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Content Outline for Teaching 

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To the Teacher 

These pages provide a synopsis of the chapter by section, including 

suggested discussion questions. Also included are the terms that fill in 

the blanks in the students’ Note-taking Worksheets that are found in the 

Chapter Resources booklets. Chapter vocabulary terms appear in bold 

within the outlines, both in the teacher and student versions. 

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Permission is granted to reproduce the material contained herein on the condition 

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Glencoe Science Level Red program. Any other reproduction, for use or sale, is 

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Glencoe/McGraw-Hill 

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ISBN 0-07-867207-4 

Printed in the United States of America. 

1 2 3 4 5 6 7 8 9 10 079 09 08 07 06 05 04

Content Outline 

for Teaching 

Table of Contents 

To the Teacher 

Chapter 1 The Nature of Science 

Section 1 What Is Science................................1 

Section 2 Science in Action ............................2 

Section 3 Models in Science............................3 

Section 3 Evaluating Scientific Explanation ..4 

Chapter 2 Measurement 

Section 1 Description and Measurement ......5 

Section 2 SI Units ............................................6 

Section 3 Drawings, Tables, and Graphs ........7 

Chapter 3 Matter and Its Changes 

Section 1 Physical Properties and Changes....8 

Section 2 Chemical Properties and Changes ..9 

Chapter 4 Atoms, Elements, and the 

Periodic Table 

Section 1 Structure of Matter ......................10 

Section 2 The Simplest Matter......................11 

Section 3 Compounds and Mixtures............13 

Chapter 5 Motion, Forces, and 

Simple Machines 

Section 1 Motion ..........................................14 

Section 2 Newton’s Laws of Motion ............15 

Section 3 Work and Simple Machines..........16 

Chapter 6 Energy 

Section 1 Energy Changes ............................17 

Section 2 Temperature ..................................18 

Section 3 Chemical Energy ..........................19 

Chapter 7 Electricity and Magnetism 

Section 1 Electric Charge and Forces ..........20 

Section 2 Electric Current ............................21 

Section 3 Magnetism ....................................22 

ii 

Chapter 8 Waves 

Section 1 What Are Waves? ..........................23 

Section 2 Wave Properties ............................24 

Section 3 Wave Behavior ..............................25 

Chapter 9 Rocks and Minerals 

Section 1 Minerals—Earth’s Jewels ..............26 

Section 2 Igneous and Sedimentary Rocks ..27 

Section 3 Metamorphic Rock and the 

Rock Cycle ....................................28 

Chapter 10 Forces Shaping Earth 

Section 1 Earth’s Moving Plates....................29 

Section 2 Uplift of Earth’s Crust ..................30 

Chapter 11 Weathering and Erosion 

Section 1 Weathering and Soil Formation ....31 

Section 2 Erosion of Earth’s Surface ............32 

Chapter 12 Atmosphere in Motion 

Section 1 The Atmosphere ............................34 

Section 2 Earth’s Weather..............................36 

Section 3 Air Masses and Fronts ..................38 

Chapter 13 Oceans 

Section 1 Ocean Water ..................................39 

Section 2 Ocean Currents and Climate........40 

Section 3 Waves..............................................41 

Section 4 Life in the Oceans..........................42 

Chapter 14 Exploring Space 

Section 1 Radiation from Space....................43 

Section 2 Early Space Missions ....................44 

Section 3 Current and Future 

Space Missions ..............................45 

Chapter 15 The Solar System and Beyond 

Section 1 Earth’s Place in Space....................47 

Section 2 The Solar System ..........................48 


iii



Table of Contents 

Chapter 16 Cells—The Units of Life 

Section 1 The World of Cells ........................51 

Section 2 The Different Jobs of Cells ..........52 

Chapter 17 Invertebrate Animals 

Section 1 What is an Animal ........................53 

Section 2 Sponges, Cnidarians, Flatworms, 

and Roundworms..........................54 

Section 3 Mollusks and 

Segmented Worms ........................56 

Section 4 Arthropods and Echinoderms......58 

Chapter 18 Vertebrate Animals 

Section 1 Chordate Animals..........................59 

Section 2 Amphibians and Reptiles..............60 

Section 3 Birds ..............................................61 

Section 4 Mammals ......................................62 

Chapter 19 The Human Body 

Section 1 Body Systems ................................63 

Section 2 Human Reproduction ..................65 

Chapter 20 The Role of Genes in Inheritance 

Section 1 Continuing Life ............................66 

Section 2 Genetics—The Study 

of Inheritance ................................67 

Chapter 21 

Section 1 

Section 2 

Section 3 

Ecology 

What is an Ecosystem....................68 

Relationships Among 

Living Things ................................70 

Energy Through the Ecosystem....71 

Chapter 22 Earth’s Resources 

Section 1 Natural Resource Use....................72 

Section 2 People and the Environment ........74 

Section 3 Protecting the Environment ........76 


iv

1 



The Nature of Science 

Underlined words and 

phrases are to be filled 

in by students on the 

Note-taking Worksheet. 

Section 1 

What is science? 

A. Science—a way of learning about the natural world 

1. Scientists ask questions about the natural world, but questions about 

art, politics, personal preferences, or morality can’t be answered by science. 

2. Answers are uncertain because new knowledge and discoveries are continually 

being made. 

3. Scientific theory—an attempted explanation for repeatedly observed patterns 

in the natural world 

4. A rule that describes a pattern in nature is a scientific law. 

B. Scientists study systems—collections of structures, cycles, and processes that 

relate to and interact with each other. 

