According to a report in Phys.org, “A University of Leed’s-led study, published in the journal Ecology Letters, overturns the common assumption that evolution only occurs gradually over hundreds of thousands of years.”
Here’s what Leed’s researchers discovered:
Researchers found significant genetically transmitted changes in laboratory populations of soil mites in just 15 generations, leading to a doubling of the age at which the mites reached adulthood and large changes in population size. The results have important implications in areas such as disease and pest control, conservation and fisheries management because they demonstrate that evolution can be a game-changer even in the short-term.
Professor Tim Benton, of the University of Leeds’ Faculty of Biological Sciences, said: “This demonstrates that short-term ecological change and evolution are completely intertwined and cannot reasonably be considered separate. We found that populations evolve rapidly in response to environmental change and population management. This can have major consequences such as reducing harvesting yields or saving a population heading for extinction.”
Although previous research has implied a link between short-term changes in animal species’ physical characteristics and evolution, the Leeds-led study is the first to prove a causal relationship between rapid genetic evolution and animal population dynamics in a controlled experimental setting. The researchers worked with soil mites that were collected from the wild and then raised in 18 glass tubes. Forty percent of adult mites were removed every week from six of the glass tubes. A similar proportion of juveniles were removed each week in a further six tubes, while no “harvesting” was conducted in the remaining third of the tubes.
Lead author Dr Tom Cameron, a postdoctoral Fellow in the Faculty of Biological Sciences at Leeds at the time of the research and now based in Umeå University, Sweden, said: “We saw significant evolutionary changes relatively quickly. The age of maturity of the mites in the tubes doubled over about 15 generations, because they were competing in a different way than they would in the wild. Removing the adults caused them to remain as juveniles even longer because the genetics were responding to the high chance that they were going to die as soon as they matured. When they did eventually mature, they were so enormous they could lay all of their eggs very quickly.”
The study entitled, “Eco-evolutionary dynamics in response to selection on life-history,” can be accessed and read in full at Wiley Online Library.
The following is from the abstract of this study:
Understanding the consequences of environmental change on ecological and evolutionary dynamics is inherently problematic because of the complex interplay between them. Using invertebrates in microcosms, we characterise phenotypic, population and evolutionary dynamics before, during and after exposure to a novel environment and harvesting over 20 generations. We demonstrate an evolved change in life-history traits (the age- and size-at-maturity, and survival to maturity) in response to selection caused by environmental change (wild to laboratory) and to harvesting (juvenile or adult). Life-history evolution, which drives changes in population growth rate and thus population dynamics, includes an increase in age-to-maturity of 76% (from 12.5 to 22 days) in the unharvested populations as they adapt to the new environment. Evolutionary responses to harvesting are outweighed by the response to environmental change (~ 1.4 vs. 4% change in age-at-maturity per generation). The adaptive response to environmental change converts a negative population growth trajectory into a positive one: an example of evolutionary rescue.