The mantle tissue attached to the bottom of the shell secretes the proteins and minerals that make up the shell and shells - which are different from the structures that normally characterize animals
Matt Collins, Scientific American
How are seashells and shells formed?
Francis Horn, a biologist at Texas State University, provides an answer:
Shells, which are the exoskeleton of clams, snails and many other molluscs, are not made of cells like the structures that typically characterize animals. They consist mainly of calcium carbonate plus a small amount of protein - usually less than 2%.
The mantle tissue attached to the bottom of the shell secretes the proteins and minerals that make up the shell. First of all, a calcium-free layer of conchiolin is formed - a protein and chitin, a polymer that is produced naturally and is used for strengthening. Next comes a layer made up of calcium-rich prisms, followed by the final pearly layer. The process is parallel to laying steel foundations (the protein) and pouring concrete (mineral) on them.
Unlike the bones of land animals, such as humans, which grow along with the growing body, snails and clams have to gradually enlarge and expand their shells by adding new material at the edges. The newest part of the snail's shell, for example, is located around the opening from which the living creature emerges, and the outer edges of the snail's shell add and build the shell around this opening.
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Yael
I have a boat and once a month I have to dive and clean the bottom of the boat, it fills up with small shells that slow down the sailing speed even though a new anti-fouling paint was recently applied at the shipyard. I would be happy to receive practical suggestions for prevention and treatment of the issue.
Hey
I'm dying for it because my friend likes oysters very much
Surely God as if who if not him?
It's a fun, science site with 4 year old thinking talkbacks
What do you mean how?? God created them which is not clear here!!
interesting,
Does anyone know the process a little more in depth?
Are the proteins deposited by the animal active in the first hours or at least in the first moments and thus absorb calcium ions? Or is the role of the proteins only structural and for some unknown reason the chalk sinks on top of them?
In corals, for example, there is an active investment of chalk, as far as I understand, by investing calcium while increasing the alkalinity of the environment. I would be happy if someone could enlighten me on the matter.