New Study Suggests a Twist on Evolutionary Theory: 'Survival of the Laziest'

Wednesday, 22 August 2018 - 12:31PM
Earth
Wednesday, 22 August 2018 - 12:31PM
New Study Suggests a Twist on Evolutionary Theory: 'Survival of the Laziest'
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Image Credit: Pexels
When you find out that elephants need to eat between 200-600 pounds of food a day, or that hummingbirds have to consume half their body weight every 24 hours, you might wonder how these animals have survived for thousands of years. Well, it turns out that slow creatures with low metabolisms may have an edge over faster, fitter, or stronger creatures, at least from an evolutionary perspective: a new study from researchers at the University of Kansas claims that 'survival of the laziest' might be a new guiding principle for what animals survive extinction and which ones become footnotes on biology textbooks.

According to Luke Strotz, the lead author on the paper: "We wondered, 'Could you look at the probability of extinction of a species based on energy uptake by an organism?' We found a difference for mollusk species that have gone extinct over the past 5 million years and ones that are still around today. Those that have gone extinct tend to have higher metabolic rates than those that are still living. Those that have lower energy maintenance requirements seem more likely to survive than those organisms with higher metabolic rates."

The study focused mainly on bivalves (which include oysters, clams, mussels, and scallops) and gastropods (which include snails and slugs), partly because our fossil records of both types of animals is unusually detailed and partly because there are still a lot of living examples to study. Though animals like hummingbirds are living example that animals with high metabolisms can still survive, this study may have uncovered an underlying pattern in the evolution of various animals.

"In a sense," says Strotz, "we're looking at a potential predictor of extinction probability. At the species level, metabolic rate isn't the be-all, end-all of extinction-there are a lot of factors at play. But these results say that the metabolic rate of an organism is a component of extinction likelihood. With a higher metabolic rate, a species is more likely to go extinct. So, it's another tool in the toolbox."

The next step will be finding whether this pattern carries over to land creatures and vertebrates, so don't plan on sleeping in all week just yet.
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