and includes all the phenomena that ensure that all the basic elements of nutrients like carbon, nitrogen, and phosphorus that are absorbed by living organisms from the environment are returned to the environment. This process involves the transfer of nutrients between abiotic and biotic factors and vice-versa. It includes the carbon cycle , nitrogen cycle, water cycle , phosphorus cycle , etc.

Conclusion – Ecosystem

Ecosystems are the complex webs of life that includes all living organisms and their physical surroundings, working together in harmony. They provide essential services like clean air, water, and food, supporting life on Earth. Understanding and protecting ecosystems is crucial for maintaining biodiversity and ensuring the well-being of both wildlife and humans. By conserving ecosystems and practicing sustainable living, we can preserve the delicate balance of nature and secure a healthy environment for future generations to thrive in.

Also Read: What are Environment and Ecosystem ? Components And Classification Of Ecosystem What is a Natural Ecosystem? Difference Between Ecosystem and Biome Food Chain and Food Web

FAQs on Ecosystem

What is the ecosystem.

It is an area where both biotic and abiotic interaction takes place, such an area is known as Ecosystem. It can be defined as the interaction between living and non-living components of the environment.

What are the Major Ecosystems?

The major eosystem are; terrestrial or land ecosystem and aquatic or water ecosystems. Terrestrial ecosystems included; forest, grassland, tundra, and desert. Aquatic ecosystem includes; freshwater and marine ecosystems.

What are the main functions of t he E cosystem?

The main functions of the ecosystem are; to maintain the balance of energy flow, to regulate nutrient cycling, to maintain transfer of energy flow between trophic levels, balance among organisms, etc.

What is the Structure of the Ecosystem ?

The structure of ecosystem is characterized by it components i.e. biotic and abiotic components. The biotic components includes all the living organisms, and the abiotic components includes physical factors like water, temperature, nutrients, etc.

Which is the Largest Ecosystem in the world?

The largest ecosystem in the world is the aquatic ecosystem or the water based ecosystem. As water covers almost around 71% of the Earth, and it consists of a huge number of organisms, it is the largest ecosystem.

What are the Functional Components of an Ecosystem?

The functional components of ecosystem involves – Productivity, Decomposition, Energy flow, and Nutrient Cycling.

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Pressing Questions About Ecosystem Restoration, Answered

• restoration
• agriculture
• deforestation

The world’s ecosystems are under threat.

Fires are turning biodiverse forests in California and wetlands in Argentina and Brazil into charred landscapes . The ocean is getting warmer and more acidic, bleaching colorful, fish-filled coral reefs across the Seychelles. The abuse of the soil, exacerbated by overuse of chemical fertilizers and pesticides, is damaging the long-term economic and ecological health of struggling farm communities in China.

These threats — such as commodity agriculture, climate change and overfishing — are specific to every land and seascape. But all forms of ecosystem degradation have one thing in common: When people hurt ecosystems, they also hurt economies, biodiversity and the climate.

The damage is reversible, though. Restoring  degraded ecosystems is not only possible, but it makes economic sense, too.

Thousands of organizations and millions of people — from entrepreneurs in South Africa to government officials in El Salvador to youth activists in the United States — have banded together to create the UN Decade on Ecosystem Restoration , a 10-year effort to prevent, halt and reverse the degradation of ecosystems worldwide. They are building on work from the past decade —  such as partnerships like AFR100 in Africa, where 30 countries pledged to restore an area of land the size of Egypt — and  are turning it into action on the ground.

Why is it Beneficial to Restore Degraded Ecosystems?

Restoring landscapes and marine ecosystems is urgent not only because they are home to countless plant and animals, but because the services they provide are worth an estimated $125 trillion every year to the global economy. Healthy ecosystems and landscapes support industries like farming, fishing, forestry and tourism, which employ 1.2 billion people . In the United States alone, ecosystem restoration is a $25 billion industry that employs 220,000 people, more than each of the coal, logging or steel industries. And globally, each $1 invested in restoring degraded landscapes can bring $7-30 in economic returns.

