An ecosystem is an ecologist system formed by the interaction of living organisms and their non-living environment.Thus, when considering an ecosystems, we are considering both the biotic and the abiotic environments in that ecosystems.

An ecosystems uses both energy and inorganic nutrients.Energy enters an ecosystem is an ecological system outside it (from the sun).Energy is covered into chemical energy and  is passed from organisms to organisms through the ecosystems.This energy that is lost as heat cannot be recycled in the ecosystems.Hence, energy has to be constantly supplied to the ecosystems.

Inorganic nutrients, on the other hand, need not be supplied form outside the ecosystems.They are obtained for abiotic environment and flow through the ecosystems in a cycle.Thus, in a balanced ecosystems , nutrients are continually recycled and are not lost.

How does energy enter the earth's ecosystems?

The biosphere includes all parts of the Earth where life can be found.The biosphere is a huge ecosystems.Light is part of the abiotic environement of this ecosystem.However, the sun is outside the ecosystems.Hence, energy enters the ecosystems from outside.

How do energy and nutrients flow through an ecosystems?

The living organisms in any ecosystems are made up of producers, consumers, and decomposers.Energy and nutrients are transferred from producers to consumers to decomposers through feeding.

Products

Producers convert energy from the sun or light energy into chemical energy and store it as food during photosynthesis, Producers are mainly green plants, but algae and certain bacteria that can photosynthesise are also producers.Producers are the only organisms that can manufacture or produce complez organic directly or indirectly affect the lives of other organisms becuase they provide energy and oxygen.

Consumers

Consumers obtain their energy by feeding on other organisms.All animals are therefore consumers.Plant eaters or herbivores feed directly on plant, hance they are known as primary consumers.Meat eaters or carnivores feed on other animals.Carnivores that feed on herbivores are known as secondary consumers.Carnivores that feed on other carnivores are tertiary consumers.

Decomposers

Decomposers obtain energy by breaking down dead organisms, faeces and excretory products.When the dead organisms and waste matter are broken down , the materials locked up in them are released.These materials, such as inorganic nutrients, carbon and nitrogen compunds, return to the physical environment and are used again by green plants.Fungi , bacteria and earthworms are examples of decomposers.

Food Chains

We can represent the feeding relationships between organisms in an ecosystems using food chains.A food chain is a series of organisms through which energy is transferred in the form of food.Each organism in a food chain feeds on the organisms before it and provides food for the organism after it.A food chain always begins with a producers.Remember, producers are the only organisms that can manufacture organic food from inorganic raw materials.

Each stage in a food chain is known as a trophic level.Generally, food chains do not have more than four trophic levels;

Producer  > Primary Consumer > Secondry Consumer > Tertiary Consumer

Producers make up the first trophic level, primary consumers make up the second trophic level and so on.

An animal that feeds on another animal is called a predator.An animal that is eaten by another animal is called a predator.An animal that is eaten by another animal is called the prey.For exampe, snakes eat rahbits, so snakes are predators of rabbits.Rabbits are the prey of snakes.

Food Webs

In a community , food chains are interlinked to form a food web.There may be two or more food chains in  a food web.

Key Ideas

 The living organisms is an ecosystem are made up of producers, consumers and decomposers.

 Prducers are mainly green plants that can manufacture food by photosyntheis.

 Consumers obtain their energy and nutrients from the organisms they feed on.

Decomposers break down dead organisms and waster matter, taking in some energy and releasing the rest to the environment.

A food chain is a series of organisms through which energy is transferred in the form of food.A food chain always begins with a producer.

A food web is made up of two or more food chains linked together.

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