000i-viii Bio TRE FM 896100

Answer Key

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Copyright © by The McGraw-Hill Companies, Inc. All rights reserved. Permission is granted to reproduce the material contained herein on the condition that such material be reproduced only for classroom use; be provided to students, teachers, and families without charge; and be used solely in conjunction with the Glencoe Biology program. Any other reproduction, for sale or other use, is expressly prohibited.

Send all inquiries to:McGraw-Hill Education8787 Orion PlaceColumbus, OH 43240-4027

ISBN: 978-0-07-896100-7

MHID: 0-07-896100-9

Printed in the United States of America.

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Table of ContentsTo the Teacher . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Dinah Zike’s Foldables® Teaching Strategies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii

Chapter 1 The Study of Life

1 Introduction to Biology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 The Nature of Science . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Methods of Science . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Chapter 2 Principles of Ecology

1 Organisms and Their Relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Flow of Energy in an Ecosystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Cycling of Matter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Chapter 3 Communities, Biomes, and Ecosystems

1 Community Ecology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Terrestrial Biomes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Aquatic Ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Chapter 4 Population Ecology

1 Population Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Human Population . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Chapter 5 Biodiversity and Conservation

1 Biodiversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Threats to Biodiversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Conserving Biodiversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Chapter 6 Chemistry in Biology

1 Atoms, Elements, and Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Chemical Reactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Water and Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 The Building Blocks of Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Chapter 7 Cellular Structure and Function

1 Cell Discovery and Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 The Plasma Membrane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Structures and Organelles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Cellular Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Chapter 8 Cellular Energy

1 How Organisms Obtain Energy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Photosynthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Cellular Respiration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Chapter 9 Cellular Reproduction

1 Cellular Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 Mitosis and Cytokinesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 Cell Cycle Regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

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Chapter 10 Sexual Reproduction and Genetics

1 Meiosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 Mendelian Genetics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 Gene Linkage and Polyploidy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Chapter 11 Complex Inheritance and Human Heredity

1 Basic Patterns of Human Inheritance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Complex Patterns of Inheritance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Chromosomes and Human Heredity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Chapter 12 Molecular Genetics

1 DNA: The Genetic Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 Replication of DNA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 DNA, RNA, and Protein . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Gene Regulation and Mutations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Chapter 13 Genetics and Biotechnology

1 Applied Genetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 DNA Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 The Human Genome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Chapter 14 The History of Life

1 Fossil Evidence of Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 The Origin of Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Chapter 15 Evolution

1 Darwin’s Theory of Evolution by Natural Selection . . . . . . . . . . . . . . . . . . . . 132 Evidence of Evolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 Shaping Evolutionary Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Chapter 16 Primate Evolution

1 Primates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132 Hominoids to Hominins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 Human Ancestry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Chapter 17 Organizing Life’s Diversity

1 The History of Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142 Modern Classification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Domains and Kingdoms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Chapter 18 Bacteria and Viruses

1 Bacteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 Viruses and Prions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Chapter 19 Protists

1 Introduction to Protists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 Protozoans—Animal-like Protists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Algae—Plantlike Protists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164 Funguslike Protists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Chapter 20 Fungi

1 Introduction to Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 Diversity of Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 Ecology of Fungi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

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Chapter 21 Introduction to Plants

1 Plant Evolution and Adaptations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 Nonvascular Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 Seedless Vascular Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184 Vascular Seed Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Chapter 22 Plant Structure and Function

1 Plant Cells and Tissues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 Roots, Stems, and Leaves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 Plant Hormones and Responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Chapter 23 Reproduction in Plants

1 Introduction to Plant Reproduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192 Flowers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 Flowering Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Chapter 24 Introduction to Animals

1 Animal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 Animal Body Plans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 Sponges and Cnidarians . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Chapter 25 Worms and Mollusks

1 Flatworms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 Roundworms and Rotifers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 Mollusks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224 Segmented Worms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Chapter 26 Arthropods

1 Arthropod Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222 Arthropod Diversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223 Insects and Their Relatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Chapter 27 Echinoderms and Invertebrate Chordates

1 Echinoderm Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232 Invertebrate Chordates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Chapter 28 Fishes and Amphibians

1 Fishes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232 Diversity of Today’s Fishes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243 Amphibians . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Chapter 29 Reptiles and Birds

1 Reptiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242 Birds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Chapter 30 Mammals

1 Mammalian Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252 Diversity of Mammals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Chapter 31 Animal Behavior

1 Basic Behaviors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262 Ecological Behaviors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

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Chapter 32 Integumentary, Skeletal, and Muscular Systems

1 The Integumentary System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262 The Skeletal System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263 The Muscular System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Chapter 33 Nervous System

1 Structure of the Nervous System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272 Organization of the Nervous System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273 The Senses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284 Effects of Drugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Chapter 34 Circulatory, Respiratory, and Excretory Systems

1 Circulatory System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282 Respiratory System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283 Excretory System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Chapter 35 Digestive and Endocrine Systems

1 The Digestive System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292 Nutrition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 The Endocrine System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Chapter 36 Human Reproduction and Development

1 Reproductive Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302 Human Development Before Birth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303 Birth, Growth, and Aging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Chapter 37 The Immune System

1 Infectious Diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302 The Immune System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313 Noninfectious Disorders. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

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Reading Essentials for Biology is an interactive textbook designed to help students use recognized reading strategies to improve their reading-for-information skills. Biology content is organized by sections within each chapter. Each section is divided into Before You Read and Read to Learn.

In Before You Read, students are encouraged to access previous knowledge they have about the subject matter. They also have an opportunity to review the Main Idea and What You’ll Learn concept statements.

The text in Read to Learn focuses on key biology concepts. Key terms are reinforced and redefined several times after they are introduced. Read to Learn contains margin features (Study Coach, Mark the Text, Reading Check, Foldables®, Think it Over, Picture This, and Applying Math) that actively involve students in their own learning by helping them understand and organize new information. In-text references and corresponding margin features about each figure assist students in understanding the figure and the biology concept it illustrates. A reading check at the end of a paragraph signals the student to answer a Reading Check question in the margin.

Teaching support for Reading Essentials for Biology can be found in your Glencoe Teacher Edition. Reading Essentials for Biology content follows the order in which material is presented in the Student Edition. In addition, Fast File Chapter Resource pages and Science Notebooks reinforce material presented in Reading Essentials for Biology.

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Dinah Zike’s Foldables® Teaching Strategies

A Foldable is a 3-D, interactive graphic organizer based on a skill. Making a Foldable gives students a fast, kinesthetic activity that helps them quickly organize and retain information. Every chapter in Reading Essentials for Biology includes a Foldable that is designed to organize important ideas in the chapter. Later, students can use the Foldable as a study guide for main ideas and key points in the chapter. Foldables can also be used for a more in-depth investigation of the key terms, concepts, or ideas presented in the chapter.

The Foldables for Reading Essentials for Biology can be created using notebook paper or plain sheets of paper. Some will require scissors to cut the tabs. Students can store their Foldables in several ways. They can use plastic bags, boxes, or three-ring binders with sheet protectors. By keeping their Foldables organized, students will have a ready study tool and a portfolio of their work.

You might also want students to make the Foldables found on the Start-UpActivities page of each chapter in the Student Edition. Students should be encouraged to keep together all the Foldables they make for a chapter and use them as they review the chapter and study for assessments.

Teaching Tips for Foldables

Do not ask high school students to carry glue and scissors from class to class. Instead, set up a small table or rolling cart in the back of the classroom and provide glue, scissors, color pencils, staplers, and anything else the students might need.

Turn one-gallon freezer bags into student portfolios. Students can carry their portfolios in their notebooks if they place strips of two-inch clear tape along one side and punch three holes through the taped edge. Cut bottom corners off the bag so it will not hold air and will stack more easily.

For additional help making these organizers and for other ideas of how to use Foldables in your classroom, refer to Dinah Zike’s Teaching Science with Foldables.

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ANSWER KEY

Reading Essentials 1

Chapter 1 The Study of Life

Section 1

Before You Read (p. 1)Students might list characteristics such as breathing, eating, and growing.

Read to Learn 1. Students should highlight the table as they

read. (p. 2)

2. atoms and molecules, cells, tissues, organs, organ systems (p. 2)

3. Possible responses: The rabbit feels hungry, so it looks for food. (p. 3)

4. An organism must maintain homeostasis. (p. 3)

Section 2

Before You Read (p. 4)Students might say that if the headline is too fantastic to be true, they do not believe it.

Read to Learn 1. A law identifies what happens. A theory

explains why something happens. (p. 4)

2. Science is guided by research. Pseudoscience involves little or no research. (p. 5)

3. human arm; both have four fingers and a thumb (p. 5)

4. We know tobacco smoke contains carcinogens. (p. 6)

5. Possible response: evaluate available information, discuss issues, and support polices that reflect my values (p. 6)

Section 3

Before You Read (p. 7)Students might suggest noting the bird’s distinctive features and looking in a bird identification book for a match to these characteristics.

