Quantitative Genetics and Natural Selection

This set of flashcards covers key concepts in population genetics and natural selection, aimed at helping students prepare for their exam.

Population genetics

The study of the distribution of alleles within populations and the mechanisms that can cause allele frequencies to change over time.

Discrete traits

Traits that take on distinct, separate forms and can be categorized into clear classes.

Quantitative traits

Traits for which phenotypes form a graded series between extremes, often influenced by multiple genes.

Continuous/metric traits

Traits that can take any value within a range, not limited to discrete categories.

Dichotomous traits

Traits that are classified into two distinct classes, often related to the presence or absence of a feature.

Evolutionary mechanisms

Processes like natural selection, mutation, and genetic drift that drive evolutionary change.

Natural selection

The differential survival and reproduction of individuals due to differences in phenotype.

Common ancestry

The principle that all living organisms share a common ancestor, as posited by Darwin.

Heritability

The proportion of variation in a trait that can be attributed to genetic differences among individuals.

Blending inheritance

A historical concept of inheritance where offspring are a blend of parental traits, leading to the potential loss of variation.

Particulate inheritance

Mendel’s model of inheritance that proposes traits are passed on through discrete units (alleles) that maintain their identity.

Mendel’s laws

The principles governing inheritance, including the law of segregation and the law of independent assortment.

Phenotypic plasticity

The ability of an organism to change its phenotype in response to environmental conditions.

Evolutionary synthesis

The integration of Darwin's theory of evolution with Mendelian genetics.

Background selection

Selection acting on deleterious alleles in a population that can constrain the evolution of neutral or beneficial alleles.

Directional selection

A mode of natural selection where one phenotype is favored over others, causing the allele frequency to shift in one direction.

Stabilizing selection

Natural selection that favors intermediate variants and acts against extreme phenotypes.

Disruptive selection

Selection that favors individuals at both extremes of the phenotypic range over intermediate phenotypes.

Sexual selection

A form of natural selection in which individuals with certain inherited traits are more likely than others to obtain mates.

Intrasexual selection

Competition between individuals of one sex (usually males) for mates of the opposite sex.

Intersexual selection

The process by which one sex, usually females, chooses mates based on certain traits.