Topic 7.2 - Populations

Question 1

What is a population? (2)

Answer 1

1) A group of organisms of the same species in a particular space at a particular time

2) That can interbreed to produce fertile offspring

Question 2

What is a gene pool?

Answer 2

All the alleles of all the genes in a population at any one time

Question 3

What is allele frequency?

Answer 3

Proportion of an allele of a gene in a gene pool (decimal or percentage)

Question 4

What does the Hardy-Weinberg principle state and what are the conditions under which the principle applies? (1+5)

Answer 4

Allele frequencies will not change from generation to generation given:

• Population is large
• No immigration / emigration (to introduce / remove alleles)
• No mutations (to create new alleles)
• No selection for / against particular alleles
• Mating is random

Question 5

What is the Hardy-Weinberg equation?

Answer 5

P^2 + 2pq + q^2 = 1

P = Frequency of one (usually dominant) allele of the gene

Q = Frequency of the other (usually recessive) allele of the gene

P^2 = Frequency of homozygous (usually dominant) genotype

2pq = Frequency of heterozygous genotype

Q^2 = Frequency of homozygous (usually recessive) genotype