Read to Learn 1. Inferences are logical conclusions based on

information from observation and other sources. (p. 7)

2. b (p. 8)

3. to test a hypothesis (p. 8)

4. reproductive rate (p. 9)

5. quantitative data (p. 9)

6. 2.8 g (p. 10)

7. to alert you to a specific danger in an activity (p. 10)

Chapter 2 Principles of Ecology

Section 1

Before You Read (p. 11)Students should list organisms such as other humans, cats, dogs, insects, and grass.

Read to Learn 1. observations, experiments, and creating

models (p. 11)

2. the air, water, and land on Earth that support life (p. 12)

3. List should include temperature range, amount of rainfall, type of soil, etc. (p. 12)

4. More organisms are added at each level. (p. 13)

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ANSWER KEY

2 Answer Key

3. Photosynthesis releases oxygen; cellular respiration releases carbon dioxide. (p. 21)

4. nitrogen-fixing bacteria in water, soil, and plant roots (p. 21)

5. ammonia (p. 22)

6. from drainage of phosphates in soil, from rocks and minerals, from decomposers (p. 22)

Chapter 3 Communities, Biomes, and Ecosystems

Section 1

Before You Read (p. 23)Students should list plants and animals that live in their area and one species of plant or animal that would have difficultly surviving in their area.

Read to Learn 1. Woodpecker population might decline. (p. 23)

2. a (p. 24)

3. the number of trout present per temperature range (p. 24)

4. They begin the process of soil development. (p. 25)

5. five (p. 25)

Section 2

Before You Read (p. 26)Students should describe the climate in their area, including seasonal differences in temperatures and precipitation.

Read to Learn 1. a (p. 26)

2. layer of permanently frozen soil below the surface of the tundra (p. 27)

3. yes, in Alaska (p. 27)

5. b (p. 13)

6. Sufficient resources are available to all members of the population. (p. 14)

7. A habitat is the place an organism lives. A niche is a the role an organism plays in its ecosystem. (p. 14)

8. Accept all reasonable answers. (p. 15)

9. commensalism (p. 15)

Section 2

Before You Read (p. 16)Students might say that its diet would consist of unprocessed foods, such as a cat living on a diet of field mice and birds.

Read to Learn 1. herbivore (p. 16)

2. They make nutrients available for use in the ecosystem. (p. 17)

3. Students should circle the plant and draw a box around the grasshopper, mouse, and snake. (p. 17)

4. Possible response: Studies focus on different aspects of feeding relationships. (p. 18)

5. in grams per meter squared (g/m2) (p. 18)

Section 3

Before You Read (p. 19)Students might list sports seasons, the seasons in nature, and their daily schedule.

Read to Learn 1. biological, chemical, and geological processes

(p. 20)

2. Students should add the labels precipitation and evaporation to figure. (p. 20)


ANSWER KEY


4. amount of precipitation (p. 28)

5. temperate deciduous forest (p. 28)

6. tropical seasonal forests: rain falls in wet season only; tropical rain forests: rain falls year round (p. 29)

7. possible response: white color for camouflage (p. 29)

Section 3

Before You Read (p. 30)Students should list characteristics such as depth, flow, and type of water (salty or fresh) of a nearby body of water.

Read to Learn 1. 30.8% + 0.3% = 31.1% (p. 30)

2. Students should label the mouth region; as the slope flattens, water flow slows (p. 31)

3. nutrient availability (p. 31)

4. because less light reaches the profundal zone (p. 32)

5. Salt water and freshwater mix in estuaries. Land and water mingle in wetlands. (p. 32)

6. remove carbon dioxide and supply oxygen; source of precipitation (p. 33)

7. spray zone (p. 33)

8. sunlight and temperature (p. 34)

9. b (p. 34)

Chapter 4 Population Ecology

Section 1

Before You Read (p. 35)Students might note that factors such as food, water, space, and weather conditions affect a population.

Read to Learn 1. uniform (p. 35)

2. Water pollution affects populations of any density. (p. 36)

3. b (p. 36)

4. Initially, the mouse population would increase. (p. 37)

5. birthrate, death rate, emigration, immigration (p. 38)

6. 3.5 million - 1.0 million = 2.5 million increase (p. 38)

7. 10,000 (p. 39)

8. r-strategists: many young, no nurturing; k-strategists: few young, provide nurture(p. 39)

Section 2

Before You Read (p. 40)Students might note that human populations are limited by carrying capacity and available resources.

Read to Learn 1. Possible response: a food duplicator (p. 40)

2. disease and war (p. 41)

3. 10.2 - 7.7 = 2.5; 2.5 + 5.6 = 8.1; 8.1 × 0.1 =

0.81 (p. 41)

4. Students should label Kenya’s pre-reproductive stage as largest and Germany’s as smallest. (p. 42)

5. Population could exceed Earth’s ability to support it, leading to disease and starvation. (p. 42)


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4 Answer Key

Chapter 5 Biodiversity and Conservation

Section 1

Before You Read (p. 43)Students might list plants, insects, domestic and wild animals, and other organisms.

Read to Learn 1. Students should circle the arctic area and

Central America. (p. 44)

2. Answers may include food, shelter, water, air, clothing, energy, or medicine. (p. 44)

3. penicillin or aspirin (p. 45)

4. Students should highlight Croton Watershed and Catskill/Delaware Watersheds. (p. 45)

Section 2

Before You Read (p. 46)Answers might include pollution, global climate change, greenhouse gases, hole in the ozone layer, and acid rain.

Read to Learn 1. an event in which a number of living things

become extinct in a short period of time (p. 46)

2. birds and mammals (p. 47)

3. excessive use of a species (p. 47)

4. b (p. 48)

5. Killer whales began to prey on sea otters because their primary food source had declined. (p. 48)

6. Animals that need large areas to roam or the protection of the inner forest would be harmed by edge effect. It would reduce their habitat. (p. 49)

7. Students should circle fish-eating birds. (p. 49)

8. Possible response: removes nutrients from soil and pollutes water (p. 50)

9. predators, parasites, and competition (p. 50)

Section 3

Before You Read (p. 51)Answers might include recycling, walking instead of driving, turning the thermostat down in winter, and turning off lights.

Read to Learn 1. high: United States, Canada; low: India,

Bangladesh (p. 51)

2. b (p. 52)

3. reduce consumption and recycle (p. 52)

4. People are allowed to use natural resources sustainably. (p. 53)

5. one-third (p. 53)

6. More of the ecosystem is destroyed. (p. 54)

7. It gives legal protection to species in danger of becoming extinct. (p. 54)

Chapter 6 Chemistry in Biology

Section 1

Before You Read (p. 55)Students might say that living things are made up of atoms and molecules, the building blocks of chemistry.

Read to Learn 1. six (p. 55)

2. carbon-13 (p. 56)

3. No; a compound cannot be broken down by physical means. (p. 56)


ANSWER KEY


4. No; it can hold up to eight electrons, but it only has six. (p. 57)

5. Students should label the innermost band of the oxygen atom first level: two electrons. They should label the outermost band second level: eight electrons. (p. 57)

6. The atom changes from neutral to a positively charged ion. (p. 58)

7. b (p. 58)

Section 2

Before You Read (p. 59)Student might know that rust has something to do with the interaction of the metal with the air.

Read to Learn 1. Reactants yield products. (p. 59)

2. Students should add the labels subscript and coefficient to the appropriate numbers in the equation. (p. 60)

3. Energy in the form of heat or light might be released during the reaction. (p. 61)

4. Possible labels: Active sites are shaped to fit certain substrates precisely. Substrates bind at the active sites to form an enzyme-substrate complex. The substrates react to form products that are released by the enzyme. (p. 61)

Section 3

Before You Read (p. 62)Students might indicate that the powder disappeared in the water or became part of the water.

Read to Learn 1. Students should label the two smaller atoms

H and the one larger atom O. They should place a – symbol next to each electron. O (p. 62)

2. Students should identify and circle five H-H-O combinations. They should recognize the dotted lines as the hydrogen bonds between molecules and not include any dotted line in their circled molecules. Five (p. 63)

3. heterogeneous—each coin can be identified individually (p. 63)

4. polarity (p. 64)

5. Students should draw another molecule with an H+ ion on the top left of the figure and draw the ion separated from the molecule on the top right to make the solution acidic. (p. 64)

6. Students should draw a circle around the buffer. (p. 64)

Section 4

Before You Read (p. 65)Students might suggest that DNA contains information that passes on traits from parents to their children.

