9/2 Lecture: Mechanisms of Evolutionary Change

What is Evolutionary Biology?

Evolutionary theory studies the changes in genetically encoded heritable traits that can be passed down through generations.

Adaptation

advantageous traits that aid survival and reproduction increase in frequency in a population over generations

Natural selection

a mechanism of evolution that selects for individuals with certain traits because those traits make them more likely to survive and reproduce in a natural environment

Mutations

randomly occurring changes in DNA sequence that usually occur during DNA replication

creates genetic variation which is required for natural selection

Mutagens

molecules or light (like UV radiation) that cause mutations

Gene Pool

the sum of all alleles for a given gene(s)

Genetic Locus

the point on a chromosome where a given gene is located

often used interchangeably with “gene”

Describe genetic structure

A population’s allele frequency and genotype frequency, which can be calculated by analyzing the genotypes of a sample of a population

Changes in allele frequency can be measured and used to determine whether or not evolution occurred.