Population Genetics and Hardy-Weinberg Equilibrium Vocabulary

Vocabulary flashcards covering trait types, allele dominance relationships, population genetics definitions, and Hardy-Weinberg equilibrium conditions.

Trait or Character

A heritable feature that varies among individuals within a population.

Discrete Traits

Heritable traits controlled by one or two genes that exhibit distinct, non-overlapping phenotypic categories, such as flower color.

Quantitative Traits

Heritable traits controlled by multiple genes that exhibit a continuous spectrum of phenotypic values, such as human height or finch beak size.

Homozygous

Having two identical alleles for a specific gene controlling a character.

Heterozygous

Having two different alleles for a specific gene controlling a character, represented as $Aa$.

Complete Dominance

An allele interaction where the dominant allele completely masks the recessive allele, causing the heterozygous genotype (e.g., $Aa$) to express the dominant phenotype.

Incomplete Dominance

An allele interaction where neither allele is completely dominant, resulting in a blended or intermediate phenotype in heterozygotes (e.g., red and white flower alleles producing pink flowers).

Codominance

An allele interaction where both alleles for a gene are expressed separately and simultaneously in heterozygotes, such as in $AB$ blood type or sickle cell hemoglobin shapes.

Relative Fitness

An individual's survival and reproductive success relative to other individuals in a population, determined by how genotype and environment interact to influence phenotype.

Microevolution

A change in allele frequencies within a population over generations.

Population

A group of interbreeding individuals of the same species residing in a specific geographical location.

Gene Pool

The total genetic variation present in a population, consisting of all copies of every allele at every locus across all population members.

Hardy-Weinberg Principle

A null hypothesis baseline stating that allele and genotype frequencies in a population will remain constant over generations when only Mendelian segregation and recombination are operating.

Hardy-Weinberg Conditions

The five requirements for a population to remain in non-evolving equilibrium: no mutation, random mating, no selection, no gene flow (migration), and a very large population size.

Hardy-Weinberg Equation

The mathematical formula $p^2 + 2pq + q^2 = 1$, where $p$ is the frequency of one allele, $q$ is the frequency of the other allele, $p^2$ and $q^2$ are homozygote frequencies, and $2pq$ is the heterozygote frequency.

Criteria for Evolution by Selection

The three conditions required for natural or sexual selection to drive evolution: individuals must differ in phenotype/genotype, variation must be heritable, and variation must affect relative fitness.

Blue-Footed Booby Mating Displays

Courtship displays performed in a non-sexually dimorphic species including nuptial gifts, mirrored displays, and focusing on blue feet to evaluate mate quality.

John Muir Zion Quote

A quote regarding Zion National Park (est. 1919): "One learns that the world, though made, is yet being made. That this is still the morning of creation."