Evolutionary biology key words

Alfred Wallace

British naturalist, explorer, geographer, anthropologist, and biologist who came up with the idea of natural selection to explain evolution, joint published with Darwin

Allele

Different forms of a gene

Allopatric

The formation of a new species as a result of an ancestral population's becoming isolated by a geographic barrier.

artificial selection

Breeding organisms with specific traits in order to produce offspring with identical traits.

Charles Darwin

English natural scientist who formulated a theory of evolution by natural selection (1809-1882)

Competition

the struggle between organisms to survive in a habitat with limited resources

Continuous trait variation

gradual, measurable differences observed within a population for a specific characteristic

Descent with modification

principle that each living species has descended, with changes, from other species over time

Discrete trait variation

traits where individuals exhibit distinct, non-overlapping categories or states, rather than a continuous range of values

Divergence

The accumulation of differences between groups

DNA

A complex molecule containing the genetic information that makes up the chromosomes.

Fitness

Ability of an organism to survive and reproduce in its environment

Fossil

A trace of an ancient organism that has been preserved in rock.

Gene flow

movement of alleles from one population to another

Genetic drift

A change in the allele frequency of a population as a result of chance events rather than natural selection.

Genotype

genetic makeup of an organism

Hardy-Weinberg equilibrium

condition that occurs when the frequency of alleles in a particular gene pool remain constant over time

Heterozygous

An organism that has two different alleles for a trait

Homozygous

An organism that has two identical alleles for a trait

Hybridisation

The production of hybrids by crossing organisms of different varieties or species.

Inheritance

The process by which physical and biological characteristics are transmitted from the parent (or parents) to the offspring

Introgression

the transfer of genetic information from one species to another as a result of hybridization between them and repeated backcrossing.

Lamarckism

An evolutionary theory (proved false by Darwin) stating that species change over time by the use and disuse of structures and the inheritance of acquired traits.

Morphogenesis

The process by which an organism takes shape and the differentiated cells occupy their appropriate locations.

Mutation

A change in a gene or chromosome.

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.

Phenotype

An organism's physical appearance, or visible traits.

Polymorphism

The coexistence of two or more distinct forms in the same population.

Reproductive isolation

Separation of species or populations so that they cannot interbreed and produce fertile offspring

Speciation

Formation of new species

Species concepts

models that describe the process by which new species arise

Sympatric

The formation of a new species as a result of a genetic change that produces a reproductive barrier between the changed population (mutants) and the parent population. No geographic barrier is present.