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Torra
01-11-2010, 12:27 PM
There's a news article (http://news.bbc.co.uk/earth/hi/earth_news/newsid_8440000/8440002.stm) that describes some findings that indicate orcas might be evolving into two separate species:



Scientists have revealed that there is not one but two types of killer whale living in UK waters.

Each differs in its appearance and diet, with males of one type being almost two metres longer than the other.
The killer whales could be at an early stage of becoming two separate species, the researchers say.
The international group of scientists has published its results in the journal Molecular Ecology.
"It's exciting to think about two very different types of killer whale in the waters around Britain," says Dr Andy Foote from the University of Aberdeen, UK, who undertook the study.
"Killer whales aren't really a species that we think of as being a regular visitor to Britain, but in fact we have two forms of these killer whales in our waters," he told the BBC.
Scientists have found different forms of killer whale that occupy particular niches in the Pacific and the Antarctic, but this is the first time that they have been described in the North Atlantic.
Dr Andy Foote undertook the study along with colleagues from universities and museums in Denmark and the UK.
Killer whales (Orcinus orca), otherwise called orcas, live in family groups called pods.
As the largest member of the dolphin family, killer whales are known for their intelligence and range of hunting behaviours.



Tooth work
There was very little prior to this study to suggest that different types of killer whale would be found in the North Atlantic.
However, Dr Foote and colleagues studied teeth from remains of killer whales stranded over the past 200 years and found a difference in tooth wear.
"We found that one form, which we call 'type 1' had severely worn teeth in all adult specimens," explains Dr Foote.
"The other form, 'type 2', had virtually no tooth wear even in the largest adults."
In the wild, killer whales that "suck up" herring and mackerel display this tooth wear.
Knowing this, the researchers suspected a difference in diet and ecological niche between the two groups.



Dolphin predator
Using stable isotope analysis that gives clues to the orcas' diet, the scientists found that type 1 is a generalist feeder, consuming fish and seals.
Type 2, on the other hand, is a specialist feeder that scientists suspect exclusively feeds on marine mammals such as small dolphins and whales.
This specialisation for alternate ecological niches has also resulted in a difference in shape and appearance.
"The two types also differed in length, with type 2 adult males being almost two metres larger than types 1 males," Dr Foote says.
The researchers also found that colour, pattern and number of teeth vary between the groups.
Dr Foote says the fish feeding type 1 killer whales are found across the North East Atlantic and around Britain.
The cetacean hunting type 2 killer whales are regularly seen off the west coast of Scotland and Ireland.



New species
Genetic analysis indicates the two types belong to two different populations.
"Type 1 specimens were from closely related populations, but the type 2 whales were more closely related to a group of Antarctic killer whales," Dr Foote explains.
Comparing the findings with studies on killer whales around the world shows that killer whales have radiated to fill different ecological niches.
"It's similar to how Darwin's finches have adapted to different ecological roles in the Galapagos, but on a larger scale," Dr Foote notes.
He suggests this could be an important discovery for the future of the animals.
"They seem to have occupied completely different ecological niches and have started to diverge morphologically. This divergence may eventually lead to the two types becoming different species."
He also recommends the two types be considered "evolutionary significant units" and monitored separately in order to more effectively conserve one of the oceans most charismatic animals.

Isabelle Warwicke
01-11-2010, 01:54 PM
This is facinating.

Ysobelle
01-11-2010, 05:03 PM
Wow. That is absolutely fascinating. We need a "Like" button here!

Torra
01-11-2010, 05:13 PM
My mind immediately went to the place where I imagine we're able to keep this data in accessible form for a few thousand years in order to compare and begin to get a "big picture" understanding of evolution, if indeed that is the mechanism at work, while continuing to observe the phenomenon first-hand for the first time nearly start to potential finish (the complete divergence and establishment of a recognized new species).

Roberto Phoenix
01-12-2010, 12:21 AM
It will be the Republicans fault-too much global warming. They will in turn get Fox news and Palin to blame the Carter administration. :-)

Or maybe Oprah.

Thistle
01-12-2010, 02:56 AM
Heard similar from a recent study done here in the US and Canada off the West Coast. In regions that have been over fished, most noticeably around Alaska-Orcas have been feeding on otters. Apparently this has been happening long enough that they have developed a preference for otters, and now only eat fish if there are no otters around.

Articles here http://www.gi.alaska.edu/ScienceForum/ASF14/1418.html and here http://www.npr.org/templates/story/story.php?storyId=4665067

wonder if there is divergence further down the line for fish-eaters vs otter eaters here. Unless, of course, sea-otters become extinct before then :(

daBaroness
01-12-2010, 11:48 AM
What's interesting to me about evolution of species is that it's been going on for millenia, yet now that we humans have a little knowledge and supposedly intelligences, we think evolution must be due to some human factor - usually negative.

To me it's the same as global warming. Yes, I think pollution and thoughtless waste of natural resources must contribute to negative changes - but the fact is, nature had been evolving for eons before the precursors of humans first crawled out of the primordial ooze. It's pretty presumptuous and self-absorbed of us as a species to think that the natural evolution process is somehow under our perview and control.

How many ice ages were there prior to our emergence from the seas? We may just be in the kind of warming phase the Earth has experienced prior to our existence.

It's called adapt and evolve. Clearly the whales are a prime and interesting example right before our eyes. Course with the human species, there are so many dysfunctional and damaged organisms that we can't be sure we're evolving as a species. ;-)

Alluring Alora
01-12-2010, 01:14 PM
What's interesting to me about evolution of species is that it's been going on for millenia, yet now that we humans have a little knowledge and supposedly intelligences, we think evolution must be due to some human factor - usually negative.

How many ice ages were there prior to our emergence from the seas? We may just be in the kind of warming phase the Earth has experienced prior to our existence.

That's what I've always said as well!
I'm sure humans' bad behavior isn't having the most positive effect on things, and I'm certain that it does influence some things. But this rock has been freezing and thawing forever. The human race can't stop the Earth from spinning, melting or freezing, just make the most of the ride!

But the whale story is FASCINATING!! :-)

Phoenix McHeit
01-12-2010, 02:06 PM
But this rock has been freezing and thawing forever. The human race can't stop the Earth from spinning, melting or freezing, just make the most of the ride!


True, but the freezing and thawing didn't have to contend with this parasite known as the Human Race before, either.

In a measly few hundred years we've depleted the natural forests by an incredible amount, polluted the waters ridiculously, over-fished and destroyed natural habitats and ecosystems, mined without restraint... all things that the 'natural order' didn't do. We, humans, are killing this planet. Basically within an evolutionary eye-blink.

I don't think its presumptuous to think that we had something to do with this divergence. Sure, it may have happened without us, but I think it wouldn't have had to, without our meddling in the ecosystems. Or at least not so suddenly.