Evolution Flashcards
What triggers evolution?
When HWE conditions are not met
Small population (bottleneck effect, genetic drift or founder effect)
Non-Random mating occurs
Mutations to alleles
Immigration/Emigration occurs (gene flow)
Natural Selection
The more variation…
The greater the chance tha variation will provide a selective advantage in a changing environment
What is a Back Mutation?
A mutation that reverses the effect of former mutations
What is Gene Flow?
The movement of alleles from one population to another due to the migration of individuals
It increases diversity in one population but reduces diversity among population
Gene flow between human populations have increased as cultural and geographic barriers have dissolved.this has reduced genetic drift between human pops.
Non-Random mating specs
RM is common in natural populations
Individuals choose mates based on desirable physical/behavioral traits
NRM prevents individuals w/ particular phenotypes from breeding. Only individuals that mate will contribute to the gene pool of the next gen.
Inbreeding specs
Benefits; can eliminate harmful recessive alleles over time
Artificial selection is often used to produce varieties of crop tat consistently express desirable traits
What are four causes of Evolution?
Genetic Drift
Founder Effect
Bottleneck Effect
Natural Selection
What is Genetic Drift?
Random fluctuation in the allele frequency of a population due to chance
Usually involves a small breeding population
What is the Founder Effect?
Gene pool change that occurs when a few individuals start a new, isolated population
Occurs freely on islands
Human populations (Amish)
What is the Bottleneck Effect?
An event causes the death of a large proportion of the population. The rest has a different allele frequency than the og. pop. (ie. Meteor vs Dinosaurs)
Starvation, disease, natural disasters, over hunting etc.
What is Natural Selection?
Individuals that are better adapted to their environment are more likely to reproduce, and therefore will make up more of the next generation
Can occur when a mutation produces a phenotype tat gives one individual a survival advantage over another
