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- 1 decade agoFavorite Answer
Whether there is the amphibians main available tail and do the four limbs classify: The frog, the toad are belong without the tail, have four limbs' anura, has approximately 3500 many kinds of; Moreover, has the tail also to have four limbs' salamander, the salamander belongs to the urodela, has 350 kinds approximately; Finally has the tail actually not to have the four limbs, the long elephant earthworm's apoda, take earthworm yuan as representative, only more than 160 kinds.
Although their outlook so difference, but still held the common characteristic - moist exposed skin, the young animal in the water with the gill breath, the adult in the land the amphibious life which with the lung, the oral cavity internal membrane and the skin breathes - because of so, only will then have “the amphibians” the name.
Says from the ontogenesis, lives in the water individual, undergoes the metamorphosis growth after the adult, then can land the life; But from overall construction's angle, both are preserving aquatic ancestor's many states, simultaneously and has many item of terrestrial vertebrate's characteristic. But because skin exposed, lacks complete keratinizing, prevents the moisture content disappearing, although causes the amphibians to be possible to leave in the boiling water to live, but cannot leave Shui Taiyuan.
If “the debarkation life” is the biological evolved tendency, then the amphibians can be only “the trier” (strict, is only “loser”), amphibians' transition nature, is evolving Shi Zhongque to hold the quite important status.