Friday, January 30, 2009
Squids are cephalopods.which is greek for "head with feet". I chose this as my picture because "Blooper" from "Mariocart" has many similarities to a squid. Squid also shoot melanin out of their 10 tentacles. Squid have differentiated from their ancestral mollusks in such a way that the body plan has been condensed antero-posteriorly and extended dorso-ventrally. What before may have been the foot of the ancestor is now modified into a complex set of tentacles and highly developed sense organs. The shell of the ancestor has been lost, with only an internal gladius, or pen, remaining. The pen is a feather-shaped internal structure that supports the mantle of squid and serves as a site for muscle attachment. It is made of chitin-like substances. The main body mass of the squid is enclosed in the mantle, which has a swimming fin along each side. It should be noted that these fins, unlike in other marine organisms, are not the main source of ambulation in most species. The skin of the squid is covered in chromatophores, which enable the squid to change color to suit its surroundings, making it effectively invisible. The underside of the squid is also almost always lighter in color than the topside, in order to provide camoflague from both prey and predator.