EVOLUTIONARY DIVERSITY

Evolution

Change in heritable traits in a population over generations

Natural selection

Process by which organisms better adapted to their environment survive and reproduce

Mutation

A change in DNA that introduces genetic variation

Gene flow

Movement of genes between populations through migration

Genetic drift

Random change in allele frequencies

Founder effect

Loss of genetic variation when a new population is established by a small group

Bottleneck effect

Reduction in genetic diversity due to a drastic population decrease

Homologous structures

Similar structures in different species due to shared ancestry

Analogous structures

Similar functions but different evolutionary origins (e.g. bat wing vs insect wing)

Convergent evolution

Independent evolution of similar traits in different lineages

Divergent evolution

Two species evolve in different directions from a common ancestor

Phylogeny

Evolutionary history and relationships among species

Phylogenetic tree

Diagram showing evolutionary relationships

Monophyletic group

A group consisting of an ancestor and all its descendants

Paraphyletic group

A group containing an ancestor and some

Polyphyletic group

A group without a common recent ancestor

Clade

A branch on the phylogenetic tree representing a monophyletic group

Speciation

The formation of new species from a common ancestor

Allopatric speciation

Speciation due to geographic isolation

Sympatric speciation

Speciation occurring within the same geographic area

Adaptive radiation

Rapid evolution of multiple species from a common ancestor to fill ecological niches

Molecular clock

Estimates evolutionary time based on DNA mutation rates

Outgroup

A species or group used for comparison when building phylogenetic trees

Node

Branch point on a phylogenetic tree showing common ancestry

Taxonomy

Science of naming and classifying organisms

Binomial nomenclature

Two-name scientific naming system (Genus + species)