Lecture 2 Flashcards
What are the assumptions of the Hardy-Weinberg Equilibrium?
- No mutations
- No migration
- No selection
- Non-random mating
- Infinite population size
Is the Hardy-Weinberg Equilibrium realistic?
No.
If a population is not in Hardy-Weinberg, what is it?
The population is evolving (not individuals).
How do populations evolve?
- Mutation
- Genetic drift
- Gene flow
- Natural selection
What do the mechanisms of evolution violate?
The assumptions of Hardy-Weinberg.
What do changes in allele frequency reult in?
Multiple mechanisms for evolution acting at once.
What is the baseline for what we expect from populations?
The hardy wienberg.
What are 2 examples of mutations?
- Super vision/tetrachromy - when someone has an additional photoreceptor in the retina and can see an increased range of colors
- Super dense bones
What are the mating rituals of 2 animals?
- Penguins - Males make nests and females find the best one and males sing and females can tell who the fattest is
- Peacock - Males dance and show off their tail feathers
What is assortative mating?
When an organism chooses a mate with preference for a similar genotype or phenotype.
What is disassortative mating?
When an organism chooses a mate with preference for different genotypes or phenotypes.
What is gene flow?
The movement of genes into or out of a population. It violates the non-migration assumption of Hardy-Weinberg..
What are 2 ways gene flow can occur?
Individuals moving or gametes moving (like pollen).
What is genetic drift?
Changes in allele frequencies due to chance events. (The alleles benefit is not related)
What assumption of Hardy-Weinberg does this violate?
An infinite population size.
What can genetic drift result in?
The loss of some alleles and the fixation of others (the rise of 100% frequency).
When does genetic drift have a stronger effect?
When there is a small population.
What are 2 types of genetic drift?
- The bottleneck effect
- The founder effect
What is the bottleneck effect?
When the size of a population is reduced due to natural disasters (or any catastrophe) that leaves only a few survivors.
What is the founder effect?
When a group of individuals break of from a population and establish a new population, which is isolated from the original population.
How is the founder effect similar to the bottleneck effect?
They both result in populations that do not represent the diversity of the original, but one uses the mechanism of colonization and the other uses catastrophe.
What is the most well-known mechanism of evolution?
Natural selection.