Scientists solve mystery of Scotland's shrinking sheep

[Peikko 1,575]

The mysterious shrinking sheep of St Kilda sounds like a job for super-sleuth Sherlock Holmes.

The case involves a rare herd of wild sheep on the remote Scottish island - known in Scottish Gaelic as Hirta - that are refusing to bow to conventional evolutionary pressure, which says big is best. Instead, they have steadily decreased in size since the 1980s.

Scientists have now stepped in to solve the conundrum, and fingered the culprit as the new Moriarty of mankind: global warming.

The experts say shorter and milder winters mean that lambs do not need to put as much weight on during their first few months of life. Smaller animals that would have perished in harsh winters a few decades ago can now survive to their first birthday. As a result, the average weight of the sheep has dropped by 81g each year.

The difference is too small to see with the naked eye, but it is important because it shows how animal populations can respond to climate change. Tim Coulson, a biologist at Imperial College London who worked on the study, said: "If animals can respond [to climate change] and can respond fairly rapidly, then evolution could play a role in helping them to adapt." The results appear in the journal Science.

Biologists have reported that several species of birds and fish are changing size and shape, which could be down to global warming. Coulson said it was difficult to say what the response of the St Kilda sheep could mean for other species.

Their island home, St Kilda, is just "vegetation and sheep" he said. In other cases, predators and competition for food from other animals complicate the picture and make it difficult to tease out the influence of changing climate.

The study looked at a herd of wild Soay sheep on Hirta that biologists have studied since 1985. Dogs are forbidden on the island, so the scientists acted as human sheepdogs to herd the animals, which are expert jumpers, towards areas where they could be weighed. "These aren't fluffy white sheep, these are small and brown and wild animals," Coulson said.

Link

[alienlovechild 75]

The difference is too small to see with the naked eye, but it is important because it shows how animal populations can respond to climate change. Tim Coulson, a biologist at Imperial College London who worked on the study, said: "If animals can respond [to climate change] and can respond fairly rapidly, then evolution could play a role in helping them to adapt." The results appear in the journal Science.

Biologists have reported that several species of birds and fish are changing size and shape, which could be down to global warming. Coulson said it was difficult to say what the response of the St Kilda sheep could mean for other species.

Pretty unlikely. We all know from global warming theories that most species will suffer under a change in climate and the idea a species can change so quickly runs against evolution theory for the most part.

"Can you observe evolution happening?

Because for many species, humans included, evolution happens over the course of many thousands of years, it is rare to observe the process in a human lifetime. Usually only laboratory scientists studying quickly reproducing life forms, like single-celled creatures and some invertebrates, have the opportunity to see evolutionary change happen before their eyes. All of us can and do experience the indirect effects of evolution nearly every day, however. One of the more important evolutionary concerns facing humans today is the emergence of antibiotic-resistant microbes. A battle against bacteria that we have been winning with medicine for the last 50 years or so is now an even race, according to some scientists -- because of the rapid rate of bacterial evolution. Similarly, the use of pesticides in agriculture has driven the evolution of resistant insects that require more or harsher chemicals to be killed. Scientists studying Galapagos finches have seen evolutionary changes in beak size and shape in just a few years. Major evolutionary transformations take much, much longer."

http://www.pbs.org/wgbh/evolution/library/faq/cat06.html

[HAL 9000 96]

This is an adaptive mechanism, one provided for by evolutionary means.

Nice find MC.

Here's one for those upper latitudes that talk about Polar Bears: (just the abstract)

Polar Bears in a Warming Climate1

Andrew E. Derocher2,1, Nicholas J. Lunn2 and Ian Stirling2

1 Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada

2 Canadian Wildlife Service, 5320-122 St., Edmonton, AB T6H 3S5, Canada

Polar bears (Ursus maritimus) live throughout the ice-covered waters of the circumpolar Arctic, particularly in near shore annual ice over the continental shelf where biological productivity is highest. However, to a large degree under scenarios predicted by climate change models, these preferred sea ice habitats will be substantially altered. Spatial and temporal sea ice changes will lead to shifts in trophic interactions involving polar bears through reduced availability and abundance of their main prey: seals. In the short term, climatic warming may improve bear and seal habitats in higher latitudes over continental shelves if currently thick multiyear ice is replaced by annual ice with more leads, making it more suitable for seals. A cascade of impacts beginning with reduced sea ice will be manifested in reduced adipose stores leading to lowered reproductive rates because females will have less fat to invest in cubs during the winter fast. Non-pregnant bears may have to fast on land or offshore on the remaining multiyear ice through progressively longer periods of open water while they await freeze-up and a return to hunting seals. As sea ice thins, and becomes more fractured and labile, it is likely to move more in response to winds and currents so that polar bears will need to walk or swim more and thus use greater amounts of energy to maintain contact with the remaining preferred habitats. The effects of climate change are likely to show large geographic, temporal and even individual differences and be highly variable, making it difficult to develop adequate monitoring and research programs. All ursids show behavioural plasticity but given the rapid pace of ecological change in the Arctic, the long generation time, and the highly specialised nature of polar bears, it is unlikely that polar bears will survive as a species if the sea ice disappears completely as has been predicted by some.

