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Bony fish have jaws and skeletons made of bone rather than cartilage. About 90% of the world's fish species are bony fish. Bony fish also have hard, bony plates called operculum which help them respire and protect their gills, and they often possess a swim bladder which they use for better control of their buoyancy.
The olfactory lobes are very large in fish that hunt primarily by smell, such as hagfish, sharks, and catfish. Behind the olfactory lobes is the two-lobed telencephalon, the structural equivalent to the cerebrum in higher vertebrates. In fish the telencephalon is concerned mostly with olfaction. [59] Together these structures form the forebrain.
There was a loss of opercular and extrascapular elements, enhancing head mobility in T. roseae compared to other tetrapodomorph fish. [1] The formation of the neck allowed for locomotion in shallow waters. This environment allows for less motility compared to the three-dimensional space that fish are able to orient themselves in.
There are similarities between fish eyes and those of other vertebrates. Usually, light enters through the fish eye at the cornea and passes through the pupil in order to reach the lens. Most fish species have a fixed size of the pupil while a few species have a muscular iris that allows for the adjustment of the pupil diameter.
Red represents a higher value (e.g. of temperature or the partial pressure of a gas) than blue so the property being transported in the channels flows from red to blue. In fish a countercurrent flow (lower diagram) of blood and water in the gills is used to extract oxygen from the environment. [6] [7] [8] All basal vertebrates breathe with gills.
A newfound fossil of a jawless fish is the oldest known vertebrate cranium preserved in 3D. The 455 million-year-old find could illuminate how vertebrate heads evolved.
The physiology of underwater diving is the physiological adaptations to diving of air-breathing vertebrates that have returned to the ocean from terrestrial lineages. They are a diverse group that include sea snakes, sea turtles, the marine iguana, saltwater crocodiles, penguins, pinnipeds, cetaceans, sea otters, manatees and dugongs.
A fish (pl.: fish or fishes) is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits.Fish can be grouped into the more basal jawless fish and the more common jawed fish, the latter including all living cartilaginous and bony fish, as well as the extinct placoderms and acanthodians.