Organism Physiology: The Octopus Bio/101 January 17, 2010 Enteroctopus Dofleini or giant octopus is a marine invertebrate organism that inhabits the oceans off the coast of the United States. Its food source consists of crabs, small fish, clams, mussels and other marine animals. The octopus is predatory by nature and has developed many adaptations in the form of advance specialized organs to aid in its survival. The octopus has developed several organs that are vital to its survival, the brain/nervous system, complex eyes and arms for capturing its prey. In this paper the topic to discuss is these different organs and how they have adapted physiologically to its environment. The Giant Octopus has a considerably larger brain in comparison to other Mollusca which wraps around the esophagus and just below the optic socket. The brain, sense organs, and central nervous system are the most highly developed of the invertebrates. During its life span the brain will continue to grow and will consist of 170 million nerve cells, of which 130 million will be optical. 350 million nerve cells will reside in the arms of the giant octopus and can distinguish objects with the same sensitivity as its sight. As the octopus moves along the ocean floor, these nerve cells allow the octopus to learn its surroundings. The animal can remember its past environments and keep a working memory of areas they have fed on in the past. When feeding in a treacherous environment both prey and predator must develop a varied range of hunting and defense behaviors. The octopus long-term and short-term memory capability from its advanced brain adaptation gives this creature a definite advantage in survival. Octopuses are stealth hunters and have the ability to change color to match the surroundings as they hide. The octopus waits for the prey to arrive within reach, then grabs it and secretes a nerve poison, stunning the prey. Chromataphores are they light reflecting cells on the skin of the giant octopus that allow it to blend into their surroundings. Each chromataphore consists of a central cell containing pigment granules which is then surrounded by 15-25 muscle fibers and receives instructions by a set of nerve cells controlled by the brain. Diagram of a chromataphore cell.

Picture of clumps of chromataphore cells on skin.

In times of distress, the octopus can detach a limb and the crawling arm serves as a distraction to the predator, allowing the octopus to escape. The octopus is a great example of adaptation in an organism and has the ability to adapt to any environment it inhabits. The brain enables the octopus to solve problems and has the ability to remember its surroundings, the brain works with the octopus’s arms similar to the way the brain works the human limbs. The brain sends nerve impulses to the arms and then the arms carryout the tasks that are signaled by the brain. The octopus can sense a predator and utilize its defense mechanism as an ink screen that disorients and confuses the predator. This allows the octopus to escape to safety. The physiological development of the organs in the octopus ensures its survival in its habitat, and makes it an excellent hunter.