Read to Learn 1. 50 percent (p. 65)

2. nucleic acids (p. 66)

3. Monosaccharides are short chains of carbohydrates. Disaccharides are two monosaccharides linked together. Polysaccharides are longer chains of carbohydrates. (p. 66)

4. do not dissolve in water (p. 67)

5. Students should label the pleat folded paper and label the helix spiral. (p. 67)

6. Proteins speed up chemical reactions. (p. 68)

7. Students should circle each of the four groupings of phosphate, sugar, and base illustrated nucleic acid. (p. 68)


ANSWER KEY

6 Answer Key

Chapter 7 Cellular Structure and Function

Section 1

Before You Read (p. 69)Students should mention that objects looked larger.

Read to Learn 1. Both are made up of cells. (p. 69)

2. Students should highlight that all living organisms are made up of one or more cells. (p. 70)

3. Object is magnified 20 × 20 = 400 × (p. 70)

4. Possible response: to see life processes taking place (p. 71)

5. b (p. 71)

Section 2

Before You Read (p. 72)Answers should suggest that nutrients would pass through, while things that could harm the cell, such as poisons, would be kept out.

Read to Learn 1. Students should highlight oxygen, water, and

glucose. Students should circle wastes, water, and carbon dioxide. (p. 72)

2. to allow the plasma membrane to survive and function in its watery environment (p. 73)

3. Students should circle one phospholipids and label its round part head and the strand part tails. (p. 73)

4. to move substances through the plasma membrane (p. 74)

5. proteins, carbohydrates, and cholesterol (p. 74)

Section 3

Before You Read (p. 75)Students should list members of their families and the jobs or chores they do.

Read to Learn 1. any of the following: produce proteins,

transform food to energy, or process (p. 75)

2. Students should highlight structures found in both plant and animal cells. They should circle cell wall and chloroplast. They should underline centriole and lysosome. (p. 76)

3. to define the cell and control protein production (p. 77)

4. to provide a large surface area for breaking the bonds of sugar molecules (p. 78)

5. to move substances within the cell (p. 78)

6. Students should highlight endoplasmic reticulum. (p. 79)

7. protein synthesis (p. 79)

Section 4

Before You Read (p. 80)Students describe how they would move a large, heavy box.

Read to Learn 1. Students should explain that molecules will

pass through the transport protein to move from an area of higher concentration to an area of lower concentration. (p. 81)

2. The concentration in its cytoplasm is the same as the concentration in the outside environment. (p. 81)

3. There is more water outside a cell than inside a cell. (p. 82)

4. Students should label the plasma membrane. (p. 82)


ANSWER KEY


Chapter 8 Cellular Energy

Section 1

Before You Read (p. 83)Students might state that objects can be powered by sunlight, electricity, and fuels such as wood, coal, oil, and natural gas.

Read to Learn 1. Energy can change form, but it cannot be

created or destroyed. (p. 83)

2. Students should circle the plant. (p. 84)

3. catabolic—energy released; anabolic—energy used (p. 84)

4. Students should circle the process that represents cellular respiration on the right and draw a square around the process that represents photosynthesis on the left (p. 85)

5. Students should circle the line between the second and third phosphate in the triphosphate group. (p. 85)

Section 2

Before You Read (p. 86) Students should note that without plants to harvest energy from the Sun, nearly all living things soon would run out of energy and die.

Read to Learn 1. Possible response: to build complex sugars

and carbohydrates (p. 86)

2. b (p. 87)

3. Students should draw an enlarged picture of the granum; showing stacks of thylakoids. (p. 87)

4. In autumn, plants break down their chlorophyll, and the other pigments of the leaves can be seen. (p. 87)

5. light-absorbing pigments and proteins (p. 88)

6. NADPH (p. 88)

7. phase one—NADPH and ATP; phase two—glucose (p. 89)

8. deserts and salt marshes (p. 89)

Section 3

Before You Read (p. 90)Sample responses: orange juice—energy from the Sun to orange tree to me; bacon—energy from the Sun to plants to pig to me

Read to Learn 1. carbon dioxide (p. 91)

2. glycolysis—cytoplasm; Krebs cycle—mitochondria; electron transport—mitochondria (p. 91)

3. glycolysis and fermentation (p. 92)

4. plants (p. 92)

Chapter 9 Cellular Reproduction

Section 1

Before You Read (p. 93)Answers might include childhood, adolescence, and adulthood.

Read to Learn 1. surface area: 2 μm × 2 μm × 6 sides

= 24 μm2; volume: 2 μm × 2 μm × 2 μm =

8 μm3 (p. 93)

2. It gets smaller. (p. 94)

3. mitosis: one cell; cytokinesis: two cells (p. 94)

4. Students should circle the S phase. (p. 95)

5. binary fission (p. 95)


ANSWER KEY

8 Answer Key

Section 2

Before You Read (p. 96)Students might name other injuries in which the body heals itself, the growth of children to adult size, or the growth of new cells to replace old cells.

Read to Learn 1. Possible response: repairing damaged cells or

creating new cells for growth (p. 96)

2. Student should highlight condensed chromosomes, nuclear membrane dissolves, mitotic spindle, centriole, and centromere. (p. 97)

3. by centromeres (p. 97)

4. They are pulled into alignment along the equator of the cell. (p. 98)

5. complete the division (p. 98)

6. microtubules (p. 99)

7. cell wall; cell shape (p. 99)

Section 3

Before You Read (p. 100)Answers might include eating fruits and vegetables, exercising, using sunscreen, and not smoking.

Read to Learn 1. mitosis and interphase (G1, S, and G2) (p. 100)

2. the uncontrolled growth and division of cells (p. 101)

3. ultraviolet radiation from the Sun (p. 101)

4. b (p. 102)

5. unspecialized cells that can develop into a variety of specialized cells (p. 102)

Chapter 10 Sexual Reproduction and Genetics

Section 1

Before You Read (p. 103)Answers will vary. Students might list their height, build, skin color, hair color or texture, eye color, or other traits.

Read to Learn 1. 1500 × 46 = 69,000 genes (p. 103)

2. Students should circle the third and fifth chromosomes. (p. 104)

3. b (p. 104)

4. Students should circle the part of each chromosome that was exchanged. (p. 105)

5. anaphase I (p. 106)

6. Prophase I: 2n; Metaphase I: 2n; Anaphase I: n; Telophase I: n (p. 106)

7. Students should circle anaphase II. The number of haploid cells produced is four. (p. 107)

8. two; four (p. 107)

9. Students should underline the daughter cells in the four possibility figures. (p. 108)

10. Half an organism’s chromosomes are inherited from each parent. (p. 108)

Section 2

Before You Read (p. 109)Student answers might include making observations, forming a hypothesis, testing a hypothesis, or performing a controlled experiment.

Read to Learn 1. Traits stay the same from generation to

generation. (p. 109)


ANSWER KEY


2. Students should fill in the middle box with F1 and the bottom box with F2. Students should fill in the empty pods with ¾ yellow, or unshaded, peas and ¼ green, or shaded, peas. (p. 110)

3. yellow seeds (p. 110)

4. green seeds (p. 111)

5. the yellow-seeded offspring (p. 111)

6. Possible answer: tracking genotypes in a cross (p. 112)

7. 3:1 (p. 112)

Section 3

Before You Read (p. 113)Students should answer that it is very unlikely that they will get the same cards twice.

Read to Learn 1. 24 × 24 = 16 × 16 = 256 (p. 113)

2. crossing over (p. 114)

3. b (p. 114)

4. Possible answers: earthworms, goldfish, flowering plants, oats, wheat, sugarcane (p. 114)

Chapter 11 Complex Inheritance and Human Heredity

Section 1

Before You Read (p. 115)Students should include parents, grandparents, children, siblings, cousins, aunts, and uncles.

Read to Learn 1. Students should circle the word homozygous.

(p. 115)

2. because they lack an enzyme that breaks down gangliosides (p. 116)

3. If both parents are of average height, it developed from a mutation. (p. 117)

4. Students should circle the black circle and the black square. (p. 117)

5. 25 percent (p. 118)

6. no (p. 118)

7. Not all people who carry the recessive allele have the trait. (p. 118)

Section 2

Before You Read (p. 119)Answers might include differences in the length, color, and pattern of fur.

Read to Learn 1. The heterozygous organism expresses both

alleles. (p. 119)

2. It changes them to a sickle or C shape. (p. 120)

3. Type B (p. 120)

4. c (p. 121)

5. female (p. 121)

6. Males must only inherit one allele to have the trait. (p. 122)

7. Students should circle XbY. (p. 122)

8. skin color, height, eye color, or fingerprint pattern (p. 123)

9. Students should circle blood types. (p. 123)

Section 3

Before You Read (p. 124)Answers might include personality traits, such as shyness, or physical traits, such as hair color, height, or skin color.


