BIOL 1001 Chapter 23 (23.1-2)

What is Microevolution?

Change in allele frequencies in a population over generations.

Do individuals evolve?

No, populations evolve.

What are Population genetics?

Study of genes and genotypes in a population.

What is a population?

Group of individuals of the same species living in the same area at the same time.

What is a Gene pool?

All alleles for all loci in a population.

What is Genetic variation?

Differences in alleles among individuals in a population.

What is Polymorphism?

Presence of two or more variations of a trait within a population.

What is a Polymorphic gene?

Gene with at least two alleles in a population.

What is a Monomorphic gene?

Gene where one allele is predominant in a population.

Most genes in healthy populations are?

Polymorphic.

Single-nucleotide polymorphism (SNP) is?

Variation caused by a change in a single nucleotide.

5 mechanisms that can change allele frequencies?

Mutation, nonrandom mating, selection, gene flow, population decrease/genetic drift.

What is Allele frequency?

Number of copies of a specific allele divided by the total number of alleles in the population.

What is Genotype frequency?

Number of individuals with a genotype divided by the total number of individuals in the population.

What is Hardy-Weinberg principle?

Equation used to determine allele frequencies in a population.

Hardy-Weinberg equilibrium?

A population where allele frequencies do not change over time.

In Hardy-Weinberg equilibrium, starting allele frequency _____ ending allele frequency.

equals.

What does Hardy-Weinberg equilibrium assume?

No evolution is occurring.

What is Hardy-Weinberg equation for allele frequencies?

p + q = 1.

What does p represent in Hardy-Weinberg?

Frequency of the dominant allele.

What does q represent in Hardy-Weinberg?

Frequency of the recessive allele.

What is the Hardy-Weinberg equation for genotype frequencies?

p² + 2pq + q² = 1.

p² represents?

Frequency of homozygous dominant genotype.

2pq represents?

Frequency of heterozygous genotype.

q² represents?

Frequency of homozygous recessive genotype.

If p = 0.8 and q = 0.2, what is p²?

0.64.

If p = 0.8 and q = 0.2, what is q²?

0.04.

If p = 0.8 and q = 0.2, what is 2pq?

0.32.

The total allele frequency in a population always equals?

1.

The total genotype frequency in a population always equals?

1.

If allele frequencies change over time, what does that indicate?

Evolution is occurring.

Conditions required for Hardy-Weinberg equilibrium?

No mutation, random mating, no migration/gene flow, large population, no natural selection.

Natural selection is NOT random because?

Beneficial alleles are favored and “sorted”.

New genetic variations arise by?

Chance/mutation.

What is Adaptation?

Genetic variation that increases survival and reproduction in a specific environment.

3 conditions required for natural selection?

Variation exists, variation is heritable, variation affects reproductive success.

What is Fitness?

Relative likelihood that a genotype contributes to the next generation.

What is Mean fitness?

Average reproductive success of a population.

Natural selection acts on the _____ but evolution occurs in the ____.

individual; population.

What is Directional selection?

Favors one extreme phenotype.

What is Stabilizing selection?

Favors intermediate phenotypes.

What is Diversifying selection?

Favors both extreme phenotypes.

What is Balancing selection?

Maintains multiple alleles in a population.

What is Gene flow?

Movement of alleles between populations.

What is a Mutation?

Ultimate source of new alleles.

What is Nonrandom mating?

Individuals choose mates based on certain traits.

Population decrease can lead to?

Genetic drift.

Hardy-Weinberg is considered the _____ hypothesis for evolution.

Null.

Why is Hardy-Weinberg useful?

It helps determine whether evolution is occurring in a population.