Topic 2- Evolution of Populations

What is a population?

Localized group of organisms belonging to the same species

What is a species?

A group of populations whose members can interbreed and produce fertile offspring

What is population genetics?

The study of the genetic composition of populations

What was the turning point for evolutionary theory?

Population genetics

What is speciation?

The origin of new species through the accumulation of small changes maintained by reproductive isolation

What is the gene pool?

All alleles of all genes in all individuals of a population

What is gene flow?

Movement of alleles between populations

What is natural selection?

Differential success in reproducing results in adaptive alleles being passed to the next generation in greater proportions

What is genetic drift?

Random changes in a gene pool due to chance events in small populations

What are 2 causes of genetic drift?

Bottleneck effect and Founder effect

What is the bottleneck effect?

A sudden decrease in population size

What is the founder effect?

Founding of a new population by a few individuals

What is natural selection?

Not all individuals are equal in their ability to survive and reproduce

What are the three types of natural selection?

Directional stabilizing and disruptive

What is directional selection?

Shifts the frequency curve by favoring individuals at one extreme of a population

What is stabilizing selection?

Individuals who are average for a particular trait are favored

What is disruptive selection?

Favors individuals who are at extremes

What is sexual dimorphism?

Sexes exhibit obvious differences in appearance

What balances polymorphism?

Different populations may favor different morphs

What is frequency dependent selection?

Reproductive success of a morph declines if it becomes too common

What is gene flow?

Exchange of alleles between two interbreeding populations

What is immigration?

New alleles entering a population

What is emigration?

Existing alleles leaving a population

What is mutation?

Structural alteration in DNA sequence

What is nonrandom mating?

Increases the number of homozygous loci

What is interbreeding?

Individuals may mate more frequently with close neighbors

What is assortative mating?

Mating with those similar to you