Ecocentric

Is High-Speed Evolution an Answer to Climate Change?

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Maybe, like Al Gore, you believe we are our own worst enemies in battling climate change. You too might think politicians manufacture denial-rhetoric to appease special interest groups, that industries are stubborn and cowardly in their resistance to the facts, and that the media sees science as a playground for concocting deception and falsehood. If so, here’s some comforting news: Even as humans dither and deal and ignore the hard truth, evolution — nobody’s fool — is already hard at work preparing for a warmer, climatologically wilder world. According to a team of researchers at McGill University in Montreal, adaptation to climate change can happen on the fly, with some organisms able to make key evolutionary changes over the course of surprisingly few generations, keeping themselves and their gene-line thriving in a world that seems to be coming to pieces.

To conduct their study, the scientists worked with a go-to species often used in genetics labs: baker’s yeast. What the organism lacks in complexity it makes up in the ease with which its simple genome can be deconstructed and understood. Lead author Andrew Gonzalez and his team tracked the fate of over 2,000 populations of yeast over a period of several months. Using a long-armed robot working round the clock, they simulated environmental stresses by exposing the yeast to high concentrations of salt, pressuring them to adapt or die in the same way that climate change forces higher animals to make similar choices. By the end of the experimental period, many of the yeast colonies had indeed successfully adjusted to the high-sodium conditions, thriving in an environment that once would have killed them.

Such nimble adaptation is  known by geneticists as evolutionary rescue, and the researchers believe that the fact that the yeast do so well has hopeful implications for humans. “The same general processes are occurring whether it’s yeast or mammals,” Gonzalez said in a statement. Still, the study has some caveats.

For one thing, while adaptation that takes place over just a few months seems lightning quick, the fact is that in yeast-years, that short period represents 50 to 100 generations — with one generation giving way to the next in just 12 hours or so. In evolutionary terms that’s still fast, but if you scale things up even as far as a plant species with a generational turnover of one year, you’re still talking about a century to make the needed adaptations; whether that’s fast enough to keep up with the planet’s rapidly changing climate is hard to say. As for humans, 100 generation means a whopping two and a half millennia — by which time the glaciers would be long gone and places like Pittsburgh could be beach front.

What’s more, while saltiness was a fair stand-in for environmental stresses in the McGill experiment, it’s by no means a perfect one, something Gonzalez himself admits. “It’s a step away still from climate change, because obviously salt is not involved in climate change,” he said. Still, the study is a landmark all the same, if only because previous experiments in evolutinary rescue have been mostly theoretical — principally mathematical models. “At the end of the day,” Gonzalez says reasonably, “we can’t do the experiment with a panda or a moose.”

For now, the McGill team will be proceeding incrementally, experimenting with small multicellular organisms such as crustaceans and terrestrial arthropods, which reproduce sexually and thus bring more resources to the adaptation game. They also want to create different communities for the organisms – by introducing predators, for instance – to test the effect on evolutionary rescue.

None of this means that we can simply evolve away from the danger of climate change, nor would it be moral to try. It oughtn’t take 100 generations to fix the problem when we could adopt a sensible environmental policy in a single legislative season. All it takes is will and commitment — qualities evolution has already afforded us in abundance. Now let’s see if we have the wisdom to use them.

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