Speciation and Extinction

Genetic Variation

Speciation

Artificial Selection

Genetic Drift

Mutations

Due to geographic isolation

Geographic isolation of a very small population, usually on islands

Partial geographic separation of different environments

No barrier. Caused by mating habits

Farming, breeding, or lab selection of traits by humans

a trait that promotes success in the natural environment

random change in the DNA sequence giving rise to genetic variation

a driving force of changes in a population over time

humans produce desired outcomes by selective breeding

changes in a species or population over generations

populations are isolated because they breed at different times

populations do not interbreed because their courtship displays differ

populations are isolated because they breed in different habitats

matings fail because eggs and sperm are incompatible

mating fail because male and female reproductive structures are incompatible