After completion of this lesson, student must be able to:

  • Define ecosystem and describe its components.
  • Describe the dependence of humans on other plants and animals to fulfill their basic needs.
  • Describe the inter-relation between plants and animals.


Main Factors that Affects Plant and Animals.

A delicate and dynamic balance which exists between the biotic and abiotic environment is called ecosystem. Air consists of oxygen (21%), nitrogen (71%) and carbon dioxide (0.03%). Abiotic components of ecosystem consist of non-living components. This note gives us information about ecosystem and factors affecting plants and animals.


The transfer of energy and materials in the form of food from one trophic level to another trophic level by the repeated process of eating and being eaten is known as food chain. The primary source of energy for detritus food chain is dead organic matter called detritus. This note gives us information about the food chain, food web, and ecosystem services.