Unit 3 Lesson 2 What Are Some Animal Life Cycles? Copyright © Houghton Mifflin Harcourt Publishing Company 1

Unit 3 Lesson 2 What Are Some Animal Life Cycles? All animals have male and female parents. But not all animals reproduce, or have young, in the same way. Copyright © Houghton Mifflin Harcourt Publishing Company 2

Life Cycles Unit 3 Lesson 2 What Are Some Animal Life Cycles? 3 Copyright © Houghton Mifflin Harcourt Publishing Company 3

Life Cycles Birds and some fish, reptiles, and amphibians lay eggs. Unit 3 Lesson 2 What Are Some Animal Life Cycles? Life Cycles Birds and some fish, reptiles, and amphibians lay eggs. Other animals, such as mammals, give birth to live young. These early stages are part of each animal’s life cycle. Copyright © Houghton Mifflin Harcourt Publishing Company 4

Life Cycles Unit 3 Lesson 2 What Are Some Animal Life Cycles? 5 Copyright © Houghton Mifflin Harcourt Publishing Company 5

Unit 3 Lesson 2 What Are Some Animal Life Cycles? A baby ostrich will hatch from an egg, and once it grows up it will find a mate to lay more eggs. Copyright © Houghton Mifflin Harcourt Publishing Company 6

Unit 3 Lesson 2 What Are Some Animal Life Cycles? A lynx will find a mate and give birth to pups which depend on their mother for food. Copyright © Houghton Mifflin Harcourt Publishing Company 7

Unit 3 Lesson 2 What Are Some Animal Life Cycles? Copyright © Houghton Mifflin Harcourt Publishing Company 8

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. Copyright © Houghton Mifflin Harcourt Publishing Company 9

Why It Matters Diversity Unit 3 Lesson 2 What Are Some Animal Life Cycles? Why It Matters Diversity 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. Copyright © Houghton Mifflin Harcourt Publishing Company 10

Unit 3 Lesson 2 What Are Some Animal Life Cycles? Copyright © Houghton Mifflin Harcourt Publishing Company 11

Frog Life Cycle Unit 3 Lesson 2 What Are Some Animal Life Cycles? 12 Copyright © Houghton Mifflin Harcourt Publishing Company 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. Copyright © Houghton Mifflin Harcourt Publishing Company 13

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. It is very different from its parents. Copyright © Houghton Mifflin Harcourt Publishing Company 14

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. Then, as a tadpole, the young frog develops four legs. Its tail will soon disappear and its lungs are almost completely developed. Finally, the frog has fully developed lungs and legs. It’s an adult! Copyright © Houghton Mifflin Harcourt Publishing Company 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. Copyright © Houghton Mifflin Harcourt Publishing Company 16

Unit 3 Lesson 2 What Are Some Animal Life Cycles? Insect Life Cycles Most insects undergo metamorphosis as they develop into adults. Ladybugs and butterflies go through complete metamorphosis, which means that there are two stages between egg and adult. Copyright © Houghton Mifflin Harcourt Publishing Company 17

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. Copyright © Houghton Mifflin Harcourt Publishing Company 18

Unit 3 Lesson 2 What Are Some Animal Life Cycles? Copyright © Houghton Mifflin Harcourt Publishing Company 19

Unit 3 Lesson 2 What Are Some Animal Life Cycles? Copyright © Houghton Mifflin Harcourt Publishing Company 20