Exam #3 - Evolution & Natural Selection

What is evolution?

Genetic change over time in a population (not individuals).

What are the five mechanisms of evolution?

Natural selection, genetic drift, gene flow, mutation, nonrandom mating.

What is fitness?

An individual’s survival and reproductive success.

What conditions are required for natural selection?

Trait variation, heritability, differential fitness, and a link between traits and fitness.

How do genetic drift and natural selection differ?

Drift is random (strongest in small populations); selection is nonrandom and fitness

What is the biological species concept?

Species are groups that can interbreed and produce fertile offspring.

What are limitations of the biological species concept?

Doesn’t apply to asexual organisms or fossils; difficult with hybrids.

What is a common ancestor?

A shared ancestral species from which two or more lineages evolved.

What does a phylogenetic tree show?

Evolutionary relationships and relative relatedness.

What indicates evolution in a population?

A change in allele frequencies over generations.

What is coevolution?

Reciprocal evolutionary change between interacting species.

What is allopatric speciation?

Speciation due to geographic isolation.

What is sympatric speciation?

Speciation without geographic separation.