美国国家公共电台 NPR Survival Of The Sluggish: Scientists Find An Upside To A Low Metabolism（在线收听）

DAVID GREENE, HOST:

All right, let me give you a big reason to listen to this next story about a clam's metabolism - because the essential conclusion is it is better to be lazy. Here's NPR's Laura Wamsley.

LAUREL WAMSLEY, BYLINE: Luke Strotz is a paleontologist at the University of Kansas who studies extinctions. But he's not so interested in big asteroids slamming into Earth. He studies small physical differences between animals that go extinct and ones that survive. And the thing that he's really hung up on is how animals use energy, their metabolism.

LUKE STROTZ: Can we look at the metabolism of an organism and say something about the likelihood of that particular species going extinct?

WAMSLEY: He and his colleagues decided to study 5 million years of mollusks.

STROTZ: Specifically, I was looking at what are called bivalves and gastropods, which essentially are clams and snails. They go back almost to the beginnings of animal life.

WAMSLEY: Checking the metabolic rates of living clams was pretty easy. The researchers can watch their vital signs, like respiration.

STROTZ: But you can't do that for a fossil organism, obviously, because they're dead. They're not respiring anymore.

WAMSLEY: So instead, they measured their shells and used climate models to estimate the metabolic rates. The results...

STROTZ: We find that the species that have gone extinct have higher metabolic rates than the species that are still currently living.

WAMSLEY: Yep, it's survival of the sluggish. On the individual level, a higher metabolism is correlated with higher rates of mortality and cell decay.

STROTZ: That that scales up to the level of the species is probably the big finding of this study.

WAMSLEY: And it means that metabolic rate could potentially be used to predict future extinction patterns. But, he cautions, the results only apply to mollusks. So we'll have to wait for more research to see if this finding applies to vertebrates and certain couch-dwelling organisms.

Laurel Wamsley, NPR News.

(SOUNDBITE OF THE AMERICAN DOLLAR'S "CAROUSEL")