Pyramid of Numbers

The pyramid of numbers is a graphical representation of the number of organisms at each trophic level in an ecosystem. It shows that the number of organisms decreases from lower to higher trophic levels. The pyramid can be of three types - upright, inverted, or spindle-shaped.

Pyramid of Number of Different Ecosystems

a) Pyramid of number of pond ecosystem - In the pond ecosystem, the primary producers are phytoplankton. They are consumed by small aquatic animals like zooplankton, which are in turn consumed by small fish, and so on. As we move up the trophic levels, the number of organisms decreases, resulting in a pyramid-shaped structure. However, the number of primary consumers in the pond ecosystem is not significantly higher than the number of producers.

b) Pyramid of number of grassland ecosystem - In the grassland ecosystem, the primary producers are grasses. They are consumed by herbivores like rabbits, which are in turn consumed by predators like foxes. In this ecosystem, the number of primary consumers (herbivores) is much higher than the number of producers (grasses). This results in an inverted pyramid of numbers.

c) Pyramid of number of tree ecosystem - In the tree ecosystem, the primary producers are trees. They are consumed by herbivores like deer, which are in turn consumed by predators like wolves. In this ecosystem, the number of primary consumers is much higher than the number of producers, resulting in an inverted pyramid of numbers.

d) Pyramid of number of both pond and tree ecosystems - In both the pond and tree ecosystems, the number of primary consumers is not significantly higher than the number of producers. However, in the tree ecosystem, the number of herbivores is higher than in the pond ecosystem.

Conclusion

Hence, the correct answer is option 'C' - pyramid of number of tree ecosystem. In the tree ecosystem, the number of primary consumers (herbivores) is much higher than the number of producers (trees), resulting in an inverted pyramid of numbers.

In pyramid of tree ecosystem, consumers are in greater number than producers. Thus, inverted pyramid of number is obtained.