VPE 511: Environment and Environmental Hygiene (2+1)

Functions of Ecosystem

FUNCTIONS OF ECOSYSTEMS

• Ecosystems have various functions performed by the structural components to ensure the persistence of the system. The green leaves (producers) prepare starch and the roots absorb water and minerals from the soil.
• The solar energy is converted into chemical energy during photosynthesis. The herbivores which feed on plants are consumed by carnivores.
• The decomposers break down the complex organic materials of dead decaying matter into simpler ones which are used by producers.
• The major functional attributes of the ecosystems are as follows.
  • Trophic structure
  • Food chain
  • Food web, Ecological pyramids
  • Energy flow
  • Nutrient cycle
  • Productivity
    • Primary Production
    • Secondary Production
  • Ecosystem Regulation
  • Ecological Succession
• Trophic structure
  • The producers and consumers are arranged in the ecosystem in a definite manner and their interactions along with population size are expressed as trophic structure. The trophic structure (food) of ecosystem is based on the existence of several trophic levels.
• Food chain
  • The sequence of eating and being eaten in a ecosystem is known as Food chain. In the ecosystem , many trophic levels are connected through food chain.
  • Example: Pond Ecosystem: Here, the following food chains take place from one trophic level to other trophic levels.
  • Phytoplankton ------Zooplankton ------Small fish --Big fish ----Tuna.
  • Phytoplankton --Zooplankton ----Fish ---Bird -----Vulture.
  • Phytoplankton ----Crab ----Carnivore ---Insect ----Small fish ----Big fish ---- Crane ----Crocodile
• Grassland Ecosystem (Grazing food chain): This food chain extends from producers through hervbivores to carnivores. The following food chains are available in this ecosystem
  • Grass ------- Grasshopper -------Frog -------Snake -----Hawk.
  • Grass -----Rabbit ------Fox -----Tiger.
  • Grass -----Butterfly ------Frog ------Snake ----- Hawk
• Detritus Food Chain: This type of food chain starts with dead organic matter and passes through detritus feeding organisms in soil. This food chain does not depend upon direct solar energy.
  • Example: Dead organic matter Algae Crabs Small fish Big fish (Mangrove Ecosystem).
  • Dead organic matter Fungi Bacteria( Forest Ecosystem).

FOOD CHAIN AND TROPIC STRUCTURE