Biodiversity

Question 1

What are the measurable components of biodiversity?

Answer 1

genetic diversity
species diversity
ecosystem diversity

Question 2

What is genetic diversity?

Answer 2

A measure of genetic differences within and between individuals, populations and species

It is the number and frequency of all the alleles within a population

Question 3

What may happen if one population of a species dies out?

Answer 3

The species may have lost some of its genetic diversity and this may limit its ability to adapt to changing conditions

Question 4

What does species diversity comprise of?

Answer 4

The number of different species in an ecosystem (species richness)

The proportion of each species in the ecosystem (relative abundance)

Question 5

What does it mean if a community has a dominating species?

Answer 5

It has a lower species diversity than one with the same species richness but no particularly dominating species

Question 6

What does ecosystem diversity refer to?

Answer 6

The number of distinct ecosystems within a defined area

Question 7

What has led to overexploitation of some species?

Answer 7

A growing human population

eg overfishing fish to the point where it is no longer sustainable

Question 8

Can populations still recover after overexploitation?

Answer 8

They can be reduced to a low level but may still recover

Question 9

What is a population bottleneck/genetic bottleneck?

Answer 9

An evolutionary even in which a significant percentage of a population or species is killed or otherwise prevented from reproducing

Question 10

What is the impact of a population bottleneck?

Answer 10

Small populations may lose genetic variation necessary to enable evolutionary response to environmental change

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

Question 11

Can species have a naturally low genetic diversity in their population and yet remain viable?

Answer 11

yes

Question 12

What is habitat fragmentation and what can lead to it

Answer 12

It is the break up of an organism’s preferred habitat

Human activities can lead to it

Question 13

Examples of habitat fragmentation

Answer 13

-clearing forests for agriculture

-clearing forest/agriculture land for housing/industry

-building dams and flooding surrounding land

-building roads

Question 14

Impact of habitat fragmentation

Answer 14

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

This may result in a decrease in biodiversity as species may be lost

Question 15

What do more isolated fragments and smaller fragments exhibit?

Answer 15

a lower species diversity

Question 16

What happens as fragmentation increases?

Answer 16

Species diversity decreases

Question 17

What is one possible way of reducing the impact of widespread habitat fragmentation ?

Answer 17

by linking isolated fragments with habitat corridors

Question 18

What is an advantage of habitat corridors and what does this lead to?

Answer 18

They allow movement of animals between fragments, increasing access to food and choice of mates

This may lead to recolonisation of small fragments after local extinctions

Question 19

What is an introduced (non-native) species?

Answer 19

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

eg grey squirrels introduced to europe

Question 20

What is a naturalised species?

Answer 20

Species that become established within wild communities

It will be able to flourish in the new environment without human impact

Question 21

What is an invasive species?

Answer 21

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

Question 22

What may invasive species be free of?

Answer 22

The predators, parasites, pathogens and competitors that limit their population in their native habitat

Question 23

What may invasive species do to native species?

Answer 23

Prey on them
Outcompete them for resources
or hybridise with them