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Scientists Observe 'Fastest' Evolution; Tiny Fish Evolved To Tolerate Colder Temperature In Three Years

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GUELPH, Ontario -- University of British Columbia researchers have observed one of the fastest evolutionary responses ever recorded in wild populations. In as little as three years, stickleback fish developed tolerance for water temperature 2.5 degrees Celsius lower than their ancestors.

The study, published in the current issue of the Proceedings of the Royal Society B, provides the some of the first experimental evidence that evolution may help populations survive effects of climate change.

Measuring three to 10 centimeters, stickleback fish originated in the ocean but began populating freshwater lakes and streams following the last ice age. Over the past 10,000 years, marine and freshwater sticklebacks have evolved different physical and behavioral traits, making them ideal models for Darwin's natural selection theory.

"By testing the temperature tolerance of wild and lab-raised sticklebacks, we were able to determine that freshwater sticklebacks can tolerate lower temperatures than their marine counterparts," says lead author Rowan Barrett from the UBC Department of Zoology. "This made sense from an evolutionary perspective because their ancestors were able to adapt to freshwater lakes, which typically reach colder temperatures than the ocean."

To learn how quickly this adaptation took place, Barrett and colleagues from Switzerland and Sweden "recreated history" by transplanting marine sticklebacks to freshwater ponds and found that in as little as three generations (or three years), they were able to tolerate the same minimum temperature as freshwater sticklebacks, 2.5 C lower than their ancestral populations.

"Scientific models have suggested that climate change could result in both a general, gradual increase of average temperatures and an increase in extreme temperatures," says Barrett, who received his PhD last week.

"Our study is the first to experimentally show that certain species in the wild could adapt to climate change very rapidly in this case, colder water temperature. However, this rapid adaptation is not achieved without a cost. Only rare individuals that possess the ability to tolerate rapid changes in temperature survive, and the number of survivors may not be large enough to sustain the population. It is crucial that knowledge of evolutionary processes is incorporated into conservation and management policy."

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Reader Comments

3 people have commented so far. cloud add your comment

"Evolve" and "Adapt" are two seperate things. This article is intentionally misleading to make evolution look scientific. If there is evidence that genetic mutations occurred in these fish then you might have evolution; but what you actually have is adaptations which are already programmed into the genetic codes of these fish. Adaptations and evolution do not mean the same thing and if you pay close attention to this article these terms are used interchangeably! Evolution=Religion!!!!
   comment# 1   - john cook · USA · Aug 5, 2010 @ 11:58am

It would seem that creatures of the wild are provided by God with the means to come through whatever His world throws at them. I say this, mind, sitting in an air-conditioned house in Georgia, with the ceiling fans going full blast, on a 98 degree day. I guess it's time to consider if He invented AC, too. All things are possible..............
   comment# 2   - John Schiffermuller · Acworth, GA USA · Aug 5, 2010 @ 12:23pm

This article is a form of blatant anti-science. By definition, there is no evolution unless there is genetic change. This demonstrates variability built in to the genetic code already present. Variability is very significant in the survival of species since it lalows a few memebers to survive extreme environmental changes. Now if they find a genetic change after three years they would have news. No news is there?
   comment# 3   - LEE BREIDENSTEIN · Milford, KS, USA · Aug 5, 2010 @ 6:49pm
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