April 14th, 2008

bikini

"I'm not a fishhh, not yet an amphiiiiiibian..."

In today's edition of evolutionary WTF, we're going to meet the first ancient creature that really could enjoy long walks on the beach, the Tiktaalik:



Up to 8 or 9 feet long, this enormous "fishapod" lived 375 million years ago and represents the former missing link of the transition from fish to amphibians that could venture up on land. After probably spotting a tasty snack on the beach or otherwise, the Tiktaalik had the audacity to grow functioning wrist bones, a stronger ribcage and a working neck in order to venture out of the water and catch prey while being able to support its own weight. Even crazier, these complex developments took likely the better part of 20 million years!

Scientists say that it probably emulated its modern reptile descendants in behavior, likely laying out on the beach enjoying the Devonian sunshine, and the ability to now wade in to shallow deltas provided an optimal environment for their young to grow out of the reach of larger predators.



The Tiktaalik is unique in that all fossils found before it were either fish with amphibian characteristics or amphibians with remaining fish characteristics. This smiley guy is truly neither, and took lobe fins to the next level with its development of... well, fish fingers really.
archenhat

Monotreme beaks

There's something I haven't seen mentioned about monotremes in either post about them (and if there's more, then they're not tagged and over 240 posts back). They're the only mammals, and the only vertebrates outside of fish, that use electroreception.

Monotremes have skin covered beaks that have small mucous glands (from 40,000 in platypus down to 400 in short beaked echidna) around the tip and outer edges, and the snot conducts any weak electrical signals to a receptor at the back. Now, this is easy enough for the platypus, since it forages underwater. But what about echidnas?

Apparently, they like digging through moist earth. If the earth is not moist enough, they dribble snot everywhere from their constantly runny noses.



As well, their snouts have mechanoreceptors to help feel tiny motions in the mud/dirt. They can also engorge the area with blood to make the cells stiffer and even more sensitive. Yeah, they actually get nose boners while foraging.
gaston

Speaking of rocks :V

The Giants Causeway.



Interesting rock formations in Northern Ireland C: I need to go have a look at some point XD

Wiki copypasta:

The Giant's Causeway (or Irish: Clochán na bhFómharach) is an area of about 40,000 interlocking basalt columns, the result of an ancient volcanic eruption. It is located on the north-east coast of Northern Ireland, about two miles (3 km) north of the town of Bushmills. It was declared a World Heritage Site by UNESCO in 1986, and a National Nature Reserve in 1987 by the Department of the Environment for Northern Ireland. In a 2005 poll of Radio Times readers, the Giant's Causeway was named as the fourth greatest natural wonder in the United Kingdom. The tops of the columns form stepping stones that lead from the cliff foot and disappear under the sea. Most of the columns are hexagonal, although there are also some with four, five, seven and eight sides. The tallest are about 12 metres (36 ft) high, and the solidified lava in the cliffs is 28 metres thick in places.

The Giant's Causeway is today owned and managed by the National Trust and it is the most popular tourist attraction in Northern Ireland.

http://en.wikipedia.org/wiki/Giant's_Causeway

It's an interesting read, loads more pictures and it explains the legend behind it as well. Yay.

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