Which is the animal with a backbone or bony skeleton?
Vertebrates only represent 2-3% of the species on Earth but they are the species that people are most familiar with. Vertebrates are animals with a backbone or bony skeleton. They also have an endoskeleton and neural crest cells.
Why are the bones of a shark made of cartilage?
Sharks are one of the oldest and least changed of all the living back-boned jawed creatures. But because their skeletons are made of cartilage much of their early fossil record is poor. Cartilage is a rubbery tissue that forms the framework for bones to ossify (harden) upon.
Why do sharks have lighter bones than other vertebrates?
Modern sharks most likely evolved their lighter cartilaginous skeletons to become faster swimmers, to evade predators and swiftly catch their prey. The loss of bone in their skeleton is also supported by the fact the oldest and most basal of all jawed vertebrates, the placoderms, had heavy bony skeletons.
How old are the bones of a shark?
Cartilage doesn’t preserve as well as bones, so the early shark fossil records are based mostly on isolated scales and teeth. Although the oldest of these shark-like scales is 480 million years old, the oldest complete shark fossil, Cladoselache, is only about 360 million years old.
What kind of skeleton does a bony fish have?
The skeleton of a modern bony fish, as shown below (and even the arrow above) represent the end point of a long period of evolution. The skeleton of the first fish was probably very like the skeleton of a modern Hagfish, which is little more than an amalgamation of pieces of cartilage.
Which is an example of a cartilaginous fish?
Cartilaginous fish are jawed vertebrates with paired fins, paired nares, scales, a heart with its chambers in series and skeletons made of cartilage rather than bone. Examples of cartilaginous fish include: In cartilaginous fish, the endoskeleton is completely made up of cartilages.
How are the jaws of a bony fish different?
Bony fish have two sets of jaws: oral jaw and the pharyngeal jaw. The oral jaw allows the fish to catch food, to bite it, and to chew it. Teeth only grow along one side of the jaw. In bony fish, reproduction is external. The fish produce a significant number of small eggs with very little yolk.
Sharks are one of the oldest and least changed of all the living back-boned jawed creatures. But because their skeletons are made of cartilage much of their early fossil record is poor. Cartilage is a rubbery tissue that forms the framework for bones to ossify (harden) upon.
