### seafood | shellfish:

Cephalopod
* All cephalopods are carnivores that have to digest large prey
  - carnivorous and possess a radula and powerful beaks
  - much better swimmers than any other species of mollusk
* All cephalopods have flexible tentacles
  - internal shells that have chambers connected by siphuncle
* All cephalopods swim by jet propulsion, however squid are the most efficient at it
  - rapidly expelling water from their mantle cavity
* Many cephalopods are good mothers and stay with their eggs until they hatch
  - short lived and only reproduce once
  - only reproduce once and die
  - rely on their acute vision to detect predators as well as locate prey
  - use venomous secretions to speed up th e death of their prey
* Most cephalopod are semelparous, they die after they lay their eggs.
* Most cephalopods also have a radula which consists of several rows of teeth
  - are semelparous, reproducing in one large effort at the end of the life-cycle
  - can change their colour to blend with their surroundings
* Most cephalopods have beaks, tentacles and jaws and are active predators
  - separate sexes and fertilization is internal
* Some cephalopods can adjust their body shape to move through the water more easily
  - move by crawling along the ocean floor or sea bed with their arms
  - exhibit extraordinary camouflage.
  * There are at least 800 different living species of Cephalopods. Cephalopods are found in all the oceans of the world and at all pelagic levels
* adapt the mollus- can body plan to an active way of life.
* also display a nocturnal feeding activity.
* also have a beak, very similar to that of a parrot, used to help bite into prey
  - parrot-like beak which is used in biting into prey
  - anatomy very different from our own
  - squirt dark ink to hide their escape
  - use their tentacles to move and help maintain their velocity
* are a class of marine mollusks
  - mollusk that includes squid, nautilus and octopus
  - mollusks, a phylum that also includes snails, chitons, clams and slugs
  - active necto-benthic carnivores
  - agile carnivores
* are all carnivorous
  - invertebrates and are closely related to other molluscs like slugs and snails
  - animals
  - benthic or pelagic, and entirely marine
  - carnivores that live only in marine habitats
  - dioecious
  - especially impressive for their advanced brains and sophisticated eyes
  - exclusively marine animals
  - throughout the world oceans at all depths
  - generally very rare fossils within the chert gravels
  - gonochoric which means their sexes are separate
  - intelligent and highly visual
* are marine and predaceous
  - animals and it can be found in oceans all around the world
  - organisms
  - predators that use beaklike jaws and a radula to crush or rip prey apart
  - predators, feeding on fish, crustaceans, and other molluscs
  - muscular animals, able to subdue struggling prey
  - of major importance in the diets of many fishes and marine mammals
  - predators and use their tentacles to capture and manipulate prey
  - so adept at using their tentacles, they can function independently
* are the aliens on Earth
  - glitziest of the invertebrates
* are the most active and intelligent of the mollusks
  - of all the molluscs and can even rival the fish for swimming speeds
  - advanced class of the mulluskes
  - highly evolved of all molluscs
  - intellectual invertebrates
* are the most intelligent invertebrates and have good senses and large brains
  - non-vertebrate animals known to exist
  - of all invertebrates
  - intelligent, most mobile, and the largest of all molluscs
  - only mollusks with a closed circulatory system with three hearts
  - onlymollusks that have a closed circulatory system
  - unique among mollusks in having a closed circulatory system
  - water-breathers, but other mollusks, including snails and slugs, exist on dry land
  - worldwide in distribution and are found in all depths of the ocean
* breathe using gills.
* can be cannibalistic especially when they are underfed.
* even have a large brain with ganglia located inside of a cranium.
* have a beak-like structure that they use to feed.
* have a closed circulation while gastropods have an open circulation
  - circulatory system, a complex brain, and well-developed sense organs
  - more developed nervous system than other mollusks
* have an amazing ability to change color very rapidly
  - endoskeleton, if any, and octopuses have no skeleton at all
  - long, flexible arms, equipped in most cases with suckers for prey capture
  - tentacles attached to the head, and ink sacs, which serve to evade predators
* have the most advanced nervous systems of all invertebrates
  - complex brain of any invertebrate
  - two kidneys and three hearts, which pump blue blood
  - unique abilities which most mollusks lack
  - very short lives
* lack feet and their shells are chambered
  - larvae, and the young develop from large, yolk-filled eggs
* live in salt water.
* means head-footed.
* move in part by jet propulsion.
* range in size from only a few grams to hundreds of kilograms.
* remains from the stomachs of sperm whales caught in the Tasman Sea.
* show some advances evolutionary adaptations.
* swim by forcing water out of the mantle cavity through the siphon.
* typically guard and clean their egg masses.
* use a strong beak to eat other animals that they catch with their tentacles
  - jet propulsion for locomotion
+ Cephalopod, Nervous system and behaviour
  * Cephalopods are the most intelligent invertebrates and have good senses and large brains. The nervous system of cephalopods is the most complex of the invertebrates, and their brain to body mass ratio falls between that of warm and cold blooded vertebrates. The brains and lives of cephalopods'. Oxford University Press
  - behaviour, Moving around
  * Oxygenated water is taken into the mantle cavity to the gills. By contracting the mantle's muscles, the water is pushed out through the siphon, made by a fold in the mantle. Motion of the cephalopods is usually backward as water is forced out forwards, but the siphon can be pointed in different directions. Some cephalopods can adjust their body shape to move through the water more easily