ANSWER KEY

10 Answer Key

Read to Learn 1. male (p. 124)

2. Sister chromatids didn’t separate properly during cell division. (p. 125)

3. Yes; nondisjunction during meiosis II produces two normal and two abnormal gametes. (p. 125)

4. Students should circle the picture corresponding to XXX, XXY, and XYY. (p. 126)

5. to test for genetic disorders in the fetus (p. 126)

Chapter 12 Molecular Genetics

Section 1

Before You Read (p. 127)Answers might include space exploration, sequencing the human genome, or the development of computers.

Read to Learn 1. rough appearance; do not cause pneumonia

(p. 127)

2. In part A, students should label the bacteria S strain. In part B, students should label the bacteria R strain. In part C, students should label the bacteria S strain. In part D, students should label the bacteria on the left S strain and the bacteria on the right R strain. (p. 128)

3. that only DNA could change R strain toS strain (p. 128)

4. protein and DNA (p. 129)

5. Students should circle the Group 1 bacterial cells. (p. 129)

6. DNA, deoxyribose instead of ribose (p. 130)

7. X-ray diffraction (p. 130)

8. cytosine pairs with guanine; thymine pairs with adenine (p. 131)

9. DNA and histone proteins (p. 131)

Section 2

Before You Read (p. 132)Answers might include cooking recipes, blueprints for a house, or items such as toys, cars, televisions, or computers.

Read to Learn 1. unwinding, base pairing, joining (p. 132)

2. Students should circle helicase, DNA polymerase, and DNA ligase. (p. 133)

3. eukaryotic: occurs in many places at the same time; prokaryotic: strand is opened at one place on the circle (p. 133)

Section 3

Before You Read (p. 134)Answers might include spoken languages, sign language, hieroglyphics, or Morse code.

Read to Learn 1. Students should draw an arrow pointing to

the polymerase. (p. 135)

2. introns (p. 135)

3. methionine-proline-glycine-leucine (p. 136)

4. c (p. 136)

5. c (p. 137)

6. Students should circle the tRNA in the P site. (p. 138)


ANSWER KEY


Section 4

Before You Read (p. 139)Students insert two and three letters. Students might notice that the sentence with three extra letters is easier to read.

Read to Learn 1. a specific enzyme (p. 139)

2. Students should circle the segment of DNA that is attached to the repressor. (p. 140)

3. Students should circle the inactive repressor. It is inactive when bound to allolactose. (p. 140)

4. guide RNA polymerase to promoter, control rate of transcription (p. 141)

5. nonsense mutation (p. 141)

6. No; one codon would be deleted, but the reading frame would remain the same. (p. 142)

7. It links thymines, forming a kink. (p. 142)

Chapter 13 Genetics and Biotechnology

Section 1

Before You Read (p. 143)Students should list physical traits, such as coat color and size; or behavioral traits, such as obedience, loyalty, or ability to do tricks.

Read to Learn 1. It produces animals and plants with a good

combination of traits. (p. 143)

2. to find out the genotype of an organism (p. 144)

3. Students should fill in the chart, top to bottom, with white, red, white. (p. 144)

4. 100 white, 0 red (p. 145)

5. 50 percent white, 50 percent red (p. 145)

Section 2

Before You Read (p. 146)Students should list tools such as toothbrushes, pencils, eating utensils, cars, telephones, and computers.

Read to Learn 1. They must isolate the rest of the DNA.

(p. 146)

2. because they have sticky and complementary ends (p. 147)

3. Students should use the figure to explain restriction enzymes to a partner. (p. 147)

4. Students should circle the plasmid DNA. (p. 148)

5. to cut long DNA molecules (p. 149)

6. gel electrophoresis (p. 149)

7. so scientists can study it (p. 150)

8. Students should underline Primer #1 and Primer #2 in Step 1. (p. 150)

9. Students should list any way listed in the paragraph. (p. 151)

10. Possible response: resistance to herbicides and pesticides (p. 151)

Section 3

Before You Read (p. 152)Students might list technology like hybrid cars, cell phones, iPods, TiVo, or new computer devices.

Read to Learn 1. 98% (p. 152)


ANSWER KEY

12 Answer Key

2. noncoding sequences, because they are different from one person to the next (p. 153)

3. creating and using computer databases to analyze the sequencing of DNA (p. 153)

4. The gene is actively making proteins. (p. 154)

5. Students should circle spots that are white in the bottom microarray and black in the top microarray. (p. 154)

6. No; an SNP occurs in at least 1 percent of people. This variation occurs in less than 1 percent of people. (p. 155)

7. Possible response: to tailor drugs to a person’s genetic makeup (p. 155)

8. a (p. 156)

9. the study and cataloging of proteins in the human body (p. 156)

Chapter 14 The History of Life

Section 1

Before You Read (p. 157)Students might include dinosaurs, extinct birds, such as passenger pigeons, and extinct mammals, such as the mastodon.

Read to Learn 1. too hot to support life (p. 157)

2. 3.5 billion years old (p. 158)

3. A. Organism dies. B. Sediments build up. C. Hard parts are replaced with minerals. (p. 158)

4. Students should label the bottom layer as the oldest and the top layer as the youngest. (p. 159)

5. the amount of isotope, its half-life, and its decay product (p. 159)

6. Answers should be between 20 and 25%. (p. 160)

7. Radiometric dating is performed on nearby igneous rocks and used to infer the age of sedimentary rock. (p. 160)

8. the formation of Earth (p. 161)

9. 90 percent of all marine organisms (p. 161)

10. K-T boundary (p. 162)

1 1. Students should add the label Pangaea to the landform in the map on the far left. (p. 162)

1 2. about 0.02 percent (p. 163)

1 3. Students should draw a circle around the Mesozoic era. (p. 163)

Section 2

Before You Read (p. 164)Students might identify that microbes landed on the bread and then multiplied.

Read to Learn 1. microscopes (p. 164)

2. He tilted the flask. (p. 165)

3. no (p. 165)

4. to simulate sunshine (p. 166)

5. clay (p. 166)

6. metabolism and reproduction (p. 167)

7. photosynthetic organisms (p. 167)

8. Students should highlight chloroplasts. (p. 168)


ANSWER KEY


Chapter 15 Evolution

Section 1

Before You Read (p. 169)People thought that plants and animals did not change. They thought that Earth was a few thousand years old.

Read to Learn 1. Possible response: fossils of marine life in the

mountains (p. 169)

2. off the coast of Ecuador (p. 170)

3. the finches eat different kinds of plants (p. 170)

4. Answers might include food, water, land, or shelter. (p. 171)

5. evolution: how a species changes over time; natural selection: how evolution could occur (p. 171)

Section 2

Before You Read (p. 172)Answer should include similar features such as four legs, a backbone, eyes, and skin; different features in frogs: live partly in water, lay eggs; cats: have live births, and fur.

Read to Learn 1. cat: walking and running; porpoise:

swimming; bat: flying (p. 173)

2. structures that are small because they no longer function (p. 173)

3. legs (p. 174)

4. the study of how living things are distributed on Earth (p. 174)

5. a trait that increases survival or reproductive success (p. 175)

6. Diseases develop more harmful forms that resist antibiotic treatment. (p. 175)

Section 3

Before You Read (p. 176)Answers might include advances such as space exploration, computer technology, and the development of better medicines.

Read to Learn 1. It does not evolve. (p. 176)

2. No; natural selection is occurring. (p. 177)

3. b (p. 177)

4. A large population dwindles and rebounds to a larger size. (p. 178)

5. It reduces fertility. (p. 178)

6. Students should highlight the solid line. (p. 179)

7. Students should highlight the dotted line. (p. 179)

8. lack of food and water (p. 180)

9. prezygotic and postzygotic isolating mechanisms (p. 180)

10. prezygotic and geographic (p. 181)

11. a (p. 181)

12. A species evolves into a number of new species in a short period of time. (p. 182)

13. a (p. 182)

Chapter 16 Primate Evolution

Section 1

Before You Read (p. 183)Students might note behaviors such as grasping objects with hands and socializing with others of their kind.


ANSWER KEY

14 Answer Key

Read to Learn 1. Students should label the thumb in the

picture as the opposable first digit. (p. 183)

2. strepsirrhines and haplorhines (p. 184)

3. large eyes (p. 185)

4. New World monkey (p. 185)

5. Both hands are free to gather food, provide defense, or grasp other branches to move. (p. 186)

6. great apes (p. 186)

7. c (p. 187)

8. Possible response: Over the last 66 million years, primates have evolved from an ancestor into several groups, including New World and Old World monkeys. One line of primates evolved into Asian apes, while another line evolved into African apes and hominids. (p. 187)

9. bigger brain (p. 188)

10. It might have been an ancestor of humans. (p. 188)

Section 2

Before You Read (p. 189)Individual can reach for food in higher places, its hands are free to do other things, and it can see farther.

