by Savitha C Muppala on  August 8, 2010 at 10:49 AM Environmental Health
 Predicting the Effects of Global Warming Using Comparative Physiology
Researchers and scientists are tapping into comparative physiology for forecasting the effects of global warming.

According to George N. Somero, Associate Director of Stanford University's Hopkins Marine Station, the comparative approach can provide insight into the ways in which past evolution under different climatic conditions determines a species' likelihood of survival in a warming world.

For example, thermal tolerance limits-the highest and lowest temperatures at which an organism can survive-differ among closely related species of porcelain crab: Tropical species are far more heat-tolerant than their counterparts in temperate climates.

According to Somero, "Tropical porcelain crabs, which live at high temperatures, live right near the edge of their thermal tolerance range, and they have little ability to further increase their thermal tolerance by acclimation."

Therefore, the tropical species is close to reaching the tipping point for coping with additional increases in temperature.

Thus, the tropical crabs have less of a margin for adaptation to warm climates while the temperate counterparts have more room to adapt

"Furthermore, the lessons we've learned from studying these marine crabs appear to apply not only to other marine animals, but also to terrestrial species."

The team is also looking at the role proteins play in an organism's ability to adapt to climate change.

"If proteins don't adapt, organisms will function at a sub-par level," said Somero.

The more abundant the number of adaptive sites that exist on a protein, the more easily that protein can undergo adaptive change.

Comparative studies must now determine how many different types of proteins will need to adapt to the predicted changes in temperature due to climate change and how much adaptive variation already exists in natural populations.

Genomic studies are also revealing differences among species in the sets of "tools" found in their genomic "tool kits." The news for certain species may be grim: Comparing genomes has revealed that long-term evolution at stable temperatures may have stripped certain species of their ability to adapt to warming.

"This is particularly true in the Southern Ocean, where the consequences of evolving in an extremely cold and very stable thermal environment over a period of 10 to 15 million years are dramatic," said Somero.

"The genes needed to allow these organisms to cope with rising temperatures may have been lost during evolution under stable cold conditions."

"Comparative physiological analysis thus can help us determine how a warming world will affect the structure of our ecosystems.

It will help us predict which organisms will be forced out and which will continue to thrive," he added.

Source: ANI

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