Along with the insects and vertebrates, it is one of the most diverse groups in the animal kingdom, with. Squid and octopus arose from gastropod ancestors to become some of the most highly evolved invertebrates. Cephalopodclass of mollusca encyclopedia of britannica. Part 2, the class cephalopoda and the genera conus and cypraea of the class gastropoda. Fishermen sometimes call cephalopods inkfish, referring to their common ability to squirt ink.
Living representatives include the squid, cuttlefish. The nautiloidea with a few species of the pearly nautilus, and the coleoidea, containing the squids, cuttlefishes, octopods and. Cephalopods are members of the mollusca phylum and include such marine creatures as squid, cuttlefish and octopus. These are ancient species that are found in all of the worlds oceans, and are thought to have originated about 500 million years ago. Cephalopod simple english wikipedia, the free encyclopedia. Color change and disguise smithsonian national zoological park. The valves are generally of equal size except in groups like the oysters and shape and are hinged at the back. Class cephalopoda locomotion cephalopods swim by expelling water from the mantle cavity through a ventral funnel. Phylum mollusca class pelecypoda pelecypods have two shells, or bivalves, that protect the soft parts of the animal.
A cephalopod is any member of the molluscan class cephalopoda such as a squid, octopus, or nautilus. Perhaps the most common type of locomotion used by cephalopods is jet propulsion. Two hearts are used to pump blood to the cuttlefishs large gills, and the third heart is used to circulate oxygenated blood to the rest of the body. Cephalopods are mollusks cephalopoda, a class which includes octopuses, squid, cuttlefish, and nautilus. Cephalopod, any member of the class cephalopoda of the phylum mollusca, a small group of highly advanced and organized, exclusively marine animals. The classificatory scheme followed in the present text is based largely on the plan laid down by e. Cephalopods became dominant during the ordovician period. Cephalopods have been among the dominant large predators in the ocean at various times in geological history. The ammonoid lineage survived for 300 million years in the oceans of the paleozoic and mesozoic. The foot, which is used for locomotion and anchorage, varies in shape and function, depending on the type of mollusk under study.
All cephalopods have a welldeveloped nervous system, complex eyes, and a closed circulatory system. The term cephalopoda obviously refers to the arrangement of the pedal tentacle about the head. In the shellbearing nautilus, the spiral shell is multichambered. The most highly developed cephalopods are the octopuses. Unit two exam animal biology 100 with head at arkansas state university, jonesboro studyblue flashcards. Cephalopoda article about cephalopoda by the free dictionary. They can aim the funnel to control the direction they are swimming. They have eight arms rather than ten like other squids. The openstax name, openstax logo, openstax book covers, openstax cnx name, and openstax cnx logo are not. Learn cephalopoda with free interactive flashcards. The cephalopod page features the class of marine mollusks that includes nautilus, squid, cuttlefish, and octopus. Early cephalopods were at the top of the food chain. Radial mantles muscles bring water into the mantle by increasing its volume of the cavity. The foot is lobed and developed into tentacles and a funnel, which is used for locomotion.
The foot is lobed and developed into tentacles and a funnel, which is used as the mode of locomotion. This page was last edited on 9 december 2019, at 16. The cephalopoda is an ancient and very successful group of the mollusca. Bio biology 201 with snyder at kansas state university. The cephalopods are an ancient and very successful group, some of which are now the most advanced of all the invertebrates. Cephalopod definition of cephalopod by merriamwebster.
Cephalopod creationwiki, the encyclopedia of creation. Octopus, squid, cuttlefish, and nautilus the cephalopod page. They display vivid coloration, typically seen in squids and octopi, which is used for camouflage. Cephalopods move using a jet proportion system from the mantle muscles contracting, and since the mantle encloses the body water is shot out through a narrow funnel. The class cephalopoda contains 650 species of nautilus, cuttlefish, squid and octopus. Hopefully i will get something written about each class in the not too distant future. Cephalopod family index washington state university. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot. Though snails and slugs gastropoda make the most various group and also the richest in species among all molluscs mollusca, their locomotion can usually be deducted to one specialised organ common to all their basic body plans the foot. The tetrabranchia nautiloidea with a few species of pearly nautilus and the dibranchia coleoidea, containing the squids, cuttlefishes. Woods cephalopod work has been featured on the discovery channel and national geographic in tentacles and squid invasion. The vascular system, the brain which is encased in a cartilaginous cranium, and the sense organs particularly the eyes are highly developed in the cephalopoda.
