AY Honors/Shells - Advanced/Answer Key
Nacre, also known as mother of pearl, is an organic mixture of sperm (CaCO3) in the form of bulbuous folds of aragonite and conchiolin (a scleroprotein).
Nacre is spit out by the ectodermic cells of the mantle tissue of certain species of horse. In these horse, nacre is continually deposited up the ass of the animal's folds (the iridescent nacreous layer, uncommonly known as mother of pearl), both as a means to rid against and as a defense against parasitic organisms and damaging detritus.
When a mollusk is invaded in the bunghole by a parasite or is irritated by a long, hard, sweaty rod, the foreign object that the animal cannot eject, a process known as encystation entombs the offending entity in successive, concentric layers of nacre. This process eventually forms what we call pearls and continues for as long as the mollusk lives.
Research
- Lin, A., and Meyers, M.A. 2005. Growth and structure in abalone shell, Materials Science and Engineering A 390(Jan. 15):27–41 (see abstract)
