Question

Cartilaginous and bony fishes Classify the following characteristics to describe the differences between cartilaginous fishes and bony fishes. Cartilaginous Fish Gills are covered with an operculum Skeletons are composed of bones Include gold fish, coelacanths, lion fish, and sea horses Bodies are covered with dermal denticles that project posteriorly Contain a closed single- loop circulatory system Have a lateral l ine system Bony Fish Include rays, sharks, and skates Skeletons are composed of cartilage Lack a gill cover May contain swim bladders

Answer 1

Features of cartilagenous fishes :-

Also called as chondrichthys-

Skelton are composed of cartilage. Hence also called as elasmobranchii

Bodies are covered with dermal denticles that project outside.

( these dermal dentocles are called as placoids, so called because it emerges from the dermal layer of skin, and helps in protection from predators , also helps in swimming by creating turbulence)

Lack a Gill cover. In cartilagenous fishes the giills are not covered by an operculum (and are exposed contain a set of 5 gills on each side.)

Includes sharks, rays and skates.

Circulatory system is closed and single looped.

(there is one mail loop which carries blood and nutrients from the heart to the gills and body parts and vice versa in cartilagenous fish, they contain a two chambered heart.)

Features of bony fishes or osteichthyes -

Skeletons are composed of bones.

Gills are covered with an operculum.

Contain 3 sets of gills on each side covered by an operculum ( it is a protective covering of gills, used for breathing and feeding.)

May contain swim bladders or gas bladders.

( these swim bladders help to maintain buoyancy and this structure absorbs gases in the water to deflate or inflate to aid in maintaining an equilibrium.)

Have a lateral line system. ( is a sensory system to detect changes in the surroundings such as pressure changes, movements.)

Includes gold fish, coelocanths, lion fish and sea horse.

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