Evolution as "survival of the laziest"?

Published 2018-09-18

Photo: University of Kansas

Evolution by natural selection is often described as “survival of the fittest”, but a new study suggests that some organisms may have a different evolutionary strategy for success: laziness. In the journal, Proceedings of the Royal Society B, researchers provide evidence that species with lower energy requirements may be less likely to go extinct.

In the study, the researchers analyzed the metabolic rates of 299 species of bivalves and gastropods in the Western Atlantic, both extinct and extant. They found that during a 5-million-year period, high metabolic rates (basal metabolic rates) were a significant predictor of extinction risk. To analyze these large-scale evolutionary trends, researchers needed a large data set. Ranging from the Pliocene period to recent species, they accomplished this by calculating metabolic rates using body size from museum collections and temperature data from climate models. In addition, the risk of extinction was elevated when the species had a smaller habitat range, indicating that range size may also play a role in the long-term survival of a species.

The next step is to determine whether these trends apply to other groups of organisms, both marine and otherwise. Factors that influence the extinction of a species are complicated and it is likely that metabolic rate is not the only predictor of extinction risk. Although the topic is complex, it provides important information on mechanisms of species survival and helps improve predictions on the likelihood of extinction of threatened species today. These results pose interesting and relevant questions on the future of extant species today, as global climate change may shift species range and influence their energetic demand as the environment changes.