Read to Learn 1. Students should circle hominoids. (p. 189)

2. The arms of hominins are shorter than their legs. (p. 190)

3. Students should highlight each discovery on the time line as they read about it in the section. (p. 190)

4. Students should color the long arms of the chimpanzee and the shorter arms of the early hominin. (p. 191)

5. easier for predators to see, cannot run as fast, appears to require more energy (p. 191)

6. at the base of the skull p. (192)

7. various primates that lived alongside human ancestors but were not human ancestors (p. 192)

Section 3

Before You Read (p. 193)Students might describe “cave men” as brutish, apelike creatures. Some might note that early humans made tools and drew on cave walls.

Read to Learn 1. long arms; could climb trees (p. 193)

2. animal meat was its food source (p. 194)

3. diverse fossils with a mix of traits of H. ergaster and modern humans (p. 194)

4. bigger and heavier (p. 195)

5. The brain generally became larger. (p. 195)

6. Students should highlight Homo sapiens. (p. 196)

7. that humans first appeared in Africa (p. 196)

Chapter 17 Organizing Life’s Diversity

Section 1

Before You Read (p. 197)Students might state that they organize books by author or by title and CDs by artist or by album name.

Read to Learn 1. Aristotle (p. 197)

2. daisy: plant that is an herb; dog: animal with red blood that lives on land; whale: animal with red blood that live in water (p. 198)


ANSWER KEY


3. He kept Aristotle’s morphological component and added behavior to the classification. (p. 198)

4. c (p. 199)

5. It should be underlined. (p. 199)

6. Categories have been changed to show evolutionary relationships. (p. 200)

7. large bodies and large skulls (p. 200)

8. species (p. 201)

9. Possible response: A poisonous plant might have a related species that is also poisonous. (p. 201)

Section 2

Before You Read (p. 202)Students should describe how they organize their class notes and how they use the information in their notes to study for tests.

Read to Learn 1. individual that best shows the characteristics

of that species (p. 202)

2. a group of organism that interbreeds and naturally produces fertile offspring (p. 203)

3. phylogenetic species concept (p. 203)

4. rare interbreeding and large differences in the DNA and skull measurements of the two populations (p. 204)

5. bodies are dominant and arms (wings) are short (p. 204)

6. their many similar nucleotide sequences (p. 205)

7. The molecular clocks of two organisms might differ slightly when studying the same genes. (p. 205)

8. ancestral: evolved in common ancestor of both groups; derived: evolved in ancestor of one group (p. 206)

9. a branching diagram that shows the proposed phylogeny of a species (p. 206)

10. chloroplasts, roots, vascular tissue, and seeds (p. 207)

Section 3

Before You Read (p. 208)Students should list unicellular or multicellular fungi such as yeast and mushrooms.

Read to Learn 1. does not need oxygen to live (p. 209)

2. because they live in the most extreme environments on Earth (p. 209)

3. plantlike protists: autotrophs; animal-like protists: heterotrophs (p. 210)

4. threadlike strands that enable the fungi to grow, feed, and reproduce (p. 210)

5. more than 250,000 species (p. 211)

6. Viruses are not considered living. (p. 211)

7. corals (p. 212)

Chapter 18 Bacteria and Viruses

Section 1

Before You Read (p. 213) Students might think that bacteria live in unsanitary places. They might not realize that bacteria live in and on them.

Read to Learn 1. b (p. 213)

2. Students should highlight each structure of the prokaryotic cell as they read about it. (p. 214)

3. Pili serve as a bridge for plasmids to cross. (p. 214)


ANSWER KEY

16 Answer Key

4. spheres, rods, and spirals (p. 215)

5. to identify the bacteria and prescribe the correct antibiotic (p. 215)

6. Students should write genetic information exchanged next to the conjugation diagram and identical cells formed next to the binary fission diagram. (p. 216)

7. Heterotrophs cannot make their own food; autotrophs can. (p. 216)

8. Possible response: saprotrophs: decompose organic materials; photosynthetic autotrophs: photosynthesis using light; chemoautotrophs: chemosynthesis of inorganic matter (p. 217)

9. Bacteria could become extinct. (p. 217)

10. Bacteria convert nitrogen gas into a form of nitrogen plants can use. (p. 218)

1 1. Some types of bacteria are helpful and important to life. (p. 218)

Section 2

Before You Read (p. 219)Students might know that humans might become infected by eating infected beef.

Read to Learn 1. cold: caused by a virus; strep throat: caused by

bacteria (p. 219)

2. Students should highlight capsid and genetic material in all three diagrams. (p. 220)

3. Students should label lysogenic portion: dormant period; lytic portion: active period (p. 221)

4. DNA from viral RNA (p. 221)

5. Students should use the figure to explain to a partner how HIV replicates. (p. 222)

6. They mutate. (p. 222)

Chapter 19 Protists

Section 1

Before You Read (p. 223)Possible questions might include: Does the organism eat other organisms? Is the organism capable of photosynthesis?

Read to Learn 1. A protist with chloroplasts could make its

own food. (p. 223)

2. b (p. 224)

3. mitochondria and chloroplasts (p. 224)

Section 2

Before You Read (p. 225)Students might note that grabbing did not work as well as letting the object drift in through their cupped hands.

Read to Learn 1. Students should highlight the oral groove and

the cilia around it, the gullet, and the food vacuole. (p. 226)

2. Possible response: Conjugation is sexual, and binary fission is asexual. (p. 227)

3. They close around the food. (p. 227)

4. by diffusion through the outer membrane (p. 228)

5. by feeding on the blood of an infected human or other mammal (p. 228)

Section 3

Before You Read (p. 229)Students should suggest foods with thick sauces, such as syrup, puddings, and pie fillings.


ANSWER KEY


Read to Learn 1. provide base of the food web; produce much

of Earth’s oxygen (p. 229)

2. one half inside the other half, forming a box (p. 230)

3. b (p. 230)

4. plenty of food and favorable conditions (p. 231)

5. It can move toward the sunlight it need to make food. (p. 231)

6. chlorophyll, cell walls, store food as carbohydrates (p. 232)

7. Possible response: It is green and eaten in salads. (p. 232)

8. One is sexual, and the other is asexual. (p. 233)

9. Students should label the gametophyte haploid and the sporophyte diploid. (p. 233)

Section 4

Before You Read (p. 234)Student responses might include warm, dark, moist, and watery conditions.


2. Students should place a 1 beside spores and a 2 beside young plasmodium. (p. 235)

3. In water, a spore produces a cytoplasm and flagella. (p. 235)

4. Students should use the figure to explain the life cycle of cellular slime molds to a partner. (p. 236)

5. enclose food in mass of threads and absorb nutrients through cell walls (p. 236)

Chapter 20 Fungi

Section 1

Before You Read (p. 237)Students might mention typical mushroom habitats, such as dead logs in the forest or damp areas of their yard.


2. Students should locate two of the lines that divide the hyphae and label them septa. (p. 238)

3. Possible response: Mutualists benefit their hosts; parasitic fungi harm their hosts. (p. 239)

4. large quantities, light weight, hard outer coats (p. 239)

Section 2

Before You Read (p. 240)Possible response: I put it wherever there is space. I put it in the same drawer each time.

Read to Learn 1. their spores have flagella (p. 240)

2. feeding, digesting, and anchoring (p. 241)

3. b (p. 241)

4. tough outer coat; can remain dormant until conditions are favorable (p. 242)

5. Students should add a title such as Reproduction of Sac Fungi. (p. 242)

6. because of their saclike ascus (p. 243)

7. They grow by enlarging rather than dividing their cells. (p. 243)


ANSWER KEY

18 Answer Key

Section 3

Before You Read (p. 244)Students might identify a disaster such as a fire, flood, or volcanic eruption. They should recognize that the disaster killed vegetation and animals and, in some cases, polluted the environment.

Read to Learn 1. using energy trapped from sunlight to

produce simple sugars (p. 244)

2. Pieces break off, blow to new locations, and form new colonies. (p. 245)

3. The partner produces food for both organisms. (p. 245)

4. Earth could be littered with dead organisms. (p. 246)

5. They decompose organic materials in pollutants. (p. 246)

Chapter 21 Introduction to Plants

Section 1

Before You Read (p. 247)Students should name characteristics such as green leaves, stems, flowering parts, and underground roots.

Read to Learn 1. Students should circle green algae. (p. 248)

2. to survive when water is scarce (p. 248)

3. The cuticle reduces water loss; the stomata enables gas exchange. (p. 249)

4. gametophyte and sporophyte (p. 249)

5. a (p. 250)

6. nonvascular plants—osmosis and diffusion; vascular plants—vascular tissue (p. 250)

Section 2

Before You Read (p. 251)Students should explain that both organisms benefit in a mutualistic relationship.

Read to Learn 1. Students should highlight vascular tissue.

