In today’s Academic Minute, Dr. Charles Mitchell of the University at Buffalo explores the evolutionary advantage of keeping things simple.
Charles Mitchell is the SUNY Distinguished Teaching Professor and Director of Graduate Studies in the Department of Geology at the University at Buffalo. Broadly, his research seeks to understand the evolutionary processes that have formed the world in which we live and that have given shape to its history. He holds a Ph.D. from Harvard University.
Dr. Charles Mitchell – Simple Organism and Evolutionary Security
We have this notion that change is always going to lead us to a better place, that evolution is always going to lead to something better.
Our new study on sea creatures called rhabdopleurids shows this isn’t always true. Rhabdopleurids are tiny critters that live on the ocean floor. They build small colonies and are minor players in their ecosystem.But they have lived this way for 500 million years — since before the time of the dinosaurs. And in doing so, rhabdopleurids have outlasted more elaborate descendants.
In a recent study, we looked at rhabdopleurids’ structure and form, and used these features to identify rhabdopleurids as ancestors of zooplankton that went extinct about 350 million years ago. While alive, these zooplankton evolved rapidly. They split into many new species and developed new traits. They found ways to live closer to the ocean’s surface. They took on important roles in their ecosystems.
Rhabdopleurids, in contrast, changed little. They stayed on the ocean floor, remaining inconspicuous. This humbler approach paid off: The rhadopleurids survived, while the zooplankton died off. This idea — that conservative approaches can bear rewards over time is not unique to biology. In finance, you can pick 'safe' investments and so expose your money to low risk. But the yield is low, as well: Values do not grow much. On the other hand, one can pick high-yield tech stocks like Facebook, but the risk of declines in valueis also high.
In biology, as we saw with the rhadopleurids, high speciation rates generally go hand in hand with high extinction rates, and likewise. Major players are impressive, but often brought low by mass extinction and other 'slings and arrows’ of fortune.