Octopus Inc.

Octopus Inc.

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Nutrition

An octopuses mouth is actually underneath its head. Inside the opening there is a beak. It is very hard and very sharp. Because octopuses like to eat things with shells like crabs, lobsters, and clams, the beak needs to be sharp enough to crack the shells. Once the octopus finds the prey, it paralyzes it until it can no longer escape. The octopus is sometimes referred to as the "Merciless Mouth." The digestive tract is complete and ciliated, with a mouth and complex stomach. The pattern of the stomach varies according to the moll The digestive tract is complete and ciliated, with a mouth, anus and complex stomach. The pattern of the stomach varies according to the mollusks diet. Food is taken up by cells lining the digestive glands arising from the stomach, and then is passed into the blood.

Respiration

The octopus uses four main methods for respiration. First, it uses a pair of well developed gills along with well developed blood vessels. Second is the mantle which is an organ found in mollusks. Third is the epidermis and that is the outer layer of skin. Fourth is the siphon which pumps water through the gill system to enable the octopus to breathe. The siphon is also used for movement as the octopus pumps his way through the water rather than swimming.

Note: The pouches which you can clearly see are called the siphons.

Body Covering

The octopuses body has three main sections: the head, the foot, and the visceral mass. The head shows increased cephalization (centralization of neural and sensory organs in the head), the foot is used for locomotion, and the visceral mass contains all of the body organs and includes the mantle.

Reproduction

A female octopus lays thousands of eggs at a time and for about six months she does not eat, but spends all of her time protecting the eggs from other sea creatures. Like Pacific salmon, a female octopus will reproduce only once during her lifetime. After her eggs hatch, the female dies. The babies are about the size of a grain of rice when they hatch. They float to the water's surface, where they live for about six weeks. At this point, they are large enough to survive life in the ocean depths. The octopus uses sexual reproduction.When octopuses reproduce, they use a specialized arm called a hectocotylus to insert spermatophores (packets of sperm) into the female's mantle cavity. The hectocotylus is usually the third right arm. In some species, the female octopus can keep the sperm alive inside her for weeks until her eggs are mature. After they have been fertilized, the female lays roughly 200,000 eggs (this figure dramatically varies between species). The female hangs these eggs in strings from the ceiling of her lair.After the eggs hatch, the young larval octopuses must spend a period of time drifting in clouds of plankton, where they feed on copepods, larval crabs and larval seastars until they are ready to sink down to the bottom of the ocean, where the cycle repeats itself. In some deeper dwelling species, the young don't go through this period. This is a dangerous time for the larval octopuses; as they become part of the plankton cloud they are vulnerable to many plankton eaters.

Bibliographys:

The International Wildlife Enceyclopedia/volume12

By:Dr. Maurice and Robert Burton

Marshall Covendish Corporation/New York

Copyrite 1969

Bibliography's:

Biology, God's Living Creation/page 528

By: Keith Graham, Laurel Hicks, Delores Shimmin, George Thompson

Copyrite 1986

A Beka Book Publications

Phylum: Mollusca

Class: Cephalopoda

Genus: Octopi

Interesting Facts

Did you know that...

an octopus has a very short life span and that some species live only six months.
an octopus has three hearts.
the octopus ranges in size from a few centimeters to the height of an octopus which is up to ten meters.
the octopus is mostly found in oceans near the equator and sometimes will live in human litter like cans. Octopuses especially look for muddy, rocky, or sandy areas.

Circulation

"The circulatory system (as shown in Figure 16.17) of an octopus is open, meaning that there are no capillaries and veins: one or more hearts pump the blood through the arteries to spaces called sinuses which surround the organs, allowing the tissues to exchange materials with the hemolymph (circulatory fluid). The hemolymph is drawn back into the heart as the heart relaxes."

Excretion

The octopuses kidneys or Metanephridium are distinct organs, not just scattered cells.Excretory functions are carried out by a pair of nephridia, tubular structures that collect fluids from the coelom and exchange salts and other substances with body tissues as the fluid passes along the tubules for excretion. The nephridia empty into the mantle cavity.

Responses

The octopus has chemical and touch receptors, statocysts (its balance), and ocelli (the eye spots). Cephalopods have a well developed brain and can even be trained. They have complex sensory organs which can easily pick up movement and their eye structure is similar to that in humans.

Movement

The octopus moves by either crawling or swimming. Its main means of slow travel is by crawling on its arms while supported in the water. Swimming is its means of fast travel. The octopus swims by expelling a jet of water from the mantle. A mantle is an organ found in mollusks--it is the dorsal body wall covering in the main body. When moving to escape a predator, the octopus spurts a cloud of ink to disorient the predator and mask its escape.

Support

An octopus has eight arms and a soft body. Each arm has two rows of suction cups. If one arm is lost, an octopus can regrow another arm. It has an eye on each side of its head and cannot hear. This marine animal has blue blood. The octopus is an invertebrate which means it has no backbone.