Expository Text. Changing. Landscapes. by Maria Gill PAIRED. Students Save Wetlands READ

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1 Expository Text Changing Landscapes by Maria Gill PAIRED READ Students Save Wetlands

2 STRATEGIES & SKILLS Comprehension Strategy: Reread Skill: Compare and Contrast Vocabulary Strategy Multiple-Meaning Words Vocabulary alter, collapse, crisis, destruction, hazard, severe, substantial, unpredictable Content Standards Science Earth Science Word Count: 1,141** Photography Credit: CORBIS/SuperStock **The total word count is based on words in the running text and headings only. Numerals and words in captions, labels, diagrams, charts, and sidebars are not included. Copyright The McGraw-Hill Companies, Inc. All rights reserved. No part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written consent of The McGraw-Hill Companies, Inc., including, but not limited to, network storage or transmission, or broadcast for distance learning. Send all inquiries to: McGraw-Hill Education Two Penn Plaza New York, New York ISBN: MHID: Printed in the United States QLM A

3 Essential Question How do people respond to natural disasters? Changing Landscapes by Maria Gill Introduction Chapter 1 Crumbling Landscapes Chapter 2 Sudden Changes! Chapter 3 Fixing the Damage Conclusion Respond to Reading PAIRED READ Students Save Wetlands Glossary/Index Focus on Science _009_CR14_LR_G4_U01W3L38_O_ indd 1 8/02/12 10:52 AM Program: CR 14 Component: LR Vendor: Learning Media Level: 38 G4 U1 W3 O PDF

4 Introduction Imagine you are in a time machine. You travel thousands of years back in time. You step out and see a very different landscape from the one you left. The mountains are taller and the rivers run straight through the land. Cliffs jut out farther over beaches. What has happened to make it all look so different? 2 Water carved out this canyon. CORBIS/SuperStock

5 A hurricane causes huge waves, which can change the coast. Earth s surface is always changing. Wind and water alter the shape of the land. Some of the changes happen over many thousands of years. Mountains and cliffs slowly wear away. Rivers gradually widen. Shaun Lowe/Vetta/Getty Images Every now and then, a natural disaster, such as a hurricane, flood, or landslide, speeds up the processes of change. These events cause changes to the landscape that are more severe. There are, however, some natural features that can protect the land from natural disasters. 3

6 Chapter 1 Crumbling Landscapes You might not think a trickle of water has much power. But over time, it creates big changes. The flowing water in rivers and streams shapes Earth s surface. In the mountains, rain collects in streams and rivers. As the water flows downhill, small rocks and sand are swept along. The river or stream leaves drops this sediment farther downhill. The movement of the rock and sand is called erosion. HOW rivers Change A fast moving river cuts a path through the land. 2. Over time, the river wears away more of the land. 3. The river deposits sediment and forms a plain. Illustration: Sarah Anderson 4

7 Erosion has worn away these cliffs and created these sea stacks. Water also changes how coastal areas look. When waves break against a cliff, air is pushed into cracks in the cliff. This slowly forces the cracks to open. Over time, rocks break off from the cracks in the cliff. Breaking waves also swirl around the bottom of cliffs and remove loose rocks. These pieces of rock break down to form sand and silt. When larger rocks are broken down into smaller pieces, it is called weathering. Stephen Reynolds Wind also causes erosion. Because wind moves soil and sand, it can shape beaches. The wind blows the sand, and hills of sand called dunes form on the beaches. 5

8 Erosion is always happening, but some natural features slow it down. Sand dunes help safeguard areas further inland. They act as barriers because they trap sand brought onshore by waves and wind. Grasses that grow along the dunes help prevent the sand from blowing away. Wetlands slow down erosion, too. Known as marshes and swamps, wetlands are covered in shallow water that can be salty or fresh. They form near rivers and lakes, and along the coast. Wetlands act like nature s sponges. They absorb water when it rains and release it slowly. This helps prevent flooding. Water from streams and rivers slows as it flows through a wetland. This allows any sediment in the water to settle in the wetland. 6 Swamp Plants The Venus flytrap is one of the unusual plants that live in wetland areas. It has adapted to living in soil that has few nutrients. Instead, it gets nutrients from feeding on insects. Steven P. Lynch