It is hypothesized [Passive voice ] that the brain of the octopus gives a task to the arm and the arm essentially decides how to carry out that task. An experiment was done [Passive voice ] that involved separating and cutting the nerves of the arm from other nerves in the body and then [consider removing "then"] tickling the arm. The response showed the injured arm reacted just as a healthy octopus’s arm would (Horton, 2008). All of this unique circuitry gives the octopus immaculate control over their bodies. The octopus prefers movement in a style closest to walking. Suckers on each arm move in unison to [Incorrect preposition--should be "with"] propel the octopus. Each sucker has up to 10,000 neurons in it (Horton, 2008Marine biologists that have studied cephalopods claim that their subjects even have personalities and “that octopuses engage in play, the deliberate, repeated, outwardly useless activity through which smarter animals explore their world and refine their skills” (Scigliano, 2003) [The citation for a direct quote needs the page number] . One scientist claims that her octopus even “bubble surfs” by spreading his mantle out and letting the aerator jets from his tank run under his body (Scigliano, 2003). . Key traits were noted out of 73 lab-bred octopuses. Discoveries showed temperamental variations at different maturity levels. Young octopuses tended to be active and aggressive whereas more mature ones tended to be more alert and quick to react to danger (Scigliano, 2003). Evidence that even though their lifespan is short their brain evolves and adapts quickly. Around the mouth of the octopus are eight arms. The eight arms allow the octopus to move, crawl, and swim around in its habitat. Octopuses crawl slowly, walking on its arms to move through the water headfirst with the arms trailing behind. When necessary, octopuses can move fast using their arms to propel it through the water similar to jet propulsion. The suckers found on the underside of the arms aid in catching prey for food, and as a weapon when threatened by the enemy. Octopus facts for kid [Unless meaning young goats, this is slang and inappropriate in academic writing; use "children"] ’s states, “Octopuses are stealthy hunters changing their color to match the surroundings as they hide. The octopus waits for the prey to arrive within reach, then grabs it and secretes a nerve poison, stunning the prey.” In times of distress, the octopus can detach a limb and the crawling arm serves as a distraction to the predator, allowing the octopus to escape. The octopus will sometimes eat its own arm and [Grammar: A run-on sentence requires a comma before "and" (or other conjunction) linking main clauses] the arm will re-grow later with no permanent damage. A neurological disorder causes this (Octopus, 2008). The octopus will also detach a limb during reproduction. The male uses a special arm, usually the third right arm, called a hectocotylus, to insert sperm into the female’s cavity. The third right arm detaches during sexual intercourse and the male dies within a few months after mating. The excellent sense of touch in the octopus is due to [Check word usage: This phrase is most accurate in referring to something owed ($5 due) or an arrival time (due at 6:00)--try "because" or "because of"] the chemoreceptors in the suckers of the arms. These chemoreceptors help the octopus taste what it is touching, and sense when the arms are out but cannot determine the position of its body or arms. The arms of the octopus are physically suited [Passive voice ] to the environment it inhabits to allow movement, reproduction, feeding, and defense. The octopus is known to be an intelligent creature and over time they have developed defense mechanisms to avoid its predators. The primary defense of the cephalopod is to hide or swim away. But [In academic writing, avoid starting a sentence with a conjunction ] when the octopus is scared [Passive voice ] it has the ability to [Express "has the ability to" as simply "can" or "could"] release ink in a squirting fashion. The ink sac in an octopus can be found below it’s [Contractions are inappropriate in college writing, spell out--it is] digestive gland. Located there is a small gland that produces the ink and then [Adjust spelling: "Then" has to do with time or conditions (The sky grew dark, then the rain fell); "than" deals with comparisons (Ice cream is sweeter than corn flakes and melts more quickly than ice)] [consider removing "then"] a larger muscular sac that stores the ink. The sac has a gland that connects to the anus. When the octopus is scared [Passive voice ] , the ink is released [Passive voice ] from the ink sac through the anus and into the funnel where it is mixed [Passive voice ] with mucous. Melanin, the main component of the ink, clings to the mucous molecules giving morphing into a cloud-like illusion allowing the octopus to swim away and leaving the predator confused. In addition to having [Writing suggestion--"having" as a transitive verb is vague. Reconsider the sentence using "possessing," "acquiring," "developing," etc. Often "having" can simply be deleted] melanin, the ink also contains tyrosinase, a very irritating chemical that temporarily suspends the predators sense of smell and irritates the eye (Mather, Anderson, & Wood, 2010). While ["While" is accurate in linking simultaneous events (in the sense of "during")--otherwise use "although," "whereas," "and," or "but"] not all species of octopuses have an ink sac the majority still alive today do. The exceptions to this are cephalopods that live in deeper, darker waters where there is very little light. The defense is useless unless the attacker has light to see (Mather, Anderson, & Wood, 2010). The octopus is a great example of adaptation in an organism and has the ability to adapt to any environment it inhabits. The brain enables the octopus to solve problems and has the ability to remember its surroundings, the brain works with the octopus’s arms similar to the way the brain works the human limbs. The brain sends nerve impulses to the arms and then the arms carryout the tasks that are signaled by the brain. The octopus can sense a predator and utilize its defense mechanism as an ink screen that disorients and confuses the predator. This allows the octopus to escape to safety. The physiological development of the organs in the octopus ensures its survival in its habitat, and makes it an excellent hunter.

Referenc Buzzle.com. (n.d.). Octopus facts for kids. Retrieved from http://www.buzzle.com/articles/octopus-facts-for-kids.htm Deb, S. (2010). Octopus brain. Open. Retrieved from http://www.openthemagazine.com/article/voices/octopus-brain. Horton, J. (2008). How octopuses work. Discovery. Retrieved fro http://animals.howstuffworks.com/marine-life/octopus3.htm#. Mather, J., Anderson, R., & Wood, J. (2010). Octopus: the ocean's intelligent vertebrate. Portland, Oregon: Timber Press. Miller, G. (2009). Tackling brain evolution with all eight arms. AAAS. Retrieved from http://blogs.sciencemag.org/origins/2009/10/tackling-brain- evolution-with.html. Octopus. (2008). New World Encyclopedia. Retrieved from http://www.newworldencyclopedia.org/entry/Octopus?oldid=794938. Scigliano, E. (2003). Through the eye of an octopus. DISCOVER. Retrieved from http://discovermagazine.com/2003/oct/feateye.