7.2 Populations

Question 1

Define species

Answer 1

A group of organisms with similar features that can breed to produce fertile offspring

Question 2

Define population

Answer 2

All the organisms of a particular species that live in the same place

Question 3

Define a gene pool

Answer 3

The range of different alleles existing for a particular locus within a population

Question 3

Define allele frequency

Answer 3

The proportion of a certain allele within a gene pool, expressed as a decimal or percentage

Question 4

What is the Hardy-Weinberg principle?

Answer 4

Allows us to estimate the frequency of alleles in a population, as well as if allele frequency is changing over time

Question 5

Give the assumptions made by Hardy-Weinberg

Answer 5

• No mutations occur to create new alleles
• No migrations in or out of the population
• No selection, so alleles are all equally passed on to the next generation
• Random mating
• Large population

Question 5

Explain the Hardy-Weinberg equation for calculating allele frequency

Answer 5

• The frequencies of each allele for a characteristic must add up to 1.0.
• The equation is therefore p+q=1
• Where p= frequency of the dominant allele and q= frequency of the recessive allele

Question 6

Explain the Hardy-Weinberg equation for calculating genotype frequency

Answer 6

• The frequencies of each genotype for a characteristic must add up to 1.0
• The equation is therefore: p^2+2pq+q^2=1
• Where p^2= frequency of homozygous dominant, 2pq= frequency of heterozygous, and q^2= frequency of homozygous recessive