Organism Physiology Paper
Lazaro Dominguez
BIO-101
November 16, 2012
Kristy Howard

Organism Physiology Paper
The Enteroctopus dofleni also known as the giant octopus, is a marine organism that can be found in the ocean waters of southern California to the Northern Pacific and across to Aleutians Islands and south to Japan ("Marinebio", 2012). The giant octopus is predatory animal that has evolved and developed traits necessary for it survival.
Anatomy

According to "Octopusworld.com" (2012), “The anatomy of a North Pacific Giant Octopus is very interesting. They tend to lie flat often on the bottom of the ocean so they seem to be like a tan starfish. It is this blending in though that makes them able to avoid detection from various types of predators. They have very long arms that are also thick. Along the length of them are many suction cups” (Anatomy). The octopus has a very large head that is spherical in shape. The shape of the head facilitates movement and makes it possible for the octopus to move around effortlessly ("Octopusworld.com", 2012). The body of the octopus is divided into following three parts: * Mantle…{paragraph continues} * The Trunk…{paragraph continues} * The Arms…{paragraph continues} The mantel is the muscular mass that encloses the vital organs. The mantel also circulates water around the enclosed gills, provides for respiration and excretion by contracting and expanding. In addition to the aforementioned functions, the mantel also aids in swimming by pushing water through the exterior funnels located near the base of the arms ("Giant Pacific Octopus", 2012). According to "Giant Pacific Octopus" (2012), “The central nervous system of the octopus is located within the trunk. This system is well developed and allows for highly coordinated movements of the arms” (Trunk). The eyes, which are also in the trunk, provide the octopus with the ability to distinguish shapes and color (light from dark). In addition to have great vision the octopus has the ability to learn image recognition a crucial element to its successful feeding behavior ("Giant Pacific Octopus", 2012). Another interesting feature of the octopus is that it has eight arms and each arm has to rows of suckers, which run along the entire length of the ventral surface of each arm. The arms are highly sensitive and are used to move the octopus around the ocean floor, however; it can also move around pushing water through its funnel and may even change direction by pointing its funnel in a different direction. In addition to providing locomotion for the octopus the arms are used for grasping, holding, and catching prey ("Giant Pacific Octopus", 2012).
Beak
According to "Marinebio.org" (2012), “Octopuses consume mostly crustaceans and mollusks, most often crabs and scallops. Other bivalves, snails, fish, sharks and even other octopuses are also eaten. Octopuses use three different techniques to gain entry to hard-shelled prey: they may pull it apart, bite it open with their beak or 'drill' through the shell. Prey that are difficult to pull or bite open are drilled: secretions from the salivary papilla soften the shell of the prey and the softened material is then scraped away with the radula to create a tiny hole in the shell. Through this hole, the octopus secretes a toxin that paralyzes the prey and begins to dissolve the connective tissue. The prey is then pulled apart and consumed” (Feeding Behavior).
Ink Sac The giant octopus has a built in defense mechanism, which is known as the ink sac. When threatened, the octopus may release a cloud of purple-black in attempt to escape or confuse its enemy. The ink can be harmful even fatal to its host, especially if the ink is released in a confined space such as an octopus den with little current flow ("Marinebio.org", 2012).
Evolution
According to "American Psychological Association” (2012), “All octopuses, along with cuttlefish and squid, are cephalopods. There are about 300 octopus species, ranging from the Giant Pacific Octopus, which can weigh 100 pounds and stretch its arms more than 15 feet, to the East Pacific Red Octopus, which weighs less than a quarter of a pound” (para. 5). Researchers have theorized that octopuses as part of their evolution lost a shell that may have protected their body; however, scientist recently found an octopus fossil that may challenge past theories regarding the evolution of the octopus. According to "Creations.com" (2012), “Five octopus fossils, supposedly 95 million years old, were recently discovered in Lebanon, catching scientists by surprise” (Fast octopus fossils reveal no evolution). Surprisingly, one of the octopus fossil looks just like what an octopus looks like today.
Conclusion
It is believed that all living things are evolving; however, when discussing the evolution of the octopus recent finding may contradict past beliefs because a 95-milliom year old octopus fossil looks identical to an octopus today. However, to understand evolution one should examine different organisms over a period of time. By studying the giant octopus one may find that its evolution depends on its environment.

Reference
American Psychological Association. (2012). Retrieved from http://www.apa.org/monitor/2008/06/octopus.aspx
Creations.com. (2012). Retrieved from http://creation.com/fast-octopus-fossils
Giant Pacific Octopus. (2012). Retrieved from http://www.for.gov.bc.ca/hfd/library/documents/bib92997.pdf
Marinebio.org (2012). Retrieved from http://marinebio.org/species.asp?id=60
Octopusworld.com. (2012). Retrieved from http://www.octopusworlds.com/north-pacific-giant-octopus.html