Biology 9700/21 — October/November 2010

Complete the passage with the most appropriate term.

Within each ecosystem there is a ................................... of organisms that interact with each other and with their environment. Each species fills a particular ................................... within the ecosystem. Feeding relationships in food webs are an example of the interactions species have with each other. In old field ecosystems in North America, producers, such as blue grass, provide energy for grazing animals. These animals form the ................................... ................................... ................................... in the food chain.

Very little of the energy consumed by grazing animals is available to carnivores.

State two reasons why this is so.

1. ______

2. ______