Unit 4

Question 1

Explain what is meant by genetic diversity (1)

Answer 1

The difference in DNA/alleles in a species population

Question 2

Species richness and an index of diversity can be used to measure biodiversity with a community. What is the difference between these to measures of biodiversity? (1)

Answer 2

Species richness measures only the number of different species, not number of individuals.

Question 3

Suggest one economic argument for maintaining biodiversity (1)

Answer 3

Some species may be important for medical uses or tourism

Question 4

Explain what is meant by a quaternary structure (1)

Answer 4

More than one polypeptide chain

Question 5

Suggest one ethical argument for maintaining biodiversity (1)

Answer 5

To prevent extinction of some species and save these organisms for future generations

Question 6

Describe how comparisons of biological molecules in species could be used to find out if they are closely related (6)

Answer 6

• Compare DNA
• Compare sequences of bases
• Compare sequences of amino acids
• Inject (animals) protein/serum into (other animal)
• Obtain antibodies
• Add protein from other animal
• Amount of precipitate indicates relationship

Question 7

Give two ways in which courtship behaviour increases he probabiity of successful mating (2)

Answer 7

• Recognition of same species stimulates release of gametes
• Recognition of opposite gender
• Indication of fertility

Question 8

Explain what is meant by stabilising selection and describe the circumstances under which it takes place (5)

Answer 8

• occurs in an unchanging environment
• selection against extremes
• species diversity is reduced
• increasing proportion of populations becomes well adapted to the environment

Question 9

Suggest reasons why populations might show very low levels of genetic diversity (3)

Answer 9

• Hunting
• Inbreeding
• Population might have been small
• Founder effect

Question 10

Explain how a larger body size is an adaptation to a colder climate (2)

Answer 10

• Larger organisms have a smaller SA:V

- less heat loss

Question 11

How do you work out species richness? (1)

Answer 11

• Take random samples of a community

- Count the number of different species

Question 12

What is the order of Taxonomic rank?

Answer 12

• Domain
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

Question 13

What is a species? (2)

Answer 13

Similar organisms that can breed to produce fertile offspring

Question 14

What two measurements are needed to calculate an index of diversity (2)

Answer 14

• no. of individuals of each species

- total no. of number of species