13.What is an Amphibian? 1

One group of vertebrate animals is the amphibians 2 Vocabulary: amphibians A cold-blooded vertebrate animal that lays eggs in water

Amphibians include frogs, toads, and salamanders 3 Amphibians are cold-blooded

4 Vocabulary: Cold-blooded The body temperature of an animal changes with the temperature of the air or water around it

When amphibians reproduce, they lay eggs, which is the first stage of the life cycle of an amphibian 5 Most lay eggs in water

The young that hatch live in the water and are called tadpoles 6 Vocabulary: tadpole A young frog or toad that has gills and a tail but no legs

The tadpole is the second stage of the life cycle of an amphibian 7 The tadpole looks very different from its parents

A tadpole has gills and a tail, but does not have legs 8 As it grows the tadpole loses its gills and grows lungs

The tadpole loses its tail and grows legs 9 When these changes are over the tadpole leaves the water and lives on land

It is now an adult frog 10 This is the third stage of the life cycle of an amphibian 1 2 3

When amphibians are adults, they live on land and breathe air with lungs 11 Most amphibians also take in air through their skin

To be able to take in air through their skins, it must be moist 12 So amphibians are found near water or in wet places