Introduction to Evolution

Biological evolution

change in the distribution of heritable phenotypes

Heritable phenotypes

can be passed from generation to generation

Phenotype

physical and functional characteristics of an organism

Microevolution

changes in a population’s gene pool that occurs over generations

population

a group of the same species living in the same area that are able to interact and mate with each other

Gene

specific sequence of DNA that spells out instructions to make a particular product

• What’s passed on to the offspring

Mutations

RANDOM changes in DNA sequence (only changes in egg/sperm DNA can be passed to offspring)

Sexual selection

Change due to mate preferences

Natural selection

change due to differences in survival and reproduction

Artificial selection

change due to human intervention

Requirements for evolutionary change

• Heritable variation in the phenotypes of individuals (due to genetic variation)

• A force (mechanism) of change

Mechanisms of microevolution

• movement

• ability to get a mate

• human intervention

• random events

• natural selection

Phylogenetic inheritance

Produce characteristics that vary continuously

Ex: Human height

Single gene locus

Different alleles produce distinct phenotypes

Common ancestor

Ancestral organism shared by two or more descendent lineages

• Ancestor that organisms have in common

Speciation

Lineage splitting event that produces two or more separate species