How predictable is evolution?
Are changes in a species random, or do they happen because of natural selection?
During a three-year study, Utah State University geneticist Zach Gompert and colleagues around the world set out to find answers in research supported by European and Canadian grants.
They started with 25 years of field data documenting the evolution of stick insects, some of them green and some of them brown (or melanistic).
“We thought selection was the main driver here and that turns out to really be true,” explains Gompert. “But, interestingly, even though we have selection (which) is both what’s causing variation in the brown morph, the melanistic morph, and in the green versus green stripe, the difference is in one case, the case of the melanistic, there are lots of different aspects of the environment that are coming into play and that are causing selection.
“And all that complexity of interaction with the environment, that’s hard to predict. So even though you have what is essentially a deterministic process, something that if you had all the information in the universe, should be predictable, you can’t predict it very well because it’s complicated and we don’t have all the information in the universe.”
Dr. Gompert said their findings are included in the Feb. 16 issue of the journal Science.