Healthy ecosystems are also a lynchpin in the fight against climate change, itself a major driver of ocean and landscape degradation. If nature were protected and restored at scale, it could provide more than one-third of the annual emissions reductions the world needs by 2030 to keep global temperature rise below 2 degrees C (2.6 degrees F). The world’s forests alone store 1.5 times more carbon than the U.S. emits every year (and could soak up 23% of global CO2 emissions every year if we let them naturally regenerate).

Restoring ecosystems can also directly serve the world’s Indigenous people and communities, many of whom rely on natural resources for their livelihoods and cultural practices. The herding culture of Kenya’s Maasai people, for example, is only sustainable if the grassy rangelands they call home — and that feed their cattle — are constantly replenished.

How Can Critical Ecosystems Be Restored?

Successful restoration is all about embracing diversity: One comprehensive study identified 108 different ecosystems, and restoration techniques vary depending on the ecosystem and location. On farms, for example, people can plant trees to shade crops like coffee, dig terraces to halt the erosion of hills, or allow native vegetation to naturally regrow in exchange for payments for reinforced ecosystem services like clean water. In the ocean, people can reseed seagrass beds to store blue carbon, or grow coral polyps in underwater nurseries to rebuild habitat for valuable fish.

What Are Some Examples of Ecosystem Restoration?

So, what are the key ecosystems that are people are restoring, and how are they doing it? Five examples of ecosystem restoration in particular are critical for the health and safety of people, biodiversity and the climate.

1. Farmlands

Farmers are the backbone of rural economies and the global food system, and they are chief among the 3.2 billion people worldwide who suffer from land degradation. While the unsustainable practices of some of them — like slash-and-burn cultivation and the overapplication of chemical fertilizers and pesticides — have contributed to the problem, others are now restoring degraded farmland and surrounding landscapes to boost agricultural productivity.

By embracing approaches like agroforestry (trees on farms), silvopasture (trees on grazing land), and low-carbon agriculture (no-till farming and cover crops) across 150 million hectares of land, restoration could generate $85 billion in net benefits, provide $30–40 billion a year in extra income for smallholders, and supply food for nearly 200 million people.

In India’s small Sidhi District alone, restoring 75% of the land with 40 million tree saplings — many of which would go on and around farms to boost crop yields or in sustainable orchards — could bring $19 million to struggling rural communities.

Investors are starting to take notice of this opportunity: Across Latin America, impact investor 12Tree  has put more than $100 million into projects that protect natural forest while producing high-quality coffee, cocoa and jobs.

In 2020 alone, the world lost 12 million hectares of tropical forests, an area of land larger than Malawi. Especially concerning is the 12% increase in annual loss within biodiverse, carbon-storing, humid primary forests. Caused by the expansion of commodity agriculture, wildfires and a host of other human activities, tree cover loss has turned some of these forests, like Indonesia’s dense jungles, into sources of carbon emissions rather than carbon sinks.

But around the world, new forests are sprouting up thanks to tree planters and people who are helping trees regenerate naturally. The economic opportunity is too great to pass up: Fully investing in Ethiopia’s forest economy, for example, could deliver a $1.91 billion return .

In Brazil, pioneers like Bruno Mariani , whose company Symbiosis Investimentos is restoring the country’s damaged Atlantic Forest with native trees like the ipê-felpudo and pau brasil , are showing that sustainable income and protecting the environment can go hand-in-hand. A monitoring platform, the Brazilian Restoration and Reforestation Observatory , is collecting data to show where these efforts are making an impact. Today, more than 11 million hectares of forest are naturally regenerating throughout the country, and local project developers are planting and maintaining new trees across dozens of areas.

3. Grasslands

Sometimes, trees aren’t the solution. The world’s grassland ecosystems, covering 31% to 43% of Earth's land , are home to countless bird and plant species and store carbon in their deep, interlocking root systems and soils. These ecosystems, which many of the world’s 200 million pastoralists need to feed their livestock, are undervalued, often plowed over for farming, sacrificed to poorly planned tree-planting campaigns, or damaged by overgrazing.

