3- Genetic Variation and Speciation

Flashcards covering key concepts in genetic variation, population genetics, natural selection, and speciation.

Phenotypic Variation

Differences in observable traits among individuals of the same species.

Genetic Variation

Differences in DNA sequences among individuals that can result in observable variations.

Allele Frequency

The proportion of a particular allele among all alleles for a gene in a given population.

Population Genetics

The study of genetic variation within populations, and involves the examination of allele frequency changes under the influence of evolutionary processes.

Gene Pool

The combined genetic information of all the members of a particular population.

Mutation

A change in the DNA sequence that can create new alleles and thus contribute to genetic variation.

Recombination

The process by which genetic material is physically mixed during meiosis resulting in new combinations of alleles.

Germ-line Mutation

A mutation that occurs in reproductive cells and can be passed on to the next generation.

Somatic Mutation

A mutation that occurs in non-reproductive cells and cannot be passed on.

Hardy-Weinberg Equilibrium

A principle stating that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences.

Natural Selection

The process by which individuals with advantageous traits survive and reproduce more successfully than others.

Artificial Selection

The intentional reproduction of individuals with desirable traits, often used in agriculture and animal breeding.

Balancing Selection

A form of natural selection that maintains two or more alleles in a population at intermediate frequencies.

Stabilizing Selection

Natural selection that favors intermediate variants by acting against extreme phenotypes.

Directional Selection

Natural selection that favors one extreme phenotype over others.

Disruptive Selection

Natural selection that favors individuals at both extremes of the phenotypic range.

Speciation

The process by which new species arise due to genetic divergence.

Allopatric Speciation

Speciation that occurs when populations are geographically separated.

Sympatric Speciation

Speciation that occurs when populations live in the same geographic area but diverge genetically.

Vicariance

The process by which a geographic barrier arises within a population, leading to speciation.

Peripatric Speciation

Speciation that occurs when a small group from a mainland population disperses to a new location.

Molecular Clock

A method for estimating the time of divergence between species based on the rate of molecular evolution.

Co-speciation

A process where two populations speciate in response to each other, maintaining a pattern of similarity in their phylogenetic trees.

Cryptic Species

Species that are morphologically similar but genetically distinct, often discovered through DNA analysis.

Hybridization

The interbreeding of individuals from two different species resulting in hybrid offspring.

Inbreeding Depression

A reduction in fitness resulting from mating between closely related individuals.