What You Need to Know

Key Concept Diagram

The Hardy-Weinberg principle states that allele frequencies remain constant in a large, randomly mating population with no selection, mutation, or migration

Natural selection changes allele frequencies when certain alleles increase reproductive success

Genetic drift is random change in allele frequency, especially significant in small populations

A gene pool is the complete set of genetic information in a population

Speciation occurs when populations diverge genetically to the point they cannot interbreed

Key Vocabulary

Gene pool

The complete set of alleles present in a population

Genetic drift

Random changes in allele frequency due to chance events, most significant in small populations

Hardy-Weinberg equilibrium

The theoretical state of a population where allele frequencies remain constant between generations

Speciation

The evolutionary process by which new species arise from existing species

Knowledge Check

Select the correct answer for each question. Click "Check Answer" to see if you are right.

Question 1

The Hardy-Weinberg principle assumes:

Populations under constant natural selection Small populations with high mutation rates Large populations with no selection, mutation, or migration Only asexually reproducing organisms

Question 2

Genetic drift is most significant in:

Very large populations Populations with no mutations Sexually reproducing populations only Small isolated populations

Question 3

Natural selection changes allele frequencies by:

Favouring alleles that increase reproductive success Causing random mutations Ensuring equal reproduction of all individuals Increasing population size

Population Genetics