Amazing study shows that evolution actually repeats itself: ScienceAlert

Evolution is often viewed as a stochastic process that affects a variety of traits that appear randomly through genetic variation.

So much so that if we were to turn back the clock on evolution and “restart the tape of life,” the late paleontologist Stephen Jay Gould He said suspiciously “Anything like Homo sapiens “It will develop again.”

But a new study of stick insects suggests that evolution may sometimes repeat itself in a predictable way, which may help us understand how organisms change in response to selection pressures.

Patrick Nossel, an evolutionary biologist at the French National Center for Scientific Research, and his colleagues have studied the camouflage patterns of stick insects, primarily Tima Christinai. After 30 years of field study data from 10 separate sites, they found that repetition is an essential part of stick insect evolution.

Since the 1990s, Nossel and his colleagues have been capturing flightless insects from roadsides in the mountains near Santa Barbara, California.

Three distinct varieties of T. Christina They camouflage themselves, either with white or plain green stripes to match their preferred host plants, or rarely with a darker shade. Stick insects lay eggs only once a year, so each year in the study represents a new generation of stick insects, without overlap.

With more than 32,000 insects in the network collected and catalogued, the team was able to tease apart the trends, finding that in all 10 geographically separated populations, the frequency of green and striped stick insects cycled from year to year in a predictable manner. If stripes become less common one year, they become more common the next year, and vice versa.

However, the proportion of rare, dark-colored insects blending into the forest floor has remained fairly low and stable over time.

“Our results suggest that evolution is repeatable and complex for the same trait,” Nossel and colleagues said Writing in their published paper.

These findings are reminiscent of previous studies that have tried to understand why evolution continues to make (and break) crabs, with their lateral body plans, strong shells, and huge claws. Research has also shown that other organisms, e.g Spinyback fishThey have a similar tendency to develop the same traits over and over again.

However, most of these results are from studies in one or a few populations, or short laboratory experiments that are not long enough to capture the emergence of genetic mutations that may lead to beneficial traits.

This new study returns to decades-old questions about determinism and chance in the history of life, but it could have future implications as well. Scientists are not involved in the work He thinks Understanding that evolution sometimes works in predictable ways can help researchers predict how organisms will change and thus manage populations.

But since Nossel and his colleagues have only looked T. Christina and their relatives, they can only speculate how the results might differ in other taxa or whether evolution might be similarly predictable in other parts of the animal kingdom and the plant world as well.

It sure seems like there are a heap of examples now, of moths and Butterflies for fishing, the birds, sheepAnd my deara species that follows predictable evolutionary paths, reverting to tested traits that help it survive.

The study was published in Advancement of science.