9 HOW A WETLAND WORKS A stream slows down. Sediment settles and nutrients are absorbed. Cleaner water leaves the wetland. Water is absorbed and stored. Wetland plants also help clean the water and absorb nutrients. Plants that love water grow in wetlands. Their roots hold the soil in place, helping reduce erosion. Illustration: Sarah Anderson 7

10 Chapter 2 Sudden Changes! Mark Reid/USGS. This town in California, was badly damaged by a landslide. 8

11 Erosion usually changes the shape of Earth very slowly. However, natural disasters can cause sudden changes. Heavy rains can be a hazard because they can trigger landslides. The ground becomes soaked and can t absorb any more water. Rocks and soil begin to slide downhill, usually moving faster and faster. If enough rocks and soil tumble down, the whole hillside can collapse. Landslides change the landscape by moving a lot of rocks and soil all at once. Landslides are also caused by unpredictable events such as earthquakes or volcanic eruptions. These natural forces can loosen and move weathered rocks and soil down hillsides. Landslides can move with the speed and power of an express train. This makes them very dangerous. They can cause millions of dollars of damage. Landslides often happen in hilly areas where there are no trees and few plants. The roots of trees and plants help to keep the soil in place. Trees and plants also absorb water in the soil. 9

12 The wind and water from hurricanes also changes the landscape. Hurricanes are powerful storms that form over the ocean. As a hurricane nears land, the wind creates substantial waves more than 40 feet high. The waves cause a lot of destruction when they reach land, smashing through storm barriers and seawalls. The waves wash away sand from beaches. After a hurricane, a beach can be much smaller. Sand and other sediment was washed ashore during Hurricane Katrina. 10

13 The rain from a hurricane can cause flooding. Shallow rivers often overflow their banks. Sand and sediment from the river are deposited, or left behind, on land. NOAA/Department of Commerce Coastal wetlands help to protect inland areas from hurricanes. When a hurricane hits the shore, it pushes a wall of water in front of it. Wetland areas can absorb and slow down some of that water. Hurricanes also weaken when they hit land. So coastal wetlands act as a buffer between the ocean and inland areas. AV Hurricane Katrina In 2005, Hurricane Katrina was a crisis for people living along the Gulf Coast. When the hurricane hit, a two-story-tall wall of water tore through levees and riverbanks in more than 50 places and flooded low-lying areas. 11

14 Chapter 3 Fixing the Damage Whenever we take away natural features such as sand dunes and wetlands, more erosion occurs. People cut down trees and remove plants to build roads or houses. In places where this is done, landslides are more likely. If the roots of trees and other plants are no longer there, rain runs off these surfaces, causing erosion or even landslides. To help slow down erosion and prevent landslides, we can plant trees and plants that have long, deep roots. This makes the land more stable. (l) watershed regeneration by AMURT Haiti. Subuddhyananda, (r) An example of the results of watershed regeneration Subuddhyananda Trees and plants with deep roots help stabilize the land. 12

15 Another way to slow down erosion is by restoring wetlands and dunes. Although people have built on many wetland areas, towns and cities are realizing that they need to restore these natural sponges. Restoring sand dunes reduces erosion farther inland. Gulf Oil Spill/Aaron Roeth Photography It is possible to fix a damaged area. First you need to know what is causing the damage. Then you need a plan, such as moving sand back into dunes or planting wetland grasses. Restoring wetlands helps prevent erosion. 13

16 Conclusion Imagine we could step back into our time machine and stop every 100,000 years. We would see the changes to mountains, rivers, and coasts. These are caused by weathering and erosion. The changes happen very slowly. Natural disasters such as hurricanes and landslides can change the landscape quickly. We can t prevent natural disasters, but we can work to restore nature s barriers and sponges to lessen the effects of erosion. ZUMA Press/Newscom Students plant grasses at a wetland area in Maryland. 14

