Corresponding Reading Material ~ Squid section in Lab Manual ~ Levinton: Chapter 8. Cephalopods. The Phylum Mollusca. General Characteristic: 1. Bilaterally symmetrical 2. Possess a mantle which secretes the shell 3. muscular foot
1. Bilaterally symmetrical
2. Possess a mantle which secretes the shell
3. muscular foot
4. radula (file-like feeding structure); modified in some
5. Possess a one way gut
6. Reproduces sexually
There are 7 different classes within the mollusk phylum:
~ Class Polyplacophora - Chitons
~ Class Aplacophora - Mollusks without shells
~ Class Monoplascophora - Mollusks with one shell
~ Class Schapoda - Mollusks with a tubular shell
~ Class Gastropoda - Gastropods, snails and their relatives
~ Class Bivalvia - Bivalves
~ Class Cephalopoda - Cephalopods, squids and octopuses
Are the most highly evolved mollusks and invertebrates.
1. A funnel derived from the molluscan foot
2. Chitinous beaks
3. Complex eyes.
4. Have a head surrounded by a foot divided into arms
5. Are carnivorous
6. Well organized nervous system
7. Have complex behaviors
The nautilus is different from many of the other cephalopods because it has retained its shell.
Today there are approximately 650 different species of cephalopods.
It lives in warm, shallow reefs off the coast of Australia, New Guinea, Indonesia, and the Philippines.
It has a life span of about 1.5 years.
The Blue Ring Octopus is the most venomous octopus.
It catches prey with its arms, bites it with its tough beak, and kills it by delivering a poison in the saliva. The poison is a neurotoxin that is strong enough to kill a human.
Navigation and Spatial Maps:
A group of Octopus at the Seattle Aquarium were subjected to 10 trials over 5 days. On the first trial each was given a floating bottle. During this trial all the individuals grabbed the bottle and brought it to their mouths. Several of the octopuses jetted water at the bottle during later trials. But two of the octopuses aimed water jets that made it circle the tank and come back to them for further jets. One octopus set it up so that the bottle circled the tank for a round trip time of 2 minutes. The other made it return every 30 seconds.