How Populations Evolve

Vocabulary flashcards based on the key concepts of population evolution, genetics, and natural selection.

Population

A group of organisms of a single species occupying a particular area at the same time.

Evolution

Genetic change occurring in a population over many generations.

Microevolution

Evolutionary changes within populations.

Gene pool

The complete set of genetic information within a population.

Allele frequencies

Relative proportion of each allele in the total population.

Hardy-Weinberg Equilibrium

A condition where allele frequencies do not change over time, indicating no evolution is occurring.

Genetic mutations

Raw material for evolutionary change; occur in gametes and provide new alleles.

Gene Flow

Movement of alleles between populations through migration.

Genetic Drift

Changes in allele frequencies due to chance events.

Bottleneck Effect

A random event that prevents most individuals from entering the next generation.

Founder Effect

When a new population starts from a few individuals, leading to a different gene pool than the original population.

Nonrandom Mating

When individuals do not choose mates randomly.

Stabilizing Selection

Selection favoring intermediate phenotypes over extremes.

Directional Selection

Selection favoring one extreme phenotype over others.

Disruptive Selection

Selection favoring extreme phenotypes over intermediate ones.

Sexual Selection

Adaptive changes in males and females to enhance mating success.

Female Choice

Females select mates based on traits that improve chances of survival or attractiveness.

Male Competition

Males compete to inseminate as many females as possible.

Genetic Variability

The presence of diverse alleles in a population, crucial for adaptation.

Polymorphisms

The occurrence of two or more different phenotypes in a population.

Heterozygotes

Individuals with two different alleles for a particular gene.

Heterozygote Advantage

When heterozygotes have a survival advantage over homozygotes.

Sickle-cell disease

A genetic disorder that affects red blood cells.

Adaptive radiation

The rapid evolution of diversely adapted species from a common ancestor.

Fitness

The reproductive success of an individual relative to others in the population.

Natural Selection

The process where organisms better adapted to their environment tend to survive and produce more offspring.

Allele

Different versions of a gene that can exist at a gene locus.

Phenotype

The observable characteristics of an organism, resulting from the interaction of its genotype with the environment.

Genotype frequencies

The proportion of different genotypes in a population.

Random Mating

Mating that occurs without regard for the genetic makeup of the partners.

Selection Pressure

Environmental factors that influence which individuals survive and reproduce.

Environmental Variation

Differences in the environment that affect the traits of organisms.

Subspecies

A taxonomic category that ranks below species, usually a geographically isolated population.

Macroevolution

Evolutionary change on a large scale, such as the emergence of new species.

Evolutionary history

The historical development of evolutionary processes in a lineage.

Trait

A characteristic or feature of an organism, influenced by its genes.

Adaptive changes

Alterations in traits that improve the survival or reproduction of a species.

Selection criteria

The characteristics that determine how natural selection operates in a population.

Gene diversity

The total number of genetic characteristics in the genetic makeup of a species.

Mutation rate

The frequency at which new mutations occur in a given gene or organism.

Carriers

Individuals who have one copy of a recessive allele that does not manifest as a phenotype.

Fitness landscape

A representation of how different genotypes perform in terms of fitness.

Adaptive landscape

A visual representation of fitness peaks and valleys based on genetic traits.

Selective advantage

A genetic advantage that enhances the likelihood of survival and reproduction.

Phenotypic variation

The variation in phenotypes that can occur within individuals of a population.

Species formation

The evolutionary process by which new biological species arise.