Evolution

Question 1

What is a genetic bottleneck?

Answer 1

a term is used to describe a sudden, dramatic reduction in the size of a population, leading to a decrease in the gene pool and a loss of alleles.

Question 2

What is the founder effect?

Answer 2

a term is used to describe the reduction in genetic variation which occurs when a small group of organisms is isolated from a larger population.

Question 3

What is stabilising selection?

Answer 3

a type of selection where allele frequencies remain relatively constant over a number of generations (reduces the range of phenotypes as alleles in the middle of the range are more likely to survive and reproduce).

Question 4

What is directional selection?

Answer 4

a type of selection where allele frequencies change over a number of generations, where the more extreme type are more likely to survive and reproduce.

Question 5

What is stated by the Hardy-Weinberg principle?

Answer 5

in a stable population with no disturbing factors, the allele frequencies of a gene will remain the same from one generation to the next.

Question 6

What are the conditions that must be met for the Hardy-Weinberg principle to apply?

Answer 6

• there’s no mutation, selection, or migration.
• the population is very large and genetically isolated.
• mating is random.

Question 7

What is speciation?

Answer 7

the formation of a new species by evolution.

Question 8

What is allopatric speciation?

Answer 8

the gene flow between two populations of a single species can be prevented by geographical isolation.

Question 9

What is sympatric speciation?

Answer 9

the gene flow between two populations of a single species can be prevented by mechanisms other than geographical isolation.

Question 10

Which sorts of populations will be affected more by genetic drift?

Answer 10

• smaller populations.
• populations experiencing genetic bottleneck.
• when there’s a founder effect.

Question 11

What Hardy-Weinburg equation can be used to predict allele frequency?

Answer 11

p + q = 1

Question 12

What Hardy-Weinburg equation can be used to predict genotype frequency?

Answer 12

p^2 + 2pq + q^2 = 1

Question 13

What does artificial selection do to a gene pool and what can this cause?

Answer 13

it reduces the gene pool
- can lead to accidental loss of useful alleles (e.g: disease resistance).
- can exaggerate certain traits, leading to health problems.
- can increase the incidence of genetic disease.