natural selection vocabulary

Adaptive radiation

Period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities

Allopatric speciation

 The formation of new species in populations that are geographically isolated from one another

Anagenesis

An evolutionary process in which species continue to exist and survive as an interbreeding population

Artificial selection

 The selective breeding of domesticated plants and animals to encourage the occurrence of desirable traits

Biogeography

The scientific study of the past and present geographic distributions of species

Bottleneck effect

 Genetic drift that occurs when the size of a population  is reduced, as by a natural disaster or human actions

Catastrophism

 The idea that sudden, short-lived, and violent events lead to the extinction of many organisms

Cladogenesis

An evolutionary splitting of a parent species into two distinct species, forming a group of species that includes an ancestral species and all of its descendants

Descent with modification

Diversity of life and the match between organisms and their environments arose through natural selection over time, as species adapted to their environments

Fossils

A preserved remnant or impression of an organism that lived in the past

Founder effect

Genetic drift that occurs when a few individuals become isolated from a larger population and form a new population whose gene pool composition is not reflective of that of the original population

Gene pool

The aggregate of all copies of every type of allele at all loci in every individual in a population

Genetic drift

A process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next.

Gradualism

An evolutionary process in which species experience changes in characteristics slowly and in regular increase, additions, or stages

Hardy-Weinberg equilibrium

 The state of a population in which frequencies of alleles and genotypes remain constant from generation to generation, provided that only Mendelian segregation and recombination of alleles are at work

Homologous structures

 Structures in different species that are similar because of common ancestry

Hybrid zone

A geographic region in which members of different species meet and mate, producing at least some offspring of mixed ancestry

Macroevolution

Evolutionary change above the species level

Microevolution

Evolutionary change below the species level; change in the allele frequencies in a population over generations

Natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits

Polymorphism

Two or more possibilities of a trait on a gene

Speciation

An evolutionary process in which one species splits into two or more species

Sympatric speciation

The formation of new species in populations that live in the same geographic area

Taxonomy

A scientific discipline concerned with naming and classifying the diverse forms of life

Uniformitarianism

 The scientific idea that many geologic processes take long periods to come to completion.

Vestigial organs

Organs, tissues, or cells in a body that are no longer the functional way they are in their ancestral form of the trait

Evolution

Descent with modification; the process by which species accumulate differences from their ancestors as they adapt to different environments over time; also defined as a change in the genetic composition of a population from generation to generation