Chapter 17 Key Terms
x alpha diversity
o Species diversity at the local or community scale. Compare beta diversity, gamma
x beta diversity
o The change in species number and composition, or turnover of species, as one
moves from one community to another. Compare alpha diversity, gamma
o The study of variation in species composition and diversity among geographic
x continental drift
x edge effects
o Biotic and abiotic changes that are associated with an abrupt habitat boundary
such as that created by habitat fragmentation.
o Occurring in a particular geographic location and nowhere else on Earth.
x equilibrium theory of island biogeography
o A theory proposing that the number of species on an island or in an island-like
habitat results from a dynamic balance between immigration rates and extinction
x gamma diversity
o Species diversity at the regional scale; the regional species pool. Compare beta
diversity, alpha diversity.
x local scale
o A spatial scale that is essentially equivalent to a community.
x regional scale
o A spatial scale that encompasses a geographic area where the climate is roughly
uniform and the species contained therein are often restricted to that region by
their dispersal capabilities.
x regional species pool
o All the species contained within a region; sometimes called gamma diversity.
x species±area relationship
o The relationship between species richness and area sampled.
o The replacement of one species with another over time or space.
o An approach to biogeography that explains the geographic distribution of species
in terms of events such as continental drift that result in the geographic isolation
of populations that once were connected to one another.