What are three characteristics of mollusk?
The three most universal features defining modern molluscs are a mantle with a significant cavity used for breathing and excretion, the presence of a radula (except for bivalves), and the structure of the nervous system.
What are 2 or 3 characteristics that separate cephalopods from other mollusks?
Cephalopods, like most mollusks, have a mantle, a mantle cavity, a radula, and a U-shaped digestive tract. Cephalopods have two kidneys and three hearts, which pump blue blood.
What is a special characteristic of cephalopods?
General characteristics: Cephalopods are fast, furious carnivorous animals that use their beaklike jaws to bite and often immobilize their prey by injecting poison. Cephalopods are the only mollusks with a closed circulatory system and a well developed nervous system with a complex brain.
Is a cephalopod a mollusk?
Cephalopods are a group of molluscs that include the pearly chambered Nautilus, squids, and the octopus. They can be divided into three categories: the Nautiloidea (chambered Nautilus), the Ammonoidea (the extinct ammonites), and the Dibranchiata (squids, the extinct belemnites, and octopuses).
What are the characteristics of cephalopods and mollusks?
Characteristics: Cephalopods are mollusks, where the foot has developed into a set of arms or tentacles. Another common feature is their ability to squirt ink when threatened. Their body is symmetrical, i.e. the left and right side of the body is identical.
What are the characteristics of cephalopods and of mollusks?
Which is not characteristics of cephalopods?
Excretory system – Cephalopods possess a single pair of large nephridia which produce nitrogenous waste and excrete it out from the body. Therefore, from the above discussion it has been clear that Sea squirt is not a cephalopod.
Why are cephalopods considered advanced mollusks?
Cephalopod mollusks such as octopus, cuttlefish, and squid (coleoids) are of special interest for studying the evolution and function of learning and memory mechanisms at the system level. They are believed to have the most advanced cognitive behaviors of all invertebrates, rivaling the abilities of many vertebrates.
What are the main characteristics of mollusks?
Characteristic Features of Phylum Mollusca
- They are bilaterally symmetrical.
- They are triploblastic, which three layers.
- They show organ system grade of organisation.
- The body is soft and unsegmented.
- Body is divisible into three regions – head, a visceral mass, and ventral foot.
- Body is covered by a mantle and shell.
What do all cephalopods have?
All cephalopods have either arms or tentacles, have blue-colored blood, and have the ability to use propulsion to help them move swiftly when needed. They use gills to breathe and are invertebrates (lack backbones). Many cephalopods grow fast and die young, the average lifespan of most is just one to three years.
Which is the most important feature of a cephalopod?
General features and importance to humans. The cephalopods agree with the rest of the Mollusca in basic structure, and the ancestors appear to have the closest affinity with the ancestors of the class Gastropoda. The best-known feature of the cephalopods is the possession of arms and tentacles, eight or 10 in most forms but about 90 in Nautilus.
What are the characteristics of the phylum Mollusca?
The animals belonging to the phylum Mollusca have soft-bodies, triploblastic and bilaterally symmetrical. The study of Mollusca is called Malacology. They are sluggish invertebrates, with a thin fleshy envelope known a the mantle. The animals belonging to phylum Mollusca are soft-bodied, triploblastic, non-metameric coelomates.
What kind of mollusks have a hinged shell?
Bivalves The mollusks that have a hinged, two-part shell joined by strong muscles are called bivalves. Clams, Oysters, and Scallops are bivalve mollusks and are a familiar food source. This group are the the most specialized and complex group. The animals in this group are squid, octopuses, cuttlefish, and chambered nautiluses.
What are the members of the cephalopod group?
Octopus, squid, cuttlefish and nautilus are members of this group. The extinct forms surpass in number those that have remained alive, and as a species, has reached a great diversity at the end of the Paleozoic and Mesozoic.