When livestock aren’t managed sustainably, the soil compacts, the grass stops growing and the desert starts spreading. In Mexico’s Chihuahua Desert, cattle ranchers are working with organizations like Pronatura , Pasticultores del Desierto and American Bird Conservancy to better manage 100,000 hectares of native grasslands. Preventing cattle from grazing on certain areas at certain times gives grasses enough time to grow back and provides a haven for migrating birds. It makes economic sense for the ranchers, too: With a healthy ecosystem, cattle have more feed.

4. Peatlands

The expansion of oil palm plantations and other farms in places like Indonesia threaten peatlands,  swampy ecosystems formed by decomposing plant matter. That’s bad news for the climate: When a hectare of carbon-rich peatland is drained, it has roughly the same climate-warming effect of burning 6,000 gallons of gasoline. In 2015, when 52% of forest fires in Indonesia occurred on drained peatlands, more than 100,000 people prematurely died (many from acute respiratory infections). The economy suffered a loss of $16 billion .

In 2016, mounting pressure from civil society forced the Indonesian government into action, and they committed to rewet and protect 2.6 million hectares of damaged peatlands within five years. While peatlands continue to burn — with more than 500,000 hectares destroyed in 2019 alone — there are many success stories of people managing their peatlands without burning them. For example, by damming the canals that originally drained and dried part of Central Kalimantan’s peatlands , local people are now sustainably managing more than 20,000 hectares and lowering the risk of future fires.

5. Ocean and Coasts

The ocean also is facing unprecedented challenges: Only 3% of it is unaffected by humans. Between 1970 and 2000 , seagrass meadows, which support 20% of the world’s largest fisheries, declined by roughly 30%, while mangrove forests, which help reduce flooding and coastal erosion, declined by 35% as coastal development and demand for charcoal expanded. Since the 1870s, half of reefs’ coral cover , which protect the homes of more than 500 million people , has died. Considering that some of these “blue carbon” ecosystems can store up to 10 times more carbon than the same expanse of forest, their declining health is concerning.

Mangroves, a special type of ecosystem where the sea and the land meet, are especially important for fisheries and protecting coastal communities against sea level rise. Every $1 invested in protecting and restoring them leads to $3 in benefits.

In Senegal’s Casamance delta, NGO Océanium and the Livelihoods Funds have mobilized 100,000 people to restore more than 10,000 hectares of mangroves — and produce an extra 18,000 tons of fish annually to boost local food security. The newly planted mangrove saplings have brought at least one positive impact to 95% of local people. In addition to protected coasts and improved food security, some farmers experienced increased rice yields in freshwater paddies that are now protected from salty ocean water.

How Can the UN Decade on Ecosystem Restoration Be Successful?

The restoration commitments that governments and corporations have for 2030 are impressive: restoring 350 million hectares of degraded landscapes, protecting and growing 1 trillion trees, expanding mangroves by 20% and sustainably managing 30 million square kilometers of the ocean.

The secret to global success, however, lies in boosting the capacity of local leaders. First, decision-makers from local and regional governments, NGOs, and small businesses need access to lessons that past restoration projects have learned, as well as monitoring data that can help them prove their success to funders and inspire others to replicate their accomplishments.

Second, they need strong public incentives and government policies that provide technical expertise and pay them for the ecosystem services they are protecting and restoring.

And finally, thousands of restoration project developers and entrepreneurs need access to training, mentorship, and networks that can help them tap into the billions of dollars of private finance earmarked for ecosystem restoration.

Kenyan Nobel Prize laureate Wangari Maathai once said that “It is the little things that citizens do that will make the difference. My little thing is planting trees.” By investing in millions of people whose own “little thing” is restoring ecosystems near and far, we can turn the dream of the UN Decade on Ecosystem Restoration into a more sustainable future for all.

Do you want to learn more about how we’re helping people restore the world’s ecosystems? Learn more about our work on forest and landscape restoration, and sign up for our newsletter.

