Enviornmental selection pressures

Selective pressure

They are factors within an environment that influence a species ability to survive in that environment

Natural selection

A mechanism for evolution in which individuals best adapt to the selected pressures in their environment allowing them to survive and pass on their alleles to the nect generation

How does selection pressure effect genetic diversity?

They can reduce the genetic diversity in the gene pool since the fittest individuals live long enough to pass their alleles to next generation

Variation

Individuals in a population vary genetically

Selection advantage

Individuals best suited to selection pressure survive to reproduce

Heritability

Advantageous traits can be passed from parent to offspring

Gene flow

Involves the introduction or removal of alleles from a population due to migration or interbreeding between two populations

How does gene flow have an effect on genetic diversity?

By introducing alleles in a population they can increase the genetic variation, or decrease it by removing alleles

Genetic drift

Is the change in a population’s allele frequencies due to sudden and random occurrences

Bottleneck effect

when a large part of a population is wiped out by a random event

Founder effect

When a smaller group of a population separate and colonise a new region and start a new population

Genetic drift category and what effect does it have on genetic diversity

Bottleneck effect - decreasing

Founder effect - decreasing

Gene flow category and what effect does it have on genetic diversity

Immigration - Increasing

Emigration - Decreasing

Interbreeding - Increase