Octopus lifecycle

Giant Pacific Octopus

Lifecycle

First, the female releases a chemical attractment. Males are drawn to the female by following the smell. So the problem is that the female may attract more than one male, who sometimes fight for the opportunity to mate with the female. The stronger one will win, but in some cases the female mates with more than one male. Once the female found its mate, the male would transfer packages of sperm to the female, with the end of its third arm, where there are no suckers. The female stores the sperm for later use. Once the male leaves, the female looks for a den in which to lay her eggs. Usually its under a large rock. She then gathers other rocks from surrounding area to close up the den, leaving just a little gap. Then she lays her really small eggs (up to 57,000). The female stays in the den for about six months, taking care of the eggs and making sure that they don't get covered by algae and bacteria. She blows oxygen across the eggs, ensuring a constant oxygen supply. The baby octopuses grow in the eggs and when the big night arrives, the nest of eggs will hatch. The tiny babies will swim to the water surface, which is a long and dangerous journey for them. The female crawls out the den and dies. The octopus larvae will move to the sea floor once they are bigger. It grows and grows and eventually, only sea lions, seals, halibuts, and lincods will be able to feed on an adult octopus. They get sexually mature in about three years and the cycle starts from the beginning.

Octopus moving

The Giant Pacific Octopus

Moving

The main method of movement used by the octopus is to crawl, using their muscular arms and suckers to anchor them to the bottom. They can also move by jet propulsion. The head of the octopus, the mantle, contains a muscular layer used to circulate water through the mantle cavity. By dilating and contracting the muscular layer opens and closes, forcing water to pass through the funnel. Some of the energy produced by this action is stored until the cavity is refilled with water, and then released as the water is pushed out the funnel, propelling the octopus head-first through the water. This method is mostly used when they have to escape from enemies or when they are following a prey.

Octopus response

Octopus Response

Octopuses have the ability to change color withis a couple seconds. They do that often to get invisible for their predators, when they are scared. But a change in color can also be a change in the octopus' mood. White is the color for fear, red for anger, and brown is the neutral color, which is most often seen. Often when an octopus feels threatened, it tries to escape, or uses its ink sac, to expel a cloud of dark ink to confuse the predator (shark or lion for example). The ink forms a dark cloud in the water. That gives the Octopus a few more seconds to escape.
Octopuses are known for being very intelligent animals. Sometimes when they feel threatened, they construct barricades made of large stones on the ocean floor. They would hide behind it so that the predators couldn't attack them.

Octopus Respiration

The Giant Pacific Octopus

Respiration

Octopus don't have lungs. They use gills to respire. The gills are located inside the mantle cavity, behind the mouth. As the octopus moves, water gets passed into its mouth to the gills and back out. The gills are made up of many feathery filaments. This filaments allow for a larger surface area, which the oxygenated water is passed over. As the water is pushed over the surface of the gills, oxygen is picked up by the blood. Because there is more oxygen in the water than there is in the blood, it diffuses from the water into the blood stream. The blood travels in an opposite direction in the gills than the water is traveling, which allows for a maximum oxygen exchange per breath. An octopus has three hearts. Two of the three pump the blood through the gills. The oxygenated blood that leaves the gills is pumped throughout the rest of the body by the third heart. That's how the cells in an octopus get the needed oxygen.

Octopus feeding and digesting process

The Giant Pacific Octopus

Feeding and digesting process
The giant pacific octopus mosty hunts at night. When it gets dark, it crewls out of its den and searches for prey. It is able to change its color so that its almost invisible between the rocks and coralls. The feeding process depends on what kind of prey the octopus is hunting. If its prey is hard-shelled, then it uses its tongue, which is covered with little teeth, to bore into the shell. If the prey is a large animal, "soft" animal, then the octopus uses its long arms which are covered with suckers, to seize and hold on to it. Then it squeezes the prey into its mouth, where it has a beak, and bites the animal injecting it with a poison, which kills its prey. Octopus may kill a multiple number of prey on an outing. It stuffs the dead prey into its digestive gland. Once the octopus is satiated, it will return back to its den and release a digestive enzyme. After a couple hours the digestion process is over, and the octopus will then expel the hollow skeleton of whatever animal it has just caught. The digestive enzyme breaks down the flesh and insides of the prey so it can suck it up as a liquid. This makes it easier for the octopus to eat larger preys such as sharks, and larger fish. Usual preys are squids, scallops, crabs, and clams.

Groups within the phylum

Main groups within the phylum
The main groups within the phylum are...

- Gastropoda (snail, snug, whelk...)



- Bivalvia (clam, oyster, scallop...)



- Cephalopoda ( squid, octopus, nautilus...)



- Polyplacophora (chiton)



- Scaphopoda (tusk shells)

common to all mollusks

What is common to all Mollusks?
All mollusks have a...

- shell
- muscular foot for moving or anchor animals
- gills (water-dwelling) or lungs (land-dwelling)
-mantle
- digestive and reproductive parts
- a tongue-like organ called radula
- an open circulatory system in which blood washes over organs
- soft body ( "mollus" means "soft" in latin)