The author would like to thank Katie Flanagan, Luciana Gallardo Lomeli, and Maria Potouroglou for their input.

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The benefits and power of assisted natural regeneration, smarter farm subsidies can drive ecosystem restoration, restoring degraded land in latin america can bring billions in economic benefits, how to manage the global land squeeze produce, protect, reduce, restore, how you can help.

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• Environmental Chemistry
• Ecosystem Components

Ecosystem - Components Of Ecosystem

This topic explains about the ecosystem and the components of ecosystem . An ecosystem is a group or community composed of living and non-living things and their interactions with each other. They can be natural as well as artificial. Every ecosystem has two components, namely, biotic components and abiotic components. Biotic components refer to all living organisms in an ecology while abiotically refers to the non-living things. These biotic and abiotic interactions maintain the equilibrium in the environment. Let’s go through the components of the ecosystem in detail.

Table of Contents

Components of ecosystem.

• Frequently Asked Questions – FAQs

Biotic components are the living things that have a direct or indirect influence on other organisms in an environment. For example plants, animals, and microorganisms and their waste materials.

Abiotic components of an ecosystem include all chemical and physical elements i.e. non-living components. Abiotic components can vary from region to region, from one ecosystem to another. They mainly take up the role of life supporter. They determine and restrict the population growth, number, and diversity of biotic factors in an ecosystem. Hence, they are called limiting factors.

A terrestrial ecosystem consists of abiotic factors like climate, type of soil or rock, altitude, temperature, nutrients, and minerals, whereas abiotic components in an aquatic ecosystem include dissolved gases, depth of water, salinity, pH of water, light intensity etc.

The significance of Biotic and Abiotic Components

Biotic components can be classified into three categories:

Producers: These include all the autotrophs. They use light energy and synthesize food on their own, e.g. plants, green algae, etc.

Consumers: These include all the heterotrophs that directly or indirectly depend on producers for their food. Consumers are further categorized as herbivores, carnivores, omnivores and parasites.

Decomposers: These include saprophytes which act on dead matter and decay them for their nutrition.

The relevance of biotic and abiotic components in an environment appears when they start interacting with each other. For example, biotic elements like plants provide food for other organisms. The soil is the abiotic element which supports the growth of the plants by providing nutrients and other essential elements. Biotic components depend on abiotic components for their survival and help in the formation of abiotic factors like soil, nutrients, etc.

Food Chains and Webs

A food chain is a chain which shows how organisms are linked to each other through food. A food web shows how two food chains are connected. A single food web consists of many food chains. Every food chain begins with producers and ends with top carnivores.

The energy flow from one level to another level in a food chain gives the trophic level of an ecosystem. The producers come at first trophic level followed by herbivores (primary consumers), then small carnivores (secondary consumers) and large carnivores (tertiary consumers) occupy the fourth trophic level.

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Major Abiotic Factors

Frequently Asked Questions – FAQs

What is the ecosystem.

The ecosystem is the community of living organisms in conjunction with non-living components of their environment, interacting as a system.

What are the different types of ecosystems?

The different types of the ecosystem include: Terrestrial ecosystem Forest ecosystem Grassland ecosystem Desert ecosystem Tundra ecosystem Freshwater ecosystem Marine ecosystem

What are the functional components of an ecosystem?

The four main components of an ecosystem are: (i) Productivity (ii) Decomposition (iii) Energy flow (iv) Nutrient cycling

Which ecosystem do we live in?

We live in a terrestrial ecosystem. This is the ecosystem where organisms interact on landforms. Examples of terrestrial ecosystems include tundra, taigas, and tropical rainforests. deserts, grasslands and temperate deciduous forests also constitute terrestrial ecosystems.

What is the structure of the ecosystem?

The structure of the ecosystem includes the organisms and physical features of the environment, including the amount and distribution of nutrients in a particular habitat. It also provides information regarding the climatic conditions of that area.

