Wednesday, November 01, 2006
Why are there more species in the tropics than in the temperate regions of the globe? Many of the world's species live in the tropics (perhaps more than half), but the reason has been debated for more than 100 years.
Many researchers have hypothesized that climatic factors somehow cause species to originate more quickly in tropical regions. In a paper appearing in the November issue of The American Naturalist, John Wiens (homepage) and a group of researchers from Stony Brook University have shown that, contrary to expectations, species seem to evolve at similar rates in tropical and temperate regions. What causes the difference in species numbers between tropical and temperate regions is not something special about the tropics that leads to more rapid speciation, but rather that the temperate areas were colonized more recently, leaving less time for species to originate and accumulate in these regions.
Continued at "Evolution: More species in the tropics because species have been there longer"
Based on the open access paper "Evolutionary and Ecological Causes of the Latitudinal Diversity Gradient in Hylid Frogs: Treefrog Trees Unearth the Roots of High Tropical Diversity" (Full Text)
[Climate, Ecology, E.O.]
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