Mechanisms of Evolutionary Change

How quickly does NS operate on populations??

DEPENDS. changes on the amount of genetic variation present and importance of that variation

What are the Strengths of Selection??

eliminates the bad variation from populations

selcetion pressure varies within the environment — can cater to whatever needs

Define Genetic Drift??

random change in allele/genotype frequencies in a population

What are the two types of genetic drift??

bottle neck

Founder

Define Bottleneck

drastic reduction in population size due to natural disasters or disease.

Define Founder Effect

when a few individuals from a larger population colonize an isolated habitat

What is the overall effect of genetic drift on genetic diversity within a population?

drift tends to drive alleles to fixation through random events within populations. drift decrease the variation within populations.

What is the overall effect of genetic drift on genetic diversity among populations?

drift increase variation among populations.

How does NS respond to mutations??

negative selection (purifying selection)

Adaptive selection

How can inbreeding occur??

individuals in a population have a greater degree of relatedness