“Survival of the Sluggish”? New Research on Energy and Extinction

Recent research has shown that species that use the most energy day to day are actually more likely to go extinct than metabolically “lazier” species. The study, conducted by a team of researchers based at the University of Kansas, examined 299 forms of molluscs who made the Atlantic ocean their home at some point over the last five million years and concluded that mollusc species with a higher resting metabolic rate died out faster than their more sluggish counterparts (pun intended). Professor of ecology and evolutionary biology Bruce Lieberman, who worked on the project, suggests, “the probable explanation is that things that were more sluggish or lazy had lower energy or food requirements and thus could make do with little when times were bad”. The team of researchers also found that this link between high metabolism and extinction was strongest when the species was found in a relatively small habitat, rather than being spread out.  Despite the extinction of these high-energy species, it was found that the overall metabolic rate of the community (made up of different species) remained largely unchanged over time, even as different species came and went.

So far, this research has been limited to sea molluscs, so there is no clear indication of whether the same principle is true for other types of animal in different habitats; for example vertebrates, or land-dwelling species. Lead author of the paper Luke Strotz points out that  “at the species level, metabolic rate isn’t the be-all, end-all of extinction – there are a lot of factors at play”. This is especially the case with extinction triggered by human action, such as pollution or deforestation. Nevertheless, the work of the research team could prove useful for conservationists in predicting which species are most at risk of extinction in the future, and therefore where resources should be allocated.

Students applying for Biology or Natural Sciences (B), especially those interested in ecology and conservation, might like to learn about current research on evolution and extinction. How far do you think the conclusions of this study can be applied? Is the same trend likely to hold true for mammals?