PRODUCERS AND CONSUMERS
ECOSYSTEMS
An ecosystem consist of a number of living organisms and their physical environment. The living organisms and their non-living environment are interrelated and interact with each other. There is a flow of energy from the non-living organisms to the living organisms. There are a number of materials cycles - that is, exchanges of materials between living and non-living parts. When we study an ecosystem we can therefore analyse its components (the structure of the ecosystem) and we can analyse its processes (the functions in the ecosystem).
There are six major components in an ecosystem:
- Inorganic substances such as carbon, nitrogen, oxygen, water, carbon dioxide etc.
- Organic compounds such as proteins, carbohydrates etc. The organic and inorganic substances in an ecosystem regulate the work of the whole system.
- Climate and other physical factors. Temperature, wind, light and rain are important physical factors. They affect all the processes in an ecosystem.
- Producers. Only green plants are able to manufacture food from simple inorganic substances. In the process known as photosynthesis green plants in the light of sun combine carbon dioxide and water and produce carbohydrates.
- Consumers. Consumers obtain their energy from green plants. Herbivores, such as cows and sheep, eat green plants but do not eat other animals. They are called primary consumers. Carnivores, such as dogs and cats, feed on other animals and are called secondary consumers.
- Decomposer, such as bacteria and fungi. Decomposers break down the tissue and excretions of other organisms. Bacteria break down the flesh of dead animals. Fungi break down plant material. They enable chemical substances to return to the physical environment.