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How do they Live?
Being the earliest tetrapods to turn to a terrestrial life, the primitive amphibians are regarded as intermediary life-forms between fishes and reptiles. Modern amphibians do not, however follow this, and in their morphology, radiating to the far corners of the earth, have achieved various forms that do not suggest any relation to this conclusion.However their features are specific to their environment. One such example is the skin, which is kept moist by mucus-secreting glands under their skin and is involved in respiration and maintenance of water balance.
Members of the three kinds of amphibians are:
Frogs and toads (anurans)are tail-less, somewhat squat amphibians with long, powerful hind limbs modified for leaping long distances. This is their mode of locomotion.
Salamanders and newts ,on the other hand , have tails and two pairs of limbs of roughly the same size and have less-specialized structures than the other two kinds of amphibians.
Caecilians are limb less, worm like, and highly adapted for a burrowing existence.
Traditionally, all these orders have been united in one class by the feature that is special to them all tetrapods - the amniotic egg. Other general defining characteristics include glandular skin that lacks epidermal structures that are common to other groups of creatures that turn adult after metamorphism
of the aquatic larvae. Other such features that they are devoid of includes:
