Foundations
The ultimate evolutionary force that creates all new alleles.
Mutation
The type of selection that favors intermediate phenotypes, reducing genetic variation.
Stabilizing Selection
The name for a change in allele frequency due to chance events, particularly in small populations.
Genetic Drift
The type of speciation that occurs without a geographic barrier.
Sympatric Speciation
The most inclusive (broadest) taxonomic level.
Domain
The geological concept, proposed by James Hutton, that suggests profound change results from slow, continuous processes.
Gradualism
The two components of Binomial Nomenclature used to name a species.
Genus and Species
The specific effect of genetic drift that occurs when a few individuals move to a new, isolated area.
Founder Effect
The type of speciation that occurs when a few individuals move to a new area and become isolated.
Allopatric Speciation
The concept on a phylogenetic tree that represents where a single lineage diverged into two or more distinct new ones.
Branch Point or Node
What is the overall change in a population's genetic composition over generations called?
Evolution
The type of selection that favors multiple extreme phenotypes while selecting against the intermediate ones.
Diversifying Selection
The condition described by the p^2 + 2pq + q^2 = 1 equation.
Hardy-Weinberg Equilibrium
The pre-zygotic barrier that prevents mating because two species are active or breed during different times of the day or year.
Temporal Isolation
A group that includes a single common ancestor and all of its descendants.
Clade
The term for structures that have similar function but do not share a recent common ancestor, such as a bird's wing and a butterfly's wing.
Analogous Structures or Homoplasy
The term for an individual's reproductive success in its environment.
Fitness
The evolutionary force that counteracts genetic drift and maintains genetic variation across populations.
Gene Flow or Migration
The rapid formation of many new species from a single ancestor to fill vacant ecological niches, often observed on islands.
Adaptive Radiation
What a Basal Taxon represents on a phylogenetic tree.
Early-Evolving Lineage or Unbranched Lineage
The three domains of life as recognized by the Linnaean system.
Bacteria, Archaea, Eukarya
The main observation made by Darwin and Wallace that is summarized as "more offspring are produced than can survive" which created a scenario for natural selection to operate
Competition
The mechanism of Horizontal Gene Transfer where DNA is transferred between prokaryotes using a pilus.
Conjugation
The post-zygotic barrier where the first generation hybrid is viable, but subsequent generations are weak or infertile.
Hybrid Breakdown
Name, in order from broadest to most specific, the eight main levels of taxonomic classification.
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species