Polar regions contain identical animals

The Census of Marine Life project, which has looked at both Arctic and Antarctic marine life, and have found a surprisingly large number which appears to live in both places, even though they are at opposite ends of the globe.

According to their press release (full pdf can be found here) researchers found "at least 235 species live in both polar seas". The species they could seems to be quite diverse.

The scientists found marine life that both poles apparently share in common include marathoners such as grey whales (www.eol.org/pages/328569) and birds, but also worms, crustaceans, and angelic snail-like pteropods, the latter discoveries opening a host of future research questions about where they originated and how they wound up at both ends of the Earth. DNA analysis is underway to confirm whether the species are indeed identical.

The census of polar marine life, made during the 2007-2008 Polar Year, have yielded many interesting results, and this newest press release shows us that there are many more to come.

PZ is getting slow

In the old days, PZ would not have let someone else scoop this story, but I guess he is getting slow now where he is king of the mountain.

ScienceDaily reports

Octopus Family Tree Traced Using New Molecular Evidence

Octopuses started migrating to new ocean basins more than 30 million years ago as Antarctica cooled and large ice-sheets grew.

I don't really have anything to add to this story, though I suggest people go read it. I just wanted to scoop PZ.

Water, water, every where, Nor any drop to drink.

I found this new finding interesting. ScienceDaily reports on a new study that shows that sea snakes drink fresh water.

Sea Snakes Seek Out Freshwater To Slake Thirst

Sea snakes may slither in saltwater, but they sip the sweet stuff. So concludes a University of Florida zoologist in a paper appearing this month in the online edition of the November/December issue of the journal Physiological and Biochemical Zoology.

Harvey Lillywhite says it has been the “long-standing dogma” that the roughly 60 species of venomous sea snakes worldwide satisfy their drinking needs by drinking seawater, with internal salt glands filtering and excreting the salt. Experiments with three species of captive sea kraits captured near Taiwan, however, found that the snakes refused to drink saltwater even if thirsty — and then would drink only freshwater or heavily diluted saltwater.

So, saltwater sea snakes can literately dehydrate while swimming in their natural environment. That means that they need to live fairly close to fresh water, which limits their possible habitat.

This is why I love the scientific process. It was thought that we knew how sea snakes slake their thirst, but someone still make sure to investigate the subject, and thus proved the common assumption wrong.

The study can be found here (unfortunately behind a pay-wall)

For more information about the sea snakes, I recommend the wikipedia entry on the subject

Evolution, devolution....

One of my friends was kind enough to send me a link to this article, and I thought I'd share it with the rest of you.

Researchers document rapid, dramatic 'reverse evolution' in the threespine stickleback fish

Adaptation coincides with the '60s cleanup of toxic pollution in Seattle's Lake Washington

It's an interesting case of evolution reverting itself, when living conditions changes.

Peichel and colleagues turned their gaze to the sticklebacks that live in Lake Washington, the largest of three major lakes in the Seattle area. Five decades ago, the lake was, quite literally, a cesspool, murky with an overgrowth of blue-green algae that thrived on the 20 million gallons of phosphorus-rich sewage pumped into its waters each day. Thanks to a $140 million cleanup effort in the mid-'60s — at the time considered the most costly pollution-control effort in the nation — today the lake and its waterfront are a pristine playground for boaters and billionaires.

It's precisely that cleanup effort that sparked the reverse evolution, Peichel and colleagues surmise. Back when the lake was polluted, the transparency of its water was low, affording a range of vision only about 30 inches deep. The tainted, mucky water provided the sticklebacks with an opaque blanket of security against predators such as cutthroat trout, and so the fish needed little bony armor to keep them from being eaten by the trout.

In 1968, after the cleanup was complete, the lake's transparency reached a depth of 10 feet. Today, the water's clarity approaches 25 feet. Lacking the cover of darkness they once enjoyed, over the past 40 years about half of Lake Washington sticklebacks have evolved to become fully armored, with bony plates protecting their bodies from head to tail. For example, in the late '60s, only 6 percent of sticklebacks in Lake Washington were completely plated. Today, 49 percent are fully plated and 35 percent are partially plated, with about half of their bodies shielded in bony armor. This rapid, dramatic adaptation is actually an example of evolution in reverse, because the normal evolutionary tendency for freshwater sticklebacks runs toward less armor plating, not more.

Of course, it's somewhat wrong to talk about reverse evolution, since the sticklebacks have undergone a evolutionary process - it's just that nature started to select for different aspects than it did when conditions were differently.

The findings have been published in Current Biology under the title Reverse Evolution of Armor Plates in the Threespine Stickleback by Kitano et al.