Evolution of Gene Pools Ib Bio

What is a gene pool

A collection of all gene types within a population

What is gene flow

Gene flow is movement between individuals and genetic materials that carry from one population to another

What are the effects of gene flow within a population

Gene flow will introduce new alleles to a population and increase genetic variation

What are the effects of gene flow across populations

Through moving around the genetic material, it can cause distant populations to share similar features, reducing chance of speiciation

What happens if there is no gene flow

If no gene flow, population will have its own gene pool

What is likely to happen if there is less gene flow between two populations

the two populations will evolve into two different species

When does allopatric speciation occur

Allopatric speciation occurs when gene flow between populations is prevented/reduced by geographic isolation.

What is allele frequency

Allele frequency is the prevalance of a specific allele out of all alleles in a gene pool

How hard is it to determine allele frequency

Almost impossible as it is difficult to obtain census from all organisms and their DNA, sampling often done through estimates

What is genetic drift

Population is altered due to random events, causes survivors to be the only ones sampled which can vary frequencies

What is the founder effect

Small group of migrants with different phenotypes establish in a new area, new area has different frequencies

What is natural selection

Different populations have different pressures acting on gene pool, maintains advantagous alleles

What are new mutations

Mutations are original source of variation, produced by change in DNA, and cause a change in the frequency relavant to a population where mutations didnt occur

What does Neo Darwinism merge with natural selection

Molecular variation in DNAs, how the variations are inherited, the different survival and reproduction of organisms, and climate change in a population over time

How do mutations alter allele frequency

Form new alleles in the group, advantagous alleles are more frequent while disadvantagous alleles are selected against

How does gene flow effect allele frequency

Depends on the number of migrants and distant population, is more likely to have a strong effect on frequencies in small populations

How does non-random mating effect allele frequency

Allows all genotypes to have an equal chance, mates are chosen based on genetic traits, is more often with close neighbors, and mates are chosen by how closely they relate

How does genetic drift effect allele frequencies

Some may leave behind less offspring due to chance, can cause rare alleles to become frequent while also causing others to disappear, noticiable in small populations

How does selection effect allele frequency

Natural selection increases frequency of advantagous trait, dominant allele is present, dominant is good trait, recessive decrease it is bad trait

what is stabilizing selection

graph increased, reduces phenotype by selecting the averages of the phenotypes

what is directional selection

graph shifts, favors individuals with phenotypes of one extreme, common in environmental change

what is disruptive selection

graph increases on extreme ends, favors individuals with phenotypes of both extremes and removes intermediate traits

What is required for a population to be in a Hardy-Weinberg condition equilibrium

population is too large to minimize changes due to chance, random mating occurs, natural selection doesnt favor between phenotypes, no new mutations, no gene flow