Human activity in the Anthropocene has become so remarkably influential that it is forcing other species to speed up their evolution or face extinction, and climate change is the biggest single threat, according to a recent paper by University of British Columbia theoretical biologist Sara Otto.
From swallows’ wings evolving to better dodge around buildings and traffic, to fish mouths changing shape to become harder to hook, to unfussy scavengers like coyotes and rats thriving, to less adaptable species like caribou vanishing outright, what we are witnessing is nothing less than “a reshaping of the tree of life,” said Otto, after her research was published in the UK-based Proceedings of the Royal Society B.
“Human impacts on the world are not just local,” she told The Canadian Press, in a story picked up by the CBC. “They are changing the course of evolutionary history for all species on the planet, and that’s a remarkable concept to ponder.”
CP says the paper is “replete with examples, from bird species slowly forgetting to migrate, to mosquito breeds adapted specifically to underground subway tunnels.” These changes are happening very swiftly, Otto stressed, correcting the widespread assumption that evolutionary processes invariably take millennia.
“Evolution happens really fast if the selection regimes are strong,” she explained. “We can see sometimes in plant populations evolutionary change in the course of years.”
If a species cannot evolve quickly enough to adapt to change, extinction follows.
While a degree of species loss is a natural part of the evolutionary process, CP adds, the rate of extinction matters hugely, as rapid and widespread losses mean that evolution overall has “less to work with in response to future changes.” Otto said people should be deeply concerned that current estimated extinction rates are 1,000 times higher than before humanity came on the scene.
“We’re cutting off options within species by eliminating variability, and we’re also cutting off options at the tree of life level by cutting off species,” she warned. “We’re losing the ability for evolution to bounce back.”
Species like dandelions and crows, rats and pigeons have weathered the period of rapid change so far, Otto added. Like coyotes, they’re actually thriving in the Anthropocene. But even these hardy species may be in for a bleak future.
“The biggest single human-caused evolutionary pressure is climate change,” she said. And battling it must be first on humanity’s to-do list, since “we’re going to lose a lot more species” if global temperature increases are not reined in.