Comment on the aquatic and terrestrial habits of amphibians.

Explanation

(i) The transition from aquatic to terrestrial living is clearly indicated in Amphibian.
(ii) They are the first vertebrates to live on land.
(iii) Amphibians have dual adaptation to live in aquatic and land environments.
(iv) The double life is called amphibious.
(v) In frogs the hind limbs have webbed feet.
(vi) The skin is moist and glandular usually without scale.
(vii) Respiration is by gills, lungs, skin and pharyngeal region.
(viii) The heart has three chambers, with two auricles and a single ventricle.
(ix) Fertilization is external.
(x) The larva is a tadpole, which is metamorphoses into an adult.