“Survival of the fittest” has popularly described evolution for
more than a century, but a new study published in the Royal
Society journal Biology Letters provides further evidence that
random genetic mutations over millions of years may also play a
powerful role. Writing online Wednesday (Oct. 3), Florida and
California scientists are the first to link the evolution of
proteins — the organic compounds that determine the structure
and function of living things — to a species’ metabolic rate.
Across species from fish to mammals, they found that rates of
protein evolution showed the same body size and temperature
dependence as metabolic rate. Specifically, their mathematical
model predicts that a 10-degree increase in temperature across
species leads to about a 300 percent increase in the
evolutionary rate of proteins, while a tenfold decrease in body
size leads to about a 200 percent increase in evolutionary
rates. “It does suggest that if there were an evolutionary arms
race between a small, hot animal and a