Bio Sem 2 Finals - Darwin

What causes the genetic variation we rely on for selective breeding?

Mutations and sexual reproduction

Where did Darwin do his important research?

Galapagos Islands

What did Darwin see on the Islands?

Different species had adaptations that matched their enviroment.

What evidence did Darwin use for proving evolution and Natural Selection?

Fossils and geographic distribution of species.

What is natural Selection?

Organisms with traits that help them survive.

What is fitness?

An organisms ability to survive and reproduce

How does “fitness” relate to Darwin?

In Darwins theory, the most fit leaves more offspring

Genotype

Genetic make up

Phenotype

Physical traits

What is disruptive selection?

Favors both extreme traits, not average.

How is distributive selection shown on a bell curve?

Bell curve with two peaks, the middle drops and both ends rise.

What is directional Selection?

Favors one extreme trait

How is directional Selection shown on a bell curve?

One tail of bell curve is stretched or shifted

What is stabilizing Selection?

Favors average traits

How is stabilizing Selection shown on a bell curve?

Taller peak around the average trait, extremes decrease

3 ways speciation may occur?

Behavioral, Geographic, and Temporal Isolation

Behavioral Isolation

Different mating behaviors

Geographic Isolation

Separated by physical barriers

Temporal Isolation

Reproduce at different times

How does natural selection work?

Works by selecting traits that improve survival.

What does natural selection act on directly?

Acts directly on phenotype