photo: Brian Jeffrey Beggerly via flickr
Undoubtedly you've seen dire predictions about the number of plant and animal species which will be forced into extinction by global warming, their habitat changing faster than they can either adapt to it or move somewhere else. Well, a fascinating new article in Yale Environment 360 by Carl Zimmer offers a glimmer of hope -- it appears that at least some species may be able to rapidly evolve to a changing climate:The conventional view of evolution is that changes happen very slowly, and that the speed at which the climate is currently changing is far to fast for evolution to offer much hope to the estimated 25% of species which could go extinct.
But as Arthur Weis of the University of Toronto puts it, "That might be the average case, but evolution can also be very rapid under the right conditions. Climate change is going to be one of those things where the conditions are met." In fact, Weis contends life will undergo an evolutionary explosion.
We're Already Seeing Evolution Occurring
This changing view of evolution has led some researchers to look for evidence that global warming is driving evolution. William Bradshaw and Christina Holzapfel at the University of Oregon, for example, have studied a mosquito that lays its eggs inside carnivorous pitcher plants. The larvae hatch in the spring and feed on the dead insects that fall in. Bradshaw and Holzapfel have demonstrated that the mosquitoes have experienced natural selection, causing them to open sooner than they did a quarter-century ago.
In some cases, natural selection is working in a straightforward way. Weis, for example, had predicted that droughts would make field mustard plants bloom earlier. In wet years, it pays for plants to grow big before they flower, so that they can make more seeds. But in dry years, they run out of water before they can reap the benefit. Instead, earlier flowering plants have more luck. "What we saw was exactly what the theoretical model predicted," says Weis.
But We Need More Research
The article goes on to say however, that ultimately a complex array of factors is at play. In some cases it may be natural selection driving changes. In others it may just the natural plasticity of a species -- humans growing taller in industrial nations over the past 200 years due to better nutrition than their ancestors, for example. In other cases it may be a combination of both, or neither, even though one appears to be the case. In short, we need to do more research to better understand what's going on.
Not All Species Will Be Able to Change
All in all though, while some species may be able to evolve quickly enough, that doesn't mean that all, or even most, will be able to -- and for all species there very well may be a limit past which no amount of evolution will be able to save them.
Read more: First Comes Global Warming, Then an Evolutionary Explosion
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