A team of researchers, led by the biology department at the University of Hawaii at Hilo, has its new study on animal biodiversity patterns on the planet featured in the Feb. 28 issue of the journal Science.
Matthew Knope, assistant professor of biology, is lead author of “Ecologically diverse clades dominate the oceans via extinction resistance,” which demonstrates that animal biodiversity in the modern oceans is best explained by lower extinction rates in animal groups that are ecologically diverse, rather than by higher origination rates, as previously predicted.
Co-authors include Andrew Bush, University of Connecticut, Luke Frishkoff, University of Texas at Arlington, Noel Heim, Tufts University, and Jonathan Payne, Stanford University.
“Animals in the oceans today are more diverse than they have ever been in the history of life on Earth and scientists have long worked to describe how they have come to be that way,” Knope said.
The study examined approximately 20,000 genera of fossil marine animals across the past 500 million years, and approximately 30,000 genera of living marine animals.
“Our findings clearly show that the most ecologically diverse animal groups are also the most dominate animals in terms of numbers of genera in the modern oceans,” Knope said. “Being a member of an ecologically flexible group makes you resistant to extinction, particular during mass extinctions, that primarily impacted ecologically homogeneous groups. The oceans we see today are filled with a dizzying array of species in groups like fishes, arthropods, and mollusks, not because they had higher origination rates than groups that are less common, but because they had lower extinction rates over very long intervals of time.”
“Understanding how biodiversity is structured, both in space and time, has always been a major focus in biology,” said Rosemary Gillespie, a professor of evolutionary biology at the University of California, Berkeley, who was not involved in the study. “A significant difficulty in doing so is that current patterns of biodiversity are dictated both by origination and extinction, and while we can infer origination rates through examination of extant biodiversity, elucidating the role of extinction is notoriously difficult. This study represents some of the most detailed and careful analyses of the fossil record to date, showing very clearly the importance of the ‘slow and steady’ development of lineages through time has been a key factor in dictating which lineages have achieved the highest diversity.”
“Perhaps the fable of the tortoise and the hare is apt in explaining marine animal diversification: some groups jumped out to an early diversity lead only to be surpassed by other groups that were more ecologically diverse and less evolutionarily volatile, with steady diversification rates and strong resistance to mass extinctions,” Knope said.
The entire study is available at bit.ly/animalbiodiversity.
