Threats to Biology 3.8

Question 1

What impact does overexploitation have on genetic diversity?

Answer 1

With overexploitation, populations can be reduced to a low level but may still recover.

Question 2

Can species with a naturally low genetic diversity still be viable?

Answer 2

Some species have a naturally
low genetic diversity in their population and yet remain viable.

Question 3

What is the bottleneck effect?

Answer 3

The bottleneck effect — small populations may lose the genetic variation necessary
to enable evolutionary responses to environmental change.

Question 4

What is the impact of the bottleneck effect on small population?

Answer 4

In small populations, this loss of genetic diversity can be critical for many species, as inbreeding can result in poor reproductive rates.

Question 5

What leads to habitat fragmentation?

Answer 5

The clearing of habitats has led to habitat fragmentation.

Question 6

What happens due to the degradation of the edges of habitat fragments?

Answer 6

Degradation of the edges
of habitat fragments results in increased competition between species as the fragment becomes smaller.

Question 7

What results in a decrease of biodiversity?

Answer 7

Habitat fragmentation

Question 8

What can be used to solve widespread habitat fragmentation?

Answer 8

To remedy widespread habitat
fragmentation, isolated fragments can be linked with habitat corridors.

Question 9

What do habitat corridors allow animals?

Answer 9

The corridors allow movement of animals between fragments, increasing access to food and choice of mate.

Question 10

What may habitat corridors lead to?

Answer 10

This may lead to recolonisation of small fragments after local extinctions.

Question 11

What are introduced species?

Answer 11

Introduced (non-native) species are those that humans have moved either intentionally or accidentally to new geographic locations.

Question 12

What are naturalised species?

Answer 12

Naturalised species are introduced species that become established within wild communities.

Question 13

What are invasive species?

Answer 13

Invasive species are naturalised species that spread rapidly and eliminate native species, therefore reducing species
diversity.

Question 14

What are invasive species free of in their new habitat?

Answer 14

Invasive species may well be
free of the predators, parasites,
pathogens and competitors that limit their population in their native habitat.

Question 15

What may invasive species do to native species?

Answer 15

Invasive species may prey on native species, outcompete them for resources or hybridise
with them.