Key Concepts in Evolutionary Biology: Adaptation, Selection, and Population Genetics

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Adaptation

Change or process by which an organism or species becomes better suited to its environment.

Allele frequency

Measure of how often a specific variance of a gene is within a population, gene pool as a decimal percentage or fraction.

Artificial selection

Intentional breeding of organisms by humans to desirable physical and intentional traits.

Ecological isolation

Form of prezygotic isolation where species or populations do not interbreed because of habitat niche or other environmental resources.

Evolution

Change in heritable traits of biological populations over generations.

Fitness

Measure of an organism's ability to survive, reproduce, and pass its genes to the next generation in a specific environment.

Founder effect

Genetic drift; where a small group of individuals breaks away from a larger population to establish a new isolated colony.

Gene flow

Transfer of genetic materials between populations through the movement of individuals.

Genotype

Non-physical tree, unique genetic makeup, specific alleles, DNA sequences inherited from parents.

Hybrid mutation

Crossing of different species or populations to create offspring hybrids that possess unique traits (heterozygous).

Microevolution

Change in allele frequencies within a single population over a short period of time.

Natural selection

Process where organisms become better adapted to their environment and tend to reproduce, increases created by Charles Darwin, also known as evolution.

Normal distribution

Bell-shaped curve that shows how a trait is spread out in a population, with most around the average and a few extremes.

Isolation mechanisms

Mechanisms that prevent different species or populations from interbreeding, maintaining genetic differences.

Phenotype

Observable, measurable traits of an organism.

Population

Group of individuals of the same species living in an area capable of interbreeding.

Reproductive isolation

Mechanisms of behaviors that prevent members of two different species from producing fertile offspring.

Sexual selection

Natural selection where certain traits evolve because they improve an individual's success in obtaining mates rather than enhancing survival.

Convergent evolution

Independent development of similar traits among unrelated or distinctly related species, driven by environmental pressures.

Divergent evolution

Process where closely related species, originating from a common ancestor, evolve different traits and become increasingly different over time due to factors such as geographic isolation and adaptation to different environments.

Gene pool

All available alleles in a population.

Genetic drift

Change in frequency of an existing gene or allele in a population due to chance or random sampling.