The raw material for evolution is much more abundant in wild animals than previously believed, according to new search from the Australian National University (ANU).
Darwinian evolution is the process by which natural selection results in genetic changes in traits that favor the survival and reproduction of individuals.
The rate at which evolution occurs depends crucially on genetic differences between individuals.
The international research team, led by ANU’s Dr Timothée Bonnet and including the University of Exeter, wanted to find out how much of this “evolutionary fuel” exists in wild animal populations.
The answer: two to four times more than previously thought.
According to Dr. Bonnet, the process of evolution described by Darwin was incredibly slow.
“However, since Darwin, researchers have identified many examples of Darwinian evolution occurring in just a few years,” Dr Bonnet said.
“A common example of rapid evolution is the peppercorn moth, which before the Industrial Revolution in the UK was predominantly white.
“With the pollution leaving black soot on trees and buildings, the black butterflies had a survival advantage because it was harder for birds to spot them.
“Because the color of butterflies determined the probability of survival and was due to genetic differences, populations in England quickly became dominated by black butterflies.”
The study is the first time that the rate of evolution has been systematically assessed on a large scale, rather than on an ad hoc basis.
The team of 40 researchers from 27 scientific institutions used studies of 19 wild animal populations from around the world.
These included beautiful faeries in Australia, spotted hyenas in Tanzania, song sparrows in Canada and red deer in Scotland.
“We needed to know when each individual was born, who they mated with, how many offspring they had and when they died,” Dr Bonnet said.
“Each of these studies lasted an average of 30 years, providing the team with an incredible 2.6 million hours of field data.
“We combined this with genetic information about each animal studied to estimate the extent of genetic differences in their ability to reproduce, in each population.”
Dr Erik Postmafrom the University of Exeter, said: “Unfortunately, the long-term future of each of these studies is uncertain, and the fact that they have been going on for so long is a testament to the dedication and persistence of generations of researchers.
“When each study began, no one could have imagined the questions they allow us to answer today, and who knows what we will learn from them in the future?”
After three years of research into tons of data, Dr. Bonnet and the team were able to quantify the extent of species changes due to genetic modifications caused by natural selection.
“The method gives us a way to measure the potential speed of current evolution in response to natural selection on all traits in a population,” Dr. Bonnet said.
“It’s something we couldn’t do with previous methods, so being able to see so many potential changes came as a surprise to the team.”
Professor Loeske Kruuk, also from ANU and now based at the University of Edinburgh, said: ‘It was a remarkable team effort which was achievable because researchers around the world were happy to share their data. in a broad collaboration.
“It also shows the value of long-term studies with detailed tracking of animal life histories to help us understand the process of evolution in nature.”
However, the researchers warn that it is too early to tell whether the actual rate of evolution is accelerating over time.
“We don’t know if species are adapting faster than before, because we don’t have a reference,” Dr Bonnet said.
“We just know that the recent potential (the amount of ‘fuel’) has been higher than expected, but not necessarily higher than before.”
According to the researchers, their findings also have implications for predictions of species adaptability to environmental change.
“This research has shown us that evolution cannot be thought of as a process that allows species to persist in response to environmental change,” Dr Bonnet said.
Dr Bonnet said that with a predicted increase in climate change at an increasing rate, there is no guarantee that these populations will be able to keep up.
“But what we can say is that evolution is a much bigger driver than we previously thought in the adaptability of populations to current environmental changes,” he said.
The research was published in the journal Science: https://doi.org/10.1126/science.abk0853
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