Give reasons.

A. Energy flow through an ecosystem is ‘one way’.

B. Equilibrium is necessary in the various bio-geo-chemical cycles.

C. Flow of nutrients through an ecosystem is cyclic.

A. Sun is the only source of energy in the ecosystem. The energy in the ecosystem flows only in one direction. The energy from the sun is used by the plants to make food through photosynthesis. The energy from plants is then passed on from one organism to another in a food chain and it never returns to the sun. Thus, energy moves in one way that is from Sun to the plants, then to herbivores and then to carnivores.

B. A biogeochemical cycle is defined as cycling of materials (nutrients) through biotic components (living organisms) and abiotic components (non-living things such as soil, water). Most important biogeochemical cycles are the carbon cycle, nitrogen cycle, oxygen cycle, and the water cycle.

The producers of an ecosystem take up inorganic nutrients from their non-living environment. These nutrients changed into the biomass of the producers. Then the biomass they are utilized by the different consumers and after death and decay of producers and consumers, the nutrients are returned to the environment. Thus, there is always a state of balance in the cycling of material in the ecosystem.

C. The green plants taking energy from the sun and inorganic nutrients such as water and carbon dioxide, nitrogen from their non-living environment involving different cycles. These nutrients changed into the biomass of the producers. Then the biomass of the producers is utilized by the different consumers. After death producers and consumers, decomposers such as bacteria and fungi break down dead body into nutrients. These nutrients are returned to the non-living environment. Thus, movement of nutrients (materials) in the ecosystem is in a cyclic manner.