species concepts/classifications

species

a group of organisms recognized as a distinct biological unit

biological species concept

a species is a group of naturally interbreeding populations that are reproductively isolated from other groups

morphological species concept

species are identified based on physical form and structure

evolutionary species concept

a species is a lineage with its own evolutionary history and distinct identity

reproductive isolating mechanism

a biological barrier that prevents gene flow between populations

premating isolation

reproductive isolation that prevents mating or fertilization

postmating isolation

reproductive isolation that occurs after mating or fertilization

subspecies

a geographically or phenotypically distinct population within a species

speciation

the evolutionary process through which new species arise

allopatric speciation

speciation resulting from geographic separation

sympatric speciation

speciation occurring without geographic separation

parapatric speciation

speciation between neighboring populations with limited gene flow

co-speciation

speciation occurring in response to evolutionary relationships between associated organisms

ring speciation

a pattern in which neighboring populations can interbreed around a geographic barrier while populations at the ends cannot

gradualism

the idea that evolutionary change occurs gradually over long periods

polytypic

a species composed of multiple geographically or morphologically distinct populations

population

a group of individuals of the same species living in the same area

race/subspecies

a geographically defined population within a species that differs in some inherited characteristics

taxonomy

the classification and naming of organisms

homology

similarity resulting from shared ancestry

analogy

similarity resulting from similar function rather than shared ancestry

primitive/ancestral

a trait retained from an earlier ancestral form

derived

a trait that evolved more recently within a particular lineage

grade

a group of organisms sharing a similar level of organization but not necessarily forming a clade

clade

a group consisting of an ancestor and all of its descendants

generalized

a structure or behavior adapted for a broad range of functions or environments

specialized

a structure or behavior adapted for a particular function or environment