Life is faster in the temperate zone
Evolution of species is more leisurely in the tropics.
Most people tend to think of the tropics as the hottest scene on the planet when it comes to spawning new life. But Canadian zoologists have found that it is actually the world's temperate zones where new species evolve and become extinct the fastest.
Read the story here.
Comments
An interesting paper, but they don't even mention the PNAS article from last year (Wright et al) which showed that substitution rates are roughly doubled at the equators. Given that this paper is entirely based on DNA difference, the whole thing looks a bit dodgy.
Posted by: jeremy | March 18, 2007 03:14 AM
The masked tityra, cited as an example of a temperate bird in the web article, is principally neotropical in its distribution. It has been recorded just once north of the Mexican border, in Texas.
That aside, pairwise comparison of closely related temperate-tropical pairs is likely to miss most examples of recent radiations, in which the tropical representatives are usually considerably more species-rich than their temperate counterparts. An argument could be made for lower rates of extinction and taxonomic turnover outside the tropics, but that argument would have to be made for truly comparable clades.
Posted by: Les Kaufman | March 19, 2007 07:29 PM