The mollusk mediafire

The model also explains how other snails develop their characteristic spiraling shells, the researchers said. The three scientists seek to understand the physics underlying seashell formation. They have published on the spiny shells of sea snails and the interlocking shells of oysters.

But the knots of Nipponites were perplexing. Mollusks create their own shells using their mantle, a fleshy outer organ. The mantle secretes calcium carbonate in layers, which harden into the shell.

When ammonites died out about 66 million years ago, they left few traces of their squishy insides in the fossil record. But evidence suggests that ammonites, like their living squid cousins, were bilaterally symmetrical; drawing a line down the middle would result in symmetrical halves. So the researchers built their model on the assumption that ammonites were bilaterally symmetrical. So how could a symmetric body secrete an asymmetric shell?

If the body grows faster than the shell, it will be too big for its shell house and will generate mechanical stress that leads the body to twist inside the shell. Moulton offered an analogy: Imagine the ammonite shell as a long, hard tube stuffed with two soft pool noodles that are longer than the tube. To relieve the stress, the noodles the soft body twist inside the tube the shell.

As the soft body twists, it rotates the edge of the mantle secreting the shell, resulting in an asymmetric shell. Manage Profile. Our goal is to provide high-quality video, TV streams, music, software, documents or any other shared files for free!

Registered users can also use our File Leecher to download files directly from all file hosts where it was found on. Just paste the urls you'll find below and we'll download file for you! If you have any other trouble downloading ween god ween satan post it in comments and our support team or a community member will help you! Posted by admin. Log in to vote 0 votes 0 helpful 0 unhelpful.