Populations and Evolution

Question 1

What is a population?

Answer 1

A group of organisms of the same species in one area at one time that can interbreed

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?

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 + q = 1

Question 6

genetic factors which explain why individuals within a population of a species may show a wide
range of variation in phenotype

Answer 6

= Mutations = primary source of genetic variation
= Crossing over between homologous chromosomes during meiosis
= Independent segregation of homologous chromosomes during meiosis
= Random fertilisation of gametes during sexual reproduction

Question 7

environmental factors which explain why individuals within a population of a species may show a wide
range of variation in phenotype

Answer 7

depends on context - eg. food availability, light intensity

Question 8

What is evolution?

Answer 8

● Change in allele frequency over time / many generations in a population
● Occurring through the process of natural selection