Bio chapter 21 b

These flashcards cover key terms and concepts related to the evolution of populations as discussed in the lecture.

Hardy Weinberg Equilibrium

A state where allele and genotype frequencies remain constant from generation to generation in a non-evolving population.

Allele Frequency

The proportion of a specific allele among all allele copies in a population.

Genotype Frequency

The proportion of a specific genotype among all individuals in a population.

Genetic Drift

A chance event that causes allele frequencies to fluctuate unpredictably from one generation to the next.

Founder Effect

A type of genetic drift that occurs when a small group becomes isolated from a larger population, leading to a new population with a gene pool different from the source population.

Bottleneck Effect

A type of genetic drift that occurs when a sudden environmental change reduces the population size drastically, potentially leading to loss of genetic variation.

Natural Selection

The process by which individuals with traits that confer a reproductive advantage are more likely to survive and reproduce, leading to adaptive evolution.

Directional Selection

A type of natural selection where individuals at one extreme of a phenotype range are favored.

Disruptive Selection

A type of natural selection that favors individuals at both extremes of a phenotype range over those with intermediate phenotypes.

Stabilizing Selection

A type of natural selection that favors intermediate variants and acts against extreme phenotypes.

Balancing Selection

A form of natural selection that maintains polymorphism in a population, preserving multiple phenotypic forms.

Heterozygote Advantage

When individuals who are heterozygous at a specific locus have greater fitness than both types of homozygotes.

Frequency-Dependent Selection

A form of selection where the fitness of a phenotype depends on its frequency relative to other phenotypes in the population.

Intrasexual Selection

A form of selection where individuals of one sex compete directly for mates of the opposite sex.

Intersexual Selection

A form of selection where individuals of one sex (typically females) choose their mates from the other sex.

Survival of the Fittest

A phrase that describes natural selection, referring to the idea that those best suited to their environment are more likely to survive and reproduce.

Hardy Weinberg Equation

A mathematical equation used to calculate allele and genotype frequencies in a population that is not evolving.