1. Unit 3 Lesson 2 What Are Some Animal Life Cycles?
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3. Unit 3 Lesson 2 What Are Some Animal Life Cycles?
All animals reproduce, or have young, but not in the same way.
Birds and some fish, reptiles, and amphibians lay eggs.
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4. Life Cycles Other animals, such as mammals, give birth to live young.
Unit 3 Lesson 2 What Are Some Animal Life Cycles?
Life Cycles
Other animals, such as mammals, give birth to live young.
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5. Who is this?

7. Unit 3 Lesson 2 What Are Some Animal Life Cycles?
Frog Life Cycle
A tadpole is an immature frog that must live in the water. It hatches from an egg.
It has gills and a tail. It breathes and swims like a fish.
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8. Unit 3 Lesson 2 What Are Some Animal Life Cycles?
Frog Life Cycle
After about five weeks, the tadpole starts to change. Tiny buds beside the tail grow into little hind legs.
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9. Unit 3 Lesson 2 What Are Some Animal Life Cycles?
Frog Life Cycle
Then, as a tadpole, the young frog develops four legs. Its tail will soon disappear and its lungs are almost completely developed.
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10. Unit 3 Lesson 2 What Are Some Animal Life Cycles?
Frog Life Cycle
Finally, the frog has fully developed lungs and legs. It’s an adult!
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11. Frog Life Cycle Unit 3 Lesson 2 What Are Some Animal Life Cycles? 11
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12. Frog Life Cycle As a frog develops, its entire appearance changes.
Unit 3 Lesson 2 What Are Some Animal Life Cycles?
Frog Life Cycle
As a frog develops, its entire appearance changes.
Metamorphosis is a major change in the body form of an animal during its life cycle.
A frog goes through a series of changes after it hatches as a tadpole.
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13. Unit 3 Lesson 2 What Are Some Animal Life Cycles?
Insect Life Cycles
Most insects undergo metamorphosis as they develop into adults.
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15. Unit 3 Lesson 2 What Are Some Animal Life Cycles?
Insect Life Cycles
In the second stage of complete metamorphosis, the insect larva hatches from its egg.
During the third stage of complete metamorphosis, the larva becomes a pupa. The insect does not move as it slowly changes into an adult.
In both of these stages, the insect looks very different from the adult.
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16. Unit 3 Lesson 2 What Are Some Animal Life Cycles?
Insect Life Cycles
Some insects, such as grasshoppers, go through incomplete metamorphosis.
After they hatch from eggs these insects look very much like the adults. They also go through changes as they grow, but they way they look does not change.
Grasshoppers get bigger and grow wings as they reach adulthood.
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17. Why It Matters Diversity
Unit 3 Lesson 2 What Are Some Animal Life Cycles?
Why It Matters
Diversity
Every living thing is different. Even young that have the same parents are not the same.
Diversity — different characteristics — is what makes everyone different from one another.
Think about a family of dogs. Even though they have the same parents, each puppy might have different colored fur. They get different features from each parent.
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