Allele Frequencies and Population Genetics: Evolution Lecture Notes

Summary

Evolution happens in populations, not individuals. Population genetics studies how allele frequencies change. It explains how evolution works, and what causes it.

Population Genetics Basics

A population is a group of individuals that can mate and produce fertile offspring. Allele frequencies show how common each allele is in a population. The Hardy-Weinberg Theorem describes a population that is not evolving.

Evolutionary Mechanisms

Evolution happens when allele frequencies change. This can be due to natural selection, genetic drift, gene flow, or mutation. Natural selection is the main way that evolution makes populations better adapted.

Speciation and Reproductive Isolation

A species is a group of populations that can interbreed. Reproductive barriers stop different species from mixing their gene pools. There are many ways to define what a species is.

Speciation and Macroevolution

Speciation is how new species form. It can happen suddenly, or over a long time. Macroevolution is the study of big changes in evolution, like new species forming.

Key terms

allele frequency

The number of copies of an allele in a population, divided by the total number of alleles.

Hardy-Weinberg Theorem

A formula that shows how allele and genotype frequencies stay the same in a non-evolving population.

gene flow

The movement of genes into or out of a population, due to migration.

genetic drift

Random changes in allele frequencies, due to chance events.

species

A group of populations whose members can breed with each other to produce fertile offspring.

speciation

The process by which new species form.

Questions this document helps with

• What is a population in genetics?
• What causes allele frequencies to change?
• How do new species form?

Summary written with AI from the document's text.