Question

Use the graph above to answer the following question. This graph shows the population trends of five populations over time. Which statement is the best explanation for the changes in population E?

a. The decline in B and D reduced the competition for resources resulting in an increase in species E.

b. Individuals of species E immigrated into this habitat from the surrounding areas

c. Species E started eating species A because the increase in E occurs concurrently with the decrease in A

d. Species C moved into the niche previously occupied by species B resulting in an increase in species E

Answer 1

The best explanation is provided by statement A.

Competition exists between organisms that occupy the same trophic levels in a food chain. The competition is due to the fact that there is a limited number of resources available to the organisms in their habitat. It is likely that organisms B and D were competing for resources such as food and space with organism E; when B and D declined in numbers, organism E had an easier access to resources and so its population increased.