*** Therefore, what some may confuse as an improvement in population and habitat is actually a temporary sign of an environment in flux that has sad consequences for the ecosystem.***

[Ban Hammer 13,982]

maybe they are becoming smaller so they can hide easier from them horny scotsmen.

[Peikko 1,575]

The difference is too small to see with the naked eye, but it is important because it shows how animal populations can respond to climate change. Tim Coulson, a biologist at Imperial College London who worked on the study, said: "If animals can respond [to climate change] and can respond fairly rapidly, then evolution could play a role in helping them to adapt." The results appear in the journal Science.

Biologists have reported that several species of birds and fish are changing size and shape, which could be down to global warming. Coulson said it was difficult to say what the response of the St Kilda sheep could mean for other species.

Pretty unlikely. We all know from global warming theories that most species will suffer under a change in climate and the idea a species can change so quickly runs against evolution theory for the most part.

"Can you observe evolution happening?

Because for many species, humans included, evolution happens over the course of many thousands of years, it is rare to observe the process in a human lifetime. Usually only laboratory scientists studying quickly reproducing life forms, like single-celled creatures and some invertebrates, have the opportunity to see evolutionary change happen before their eyes. All of us can and do experience the indirect effects of evolution nearly every day, however. One of the more important evolutionary concerns facing humans today is the emergence of antibiotic-resistant microbes. A battle against bacteria that we have been winning with medicine for the last 50 years or so is now an even race, according to some scientists -- because of the rapid rate of bacterial evolution. Similarly, the use of pesticides in agriculture has driven the evolution of resistant insects that require more or harsher chemicals to be killed. Scientists studying Galapagos finches have seen evolutionary changes in beak size and shape in just a few years. Major evolutionary transformations take much, much longer."

http://www.pbs.org/wgbh/evolution/library/faq/cat06.html

What are you saying? That despite the evidence, in reality these sheep are the same size?

[rooster 1]

maybe they are becoming smaller so they can hide easier from them horny scotsmen.

You don't think Scandal or Marc have been in Scotland lately do you?

[spookyturtle 9,466]

maybe they are becoming smaller so they can hide easier from them horny scotsmen.

You don't think Scandal or Marc have been in Scotland lately do you?

Heh heh, sheep.

[alienlovechild 75]

What are you saying? That despite the evidence, in reality these sheep are the same size?

I thought you believed in evolution?

"If animals can respond [to climate change] and can respond fairly rapidly, then evolution could play a role in helping them to adapt."

Usually, evolution is thought of as a very slow process and certainly not something that happens within a human lifetime in higher order animals.

[Peikko 1,575]

So, you are saying that they are the same size then?

[spookyturtle 9,466]

So, you are saying that they are the same size then?

If they are smaller, they can't run as fast and would be easier to catch.

[HAL 9000 96]

What are you saying? That despite the evidence, in reality these sheep are the same size?

I thought you believed in evolution?

"If animals can respond [to climate change] and can respond fairly rapidly, then evolution could play a role in helping them to adapt."

Usually, evolution is thought of as a very slow process and certainly not something that happens within a human lifetime in higher order animals.

Actually... like I said above- evolution is the process. Adaptation is a process defined by evolution. The genetic capability to deal with certain changes... or the mechanisms for adapting to changes on a microevolutionary time scale... are present within a species or not within a certain time scale that pertain to a certain given set of environmental events.

Evolution is thought of as slow because it involves breeding over many, many generations upwards to thousands of years.

[alienlovechild 75]

So, you are saying that they are the same size then?

No and no again. That's not what I said.

I was commenting on conventional evolutionary theory and thinking you might have had an opinion on it in this case.

[Peikko 1,575]

I don't think you know what you are saying, regardless you make no sense. It appears as though you are trying to refute an argument that has not been put forward, yet again

[alienlovechild 75]

Actually... like I said above- evolution is the process. Adaptation is a process defined by evolution. The genetic capability to deal with certain changes... or the mechanisms for adapting to changes on a microevolutionary time scale... are present within a species or not within a certain time scale that pertain to a certain given set of environmental events.

Evolution is thought of as slow because it involves breeding over many, many generations upwards to thousands of years.

What's the highest order of animal capable of evolutionary change within a human lifespan then?

[HAL 9000 96]

Actually... like I said above- evolution is the process. Adaptation is a process defined by evolution. The genetic capability to deal with certain changes... or the mechanisms for adapting to changes on a microevolutionary time scale... are present within a species or not within a certain time scale that pertain to a certain given set of environmental events.

Evolution is thought of as slow because it involves breeding over many, many generations upwards to thousands of years.

What's the highest order of animal capable of evolutionary change within a human lifespan then?

Hypothetically, any. Capability is only as good as the genes we've inherited through genetic drift as a particular species/genus/order/etc.