Most members of which class of chordates exhibit a mixture of aquatic and terrestrial adaptations?

Amphibians are aquatic when you consider their reproductive habit. The eggs and sperms are deposited in water where external fertilisation takes place.

Thus adult amphibians may have to return to water, for which they may retain webbed feet, such as members of class Anura. Many amphibians will continue a life in water, as in the case of salamanders and newts.

An aquatic larval stage is present in lifecycle. The tailed larva is gill breathing, equipped with lateral line sense organ like fishes.

A pair of lungs in amphibians give them additional advantage to adapt and live in terrestrial habitats. They prefer moist environment, and also keep their skin moist by secretion of mucus so that cutaneous breathing can continue.

Amphibians are ectothermic: to avoid extreme temperatures they may hibernate, which is an adaptation related with terrestrial life.

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Amphibians.