Our environment is characterized by interactions between physical or abiotic components (such as atmosphere, geology and soil) and living, biotic components (e.g. the organisms^ ecosystems). Within the biotic part of the environment, a fundamental distinction is made between plants and animals. Thus, biologists distinguish between these organisms which make their own food from simple inorganic material (autotrophic organisms) and those which require complex organic molecules already constructed from them (heterotrophic organisms).
It is important to note that:
- Heterotrophs are unable to construct their own organic molecules from a solely inorganic source and as such must feed on autotrophs in order to survive.
- The autotrophs are also known as primary producers, while the heterotrophs are consumers.
- However, through a feeding relationship, the different organisms form a food chain as see illustrated below:
The distinction according to feeding habit is an important one in ecology, as it allows for a structural classification of hierarchical structure within ecosystems. In this hierarchy, the key role is played by those organisms which contain chlorophyll (green plants) and are therefore able to make organic compounds from simple inorganic molecule by utilizing solar energy to drive the reaction. This process is called photosynthesis.
Green plants with their ability to fix solar energy form the basis of the ecosystem hierarchy, and they are eaten by other organisms which live above them in the classification (of consumers). These in turn are eaten by other organisms higher (secondary consumers) up hierarchical system. This type of hierarchy is known as the food chain. The various components of the food chain form a food web, whose food chains are linked together functionally to produce a dynamic and interacting system, the ecosystem, which is the building block of the biosphere. Food webs are indispensable in ecosystems as they allow an organism to obtain its food from more than one type of organism of the lower trophic level.
francis1897 answered the question on
February 27, 2023 at 11:11