300C+Lec+9+-drift+and+gene+flow

Fitness

The ability of an individual to survive and reproduce, influencing allele frequency changes in a population.

Natural Selection

A process where organisms better adapted to their environment tend to survive and produce more offspring, acting as a filter for beneficial alleles.

Genetic Drift

Random changes in allele frequencies in a population, often more pronounced in small populations.

Gene Flow

The movement of alleles between populations due to the migration of individuals, resulting in homogenization of allele frequencies.

Mutation

The creation of new alleles through changes in DNA that can be beneficial, deleterious, or neutral to an organism.

Directional Selection

A type of natural selection that favors a change in a single direction in phenotypes or allele frequencies.

Stabilizing Selection

Natural selection that favors intermediate phenotypes and acts against extremes.

Disruptive Selection

Selection that favors extreme phenotypes and acts against average phenotypes, potentially leading to speciation.

Balancing Selection

A type of selection that maintains genetic diversity by favoring multiple alleles in a population simultaneously.

Rarity Advantage

A selective advantage for alleles that become rare, often seen when common phenotypes are targeted by predators or competitors.

Founder Effect

A phenomenon where a new population is established by a very small number of individuals from a larger population, leading to reduced genetic variation.

Bottleneck Effect

A sharp reduction in the size of a population due to environmental events or human activities, affecting genetic diversity.

Pleiotropy

The ability of a single gene to affect multiple traits, leading to genetic correlations that can constrain adaptation.

Fitness Trade-offs

Compromises in the performance of traits, where adaptations in one area can detract from performance in another.

Historical Constraints

Limitations in evolution due to the existing structures and functions inherited from ancestors.

Heterozygote Advantage

The condition where heterozygous individuals have a higher fitness than homozygous individuals, contributing to balancing selection.

Local Adaptation

The process where populations become better suited to their local environments, often influenced by genetic drift or selection.

Mean Fitness

The average fitness of individuals in a population, which can change due to natural selection or drift.

Genetic Correlation

When the selection of one trait influences the selection of another due to their genetic linkage.

Adaptive Radiation

The rapid evolution of diversely adapted species from a common ancestor in response to the availability of new habitats.

Allele Frequency

The relative frequency of an allele at a genetic locus in a population, often expressed as a proportion.