Component 1.6 - Extinction And Conservation

Question 1

What are the main reasons for species becoming endangered?

Answer 1

• Natural selection
• Habitat destruction
• Pollution
• Hunting and collecting
• Competition from domestic animals

Question 2

How does natural selection endanger species?

Answer 2

1) Human activities are causing habitats to change faster that new mutations allow species to adapt
2) Individuals adaptations are not favourable in their environment and therefore they are selected against and are less likely to breed successfully
3) Driven to extinction faster

Question 3

Describe how loss of hedgerows causes species to be threatened

Answer 3

• Hedgerows provide habitat for insects and nesting sites for birds
• Varying light intensity and water availability for plants
• Enable species to move from one area to the next maintaining biodiversity
• Consequences at higher trophies levels

Question 4

Describe how pollution contributes towards species being threatened

Answer 4

PCBs (polychlorinated biphenyls) - ingested in food and harmful to animals

Oil - can contaminate drinking water and oil washed up on beaches and is ingested by shore dwelling animals

Question 5

Describe how hunting contributes to the endangering of species

Answer 5

• Used in some traditional medical practices e.g tiger and rhino horn
• Trophy hunting
• Overfishing

Question 6

Describe how the introduction of domestic animals can endanger species

Answer 6

• Provides competition e.g rats on European ships ate dodo eggs in Madagascar

Question 7

What is conservation?

Answer 7

The sensible management of the biosphere and the enhancement of biodiversity locally

Question 8

Describe how habitat protection works as a method of conservation

Answer 8

• Protects the species that live there and act as a living gene bank
• Nature reserves
• SSSIs (sites of special scientific interest) may have legal protection and be monitored by wardens

Question 9

Describe how international cooperation has acted as a method of conservation

Answer 9

• Restricting trade e.g Ivory and whaling

- Many want international laws allowing ‘scientific whaling’ to be stopped

Question 10

Describe how sperm and seed banks are good methods of conservation

Answer 10

Sperm banks:

• Store genes of economically important animals and threatened species
• Sperm samples can be sent round the world for breeding

Seed banks:

• Maintain stocks of traditional and vulnerable varieties
• Plants grown from these seeds reproduce and another generation can be collected

Question 11

Describe how breeding programmes in zoos and botanical gardens is a good method of conservation and what this can lead to

Answer 11

• Endangered species are kept together in the hope that they breed
• Records of mating are kept so thar genetic diversity can be increased
• Following some successful breeding programmes some species are reintroduced into their former habitats

Question 12

What are the ethical reasons behind conserving animals?

Answer 12

• Each species represents a particular combination of genes and alleles
• The uniqueness of each animal is intrinsically valuable

Question 13

Describe why conservation is particularly important to man

Answer 13

1) Potential medical uses - many many medicinal drugs are synthesised by plants
2) There are potential drugs not yet discovered and therefore the extinction of plants that have not been invested is an incalculable loss.

Question 14

Describe why conservation is important to protect genes useful to species

Answer 14

• Selective breeding of plants and animals increases genetic uniformity, with the loss of rarer alleles.
• Important qualities need to be bred back into cultivated varieties but if environments are threatened this could not be possible