evolution Flashcards
natural selection
little variations in an individual can give them more chance of surviving and having lots of kids
acts on phenotype
artificial selection
natural selection done by humans on animals for traits we want
what does evolution act on
the genotypic variation of the population
what is the sum of the alleles in the pop called
gene pool
what is a local population that interbreeds
a Mendelian population
what is the frequency of both alleles added together
1
frequency of one allele+frequency of other allel= 1
how to calculate allele frequency
nbr of copies of the allele in pop/ sum of alleles in pop
homozygous for the thing you want+ heterozygous/total popoulation
how to calculate gene frequency
nbr of ppl with that genotype/ total nbr of ppl in population
what is a hardy Weinberg equilibrium
what 5 assumptions must be made
a population of sexually reproducing organisms that allele and genotype frequencies dont change from after one generation of random mating no evolution happened 1)random mating 2)large population 3)no migration 4)no mutation 5)natural selection has no effect on the allele
what is the hardy Weinberg equation
p+q=1
where p= dominant phenotype and q is recessive phenotype
p^2+2pq^2+q^2=1
where p^2 is AA 2pq^2 is Aa and q^2 is aa
go over slide 13 of evolution I dont get it
ok
when would allele frequencies stay the same year after yearq
Harvey Weinberg equilibrium
what are the evolutionary agents
mutation gene flow genetic drift nonrandom mating natural selection
its natural for things to not be random meaning there are mutated flowy drifting aliens around
What is mutation
is mutation often
its a change in the DNA it doesn’t happen often but it happens enough to be seen in the population
what is gene flow
when ppl migrate to another group
the immigrants can add alleles to the gene pool or can change the frequency of alleles present in the population.
what is genetic drift
effect on small population
effect on big population
what are the types of genetic drift
random loss of individuals and alleles they have
for a small population: it can effect the allele frequencies
for big population: sometimes the population goes through some periods of population bottleneck
2 types: founder effect, bottleneck effect
what is population bottleneck
its when something (tsunami, new predator, heat wave, etc) causes a bunch of the population to not survive and reduces the genetic variation, the next generation will have allele frequencies that reflects the survivors allele frequencies
Genetic drift
what is founder effect
its when some ppl leave the group and start a new population (not joining an existing one) the new alleles will reflect those of the ppl who pioneered
genetic drift
what is non random mating
when you prefer to mate with one type of person,
if you only mate with ppl of same phenotype then homozygous will be more present
what’s the result of natural selection, how does it happen
adaptation
one trait allows you to survive and have more kids meaning your alleles are more present in the population
what is the reproductive contribution of a phenotype compared to generations relative to the contributions of other phenotypes called
fitness
how does natural section act on quantitative variation things
quantitative variation is when many alleles on different parts of the gene
it does stabilizing, directional and disruptive selection
what is stabilizing selection
favours average individuals
its when the extremes of the population dont have kids (ex: weight at birth)
what is directional selection
it favours the individuals that are closer to one side of the mean of the population
its when one extreme has more kids (ex: long necked giraffes win more fights so they have more kids so the extreme of long necks is favoured)
genetic variation is reduced
what is disruptive selection
it favours to both sides of the mean
its when ppl at both sides of the extreme have more kids
ex: (black and white snails blend in well with the rocks)
the graph looks like an m
