Bio 101 Week 4 Assignment

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Organism Physiology: The Octopus

The cephalopodor octopus is a marine organism that inhabits many diverse regions of the ocean. Its food source consists of crabs, small fish, clams, mussels and other marine animals. The octopus is a predatory animal and has developed many skills to aid in its survival in the environment it has adapted to.

The octopus has several main organs that are vital to its survival; the brain for its intelligence; the ink sack for its defense; and the arms for capturing its prey. This paper will discuss these different organs and how they have evolved physiologically to its environment.

Unlike its other cousins in the Mollusca family, octopuses have a considerably large brain in comparison to their bodies. In fact, they have the largest and most complex brain of any invertebrate. Even in the United Kingdom, under the Animals (Scientific Procedures) Act of 1986 has given the species a title of honorary vertebrate (Deb, 2010).

The brain sits just below the optic canal and wraps around the esophagus of the octopus. The brain is composed of 50 to 75 lobes and about half a billion neurons. Roughly two thirds of the neurons lie in the arms of the octopus, which uniquely have their own nervous systems (Miller, 2009). It is hypothesized 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 that involved separating and cutting the nerves of the arm from other nerves in the body and 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 propel the octopus. Each sucker has up to 10,000

neurons in it (Horton, 2008). As the octopus moves along the ocean floor, these neurons allow the octopus to learn its surroundings. They can remember the environments and keep a working memory of areas they have fed on in the past that may be more dangerous than others. When feeding in a treacherous environment both prey and predator must develop a varied range of hunting and defense behaviors.

Marine 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). 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’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...
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