What did cephalopods evolve from?
mollusc
Cephalopods evolved during the Cambrian ($530 Ma) from a monoplacophoran-like mollusc in which the conical, external shell was modified into a chambered buoyancy apparatus.
Is a cephalopod a fish?
Cephalopods are all marine. Fish live in both marine and freshwater environments, and there is in fact strong evidence that all marine fish have descended from ancestors living in fresh waters. Each of the major forms of modern cephalopods has a fish counterpart: In tide pools and rocky substrata: Octopus vs.
What are cephalopods related to?
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).
Where do cephalopods come from?
The cephalopods are a diverse class of mollusks (a group that also includes snails and bivalves) that emerged during an explosion of animal diversity in the oceans during the Cambrian period, over 500 million years ago (mya). Today, scientists divide the living cephalopods into three groups, called superorders.
How long ago did cephalopods evolve?
Tannuella is the oldest fossil to have been assigned to the cephalopods, dating from the Early Cambrian (Atdababian and Botomian), ~522 million years ago. Its position in this group is suggested based on its shape and the presence of chambers.
Which of these is a cephalopod?
Cephalopod, any member of the class Cephalopoda of the phylum Mollusca, a small group of highly advanced and organized, exclusively marine animals. The octopus, squid, cuttlefish, and chambered nautilus are familiar representatives.
Why are cephalopods so big?
Although some of these groups are known from scant fossil material, or in some cases a single specimen, it appears that gigantism has evolved a number of times in cephalopods. In living Architeuthis and Mesonychoteuthis species large size is thought to be an adaptation to the harsh environment of the ocean depths.
What is the oldest cephalopod fossil?
Tannuella
Tannuella is the oldest fossil to have been assigned to the cephalopods, dating from the Early Cambrian (Atdababian and Botomian), ~522 million years ago. Its position in this group is suggested based on its shape and the presence of chambers.