AP Biology Vocabulary & Roots: Ch. 24
1. allopatric speciation- The formation of new species in populations that are geographically
isolated from one another.
2. allopolyploid- A fertile individual that has more than two chromosome sets as a result of two
different species interbreeding and combining their chromosomes.
3. autopolyploid- An individual that has more than two chromosome sets that are all derived from a
single species.
4. biological species concept-Definition of a species as 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.
5. ecological species concept-A definition of species in terms of ecological niche, the sum of how
members of the species interact with the nonliving and living parts of their environment.
6. hybrid-Offspring that results from the mating of individuals from two different species or two
true-breeding varieties of the same species.
7. hybrid zone-A geographic region in which members of different species meet and mate,
producing at least some offspring of mixed ancestry.
8. macroevolution-Evolutionary change above the species level, including the origin of a new
group of organisms or a shift in the broad pattern of evolutionary change over a long period of time.
Examples of macroevolutionary change include the appearance of major new features of organisms
and the impact of mass extinctions on the diversity of life and its subsequent recovery.
9. morphological species concept-A definition of species in terms of measurable anatomical
criteria.
10. phylogenetic species concept-A definition of species as the smallest group of individuals that
share a common ancestor, forming one branch on the tree of life
11. postzygotic barrier-A reproductive barrier that prevent hybrid zygotes produced by two
different species from developing into viable, fertile adults.
12. prezygotic barrier-A reproductive barrier that impedes mating between species or hinders
fertilization if interspecific mating is attempted.
13. punctuated equilibria-In the fossil record, long periods of apparent stasis, in which a species
undergoes little or no morphological change, interrupted by relatively brief periods of sudden
change.
14. reinforcement-A process in which natural selection strengthens prezygotic barriers to
reproduction, thus reducing the chances of hybrid formation. Such a process is likely to occur only
if hybrid offspring are less fit than members of the parent species.
15. reproductive isolation-The existence of biological factors (barriers) that impede members of
two species from producing viable, fertile offspring.
16. speciation- An evolutionary process in which one species splits into two or more species.
17. 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.
18. sympatric speciation-The formation of new species in populations that live in the same
geographic area.
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Word Roots
auto- = self; poly- = many (autopolyploid: a type of polyploid species resulting from one species
doubling its chromosome number to become tetraploid)
macro- = large (macroevolution: long-term evolutionary change that produces new groups of
organisms)
post- = after (postzygotic barrier: any of several speciesisolating mechanisms that prevent hybrids
produced by two different species from developing into viable, fertile adults)
sym- = together; -patri = father (sympatric speciation: a mode of speciation occurring as a result of
a radical change in the genome that produces a reproductively isolated subpopulation in the midst of
its parent population)
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