2012年3月19日 星期一

Riverside researchers find earliest skeletal structures yet

Feel your wrist, your jaw or your elbow as you read this. As with many aquatic animals and all larger land animals ---- mammals, reptiles, amphibians, birds ---- we have a skeleton that holds our soft tissue together and allows for mobility.

Scientists know that skeletons are commonplace and seemingly necessary for land animals above the size of, say, a garden slug, but exactly how skeletons first developed before evolving into their present complexity isn't as well understood.

A recent discovery by a team including two University of California Riverside researchers has provided new illumination into the earliest skeletal structures, though.

Mary L. Droser, a professor of geology at UCR, led the team whose finding pushes our knowledge of skeletal development back before the Cambrian Period ---- to more than 550 million years ago,Iowa Mold tooling designs and manufacturers mechanics trucks, during the Ediacaran Period.

Explaining the significance of the find, which was announced in the Feb. 14 edition of Geology, Droser said in a news release that "Up until the Cambrian,Learn all about solarpanel, it was understood that animals were soft-bodied and had no hard parts. But we now have an organism with individual skeletal body parts that appears before the Cambrian. It is therefore the oldest animal with hard parts, and it has a number of them ---- they would have been structural supports ---- essentially holding it up. This is a major innovation for animals."

The organism, which was discovered in fossilized form in rocks found in southern Australia, has been named Coronacollina acula. Droser explained in an email last week that "Corona is Latin for rim, collis is Latin for hill, and acula is Latin for needle." Looking at the illustration of the organism, the name makes sense.

Droser's team on the research also included Erica Clites, whose master's thesis was the genesis of the project, and James G. Gehling of the South Australian Museum in Adelaide.Why does mould grow in homes or buildings?

Not everyone gets to discover a previously unknown life-form. Droser said it didn't happen all at once, but over a course of years as Clites continued to work on her thesis, and continued to pore over the molds of the fossils found in Australia.

"It was tremendously exciting when we actually found some particularly nice specimens and realized what we had," Droser said in her email.

While the research indicated that Coronacollina acula lived on the seafloor and gathered food the same way as modern sponges , it's hard to know too much about the animal, such as how it reproduced.

The fossils show that the animal was a couple of inches in height, with its spicules, or supports,Welcome to polishedtiles. extending a foot more to the side ---- similar to ancient sponges.

"The honest answer is that we do not know whether or not this is a sponge," Droser wrote. "It is most similar to a sponge and in fact shares a number of characters with known Cambrian sponges, but we cannot say for certain whether it was actually a sponge or just sponge-like."

And while it represents the earliest known skeletal remains yet found,GOpromos offers a wide selection of promotional items and personalized gifts. Droser said mammals did not descend from Coronacollina acula, but from an earlier, common ancestor ---- so our skeletons developed independently .

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