Path followed:
1. Is the fault in the components that perform any physical action?
Answer: Yes
2. Is the fault in components that move?
Answer: Yes
3. Is the fault in components that make the mechanism move?
Answer: Yes
4. Is the faulty component designed to move the mechanism around?
Answer: Yes
5. Is the faulty component needed for stability?
Answer: Yes
6. Does the faulty component manipulate smaller objects?
Answer: No
7. Are there any external resources that can be used by the mechanism?
Answer: No
8. Does the adaptation continue after replacing the faulty component?
Answer: Yes
9. Does any material need to be removed before the adaptation takes place?
Answer: Yes
100) Blackback land crab, Gecarcinus lateralis
Blackback land crabs can be found along the coasts of eastern states of the United States and the Gulf of Mexico (United States). This crab lives on the beaches for most of their lives until they are reproducing, then they go to the oceans and lay they egg. Land crabs have the ability of regenerating their leg if it was torn off or autotomized.
Soon after the limb is lost a scab is formed over the wound from coagulation. The membrane nearest the breakage plane also stretches to cover the wound. Epithelial, endothelial, and mesenchyme cells migrate to the injured site and begin to proliferate. The
mesenchyme cells differentiate into the tissue of the new limb and create a small projection from out of the scab (Holland & Skinner). The tissues then begin to arrange into segments to form the various parts of the leg. Mesenchyme cells also differentiate into chondrocytes that form the muscle in the basi-ischium where the limb autotomy occurs (Holland & Skinner). Once the limb grows to a certain point it will begin preparing for ecdysis by first allowing the epidermis to separate from the old exoskeleton (Holland & Skinner). The cells in the epidermis begin to enlarge and synthesize the new epi- and exocuticular layers on the exoskeleton which will be able to grow once the old exoskeleton
has been removed (Holland & Skinner). When the exoskeleton is lost a regenerated leg will emerge that can be used like all the other legs.
United States. National Park Service. “Blackback Land Crab.” National Parks Service. U.S. Department of the Interior, 28 Dec. 2014. Web. 28 Dec. 2014.
http://www.nps.gov/pais/naturescience/blackback_crab.htm
Holland, Christie A., and Dorothy M. Skinner. “INTERACTIONS BETWEEN MOLTING AND REGENERATION IN THE LAND CRAB.” Biological Bulletin 150 (1976): 222-40. Biological Bulletin. Web. 28 Dec. 2014.
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