Ecosystems — BIOLOGY STD 12 Science — Question

• Structure: The base always represents the producers or the first trophic level and the apex represents top level consumer or the last trophic level.

• Ecological pyramids are of three types:

1. Pyramid of number: The relationship between producers and consumers in an ecosystem can be represented in the form of a pyramid in terms of number called pyramid of number.

2. Pyramid of biomass: The relationship between producers and consumers in an ecosystem can be represented in the form of a pyramid in terms of biomass called pyramid of biomass.

It can be:

1. Upright, e.g., in case of grassland ecosystem;
2. Inverted, e.g., in case of pond ecosystem.

3. Pyramid of energy: The relationship between producers and consumers in an ecosystem can be represented in the form of a pyramid, in terms of flow of energy called pyramid of energy. It is always upright because energy is always lost as heat at each step.