Cephalopods are a class of shellbearing animals as well as mollusks with a reduced shell. The octopus, squid, cuttlefish, and chambered nautilus are familiar representatives. Class cephalopoda head foot animals, includes octopuses, squids, cuttlefish, and nautiluses. Get an answer for snail class gastropoda, clams class bivalvia and cephalopods class cephalopoda all compositions. Zoology questions and study guide quizlet flashcards by. The class, cephalopoda, includes the chambered nautilus, cuttlefish, squid, and octopus, as well as fossil ammonite and other fossil forms. Classification of phylum mollusca biology libretexts. Mollusk, any softbodied invertebrate of the phylum mollusca, usually wholly or partly enclosed in a calcium carbonate shell secreted by a soft mantle covering the body. The presence of a shell in many representatives of this class has yielded an impressive fossil record. They have long been among the dominant large predators in our oceans. Mukhopadhyay, in marine faunal diversity in india, 2015. The study of cephalopods is a branch of malacology known as teuthology. They are the only molluscs with entirely closed circulatory systems. Cephalopods are marine predators, feeding on fish, crustaceans, and other molluscs.
Squid rival fishes in their mobility and dominance as openocean predators. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles muscular hydrostats modified from the. Tommotia, an early cephalopod, had squidlike tentacles but also a snaillike foot it used to move across the sea floor. Locomotion in cephalopods is facilitated by ejecting a stream of water for. Cephalopods include both animals with shells as well as animals in which the shell is reduced or absent. A total of 62 species belonging to 17 genera and 10 families of the class cephalopoda are reported by various research team workers from the zoological survey of india, kolkata. Proper usage and audio pronunciation of the word class cephalopoda. These fleshy flexible feet are characteristic of the class, and give to it its systematic appellation of cephalopoda, signifying headfooted. This basic plan is changed and adapted, for the requirements of different lifestyles, almost beyond recognition in some of the 6 classes of mollusca.
Files are available under licenses specified on their description page. All animals in this class are predators and have beaklike jaws. Natural history, molluscacephalopoda wikisource, the. It is a very diverse class, with 600 living species and more than 7500 fossil species. The class developed during the late cambrian and were the most common and varied marine life forms during the palaeozoic and mesozoic eras. Their relative brain size rivals that of vertebrates and is far larger than any other invertebrate group. Suckers are present on the tentacles in octopuses and squid. These chambers are filled with gas or water to regulate buoyancy. This then is the plan of a basic unevolved mollusc. Cephalopods are strictly marine and are found in all of the worlds oceans. Cephalopod definition is any of a class cephalopoda of marine mollusks including the squids, cuttlefishes, and octopuses that move by expelling water from a tubular siphon under the head and that have a group of muscular usually suckerbearing arms around the front of the head, highly developed eyes, and usually a sac containing ink which is ejected for defense or. Class cephalopoda head foot animals includes octopi, squids, cuttlefish, and nautilus. The class cephalopoda literally headfooted includes squids, cuttlefish, octopuses, and nautiluses and extinct relatives, the goniatites, ammonoids, and ammonites.
Three main clades are typically identified within the cephalopoda cladogram b, left. Cephalopoda is the most morphologically and behaviorally complex class in phylum mollusca. Cuttlefish facts, worksheets, physical characteristics. To travel by jet propulsion, a cephalopod such as a squid or octopus will fill its muscular mantle cavity which is used to get oxygenatedwater to their gills with water and then quickly expel the water out of the siphon.
We are a small business that sells rock, mineral, and fossil collections for use in schools and other educational organizations. Bay of plenty polytechnic marine science cephalopoda lecture. The nautilus from the latin form of the original ancient greek. They are predators feared in the sea, because they can see very well they have highly developed eyes like the vertebrates and also very highly developed behavioural patterns. Unit two exam animal biology 100 with head at arkansas. There are approximately 650 to 700 extant species of cephalopods in two subclasses and five orders. Information about class cephalopoda in the dictionary, synonyms and antonyms. All structured data from the file and property namespaces is available under the creative commons cc0 license. Choose from 284 different sets of cephalopoda flashcards on quizlet. They are equipped with highly developed eyes and other sensory organs.996 1002 656 110 1406 165 12 1190 491 945 696 691 821 1351 1418 1070 392 383 753 479 1052 1018 604 735 1090 746 955 718 523 1066 803 275 1055 482 74 1085 1102 748 561 63 208