Question

(a) How is energy introduced into the ecosystem?
(b) Consider the following food chain (i) Plants → Mice → Snakes → Hawks
(ii) Plants → Mice →Hawks
If energy available at the producer level in both the food chains is 100 J, in which case will hawks get more energy as food and by how much? Justify your answer.

Answer 1

Explanation:

To answer this question it is important to discern between autrophic organisms and heterotrophic. Autotrophic organisms are essentially the introducers of energy into a system, as they power their metabolic systems to produce their own food by using the energy derived from various reduction pathways that move around electrons or set up chemical gradients—pathway like photosynthesis is a good general example, where initial excitation comes from light energy, but for organisms like sulfur reducers the initial energy comes from the redox reactions of sulfur compounds. It is the the biomass of these organisms that constitutes the bedrock of energy in an ecosystem. Heterotrophs get their energy by consuming food that is already made in the environment, and so are not part of the introduction of energy into an ecosystem, only the conversion of it.