Chapter 16.0 Biodiversity
the numbers of species in most groups of organisms—plant, animal, and perhaps
microbial—increase markedly toward the equator
diversity increases without limit over time, barring catastrophes such as meteorite
impacts that cause mass extinctions of species.
Tropics older than rest so most diverse
Second theory says thatdiversity reaches an equilibrium, new specie, specie going
geographic factors also affect species richness.
the niche relationships of species provide an informative measure of community
The more overlap the more species compete in niches
Species must be at carrying capacity (equilibrium) to be crowded and to coexist in same niche, if
not it won’t be necessary.
Nonflying mammals are no more diverse at equator than temperate regions
Temperature difference so epiphytes go to tropic, and herbivorous insects go to tropics because
more plant food
Morphology as a indicator of ecological role
Average niche greadth remains the same in communities with diff # of species
ecies diversity increases as a stream becomes larger and presents more kinds of
habitats and a greater variety and abundance of food items.
diversity appears to be correlated with temperature, ecosystem productivity,
topographic heterogeneity within a region, and the structural complexity of local
he production of new species by the splitting of evolving lineages
Species also disappear; indeed, most of the species that have ever existed are
Equilibrium theory of island biogeography.
The principle that the numb