Energy Flow in Ecosystem

ENERGY FLOW IN ECOSYSTEM

v     All organisms must obtain a supply of energy and nutrients from their environment in order to survive.

^v   The transformations of energy in an ecosystem begin first with the input of energy from the sun.

^v   Because, it is the first step in the production of energy for living things, it is called “Primary production”.

^v   Photosynthesis -- Chemical reaction where green plants use water & carbon dioxide to store the sun’s energy in glucose.

^v   ENERGY is stored in glucose.

^v   Glucose is stored as starch in plants

^v   The majority of autotrophs are photoautotrophs that harness the energy of the sun and pass some of this energy onto consumers through feeding pathways.

^v   The energy contained within producers and consumers is ultimately passed to the decomposers that are responsible for the constant recycling of nutrients.

^v   Thus, there is a one-way flow of energy through the biotic community and a cycling of nutrients between the biotic and abiotic components of the ecosystem

^v   Energy flow cannot occur in reverse direction.

^v   Starts from autotrophs (the producer level, i.e., first trophic level) to Heterotrophs including plant eaters or Herbivores (second trophic level) and so on.

^v   The amount of energy decreases with successive trophic levels.

^v   Only About 1% of energy from the sun is used by green plants & rest remains unutilized.

^v   Similarly, there is loss of energy in each trophic level.

^v   The transfer of food energy between the organisms in an ecosystem can be tracked by constructing food chains, food webs, pyramids of numbers, biomass and energy and energy flow diagrams.