The raw material for evolution is much more abundant in wildlife than we previously thought, according to new research from the Australian National University (ANU).
Darwinian evolution is the process by which natural selection results in genetic changes in traits that promote the survival and reproduction of individuals.
The rate at which evolution takes place largely depends on genetic differences between individuals.
The international research team, led by Dr Timothée Bonnet of ANU and including the University of Exeter, wanted to know how much of this “fuel of evolution” exists in wildlife populations.
The answer: two to four times more than previously thought.
According to Dr. Bonnet, the evolutionary process Darwin described was incredibly slow.
“Since Darwin, however, researchers have identified many examples of Darwinian evolution that have occurred in just a few years,” said Dr. Bonnet.
“A well-known example of rapid evolution is the pepper moth, which was predominantly white before the industrial revolution in the UK.
“Because pollution left black soot on trees and buildings, black moths had a survival advantage because it was more difficult for birds to spot them.
“Because the color of the moth determined survival and was due to genetic differences, populations in England quickly became dominated by black moths.”
The study marks the first time that the rate of evolution has been systematically evaluated on a large scale rather than on an ad hoc basis.
The team of 40 researchers from 27 scientific institutions used studies of 19 populations of wildlife from around the world.
These include beautiful fairy kings 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,” said Dr. Bonnet.
“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 degree of genetic differences in their reproductive capacity in each population.”
dr. Erik Postmafrom the University of Exeter, said: “Unfortunately, the long-term future of any of these studies is uncertain, and the fact that they have been running for as long as they have been a testament to the dedication and perseverance of generations of researchers.
“When each study began, no one could have imagined the questions they have us answering today, and who knows what we’ll learn from them in the future?”
After three years of sifting through massive amounts of data, Dr. Bonnet and team were able to quantify how many species changes occurred as a result of genetic changes caused by natural selection.
“The method gives us a way to measure the potential rate of current evolution in response to natural selection for all traits in a population,” said Dr. Bonnet.
“This is something we haven’t been able to do with previous methods, so it was a surprise for the team to see so much potential change.”
Professor Loeske Kruuk, also from ANU and now based at the University of Edinburgh, said: “This was a remarkable team effort that was achievable as researchers from around the world were eager to share their data in a large collaboration.
“It also demonstrates the value of long-term studies with detailed monitoring of animal life histories to help us understand the evolution process in the wild.”
However, the researchers caution that it’s too early to say whether the true rate of evolution is accelerating over time.
“Whether species are adapting faster than before, we don’t know, because we don’t have a baseline,” said Dr. Bonnet.
“We just know that the recent potential (the amount of ‘fuel’) is higher than expected, but not necessarily higher than before.”
According to the researchers, their findings also have implications for predictions of the adaptability of species to environmental changes.
“This research has shown us that evolution cannot be discounted as a process by which species can survive in response to environmental changes,” said Dr. Bonnet.
dr. Bonnet said that with predicted climate change set to accelerate at an increasing rate, there’s no guarantee these populations can keep up.
“But what we can say is that evolution is a much more important driver than we previously thought in the adaptability of populations to current environmental changes,” he said.
The research is published in the journal Science: https://doi.org/10.1126/science.abk0853
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