(p. 251)

2. their leaflike structures (p. 252)

3. Both are nonvascular. Bryophytes have multicellular rhizoids; hepaticophytes have unicellular rhizoids. (p. 252)

Section 3

Before You Read (p. 253)Students should explain that plumbing supplies water and disposes of wastes.

Read to Learn 1. a plant that lives anchored to another plant

(p. 253)

2. moist environment (p. 254)

3. Students should highlight rhizome and color the fronds green. (p. 254)

Section 4

Before You Read (p. 255)Students should list products such as pasta, green beans, and oatmeal.

Read to Learn 1. It limits competition. (p. 255)

2. The sporophyte generation is dominant in both. (p. 256)

3. Students should write the numbers 1 to 5 from left to right on the lines above the tree. (p. 256)


ANSWER KEY


4. The male does not produce bad-smelling seed coats. (p. 257)

5. Evergreens have leaves year-round and block more wind. (p. 257)

6. Only angiosperms have flowering plants. (p. 258)

7. perennial (p. 258)

Chapter 22 Plant Structure and Function

Section 1

Before You Read (p. 259)Students should name three structures found in plant cells, such as nucleus, chloroplasts, and ER. Accept all correct responses.

Read to Learn 1. They vary depending on their function.

(p. 259)

2. to survive in sometimes harsh environments (p. 260)

3. both provide support (p. 260)

4. apical meristems, intercalary meristems, lateral meristems (p. 261)

5. to absorb water and nutrients (p. 261)

6. Students should circle the center image.(p. 262)

Section 2

Before You Read (p. 263)Answers should include parts such as leaves, stems, roots, fruit, or flowers. Students should describe the function of one of the parts they listed.

Read to Learn 1. epidermis, cortex, vascular tissue (p. 263)

2. Students should highlight pericycle. (p. 264)

3. taproots (p. 264)

4. to support the leaves and reproductive structures of the plant (p. 265)

5. Students should highlight palisade mesophyll cell. (p. 265)

6. the opening and closing of the stomata (p. 266)

7. Students should circle either simple or compound. (p. 266)

Section 3

Before You Read (p. 267)Students might indicate that their body shivers or their skin forms goose bumps.

Read to Learn 1. High concentrations of the hormone can

stunt growth. (p. 267)

2. cause cell elongation, increase enzyme production, affect seed germination (p. 268)

3. Students should draw on a separate sheet of paper examples of each tropism. (p. 268)

Chapter 23 Reproduction in Plants

Section 1

Before You Read (p. 269)Students might list traits such as hair color and texture; eye color; and eye, nose, and mouth shape.

Read to Learn 1. No, it lacks reproductive structures. (p. 269)

2. sporophyte (p. 270)


ANSWER KEY

20 Answer Key

3. Students should explain to a partner the alterations of generations. (p. 270)

4. gametophyte stage (p. 271)

5. Students should highlight the archegonium and circle the antheridium. (p. 271)

6. Students should circle zygote. (p. 272)

7. The fern spore probably would not grow. (p. 272)

8. a pollen grain (p. 273)

9. Pollen grain lands near micropyle and is trapped in a pollen drop. Ovule absorbs pollen drop, pulling the pollen grain to the micropyle. (p. 273)

Section 2

Before You Read (p. 274)Answers should include parts of a flower, such as petals, stem, and pollen.

Read to Learn 1. Students should add the label peduncle.

(p. 274)

2. male: stamen; female: pistil (p. 275)

3. Students should label the left figure eudicot and the right figure monocot. (p. 275)

4. self-pollinating flowers (p. 276)

5. long-day plants (p. 276)

6. winter, spring, or fall (p. 277)

7. Possible answers: short-day: pansies, poinsettias, tulips; long-day: lettuce, asters, coneflowers; intermediate-day: sugarcane, some grasses; day-neutral: corn, cotton, tomatoes (p. 277)

Section 3

Before You Read (p. 278)Students might suggest that tomatoes are fruits because they have seeds that develop from ovaries.

Read to Learn 1. four nuclei (p. 278) 2. the agricultural history of certain regions

(p. 279) 3. Students should highlight the tip of the pollen

tube and circle the embryo. (p. 279) 4. It has to be long enough to get into the ovary.

(p. 280) 5. monocot: seed has one cotyledon; eudicots:

seed has two cotyledons (p. 280) 6. one that forms from flowers with multiple

female organs that fuse as the fruit ripens (p. 281)

7. by water, animals, and wind (p. 281) 8. The cotyledons of eudicots are above ground

and they usually stay below ground in monocots. (p. 282)

Chapter 24 Introduction to Animals

Section 1

Before You Read (p. 283)Students might list body coverings such as feathers, shells, scales, or fur.


2. Animal cells do not have cell walls. (p. 284)

3. Students should highlight fragmentation and regeneration. (p. 284)

4. Students should highlight the gastrula and label its opening. (p. 285)

5. nervous tissue and skin (p. 285)


ANSWER KEY


Section 2

Before You Read (p. 286)Students might mention features of a bird such as feathers, beak, and the ability to fly.

Read to Learn 1. if the animal has tissues (p. 286)

2. Students should label the jellyfish radial symmetry and the hummingbird bilateral symmetry. (p. 287)

3. b (p. 288)

4. limits tissue, organ, and system development (p. 288)

5. compare how embryos develop (p. 289)

6. The mesoderm splits and the coelom forms between the pieces. (p. 289)

Section 3

Before You Read (p. 290)Students might mention contributions such as taking out the trash, washing dishes, or sweeping floors.

Read to Learn 1. Students should highlight pore cell and circle

osculum. (p. 290)

2. in two layers of cells, with jellylike substance between them (p. 291)

3. Closing the pores keeps out harmful substances. (p. 291)

4. No, the larva swims freely. (p. 292)

5. produce chemicals that help fight infection, swelling, and tumors (p. 292)

6. Students should highlight that sponges and cnidarians are similar in movement and reproduction, but different in body plan, feeding and digestion, and response to stimuli. (p. 293)

7. b (p. 293)

8. polyp and medusa (p. 294)

9. The fish is protected from predators. (p. 294)

Chapter 25 Worms and Mollusks

Section 1

Before You Read (p. 295)Students might suggest that animals use mucus to lubricate for easy movement and to help them stick to surfaces.

Read to Learn 1. to attach to their hosts (p. 295)

2. Students should highlight the mouth, pharynx, and digestive cavity. They should circle the mouth, excretory tubule, and flame cell. (p. 296)

3. keeps the flatworms from being swept away in current (p. 296)

4. Each half will grow missing parts to form two planarians. (p. 297)

5. helps them locate prey (p. 297)

Section 2

Before You Read (p. 298)Students might state that hand washing removes bacteria and viruses from the hands. Often people put their hands to their mouths, infecting themselves.

Read to Learn 1. diffusion (p. 298)

2. 0.33 s × 4 segments = 1.32 s (p. 299)

3. Possible response: avoid or thoroughly cook pork or wild game (p. 299)


ANSWER KEY

22 Answer Key

4. Possible response: Children are often less careful about washing their hands after playing in the dirt. (p. 300)

5. to bring in food or move (p. 300)

Section 3

Before You Read (p. 301)Students might describe the pressure of the water against their hands or swim fins.

Read to Learn 1. They have no need to scrape anything to

obtain food. (p. 301)

2. snail’s shell: outside body; squid’s shell: reduced, below the mantle (p. 302)

3. b (p. 302)

4. remove wastes from blood (p. 303)

5. a clam (p. 303)

6. Predators know from the colors that they are poisonous and might not eat them. (p. 304)

7. foot (p. 304)

Section 4

Before You Read (p. 305)Students might mention that links give the necklace or bracelet flexibility.

Read to Learn 1. In one color, students should highlight the

mouth, crop, gizzard, intestine, nephridia, and anus. In another color, students should highlight the dorsal blood vessel, hearts, and ventral blood vessel. Students should circle the brain and ganglia. (p. 306)

2. protects the young until they hatch (p. 307)

3. Clotting slows the blood flow, making it harder for the leech to drink. (p. 307)

4. Students should highlight front and rear suckers. (p. 308)

5. c (p. 308)

Chapter 26 Arthropods

Section 1

Before You Read (p. 309)Students should list advantages such asprotection and disadvantages such as difficultyof movement.

Read to Learn 1. support, protection, slowing water loss,

muscle attachment (p. 310)

2. The new exoskeleton would be the same size as the old one, leaving no room to grow. (p. 310)

3. Students should underline gills and spiracle. (p. 311)

4. delivering nutrients, removing wastes (p. 311)

5. Malpighian tubules, nephridia (p. 312)

6. Students should sketch a six-sided plane. (p. 312)

Section 2

Before You Read (p. 313)Students might recognize that spiders spin asilk-like substance into a web. Spiders capture prey in the web.

