Molluscs. Cephalopods. Gastropods. Bivalves. Anatomy. The basic body plan of mollusks consists of : A muscular foot , the mantle ( contains glands that secrete the shell ) and the visceral mass ( heart , digestive organs ). OCTOPUS ( cephalopod ).
Molluscs Cephalopods Gastropods Bivalves
Anatomy The basic body planofmollusksconsistsof: A muscularfoot, the mantle (contains glandsthat secrete the shell) and the visceral mass (heart, digestive organs)
OCTOPUS (cephalopod) The mosthighlyevolvedof the invertebrates. Muscularfoothasevolvedintotentacles. Octopus have no bonestructurebut do have a skull, a shellrudiment and a beak.
An octopus haseightarms, eachwithtworowsofsuctioncups. Ifitlosesanarm, itwilleventuallyregrowanotherone.
DefenseMechanisms 1.Their maindefense system is AVOIDANCE MIMICRY: Theyuse camouflage toescapepredators and catch prey . Theyreleaseink and initiate flight.
How do they camouflage? Bychangingshape: It can flatten out or contract inward in a variety of shapes. It can imitate a fish, like the flounder, or a sea snake. Bychanging color: Sacs of yellow, red, brown and black pigment called chromatophores cover their bodies and allow them to change colors and patterns by contracting their muscles. Tightening certain muscles can also transform the texture of their skin to look like the smooth ocean floor or a craggy reef.
The octopuses of the genus Grimpoteuthis are also known as "Dumbo Octopuses" from the ear-like fins protruding from the top of their head-like bodies, resembling the ears of Walt Disney's flying elephant. They live at extreme depths: 3000-4000 m.
The beautiful and deadly Blue-ringed Octopus can be found in the Pacific Ocean between Australia and Japan. When it is full grown, it is only the size of a golf ball.
The Giant Pacific Octopus, the largest and longest living species of octopus , can be found in the Pacific Ocean, from California To Alaska. The biggestonefoundto date weighed 272 Kg and hadanarmspanof 9 m.