bio vocab ch24

morphological species concept

definition of a species in terms of measurable anatomical criteria

ecological species concept

definition of a species in terms of ecological niche, the sum of how members of the species interact with the nonliving and living parts of their environment

prezygotic barrier

a reproductive barrier that impedes mating between species or hinders fertilization if interspecies mating is attempted.

species

a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable, fertile offspring with members of other such groups.

reproductive isolation

the existence of biological factors (barriers) that impede members of two species from producing offspring

punctuated equilibria

in fossil record, long periods of apparent stasis, in which a species undergoes little or no morphological change, are interrupted by relatively brief periods of sudden change

allopatric speciation

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

biological species concept

Definition of a species as a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring but do not produce viable, fertile offspring with members of other such groups.

hybrid zone

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

polyploidy

A chromosomal alteration in which the organism possesses more than two complete chromosome sets.

sympatric speciation

The formation of new species in a population that lives in the same geographic area

hybrid

offspring that results from the mating of individuals from two different species or from two true-breeding varieties of the same species

reinforcement

A process in which natural selection strengthens prezygotic barriers to reproduction, thus reducing the chance of hybrid formation. occur only if hybrid offspring are less fit than members of the parent species

postzygotic barrier

a reproductive barrier that prevents hybrid zygotes produced by two different species from developing into viable, fertile adults

allopolyploid

a fertile individual that has more than two chromosome sets as a result of two different species interbreeding and combining their chromosomes

autopolyploid

An individual that has more than two chromosome sets that are all derived from a single species

macroevolution

Evolutionary change above the species level. Origin of a new group of organisms through a series of speciation events and the impact of mass extinctions on the diversity of life and its subsequent recovery

microevolution

evoluntary change below the species level, a change in the allele frequencies in a population over generations

speciation

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