Environmental Studies(ES)

ENVIRONMENTAL STUDIES

Lesson 8: Ecosystems

Functions of an ecosystem

It involves

• Energy cycles – production and respiration rates of the community
  
• Rate of materials/nutrient cycles – bio-geo chemical cycles
  
• Food chains
  
• Diversity – interlinks between organisms
  
• Evolution
  

Thus, in any ecosystem, the structure and function are studied together.

Components of an ecosystem

From the trophic (Trophe = nourishment) stand point, an ecosystem has two components

• Autotrophic component (self-nourishing):
  The fixation of light energy, use of simple inorganic substances like carbon and water, synthesis of hexose sugars to complex substances such as polysaccharide carbohydrates (starches) and further fat and protein synthesis predominate in this component.
  
  
• Heterotrophic component (other-nourishing):
  In this component, utilization, rearrangement and decomposition of complex substances predominate. These are macro consumers such as herbivores, carnivores and omnivores (Phagotrophs) and micro consumers such as decomposers, osmotrophs and saprotrophs.
  The ecosystem is the basic functional unit in ecology, since it includes both biotic communities and Abiotic environment, each influencing the properties of the other and both necessary for maintenance of life. The two major aspects of an ecosystem are structure and function which have to be studied together.