Theme 4b Pt 1 Flashcards
What is a population
An interbreeding group of individuals that belong to the same species and live within a restricted geographical area
They have equal access to breeding partners
What is our null hypothesis for evolution
If evolution is change in allele frequency over time, then null is that there is no change in allele frequency over time
When does evolution not occur
When there’s no variation
When variation is not heritable
When variation is heritable but has no consequence on fitness
What are the causes of evolution
Mutations
Migration (gene flow)
Natural selection
Genetic drift (random environmental events that change allele frequency)
What is population genetics
Looking at consequences of genetics in population rather that just an individual
When did the hardy weinberg assumptions get made, why?
In 1908
To to see what will happen to a single trait in the absence of evolution
What is the first hardy weinberg assumption
A single locus with two alleles doesnt change state through generations
(No mutations, or new alleles arise in the populations)
What is the second hardy wiens berg assumption
Alleles are not added to the population,
no gene flow, migration from other populations
What is the third hardy weinberg assumption
Why and give example?
The population is infinite in theory
Eliminates effect of random stuff changing allele frequencies since the populations so big
Ex. Frequencies change by the number of matings when you have a small population (genetic drift)
What is the 4th hardy assumption
Natural selections does not effect the alleles under study
All individuals in the population have same fitness, same probability of surviving to breed, same mating and fertilization ability
What is the fifth assumption
Random mating occurs
If the allele frequency’s are constant throughout generations, the populations is ______
In equilibrium
What is probability theory
The probability of two independent events occurring together is the product of their individual probabilities
What happens due to the gametes being haploid and mixing randomly in HWE
If there is no selection at the genotype level, all of the gametes go back into gene pool for next gen
How can a population go to HWE if it’s isn’t already
One round of random mating with all other HWE conditions met causes it to go back to equilibrium
