The evolution of animals could be happening four times faster than was previously thought, according to a new study conducted by Australian National University.
The scientists have analysed the already-existing long-term datasets of genetic information of 19 different wild animal groups from across the world, and came to the realisation that the more genetic differences there are within species, the faster evolution happens.
The researchers referred to the phenomenon as the "fuel of evolution".
The team developed quantitative genetic methods to mine the datasets, and found that "additive genetic variance in relative fitness is often substantial and, on average, twice that of previous estimates".
"The method gives us a way to measure the potential speed of current evolution in response to natural selection across all traits in a population," said evolutionary ecologist Timothee Bonnet. "This is something we have not been able to do with previous methods, so being able to see so much potential change came as a surprise to the team."
The average length of each field study is about 30 years, with the longest one taking 63 years, and the shortest one concluding in 11 years. The team examined the evolutionary process of such animals as Australia's fairy-wrens, Canada's song sparrows, Tanzania's spotted hyenas and Scotland's red deer.
As this is the first study of evolution so great in scale, researchers still need more evidence to say for sure that evolution is happening faster than Charles Darwin thought.
"This research has shown us that evolution cannot be discounted as a process which allows species to persist in response to environmental change," Bonnet noted. "What we can say is that evolution is a much more significant driver than we previously thought in the adaptability of populations to current environmental changes."