Rachel Nuwer

Oct 31 2013

Fri Nov 30  2018

Octopuses are waaay old. The oldest known octopus fossil belongs to an animal that lived some 296 million years ago, during the Carboniferous period. That specimen belongs to a species named Pohlsepia and is on display at the Field Museum in Chicago. Harmon Courage describes it as a “flattened cow patty” or a “globular splat,” but a close examination reveals the tell-tale eight arms and two eyes. Researchers aren’t sure, but possibly there’s an ink sack there, too. In other words, long before life on land had progressed beyond puny pre-dinosaur reptiles, octopuses had already established their shape for the millions of years to come.

Oldest known octopus fossil is approx. 295 million years old.

Shape was less refined and detailed than today, though internal layout was similar.

Not found

Not Found

Fri Nov 30 2018

Northern Pacific Ocean from Japan to Alaska and California

Octopuses, including the giant Pacific octopus, are also known for having blue blood thanks to a copper-rich protein called hemocyanin in their bloodstream, which is efficient for oxygen transport in cold ocean environments.

Giant Pacific octopuses only live an average four to five years in the wild, yet they are still considered one of the longest-living octopus species. Octopuses typically die shortly following breeding. After mating, a female will lay up to 74,000 eggs or more in a deep den or cave and live there for seven months watching over them. During this time, dedicated mothers won’t venture out for food, and shortly after the young hatch, the mother will die. Because of this behavior, it is difficult to know population numbers of the giant Pacific octopus. Even though these octopuses are still commercially fished in both North America and Japan for food and bait, populations have been naturally resilient so far.

They can be found in the Northern Pacific Ocean, from Japan to Alaska– along with California.

Hemocyanin is helpful for oxygen transport in the bloodstream when living in cold environments.

Christy McKinnon

2001

Dec 2 2018

They are active members of the marine food web, which supports all life in the sea.  As plankton, they consume other plankton and are also an energy source for other types of primary consumers.  Adult diet includes mostly crustaceans, mollusks, and fish including small crabs, bivalves, snails and other octopus (Sheel 2001c).  When eating shelled prey they may use arms to pull it apart, bite it with its beak or use the radula to actually drill through the shell.  The mouth is able to secrete enzymes that soften the shell and toxins to paralyze prey and dissolve tissue.

When quick moving food approaches it is carefully observed by the octopus, which changes color to a deep reddish brown upon the sighting.  If it is not too intimidated, (octopus are timid creatures), it leaps out of it’s home and smoothly stalks the prey until it attacks, covering it’s victim with it’s interbranchial web and gathered by the arms to the mouth.  When these animals thrive on slow moving organisms, hunting is most successful by touch.  The octopus scurries about rocks in search of food that lives in the crevices of rocks and under stones.

The phylum Mollusca is a group of over 150,000 known soft bodied animal species that have a muscular foot, (usually used for movement), a visceral mass containing most of the internal organs, and a mantle, (a fold of tissue above the visceral mass which in many mollusks secretes a shell made of calcium carbonate (Campbell 1999.)

Mollusks shared a recent common ancestor with the Lophophorate phyla which are suspension feeding animals that have ciliated tentacles surrounding their mouth that draw in water despite their sessile existence.  All lophophorates, such as tube worms and lamp shells, secrete some type of hardy substance which creates the animals tube or shell (Campbell 1999).  

It seems that mollusks evolved most directly from the lamp shells which greatly resemble clams but have tentacles surrounding their mouth.  The class Bivalvia, including clams, oysters, mussels and scallops, are the mollusks that most closely resemble these animals. The muscular foot becomes substantially more adapted for locomotion in Gastropods, a distinct head appears, suspension feeding is lost to grazing and the development of the radula, and tentacles appear much more profound and provide advanced sensory ability when compared with Bivalves. 

Active members of marine food web. Consume other plankton, and serve as an energy source for other primary consumers. Diet includes crustaceans, mollusks, small crabs, fish, bivalves, snails, and other octopus (if provoked). Cephalopoda means head foot. Mollusks are closely related to the Lophophorate phyla. Examples include tube worms and lamp shells.

Christy McKinnon

2001

Dec 3 2018

Octopus belong to the class Cephlaopoda, meaning “head foot,” which is a group of carnivorous animals with a closed circulatory system, advanced nervous system, well developed sensory organs, and a complex brain.  Most cephalopods have a mouth with a beaklike jaw that is located at the center of several long tentacles and are capable of injecting poison into their victims.  All but the chambered nautiluses have a reduced, internal or missing shell (Campbell 1999). 

The shell in octopuses and squid has been lost as these animals became advanced predatory carnivorous invertebrates, while other structures characteristic of cephalopods became more pronounced.  “The ancestors of octopuses and squids were probably shelled mollusks that took up a predaceous lifestyle, the loss of the shell occurring in later evolution.  Shelled cephalopods called ammonites, many of them very large, were the dominant invertebrate predators of the seas for hundreds of millions of years until their disappearance during the mass extinctions at the end of the Cretaceous period (Campbell 1999).  

From such an ancestral creature, evolved the various families, genus and species of Octopoda, which are characterized by their eight arms that may be fused together by a web, are nocturnal, solitary creatures with a high growth rate and usually die after spawning, including O.dofleini.  O.  dofleini, as well as the other species that belong to this order have acquired their unique characteristics through an evolutionary process known as adaptive radiation.  Adaptive radiation is defined as the emergence of numerous species from a common ancestor introduced into an environment, presenting a diversity of new opportunities and problems (Campbell 1999).  During adaptive radiation various traits of various individuals depending on the environment become favored by natural selection and successfully dominate the next generation while unfavorable traits are eliminated.  After numerous generations, traits, such as arm length or number of spots, become so different for the entire population of Octopoda that new species develop.  

Belong to class Cephalopoda. Means head foot. Closed circulatory system, advanced nervous system, well developed sensory organs. Previously had noticable shells, though they became lost.