1. Is the fault in the components that perform any physical action?
Answer: No
2. Is the faulty component part of the mechanism’s body?
Answer: Yes
3. Is the faulty component in the structure of the mechanism?
Answer: No
4. Does the damaged component provide protection?
Answer: Yes
5. Is the component serve any other purpose than protection?
Answer: No
6. Can the adaptation occur at any time after failure?
Answer: Yes
7. Can the adaptation occur in different areas of the mechanism?
Answer: Yes
24) Snail, Achatinoidea
Snails can be found on every continent, except Antarctica, and even in the oceans. They are herbivores and use microscopic teeth on their tongue to shred their food (ÒSnailÓ). Snails have the ability of building new layers of their shell so that a crack or break could be covered up by new shell before it hurts the snail.
The snail uses various cells to create specific layers of their shell. At the rim of the shellÕs mouth there are transversal cells that secrete calcareous matter that will solidify into prisms or plate crystals (Nordsleck). The prism layer is the ostracum and other cells that secrete organic skin made of conchin cover it (Nordsleck). The last layer of cells cover the entire mantle on the inside and it adds amorphous calcium carbonate material to thicken the shell wall (Nordsleck). Snails are continually building and repairing their shells with the amorphous matter and you can see distinctly where they have been hurt from the different pigment given off by the amorphous matter.
“Snail.” Snail (Achatinoidea). A-z-animals.com, 2013. Web. 27 Nov. 2014.
http://a-z-animals.com/animals/snail/
Nordsleck, Robert. “The Gastropod Shell- Part1.” Snails and Slugs (Gastropoda). The Living World of Molluscs, 2013. Web. 27 Nov. 2014.
http://www.molluscs.at/gastropoda/index.html?/gastropoda/morphology/shell.html
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