Unit 4 Lesson 3 How Do Plants Grow and Reproduce? Nonvascular plants Spore Gymnosperm Angiosperm Germinate Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 3 How Do Plants Grow and Reproduce? Tubes for Transport Nonvascular plants are simple plants that lack vascular tissue, which easily transports water from the ground into the plant. They grow in damp places and almost never grow taller than 10 cm. Nonvascular plants move materials by absorbing nutrients and water in the same way that a sponge absorbs water. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 3 How Do Plants Grow and Reproduce? Tubes for Transport Vascular plants have vascular tissues that allow them to move water, nutrients, and sugars across long distances. Vascular tissue contains tiny tubes, which move water and nutrients up a plant in the same way that water moves up a straw. Most plants, including trees, grasses, and shrubs, are vascular plants. Copyright © Houghton Mifflin Harcourt Publishing Company

Tubes for Transport Vascular plants have true leaves and roots. Unit 4 Lesson 3 How Do Plants Grow and Reproduce? Tubes for Transport Vascular plants have true leaves and roots. Vascular tissue includes two kinds of smaller tubes. Xylem carries water and nutrients from the roots to the other parts of the plant. Phloem carries sugar from the leaves to the rest of the plant. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 3 How Do Plants Grow and Reproduce? No Seeds, Please! A spore is a single reproductive cell that can grow into a new plant. Both nonvascular plants, such as mosses and liverworts, and vascular plants, such as ferns, use spores to reproduce. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 3 How Do Plants Grow and Reproduce? No Seeds, Please! All of these plants have a sexual generation and an asexual generation in their life cycles. For example, the sexual generation of moss has male parts producing sperm and female parts producing eggs. When sperm and egg combine, the fertilized egg grows into a stalk. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 3 How Do Plants Grow and Reproduce? No Seeds, Please! The stalk is the asexual generation of moss. A capsule grows at the end of the stalk, forming spores that shoot out when the capsule opens. These spores land on the ground and develop into threadlike plants that form buds, which turn into green “leafy” structures. The “leafy” sexual generation of moss, the most familiar form of the plant, makes food and root-like structures that anchor the plants to the ground. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 3 How Do Plants Grow and Reproduce? No Seeds, Please! Like mosses, ferns also use spores to reproduce. In ferns, the reproductive spores form inside clusters on the underside of the leaflets. The spores are released and fall to the ground when the pockets burst. The spores then grow into a tiny fern plant. This structure releases sperm and egg cells that, once fertilized, grow into a young fern. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 3 How Do Plants Grow and Reproduce? No Seeds, Please! The young fern grows into the large, upright fern plant, called the frond. This is the asexual generation of the fern. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 3 How Do Plants Grow and Reproduce? Seed Power! While spores need to stay moist and sprout soon after release, seeds have a covering that protects them until conditions are right for sprouting. Gymnosperms are plants that do not produce seeds in flowers. Gymnosperm seeds have a protective seed coat, but are not enclosed by fruit. Cone-producing plants, called conifers, are the most common gymnosperms. Conifers include pine, fir, spruce, and cedar trees. Copyright © Houghton Mifflin Harcourt Publishing Company

Seed Power! Angiosperms are plants that produce seeds in flowers. Unit 4 Lesson 3 How Do Plants Grow and Reproduce? Seed Power! Angiosperms are plants that produce seeds in flowers. Since angiosperm seeds are often enclosed in fruit, they are easily spread when animals eat the fruits. Gymnosperm seeds may also be spread by animals, but typically fall to the ground and grow where they land. Copyright © Houghton Mifflin Harcourt Publishing Company

From Flower to Fruit to Seed Unit 4 Lesson 3 How Do Plants Grow and Reproduce? From Flower to Fruit to Seed Typical flowers have both male and female reproductive parts. A male part, the anther, produces pollen, or the sperm. The female parts include the stigma and the ovary, which contains eggs in ovules. Copyright © Houghton Mifflin Harcourt Publishing Company

From Flower to Fruit to Seed Unit 4 Lesson 3 How Do Plants Grow and Reproduce? From Flower to Fruit to Seed Flowers produce nectar that organisms may eat. When an organism gathers nectar, pollen may brush onto it. The organism carries this pollen when it moves to the next flower. This process is called pollination. When the pollen reaches the stigma, it travels down to the ovary and fertilizes the ovules. This process is called fertilization. Copyright © Houghton Mifflin Harcourt Publishing Company

From Flower to Fruit to Seed Unit 4 Lesson 3 How Do Plants Grow and Reproduce? From Flower to Fruit to Seed Fertilized ovules develop into seeds, and the ovule wall becomes a seed coat. The ovary that holds the seeds develops into the fruit, such as a pumpkin. The development of a pumpkin seed into a mature pumpkin fruit follows a sequence of events. Copyright © Houghton Mifflin Harcourt Publishing Company

From Flower to Fruit to Seed Unit 4 Lesson 3 How Do Plants Grow and Reproduce? From Flower to Fruit to Seed Pollen enters the flower’s ovary and fertilizes the ovules. The ovary grows and the petals fall off. The ovules develop into seeds inside the ovary. Finally, the outer layer of the ovary thickens to form a fruit around the seeds. The mature pumpkin is filled with seeds. Copyright © Houghton Mifflin Harcourt Publishing Company

From Flower to Fruit to Seed Unit 4 Lesson 3 How Do Plants Grow and Reproduce? From Flower to Fruit to Seed Identify the following parts of a flower: anther, ovary, ovules, petals, stigma. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 3 How Do Plants Grow and Reproduce? How Seeds Grow Seeds have a hard outer coat that protects them and allows them to rest until the environment is right for growing. Many plant seeds rest during winter and then germinate, or start to grow, when the ground becomes warm and moist in the spring. A dormant seed lies in the soil until conditions are right for growing. The seed germinates by absorbing water and breaking through the seed coat. Copyright © Houghton Mifflin Harcourt Publishing Company

Unit 4 Lesson 3 How Do Plants Grow and Reproduce? How Seeds Grow The embryo continues to grow and a stem pushes upward. Cotyledons provide energy for growth and roots form and begin growing downward. Leaves mature and the plant starts absorbing more energy from sunlight. It continues to grow as the shoot pushes upward. The plant grows and matures until it produces flowers and fruit. Copyright © Houghton Mifflin Harcourt Publishing Company