Factors affecting population change

Question 1

What are Density-Dependent factors?

Answer 1

Density-Dependent: Factors that limit population growth are ones that intensify with increased populations.

Darwin’s theory of Natural
Selection states that competition for
resources will inherently limit population
size.

Question 2

What is Intraspecific competition?

Answer 2

It is when individuals of the same species compete for the same resources (food, shelter, mating).

As the population increases, so does competition, as a result the growth rate slows.

Question 3

What is an example of Intraspecific competition?

Answer 3

As a deer population reaches/exceeds carrying capacity, the amount of available food for the individuals decreases.

The stronger, fitter
individuals fare better and
have greater reproductive
success

Question 4

What are density dependent factors?

Answer 4

Predation: Predators often have a preference in prey. Prey that are more abundant become easy targets and are more likely to be eaten than individuals in smaller populations.

Destruction of habitat = prey in close range of hunters.

Question 5

What is another density dependent factor?

Question 6

What’s the Alee effect?

Answer 6

Population that are too small may also see a decrease in their per capita growth rate.

When populations are small, individuals may have trouble finding a mate = low reproductive success.

Question 7

What is loss of genetic variation?

Answer 7

A smaller population size = inbreeding which leads to and a loss of genetic variation.

Question 8

What is the minimum viable population size?

Answer 8

The Minimum Viable Population Size is the smallest number of individuals that ensures a population can persist

This MVPS must provide enough genetic variation to cope with changes in the environment.

Question 9

What is an example of Human Intervention?

Answer 9

The usage of pesticides. This can cause biomagnification. Swanson Hawks are decreasing in numbers because of the usage of pesticides.

Question 10

What is an example of Habitat destruction?

Answer 10

Habitat destruction from humans and natural disasters is another density independent growth limiting factor.

Question 11

What is a Limiting Factor?

Answer 11

Limiting Factors prevent populations from reaching their biotic potential (greatest possible growth rate).

Of all resources required by an organism, the one in shortest supply is the limiting factor.