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: No
51) Freshwater pearl mussel, Margaritifera margaritifera
Freshwater pearl mussels can be found in Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Ireland, Latvia, Luxembourg, Norway, Poland, Portugal, Russia, Spain, Sweden, and the United Kingdom (Molluscs Specialis Group 1996). They are currently marked as endangered. Freshwater pearl mussels have the ability of regenerating shell layers.
The mantle resides under the shell and protects the soft part of the body. It has calciferous cells that proliferate and create calcium carbonate rings around the shellÕs rim which are called umbos (Nordsieck). As more cells are added to the rim near the mantle they start to move up the shell in a cohesive manner creating a hard protective layer. You can tell how old a mussel is by looking at how many layers it has like a tree. Objects can also be caught in between the mantle and the shell and get covered with the aragonite, calcium carbonate mixture to create a pearl (Nordsieck).
Mollusc Specialist Group 1996. Margaritifera margaritifera. The IUCN Red List of Threatened Species. Version 2014.3. Web. 7 Dec. 2014.
http://www.iucnredlist.org/details/12799/0
Nordsieck, Robert. “Mussels and Clams (Bivalvia).” Mussels and Clams (Bivalvia). The Living World of Molluscs, 2014. Web. 7 Dec. 2014.
http://www.molluscs.at/bivalvia/index.html?/bivalvia/main.html
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