Slide 1 From Tadpole to Frog What do you know about frogs? What more would you like to learn about frogs? Have you ever seen a frog swimming in a pond or sitting on a lily pad? Has the sound of a frog croaking ever kept you up at night? Frogs live all over the world except in Antarctica. There are thousands of kinds, or species, of frogs. They come in different colors and sizes. The biggest frogs can be one foot long. The smallest frogs are only about one-half inch long. All frogs are amphibians. That means that they can live in water and on land. All frogs have sturdy back legs that help them leap big distances. And all frogs have a similar life cycle. They grow and develop in the same way.

Slide 2 From Tadpole to Frog (Cont.) How do frogs grow and develop? They go through different stages. First, female frogs lay eggs—usually in the water. Frogs often lay thousands of eggs at one time. That’s because not all of the eggs will hatch. A jellylike substance surrounds the eggs. That helps to protect them. The next stage begins when the eggs hatch. Most eggs hatch in fewer than 25 days. Some eggs hatch in as few as 3 days! When an egg hatches, a tadpole comes out. A tadpole looks more like a fish than a frog. It breathes through gills on the outside of its body. It has eyes, a mouth, and a tail, too. It swims around and eats tiny plants. After a few weeks, the tadpole starts to change. Back legs start to form. The gills on the outside of its body disappear, and the tadpole develops lungs. Now the tadpole must breathe air. That means it has to come to the surface of the water to get air to breathe.

Slide 3 From Tadpole to Frog (Cont.) Now that the tadpole has its back legs, what occurs next? Its front legs start to grow! The tadpole begins to look like a little frog with a long tail. Soon the tadpole’s tail begins to shrink. That’s because the tail is going back inside the tadpole’s body. The tadpole gets nutrients from the tail. By about 12 weeks from the time the tadpole hatched from its egg, it becomes a froglet. It looks like an adult frog except that it still has a small tail. The froglet starts to eat small bugs. It also starts to spend some time out of the water. Soon the froglet will start the next stage of its life. It will become a frog!

Slide 4 From Tadpole to Frog (Cont.) About 16 weeks after the tadpole fi rst hatched from its egg, it becomes a mature frog. At this stage, the frog no longer has a tail. The frog spends most of its time on land now. Its lungs allow it to breathe air. And it uses its sturdy back legs to hop from place to place in search of food. The frog eats crickets and other bugs, catching them with its long, sticky tongue. Now the mature frog is ready to start the cycle all over again. A female frog returns to the water to lay eggs. What will happen next? Tadpoles will hatch from the eggs. Soon each tadpole grows back legs. Later, it grows front legs, and its tail starts to shrink. The tadpole turns into a froglet. Then the froglet becomes a mature frog. What do you think will happen next? Unit 5, Week 4 From Tadpole to Frog 1. What do you know about the way a bird develops? 2. How do people travel great distances? 3. What are some baby animals that hatch from eggs? 4. What are some baby animals called? What are they called when they become mature? 5. What healthy foods give us the nutrients that we need? 6. When does your birthday occur? 7. What can you wear to protect your feet from rain and snow? 8. What makes an ice cube shrink? 9. What are some things that are sturdy? 10. What do swimmers do when they come to the surface of the water?