Question

18. Write any 4 general features of class: Chondrichthyes, Osteichthyes, Amphibia Reptiles, Aves and Mammalia.​

Answer 1

Answer:

Chondrichthyes is a class that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or bony fishes, which have skeletons primarily composed of bone tissue. Chondrichthyes are jawed vertebrates with paired fins, paired nares, scales, and a heart with its chambers in series. Extant chondrichthyes range in size from the 10 cm (3.9 in) finless sleeper ray to the 10 m (32 ft) whale shark.

Osteichthyes , popularly referred to as the bony fish, is a diverse taxonomic group of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilage. The vast majority of fish are members of Osteichthyes, which is an extremely diverse and abundant group consisting of 45 orders, and over 435 families and 28,000 species.

Amphibians are ectothermic, tetrapod vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia.

Reptiles, as most commonly defined, are the animals in the class Reptilia /rɛpˈtɪliə/, a paraphyletic grouping comprising all amniotes except synapsids (mammals and their extinct relatives) and Aves (birds).[1] The class comprises turtles, crocodilians, snakes, amphisbaenians, lizards, tuatara, and their extinct relatives. In the traditional Linnaean classification system, birds are considered a separate class to reptiles.