Explain how animals in Vertebrata are classified into further subgroups.
Vertebrata is divided into two superclasses, viz. Pisces and Tetrapoda. Animals of Pisces have streamlined body with fins and tails to assist in swimming. Animals of Tetrapoda have four limbs for locomotion. Tetrapoda is further classified into following classes: (a) Arnphibia: Are adapted to live in water and on land. Can breathe oxygen through skin when under water. (b) Reptilia: These are crawling animals. Skin is hard to withstand extreme temperatures. (c) Aves: Forelimbs are modified into wings to assist in flying. Beaks are present. Body is covered with feathers. (d) Mammalia: Mammary glands present to nurture young ones. Skin is covered with hair. Most of the animals are viviparous.
