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Evolution moves at a snail’s pace – which study shows is a lot quicker than we thought
New collaborative research out today from the Â鶹´«Ã½ÉçÇøÈë¿Ú and a team of international scientists has discovered that evolution can happen much faster than initially thought.
Evolution is thought of as a very slow process which takes thousands or millions of years. But in this scientists have found that if the environment changes, some organisms can quickly adapt and evolve – even changing the way they function and appear.
Research into the intertidal snail littorina saxatilis, better known as the rough periwinkle, has revealed that they can evolve in as quick as three years, when placed in a new habitat.
Sussex researchers analysed the DNA of these snails over time, and identified a genetic variation that can be used to fuel an adaptive response if environments suddenly change.
These observations are evidence of the speed at which local adaption can occur and may help researchers make more accurate predictions about how species could adapt to changing climates.
Dr Sean Stankowski, Lecturer in Ecology and Evolution at the Â鶹´«Ã½ÉçÇøÈë¿Ú and co-author of the paper says:
“What we have found is that snails are not as slow as you might think. The rough periwinkles we studied were able to quickly shift their physical traits like shell size and shape.
“Instead of only measuring changes in traits, we also studied the snails DNA which contains the instructions needed to build these adaptations. We were able to use information from other populations to quite accurately predict how the DNA sequences would evolve. This study was conducted over a 30-year period, but most of the changes we observed were achieved in the first three.”
The study first began over 30 years ago, after a toxic algal bloom in Sweden in 1992 saw many of the small rocky islands, known as ‘skerrys’ wiped clean of organisms.
Swedish scientist, Professor Kerstin Johannesson (who co-authored the paper), used this as an opportunity to understand whether new organisms could adapt to life on the skerrys.
Professor Johanneson took snails from a crab-infested habitat and transplanted them onto an empty skerry. The transplanted snails initially had large, thick shells which are adaptations to make it harder for crabs to crack them open.
These snails do not do well in wave swept environments because they are heavy and get washed off the rocks easily. Wave swept environments are habitats for small hydrodynamic snails with a very thin shell, which is well suited to hanging on to the rocks.
After putting the crab-adapted snails into the wave habitat, Prof Johanneson tracked the population over time, and found that they rapidly adapted to life on the skerry. After only three years, they looked almost identical to snails found in wave habitats. Sussex researchers then found that their DNA sequences also became more ‘wave habitat-like', reflecting the spread of genetic variants that improve survival in wave-swept environments.
Dr Stankowski says:
“The Earth’s history shows that when environments change, evolution finds a way to keep life going – it's incredible the kinds of environmental challenges it's able to solve. This research is just one example of how organisms can evolve at this kind of rate, and we look forward to seeing what other observations can be made in future. A lot of people think that you can't observe evolution, but we absolutely can, it’s going on all around us.”