chapter 18

Question 1

What are the differences between the interdependent community and independent community perspectives of Frederic Clements and Henry Gleason?

Answer 1

The species in interdependent communities all rely on each other for survival; species in independent communities do not rely on each other for survival

Question 2

Given that the distributions of many animals are determined by the species composition of the plant community, what might you predict about the diversity of animals in an ecotone with a more diverse ecosystem on one side and a less diverse ecosystem on the other side?

Answer 2

The amount of diversity would be higher than either ecosystem

Question 3

What did Robert Whittaker’s data on plant species composition along gradients of temperature and moisture in mountains show?

Answer 3

It provided evidence that challenged the concept of interdependent communities.

Question 4

Species richness is

Answer 4

the number of species in a community.

Question 5

The difference between log-normal abundance distributions and rank-abundance curves is

Answer 5

a rank-abundance curve orders species by abundance; a log-normal distribution groups similarly abundant species together.

Question 6

Why does an increase in total resources or number of added resources commonly lead to declines in species diversity?

Answer 6

Species diversity is usually highest at intermediate values of resources.

Question 7

At what frequency of disturbance would the most diversity be expected?

Answer 7

medium frequency

Question 8

When discussing trophic levels a guild is

Answer 8

a group of species that feed on similar items.

Question 9

Trait-mediated indirect effects

Answer 9

include effects caused by changes in the distribution or behavior of an intermediate species.

Question 10

What does it mean when a community is said to exhibit top-down control?

Answer 10

The abundance of trophic groups is determined by the presence of predators.