Unit 3 Key Area 8

Question 1

What is the result of overexploitation of natural resources?

Answer 1

Populations of organisms can be reduced to very low levels however can recover.

Question 2

Explain the bottleneck effect?

Answer 2

The bottleneck effect describes the phenomenon by which small populations of organisms may lose the genetic variation required to enable the population to respond to environmental changes.

Question 3

What impact can a loss of genetic diversity have on small populations of organisms?

Answer 3

In small populations a loss in genetic diversity can cause critical issues with a species as inbreeding can result in poor reproductive rates.

Question 4

What effect has the clearing of habitats had?

Answer 4

Habitat fragmentation

Question 5

What effect does the degradation of the edges of habitat fragments have?

Answer 5

Degradation of the edges of habitat fragments has caused increased competition between members of the same species and different species as the habitat fragment gets smaller and natural resources become more scarce. This may also result in a decrease in biodiversity

Question 6

What can be said about species diversity in isolated fragments or smaller habitat fragments?

Answer 6

More isolated fragments and smaller fragments can result in a lower species diversity being exhibited.

Question 7

What can we do to remedy habitat fragmentation?

Answer 7

To remedy widespread habitat fragmentation we can set up habitat corridors to link fragments together.

Question 8

What do habitat corridors do?

Answer 8

Habitat corridors allow for movement of animals between fragments, this increases access to both food and choice of mate. Habitat corridors can lead to the repopulation of smaller fragments after local extinctions

Question 9

Define the term introduced species?

Answer 9

Species that humans have moved either intentionally or accidentally to new geographic locations

Question 10

What is meant by the term naturalised species?

Answer 10

An introduced species that has become established in wild communities.

Question 11

What is meant by the term invasive species?

Answer 11

invasive species are naturalised species that spread rapidly and eliminate native species. This reduces species diversity. Invasive species may have no natural predators to keep populations in check. They might hunt native species, or hybridise with native species.