17 Summarize Summarize what you have learned from Changing Landscapes. Use your graphic organizer to help. Text Evidence 1. How can you tell Changing Landscapes is an expository text? GENRE 2. Compare the three diagrams of a river on page 4. What is the same? What is different? COMPARE AND CONTRAST 3. What is the meaning of wear on page 3? What words help you figure out the meaning? MULTIPLE-MEANING WORDS 4. Write about the similarities and differences between landslides and hurricanes. Use details from the text in your answer. WRITE ABOUT READING 15

18 Compare Texts Read about how students in Florida are helping to prevent erosion. Students Save Wetlands Over the past 100 years, many wetland areas in Tampa Bay, Florida, have been destroyed to build houses, roads, and stores. People didn t think wetlands were important. Today people know that wetlands act as barriers against storms and help reduce erosion. They also improve the quality of the water and provide food and homes for wildlife. Students in the Tampa Bay area are growing and planting wetland grasses to help bring back these important areas. 16

19 Yvette C. Hammett/Staff Growing Wetland Grasses 1. The students plant grasses in a pond. 2. They check the growth of the grasses and test the water. 3. After six to eight months, the students dig up and separate the grasses. They replant the grasses so they have more room to grow. 4. Once the grasses have grown, the students replant them in a wetland in Tampa Bay. 17

20 Healthy Coastal Areas The grasses the students have planted will help provide stability for the shoreline and prevent erosion. The grasses will also provide habitats for the animals and fish living there. These students have made a big difference. In one year, they were able to restore almost 24 acres of wetlands along the Florida coast. Students work together to plant sea grasses. Farmer and Rancher Newspaper Make Connections Why is restoring coastal areas important? ESSENTIAL QUESTION How do people in Changing Landscapes and Students Save Wetlands prevent erosion? TEXT TO TEXT 18

21 Glossary barriers (BAR-ee-urz) obstacles that stop things from getting through (page 6) erosion (i-roh-zhuhn) the movement of rock caused by rain, wind, or glacial ice (page 4) landslide (LAND-slighd) earth or rocks that have slid down a hill (page 3) restoring (ri-stawr-ing) returning something to how it was (page 13) sediment (SED-uh-muhnt) rocks, sand, and other small particles carried and deposited by water or wind (page 4) stable (STAY-buhl) firm or solid (page 12) weathering (WETH-uhr-ing) the slow wearing away of rocks (page 5) wetlands (WET-landz) areas of land that are covered by shallow water for part of the time (page 6) Index flooding, 3, 6, 10, 11 Hurricane Katrina, 10, 11 hurricanes, 3, 9 11, 14 landslides, 3, 8, 9, 12, 14 sand dunes, 5, 6, 12, 13 wetlands, 6, 7, 11 14,

22 Purpose To understand the damage a natural disaster can cause and how to prepare for one Procedure Step 1 Step 2 Step 3 Step 4 Pick a type of natural disaster you want to learn more about. Using the library or the Internet, research the kinds of damage the natural disaster causes. Research how people can prepare for the natural disaster, such as buying canned food and bottled water, or making an emergency kit. Create a poster that summarizes what you learned. Make sure you include what the disaster is, the hazards it creates, and how people can prepare and stay safe. Conclusion How are the ways someone can prepare for the disaster you researched similar to how someone can prepare for other disasters? How are they different? 20

23 Literature Circles Nonfiction The Topic What is Changing Landscapes mostly about? Text Structure How does the author organize information in Changing Landscapes? Vocabulary What new words did you learn in the text? What helped you understand their meanings? Conclusions What is the most important thing you learned about preventing erosion? Author s Purpose Why do you think the author wrote Changing Landscapes? What message did she want you to understand?

24 Take Action Science GR P Benchmark 38 Lexile TK Grade 4 Unit 1 Week 3 ISBN MHID EAN