July 27, 2009

A tanning booth for Al?

This kind of reinforces what everyone knows, as a general rule a warmer climate is better for life and biodiversity than cold weather.

FROM- Science Alert

Heat may speed up evolution

Mammal species living in the tropics are evolving faster than their counterparts living in cooler environments, according to research carried out by New Zealand researchers.

It had previously been assumed that rates of genetic change in warm-blooded animals were independent of climate.

The new study demonstrates that DNA evolution occurs substantially faster in mammal species living in warmer environments relative to those living in cooler environments.

Led by AUT University evolutionary biologist Len Gillman, the team was also made up of researchers from the School of Biological Sciences at the University of Auckland, including Dr Shane Wright, whose earlier work was highly influential in establishing differing evolution rates between plants in different climates.

In this and previous work, Wright’s research has been supported by Ngā Pae o te Māramatanga, the Māori Centre of Research Excellence.

Gillman says the rate of evolution was markedly different, and over prolonged evolutionary periods of time, this difference in evolutionary rate might account for the enormous accumulation of biodiversity in warmer areas like the tropics.

“The results show that species occupying warmer climates have almost 50 per cent more DNA evolution relative to those in cooler climates. These results come from pairs of species generally living in close proximity to each other so we would expect the effect to be far more pronounced over continental and global scales.”

Gillman’s research has also identified potential negative evolutionary consequences of scarce basic resources related to available energy supply.

Australasian marsupials in the study showed less significant increases in their rates of evolution when compared to their counterparts living in cooler climates and it is thought that this might be linked to the drought conditions in the warmer environments of Australia.

Gillman says there are indications that the slowed rates of evolution may be due to periods of hibernation or inactivity of animals living in cooler environments.

“Earlier research we carried out identified faster rates of DNA evolution in plants living in tropical regions but other scientists did not believe that climate could possibly have any bearing on mammal evolution given their constant body temperatures.”

“These results provide support for the hypothesis that high tropical species richness is caused by faster rates of evolution and speciation in warmer climates.”

The study, which is the largest of its kind, involved a comprehensive global data set that included 260 mammal species, from 10 orders and 29 families.

The research findings of Len Gillman and Shane Wright have today been published internationally in the Royal Society’s biological research journal Proceedings B.


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