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Reaching a cautious hand out to pet the snake, Jesse said, “Well, Simba’s skin is dry, thick, and scaly. Those frogs look damp. And from what I know about frogs, they do need to stay moist.” “That’s exactly right!” said Mia. “The skin of the amphib-

amphibian a cold-blooded organism who lives in the water during its early life and then on land as an adult reptile a cold-blooded animal that lays eggs on land and has dry, scaly skin Words to Understand

ians is thin and has to be moist. These animals have adapted to different environments. Also, reptile skin is made of scales, while amphibian skin is smooth. That’s because the reptiles molt, or shed their skin as they grow. The scales make that process easier. Amphibians don’t molt, so their skin can grow as their body grows. Also, water is important to the life cycle of an amphibian, like the frogs here. Amphibians lay their eggs in water and spend the early part of their lives in water. Adults live on land, but will return to the water to lay their eggs. “But reptiles don’t do that. They lay their eggs on land. Their eggs have a thick shell that lets oxygen into the egg. The egg has fluids and a yolk to keep the embryo cushioned, safe, and fed while in the egg. These eggs don’t need to be in the water because the egg is designed to con- serve water.” “That sounds a little bit like a chicken egg,” Gabriella realized.

“Yes, it does. But instead of sitting on their eggs, like a hen does, to keep them warm, a reptile will usually cover their eggs in sand and wait for the sun to warm them.” “That’s right! One time we were on the beach and saw turtles laying eggs in the sand.”

These frogs began life as tadpoles, animals that are adapted to live in water.

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