Unit 3 Week 2 Flashcards
coherent understanding of the relationship between natural selection and genetics by 1940s
modern synthesis
used to study how selective forces change a population through changes in allele and genotypic frequencies
population genetics
rate at which a specific allele appears within a population
allele frequency
sum of all alleles in a population
gene pool
when alleles spread through every individual of a population, they become _____
fixed
allele frequencies within a population change randomly with no advantage to the population over existing allele frequencies
genetic drift
event that initiates allele frequency change in an isolated part of the population that’s not part of the original population
founder effect
states that population’s allele and genotypic frequencies are inherently stable
Hardy- Weinberg principle of equilibrium
frequencies of genotypes
genetic structure
populations consisting of two or more variations of particular characteristics
polymorphic
distribution of phenotypes among individuals
population variation
fraction of phenotype variation that we can attribute to genetic differences among individuals in a population
heritability
diversity of alleles and genotypes within a population
genetic variance
when scientists breed animals, they try to ______ the genetic variance as much as possible to keep a diverse population of the animal
increase
mating of closely related individuals that usually brings together deleterious recessive mutations that can cause abnormalities/ susceptibility to disease
inbreeding
when a family of carriers interbreed with each other and the likelihood of two carriers mating and producing diseased offspring is much higher
interbreeding depression
a specific quality driving shifts in the genotype of a population
selection pressure
large populations are _______ susceptible to the effects of genetic drift
less
natural events that kill a large portion of the population magnify genetic drift
bottleneck effect
genetic structure changes to match that of the new population’s founding parents
founder effect
flow of alleles in and out of a population due to the migration of individuals or gametes
gene flow
changes to organism’s DNA that are important drivers of diversity in populations
mutations
type of mating that includes mate choice or location based selection
nonrandom mating
an individual’s preference to mate with partners who are phenotypically similar to themselves
assortative mating
geographic separation between populations that leads to differences in the phenotypic variation between populations
geographical variation
given species’ populations vary gradually across ecological gradient
cline
when gene flow is restricted, individuals will show _______ differences in phenotype along cline
abrupt
rate at which specific genotype appears in a population
genotype frequency
the requirements of the Hardy Weinberg principle are:
- have random mating among individuals
- experiences no mutations in alleles
- be under no natural selection
- be of infinite population size
- have no gene flow
