Lecture 4 - Competition and Predation

Question 1

When does competition occur?

Answer 1

When resources are scarce

Question 2

What is intraspecific competition?

Answer 2

Competition that occurs between members of the same species.

2. Availability of the resources determines the size of the population

Question 3

What is interspecific

Answer 3

competition occurs between members of different species.

Question 4

What is the competitive exclusion principle? (Gause law)

Answer 4

No two species can occupy the same niche indefinitely when resources are limiting

Question 5

What is a Niche?

Answer 5

Role that an organism plays in an ecosystem

Question 6

Why is it difficult to obtain reliable data for predation?

Answer 6

1. Prey is killed by predator
2. Area is huge and prey can escape
3. Scientists prefer using observation of populations in the field.

Question 7

What happens during a predator-[prey relationship? (See picture for more detail)

Answer 7

1. Predators eat their prey, therefore reducing population of prey.
2. Fewer prey left = predators start competing for food
3. With fewer predators left, fewer pray are eaten so the population increases
4. With more prey predator population begins to increase

Question 8

What is selection pressure?

Answer 8

1. Predator cycle lags behind prey cycle, population crashes hence exerting a selection pressure. (Sudden change in population)

Question 9

What is the difference between in-situ and situ

Answer 9

In-situ means to examine the phenomenon exactly in place where it occurs.
2. Situ means laboratory

Question 10

Why are predator-prey relationships difficult so study?

Answer 10

1. Predators may eat more than one type of prey
2. Other limiting factors exist e.g. lack of food, disease
3. In situ studies give complicated results