preview

Sephia Officinalis Research Paper

Decent Essays
The class of the Sepia officinalis is Cephalopoda which can be thought of in three groups: the Nautiloidea, Ammonoidea and Coleoidea each of which have adapted and evolved independently of each other (A Broad Brush History of the Cephalopoda). "Cuttlefish, along with octopuses and squid, are cephalopods—animals from an ancient branch of the tree of life that have been trolling the oceans for more than 500 million years. Cuttlefish were around long before the first shark or fish ever evolved. Their cephalopod ancestors were encased in a shell that acted as protection from predators, but the modern cuttlefish has developed an even better defense: camouflage" (http://www.pbs.org/wnet/nature/animal-guides/animal-guide-cuttlefish/1161/). The Nautiloidea…show more content…
They appeared at about the same time as the ammonites. The two groups have some anatomical and developmental traits in common that set them apart from the nautiluses, but they are much different. Ammonites relied on their shells for defense as well as buoyancy while coleoids had internal shells that they did not use for defense. Some coleoid groups have also discarded the shell as a buoyancy aid. Seen in Figure 3, Octopuses, and their close relatives, the vampyromorphs, have lost their shells independently. The squids have shells that no longer provide buoyancy but unlike octopuses, the squids kept their shell for support…show more content…
All cephalopods have arms, but not all cephalopods have tentacles. Octopuses, cuttlefish, and squid have eight arms, but only cuttlefish and squid have two tentacles. Squid and cuttlefish have one pair of tentacles which they use to strike their prey (http://www.ucmp.berkeley.edu/taxa/inverts/mollusca/cephalopoda.php). These prove that squids and cuttlefish evolved away from octopuses by having tentacles to strike prey. The main difference between the cuttlefish and the squid are the internal shells. The squid has remains of an internal shell while the cuttlefish have a cuttlebone. Seen in Figure 3, the Sepia and types of squid and octopus
    Get Access