Read to Learn 1. Students should circle Spiders and Their

Relatives. (p. 313)

2. Students should add descriptions similar to the following: chelipeds—catch and crush food; walking legs—walking; swimmerets—swimming (p. 314)


ANSWER KEY


3. It would help subdue the prey it bites. (p. 314)

4. Food is easier to ingest after it is softened. (p. 315)

5. ticks, mites, scorpions (p. 315)

Section 3

Before You Read (p. 316)Students should list different types of insects that live in their area.

Read to Learn 1. Possible responses: adapted for different

functions; hind legs adapted for jumping (p. 316)

2. adaptations (p. 317) 3. piercing/sucking (p. 317) 4. exoskeleton (p. 318)

5. pupa (p. 318)

6. molting (p. 319)

7. Student sketches should show: (1) circle, (2) straight line (possibly with a waggle), (3) figure eight (p. 319)

8. lice and blood-sucking flies (p. 320)

9. similar—live in moist places; different—number of legs per segment (p. 320)

Chapter 27 Echinoderms and Invertebrate Chordates

Section 1

Before You Read (p. 321)Students might note that many animals use camouflage to confuse predators.

Read to Learn 1. deuterostome development and endoskeleton

(p. 321)

2. movement and food collection (p. 322)

3. Students should highlight the madreporite, ring canal, radial canal, tube feet, and ampulla. (p. 322)

4. Possible response: Digesting within the prey’s shell makes the food small enough to extract through a small crack. (p. 323)

5. The bony plates are movable. (p. 323)

6. c (p. 324)

7. The body of a sand dollar is enclosed in a hard test that looks like a shell. (p. 324)

8. a respiratory tree (p. 325)

9. The snail population would decline as an increasing sea urchin population ate more kelp. (p. 325)

Section 2

Before You Read (p. 326)Students should recall that vertebrates have a backbone and invertebrates do not.

Read to Learn 1. Students should highlight each structure as

they read about it. (p. 326)

2. thyroid gland (p. 327)

3. b (p. 328)

4. It enabled a side-to-side swimming motion, leading to the first large animals. (p. 328)

Chapter 28 Fishes and Amphibians

Section 1

Before You Read (p. 329)Students might describe the movement of fins as the fish swim or explain that the fish’s body bends as it swims.


ANSWER KEY

24 Answer Key

Read to Learn 1. cartilage and bone (p. 329)

2. just above the nerve cord (p. 330)

3. jaws, lungs, and vertebral column (p. 330)

4. Possible response: It might roll or move toward the side without the fin. (p. 331)

5. Possible response: during a drought to keep lungfish alive until rain returns (p. 332)

6. Students should circle atrium and ventricle. (p. 332)

7. In one color students should highlight the stomach and intestine. In another color, students should highlight the gallbladder, liver, and pancreas. (p. 333)

8. kidney (p. 334)

9. Students should circle cerebellum. (p. 334)

10. producing millions of eggs, increasing chances that some offspring will survive (p. 335)

1 1. s-shaped (p. 335)

Section 2

Before You Read (p. 336)Students might describe a shark as a large fish with many sharp teeth. Some students might mention an upright fin on the shark’s back.

Read to Learn 1. skin and bones (p. 336)

2. Lampreys are parasites; hagfishes are scavengers. (p. 337)

3. Possible response: pointed head (p. 337)

4. a (p. 338)

5. lampreys, hagfish, and ostracoderms (p. 339)

6. damming rivers and polluting waterways (p. 339)

Section 3

Before You Read (p. 340)Students might note that the tadpole sprouts legs and its tail shortens.

Read to Learn 1. Students should highlight lungs. (p. 340)

2. larvae: aquatic, use gills; adults: live on land, use lungs (p. 341)

3. In one color students should highlight the oxygen-poor segments. In another color, students should highlight the oxygen-filled segments. (p. 342)

4. to raise its body temperature (p. 342)

5. to keep the embryo from drying out and dying (p. 343)

6. Salamanders live on land. Newts are aquatic all their lives. (p. 343)

7. Students should highlight caecilians, salamanders, and frogs and toads. (p. 344)

8. Amphibians need water to reproduce. (p. 344)

Chapter 29 Reptiles and Birds

Section 1

Before You Read (p. 345)Students might describe the movie dinosaurs as huge, fierce predators with sharp teeth.

Read to Learn 1. amnion: provides aquatic environment;

allantois: collects embryo’s wastes; chorion: allows oxygen to enter and keeps fluid inside (p. 345)

2. Students should highlight the septum. (p. 346)

3. maintains balance of water and minerals in body (p. 347)


ANSWER KEY


4. Possible response: Crocodile’s body is off the ground when it moves, reducing friction. (p. 347)

5. alligators and crocodiles (p. 348)

6. breadth of snout and whether lower teeth are visible when mouth is closed (p. 348)

7. c (p. 349)

8. It would increase. (p. 349)

Section 2

Before You Read (p. 350)Students might note that its parts seemed to stick together or that it is fluffy, soft, and delicate.

Read to Learn 1. produces heat and energy needed for flight

(p. 350)

2. a (p. 351)

3. In one color, students should highlight the path of inhalation. In another color, students should highlight the path of exhalation. (p. 351)

4. two ventricles keep oxygen-rich andoxygen-poor blood separate (p. 352)

5. Students should circle the gizzard. (p. 352)

6. cerebellum (p. 353)

7. Students should highlight Sphenisciformes and Struthioniformes. Students should circle Ciconiiformes, Procellariiformes, Sphenisciformes, and Anseriformes. (p. 353)

8. Students should highlight the feathers. (p. 354)

9. Illegal trade would decline because it would not be profitable. (p. 354)

Chapter 30 Mammals

Section 1

Before You Read (p. 355)Students might recognize that hair and fur protect mammals from weather extremes of temperature, water, predation, and infections. Elephants, whales, and naked mole rats are a few mammals that do not have much hair on their bodies.

Read to Learn 1. Students should highlight hair and mammary

glands. (p. 355)

2. camouflage (p. 356)

3. high metabolic rate (p. 356)

4. flying squirrel (p. 357)

5. a (p. 357)

6. b (p. 358)

7. The large, sharp, narrow shape is good for piercing prey. (p. 358)

8. a (p. 359)

9. septum (p. 359)

10. conscious activities and memory (p. 360)

1 1. horse (mammal) (p. 360)

1 2. elephant (p. 361)

1 3. A mole can dig and burrow, while a bat can fly. (p. 361)

Section 2

Before You Read (p. 362)Possible response: Kangaroos live in Australia, move by leaping, and carry their young in pouches.


ANSWER KEY

26 Answer Key

Read to Learn 1. Placentals could threaten the survival of

marsupials. (p. 363)

2. Chiroptera (p. 363)

3. Lagomorphs have a second set of incisors behind the first. (p. 364)

4. Both have hoofs and eat plants. (p. 364)

5. therapsids (p. 365)

6. hair (p. 366)

7. Dinosaurs disappeared, and flowering plants thrived. (p. 366)

Chapter 31 Animal Behavior

Section 1

Before You Read (p. 367)Answers will vary. Students might say they were born able to cry when hungry, and that they learned to use silverware to eat.

Read to Learn 1. genes and past experiences (p. 367)

2. The goose would roll the ball into the nest. (p. 368)

3. The stimulus must have no positive or negative effects. (p. 369)

4. Students should label the bell and the food bowl as the stimuli and the saliva as the response. (p. 369)

5. stimulus: test; response: study; reward: good grade (p. 370)

6. Students might mention problem solving or planning. (p. 370)

Section 2

Before You Read (p. 371)Students might suggest that animals make sounds to warn of a predator or to attract the attention of a potential mate.

Read to Learn 1. to establish control of a resource (p. 371)

2. a territory contains needed resources (p. 372)

3. lower temperatures and less daylight (p. 372)

4. to attract a mate (p. 373)

5. b (p. 373)

6. The animal can obtain nutrients while avoiding predators. (p. 374)

Chapter 32 Integumentary, Skeletal, and Muscular Systems

Section 1

Before You Read (p. 375)Student lists might include functions such as protection, sense of touch, and temperature regulation.

Read to Learn 1. Students should highlight sebaceous gland and

hair follicle. (p. 376)

2. c (p. 376)

3. for proper bone formation (p. 377)

4. increases risk of skin cancer (p. 377)

Section 2

Before You Read (p. 378)Students should recognize that the knee allows a back-and-forth movement but not much side-to-side or twisting motion.


ANSWER KEY


Read to Learn 1. to bring oxygen and nutrients to living bone

cells (p. 378)

2. The system brings oxygen and nutrients to living bone cells. (p. 379)

3. to break down old bone cells (p. 379)

4. 8 hours (p. 380)

5. cartilage and spongy bone are not as strong as compact bone (p. 380)

6. Students should highlight the type of movement allowed by each joint. (p. 381)

7. Any three: support, protection, production of blood cells and platelets, storage (p. 381)

Section 3

Before You Read (p. 382)Students should list their favorite physical activities and determine which type of activities they prefer.

