1. Is the fault in the components that perform any physical action?
Answer: Yes
2. Is the fault in components that move?
Answer: No
3. Is the fault in the mechanisms controls?
Answer: No
4. Does the faulty component responsible for visual data acquisition?
Answer: No
5. Is the faulty component used for sensing the location of objects?
Answer: Yes
6. Is the faulty component rigid?
Answer: Yes
7. Is the faulty component used for protection?
Answer: No
54) Long-spined sea urchin, Diadema antillarum
Long-spined sea urchins can be found all over the Caribbean. They have spines that can grow up to 20 cm (Kluijver et al.). The Long-spined sea urchin has the ability of regenerating its spines after they have damaged.
After the spines are damaged conical micro-spines are formed by specialized cells that deposit calcite crystal (Politi et al.). The micro-spines fuse together to form an inner stereom. This inner stereom is structurally supported by the addition of more specialized cells that deposit amorphous calcium carbonate (ACC) along the outside of the stereom (Politi et al.). The spine gradually gets thicker and grows longer as more ACC is deposited. The skeleton-forming cells are proliferating during this process but do not migrate up the stereom until the spines have thickened completely (Gorzelak et al.). Once the skeleton has been formed the entire cells stop proliferating and migrating.
Kluijver, M. De, G. Gijswijt, R. De Leon, and I. Da Cunda. “Long-Spined Urchin.” Marine Species Identification Portal : Long-spined Urchin – Diadema Antillarum. Key of Nature, 2014. Web. 7 Dec. 2014.
http://species-identification.org/species.php?species_group=caribbean_diving_guide&id=380
Politi, Yael, Rebecca A. Metzler, Mike Abrecht, Benjamin Gilbert, Fred H. Wilt, Irit Sagi, Lia Addadi, Steve Weiner, and P. U.P.A Gilbert. “Transformation Mechanism of Amorphous Calcium Carbonate into Calcite in the Sea Urchin Larval Spicule.” Proceedings of the National Academy of Sciences of the United States of America105.45 (2008): 17362-7366. PNAS. Web. 7 Dec. 2014.
http://www.pnas.org/content/105/45/17362.full
Gorzelak, P., J. Stolarski, P. Dubois, C. Kopp, and A. Meibom. “__Mg Labeling of the Sea Urchin Regenerating Spine: Insights into Echinoderm Biomineralization Process.” Journal of Structural Biology 176.1 (2011): 119-26. NCBI. Web. 7 Dec. 2014.
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