B3

Question 1

Definition of an ecosystem

Answer 1

A unit containing of all the organisms and their environment, interacting together, in a given area

Question 2

Biodiversity

Answer 2

Number of species that live in an area

Question 3

Why do food chains usually have fewer than five trophic levels?

Answer 3

Energy loss between trophic levels—when primary consumers eat producers, only 10% of their energy is passed, same when secondary consumers eat primary ones. The rest of the energy is lost in various ways, like:
- respiration
- body heat
- waste (not all food is digested)

Hence, there is often not enough energy as you go up the trophic levels to support and maintain a species.