Read to Learn 1. It is not consciously controlled. (p. 382)

2. Smooth muscle: lining of hollow organs, such as stomach, intestines, and bladder. Cardiac muscle: heart. Striated muscle: skeletal muscles. (p. 383)

3. moves downward (p. 384)

4. lactic-acid fermentation (p. 384)

5. a (p. 385)

Chapter 33 Nervous System

Section 1

Before You Read (p. 385)Students might say that they jerked their hand away from the object quickly.

Read to Learn 1. Students should add a title such as Nerve Cell.

(p. 385)

2. Possible response: Sensory neurons would send signals, but motor neurons would not get the message to act. (p. 386)

3. a stimulus that has reached threshold (p. 386)

4. a path along which an electrical signal passes (p. 387)

5. Students should use the figure to explain how channels open and the electrical signal is sent like a wave down the length of the axon. The movement of sodium ions and potassium ions create the change in the charge inside and outside the cell. (p. 387)

6. to insulate the axon (p. 388)

7. Students should write neurotransmitter on the line. (p. 388)

Section 2

Before You Read (p. 389)Any sensory information would be an appropriate response. Possible answers include pain, sounds, and images.

Read to Learn 1. first box: Sensory neurons; third box: Motor

neurons (p. 389)

2. They both have large surface areas to increase the function of the structures. (p. 390)

3. Students should circle medulla oblongata and pons. (p. 390)

4. vertebrae (p. 391)

5. sympathetic nervous system (p. 391)


ANSWER KEY

28 Answer Key

Section 3

Before You Read (p. 392)Students might describe that their appetite was poor and that food seemed to have little taste.

Read to Learn 1. taste buds (p. 392)

2. Students should add rods and cones beside the retina. (p. 393)

3. cochlea (p. 393)

4. c (p. 394)

5. because your fingertips perform tasks that require a keener sense of touch than your elbows (p. 394)

Section 4

Before You Read (p. 395)Students should list reasons to take legal drugs, such as to relieve pain or to treat a bacterial infection.

Read to Learn 1. to send an action potential to the next neuron

(p. 395)

2. Students should draw an arrow pointing downward from the axon toward the dendrite. (p. 396)

3. They get a burst of energy to help them feel awake and alert. (p. 396)

4. short-term: increased heart rate, irregular heart beat; long-term: permanent damage to blood vessels in brain (p. 397)

5. Possible responses: memory problems, poor coordination, anxiety (p. 398)

6. to avoid physical and psychological problems; to avoid becoming addicted (p. 398)

Chapter 34 Circulatory, Respiratory, and Excretory Systems

Section 1

Before You Read (p. 399)Students should record about 70 beats per minute.

Read to Learn 1. arteries, capillaries, and veins (p. 399)

2. b (p. 400)

3. increases the heart rate (p. 401)

4. right atrium (p. 401)

5. 125 - 120 = 5; 5/125 = .04 × 100 = 4% (p. 402)

6. Students should highlight the blood’s path from the heart to the body and back. (p. 402)

7. b (p. 403)

8. enables transportation of oxygen and some carbon dioxide (p. 403)

9. O (p. 404)

10. heart attack, stroke (p. 404)

Section 2

Before You Read (p. 405)Students should record the number of breaths they take in one minute. Students might suggest that they think about breathing after strenuous exercise or when they have a respiratory infection.

Read to Learn 1. It involves gas exchange with the atmosphere

and the blood. (p. 405)

2. nose hairs, cilia, mucous membranes (p. 406)


ANSWER KEY


3. Students should circle alveoli. (p. 406)

4. down during inhalation and up during exhalation (p. 407)

5. emphysema (p. 407)

Section 3

Before You Read (p. 408)Students might note that the excess trash would attract bugs and rodents and create an unpleasant odor.

Read to Learn 1. filter wastes, water, and salt from blood

(p. 408)

2. Students should highlight the kidney structures. (p. 409)

3. Possible response: Homeostasis could be upset. (p. 409)

4. kidney stones (p. 410)

5. not enough donated kidneys to meet the need (p. 410)

Chapter 35 Digestive and Endocrine Systems

Section 1

Before You Read (p. 411)Students should note that their body responded by coughing. They might recognize that this expels food out of the windpipe.

Read to Learn 1. chemical digestion (p. 411)

2. esophagus (p. 412)

3. Students should circle the pancreas, gallbladder, and liver. (p. 412)

4. Students should label the liver as the organ that produces bile and the gallbladder as the organ that stores bile. (p. 413)

5. to absorb water from chyme (p. 413)

Section 2

Before You Read (p. 414)Students might recognize that fatty and sugary foods are not the best choices for a healthful diet.

Read to Learn 1. Students should multiply the Calories used

per hour by 7. (p. 414)

2. b (p. 415)

3. how to combine fruits and vegetables to include all eight essential amino acids (p. 415)

4. grains, vegetables, dairy (p. 416)

5. 7 × 2 = 14 g (p. 416)

Section 3

Before You Read (p. 417)Students might describe feeling their heart beating faster and their breathing rate increasing.

Read to Learn 1. a (p. 418)

2. thyroid gland (p. 418)

3. Students should circle glucagon and insulin. (p. 419)

4. aldosterone (p. 419)

5. Hormones signal specific organs or tissues to respond appropriately. (p. 419)

6. antidiuretic hormone (ADH) and oxytocin (p. 420)

7. c (p. 420)


ANSWER KEY

30 Answer Key

Chapter 36 Human Reproduction and Development

Section 1

Before You Read (p. 421)Possible response: Males usually have more muscle than females. Males have different reproductive organs than females. Males do not have breasts.

Read to Learn 1. Students should underline testis. (p. 421)

2. antidiuretic hormone or insulin (p. 422)

3. both produce sex cells (p. 423)

4. Students should highlight ovary. (p. 423)

5. Males produce millions of sex cells. Females produce only one sex cell each month. (p. 424)

6. the shedding of the endometrium (p. 424)

7. Estrogen stimulates the anterior pituitary to release a large quantity of LH, causing ovulation. (p. 425)

8. LH (p. 425)

Section 2

Before You Read (p. 426)Students should describe physical changes such as an enlarged abdomen or enlarged breasts.

Read to Learn 1. The tips of sperm release an enzyme that

weakens the egg’s plasma membrane. (p. 426)

2. 46 (p. 427)

3. Students should trace from fertilization down to the oviduct to implantation in the uterus. (p. 427)

4. villi (chorion) and uterine lining (p. 428)

5. Students should underline umbilical cord. (p. 428)

6. to keep the corpus luteum from breaking down and to keep the levels of estrogen and progesterone high (p. 429)

7. to receive medical care until it can breath on its own and until its immune develops fully (p. 429)

8. to treat problems early and to give the newborn the highest possible quality of life (p. 430)

9. genetic problems (p. 430)

Section 3

Before You Read (p. 431)Students should note changes such as increased height and weight.

Read to Learn 1. surgical removal of the baby through the

mother’s abdomen, rather than through the mother’s vagina (p. 431)

2. from puberty to adulthood (p. 432)

3. graying hair, becoming shorter, skin losing elasticity (p. 432)

Chapter 37 The Immune System

Section 1

Before You Read (p. 433)Answers will vary, depending on the disease students choose and their knowledge of it.

Read to Learn 1. Some microorganisms are pathogens. (p. 433)

2. d, c, a, b (p. 434)


ANSWER KEY


3. Cleaning the countertop destroys reservoirs. (p. 435)

4. c (p. 435)

5. through direct contact (p. 436)

6. harmful chemicals produced by bacteria (p. 436)

7. A pandemic is more widespread, covering a larger region. (p. 437)

8. b (p. 437)

Section 2

Before You Read (p. 438)Students might report that the injury site looked red and felt hot and painful.

Read to Learn 1. It helps to move infected mucus out of the

body. (p. 438)

2. Phagocytic white blood cells engulf and absorb foreign microorganisms. (p. 439)

3. lymphatic system (p. 439)

4. to help provide specific immunity (p. 440)

5. Students should associate the labels as follows. Bone marrow: produces T cells. Thymus gland: activates T cells. Spleen: destroys damaged red blood cells. (p. 440)

6. mitosis (p. 441)

7. Loss of helper T cells reduces the body’s ability to fight off diseases. (p. 442)

Section 3

Before You Read (p. 443)Students might describe symptoms such as itchy, watery eyes, sneezing, stuffy nose, or skin rash.

Read to Learn 1. production of insulin by the pancreas or the

cells do not recognize insulin (p. 443)

2. in any tissue or organ (p. 444)

3. more severe, more histamine released,life-threatening (p. 444)


000i-viii Bio TRE FM 896100

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