“Once organisms get big, they have a clear ecological advantage because the physics around how they capture food become totally different,” said Simpson, assistant professor in the Department of Geological Sciences and the CU Museum of Natural History. “But the hard part for researchers has been explaining how they got big in the first place.”
In his latest study, Simpson draws on a series of mathematical equations to argue that this all-important shift may have come down to hydrodynamics—or the pursuit of a more efficient backstroke.
Roughly 750 million years ago, and for reasons that scientists are still debating, the planet became suddenly and dramatically colder—a period of time called “Snowball Earth.” To adapt to these frigid conditions, which can make swimming more difficult, small organisms like bacteria may have begun to glom together to form larger and more complex life.
Simpson still has a lot of work to do before he can prove his theory. But, the geologist said, the results could help to reveal how the ancestors of all modern multicellular life, from flowers to elephants and even people, first arose on Earth.
“By swimming together, these cells could remain small on an individual level but still produce more power,” Simpson said. “They become both bigger and faster as a group.”