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Call for consultant(s) to support gender integration in policy and regulation for community-centred connectivity models

Terms of reference

The LocNet team seeks a gender policy consultant/s to work with us on Gender Integration in Policy and Regulation for community-centred connectivity within the Local Access and Community Networks (LocNet) initiative. The LocNet initiative is a collective effort led by the Association for Progressive Communications (APC) and Rhizomatica. This initiative aims to contribute to an enabling ecosystem for the emergence and growth of community networks and other community-based connectivity initiatives in Africa, Asia, and Latin America and the Caribbean (LAC). It is part of a multi-year, multi-donor strategy envisaged to address the human capacity and sustainability challenges – along with the policy and regulatory obstacles – that limit the growth of community-centred connectivity initiatives. This project aims to contribute to our vision of digital inclusion: rural, remote and marginalised communities have the opportunities, capacities and resources to achieve and shape meaningful community-centred connectivity that contributes to strengthen local well-being, economies and cultures.

The main purpose of the assignment

We are looking for a gender policy consultant/s to work with our team and to conduct an assessment of the priority and opportunity areas and for the development of a report which will support Gender Integration in Policy and Regulation for Community-Centred Connectivity. The consultancy will start on 1 November 2024 and run through to 28 February 2025 .

This assessment will support the policy and gender leads of the LocNet team to design and plan workshops for the integration of gender in policy and regulation for community-centred connectivity. Working with the LocNet initiative team, the consultant/s is/are expected to develop a proposal of their work plan and a consolidated budget, conduct the assessment, and write a report of the findings. The proposal will include the objectives, methodology, assessment and mapping instruments, and a detailed time log of the consultancy. The proposal will be reviewed and approved by the LocNet team members responsible for this area of work.

The report document will include a background section on the current regulatory ecosystem for community-centred connectivity, the status of gender in community networks, along with the specific opportunity areas for gender integration in policy and regulation in Africa. The assessment will also consider specific regional indicators, including existing policy and regulatory frameworks for community-centred connectivity and gender digital divide projects. 

The deadline for submitting the report document is 22 February 2025. The consultant/s will be responsible for the below deliverables in the form of a written report:

• Conduct the mapping of existing gender mainstreaming guidelines in ICT data, research, policy and/or regulation.
• Identify gender and community networks documents in policy related to ICTs and community-centred connectivity.
• Identify actors working in the intersecting areas of policy, community-centred connectivity and gender.
• Interview stakeholders in the field to get their impressions on what is needed and what is helpful.
• Analyse the existing work of gender in ICT policy and document and players, what elements are seen as successful, where there remain gaps.
• Identify opportunities and spaces where the topics of gender integration in policy and regulation related to ICTs and community-centred connectivity are discussed.
• Identify recommendations on how LocNet can address gaps in Africa, as well as in LAC and Asia.

Qualifications, background, and experience

We are looking for an experienced consultant or team of consultants who has/have worked with international networks and international civil society organisations (CSOs) in Africa on gender assessment approaches in ICT. Knowledge and understanding of the policy and regulatory ecosystems in Africa, the internet, telecommunications industry, digital technologies, human rights, community dynamics and development issues are essential. LocNet is a virtual team and we expect the evaluation to be conducted mainly through online platforms. The consultant(s) should have excellent English communication skills.

Duration of the assignment

The assignment period is from 1 November 2024 through 28 February 2025.

Interested consultants are invited to send a proposal outlining:

• Their approach and methodology for the assessment (as outlined above).
• An estimate of the number of days required for completing the consultancy and day rates.
• Their CVs with information about qualifications, competence and experience relevant to the assignment.
• A sample of previous work reports and deliverables that demonstrate the assessment approaches, methodologies and contexts in which they have worked.
• Two references: names, relationship, contact details; at least one of which should be related to a recent evaluation conducted.

Please send this information via email with the subject line, “Consultant – LocNet Gender Integration in Policy” to: [email protected] by 18 October 2024 . 

Please note that only shortlisted candidates will be contacted.

Download the call in PDF format here.