Biodiversity

Question 1

Explain how comparing DNA, mRNA and amino acid sequences can indicate relationships between organisms within a species and between species.

Answer 1

• More differences in sequences → more distantly related.
• As mutations build up over time
• More mutations cause more changes in amino acid sequences

Question 2

How can genetic diversity within or between species be measured?

Answer 2

• Comparing frequency of measurable or observable characteristics
• Comparing base sequence of DNA
• Comparing base sequence of mRNA
• Comparing amino acid sequence of a specific protein encoded by DNA and mRNA

Question 3

What is biodiversity?

Answer 3

• Variety of living organisms
• Can relate to a range of habitats, from a small local habitat to the Earth

Question 4

What is a community?

Answer 4

All populations of different species that live in an area

Question 4

What is species richness?

Answer 4

A measure of the number of different species in a community

Question 5

What does an index of diversity do?

Answer 5

Describes the relationship between:
1. The number of species in a community (species richness)
2. The number of individuals in each species (population size)

Question 6

Suggest why index of diversity is more useful than species richness

Answer 6

• Also takes into account the number of individuals in each species
• So takes into account that some species may be present in small or high numbers

Question 7

Describe how index of diversity values can be interpreted.

Answer 7

• High → many species present (high species richness) and species evenly represented
• Low → habitat dominated by one / a few species

Question 8

Explain how some farming techniques reduce biodiversity.

Answer 8

Destruction of hedgerows.
Selective Breeding.
Monocultures.
Overgrazing.
Filling in ponds and draining wetlands.

Question 9

Explain the balance between conservation and farming.

Answer 9

• Conservation required to increase biodiversity
• But when implemented on farms, yields can be reduced, reducing profit / income for farmers
  Eg. by reducing land area for crop growth, increasing competition, increasing pest population
• To offset loss, financial incentives /grants are offered

Question 10

Give examples of how biodiversity can be increased in areas of agriculture.

Answer 10

• Reintroduction of field margins and hedgerows (where farmers only grow one type of crop)
• Reduce use of pesticides
• Growing different crops in the same area (intercropping)
• Using crop rotation of nitrogen fixing crops instead of fertilisers