C. Science is divided into three main branches that study different systems. 

1. Life science studies living things and how they interact. 

2. Earth and space systems are studied in Earth science. 

3. Physical science studies matter and energy. 

4. The practical use of science is called technology. 

Discussion Question 

What is the difference between a scientific theory and a scientific law? A scientific theory 

explains, and a scientific law describes. 

The Nature of Science 1

1 








Section 2 

Science in Action 

A. The scientific method includes observing, questioning, and researching; forming 

an hypothesis; predicting an outcome; investigating; analyzing; forming conclusions, 

communicating findings; and repeating the process. 

B. Scientists infer conclusions based on observations. 

C. A controlled experiment is one type of scientific investigation. 

1. Factors that can be changed in an experiment are variables. 

2. Constants are variables that remain unchanged. 

D. Safety is important for both laboratory and field scientists 


What does a scientist use to infer a conclusion? observations 


1 








Section 3 

Models in Science 

A. Model—representation of an object or event used as a tool for understanding the 

natural world 

B. Models come in three basic types. 

1. Physical models can be seen and touched. 

2. Computer models can be seen on a computer screen but not touched. 

3. Idea models are concepts that describe how someone thinks about something 

in the natural world. 

C. Models have several uses. 

1. Models communicate observations and ideas. 

2. Models can test predictions. 

3. Models can save time, money, and lives. 

D. Models change over time as new observations and discoveries are made. 


What are the purposes of models? to communicate, to test predictions, and to save time, 

money, and lives 


1 

Section 4 



Evaluating Scientific Explanation 






A. Critical thinking—using what is known to decide if new facts should be agreed 

with or believed 

B. Data should be evaluated. 

1. The data should be specific and exact. 

2. Observations should be carefully, accurately, and completely noted. 

3. Data must be repeatable to be reliable. 

C. Conclusions should be evaluated. 

1. Conclusions should make sense. 

2. Other explanations should be considered before a single conclusion is reached. 

D. Advertising claims should be carefully analyzed since they are designed to sell 

products rather than to promote scientific evidence impartially. 


What aspects of a scientific explanation should be carefully evaluated? the data and 

conclusions 


2 

Section 1 



Measurement 

Description and Measurement 





A. Measurement—describes world using numbers 

1. Types of measurement—distance, time, speed, volume, mass 

2. Measurement can also help describe events. 

B. Approximated measurement based on previous experience is estimation. 

1. Estimation is useful when actual measurements are not easily made. 

2. Estimation can check that an answer is reasonable. 

3. When you estimate, you often use the word about. 

C. Precision and accuracy 

1. Precision—a description of how close measurements are to each other 

a. Used to discuss number of decimal places a measuring device can measure 

b. Degree of Precision—today’s measuring devices are more precise. 

2. Accuracy—comparison of measurement to actual value 

3. Precision and accuracy are important in many medical procedures. 

4. Measurements can be rounded when precision is not needed. 

5. Significant digits—reflect true precision of a calculation 

a. Multiplication or division—measurement with the fewest digits determines 

the number of significant digits. 

b. Addition or subtraction—significance determined to the place value of the 

least precise measurement 


How can estimation be useful? when actual measurements are too difficult to obtain; when 

verifying realism of a calculation 

Measurement 5

2 



Measurement 





Section 2 

SI Units 

A. The International System—SI units, in multiples of ten,provide a standard of 

consistent measurement for global science, business, and industry. 

B. Length—the distance between two points; SI unit—meter 

1. Measure pencil—use centimeters 

2. Measure distance from New York to Chicago—use kilometers 

C. Volume—amount of space an object takes up; SI unit—cubic meter 

1. To find volume of regular shape—measure length, width, and height and 

multiply 

2. To find volume of irregular shape—volume by immersion 

D. Mass—amount of matter in an object; SI unit—kilogram 

E. Weight—measurement of force; SI unit—newton 

F. Temperature—measure of kinetic energy in particles of matter; SI unit—kelvin 

G. Time—interval between two events; SI unit—second 

H. Rate—amount of change of one measurement in a given amount of time 


Why is it important to have one international system of measurement? to avoid confusion 

Measurement 6

2 

Section 3 



Drawings, Tables, and Graphs 

Measurement 





A. Scientific Illustrations—often make information more clear than written text 

can 

1. Drawings—can emphasize only necessary details or show things you can’t see 

2. Photographs—show an object exactly as it is at a single moment 

B. Tables—display information in rows and columns for easier comprehension 

C. Graphs—collect, organize, and summarize data visually 

1. Line graph—shows relationship between two variables, which must be 

numbers 

2. Bar graph—uses bars of different sizes to show relationships between variables; 

one variable is divided into parts; the other variable is a number 

3. Circle graph—shows parts of a whole as percentages 

4. Scales on graphs must be carefully constructed and analyzed so users easily 

understand the information. 


How are graphs useful? They visually present data in an easy to understand way. 

Measurement 7

3 

Section 1 



Physical Properties and Changes 

Matter and Its Changes 





A. Physical property—any characteristic of matter that can be observed or 

measured without changing the identity of the matter; a physical change 

makes physical properties change, but identity remains the same. 

1. Length and mass (amount of material in an object) are properties that can be 

measured. 

2. Volume is a measure of how much space an object takes up; density is the 

amount of mass a material has for a given volume. 

3. Density changes as pressure or temperature change. 

B. Solid, liquid, gas, and plasma are four states of matter; state of matter depends 

on its temperature and pressure. 

1. Matter is made up of moving particles; solid particles have less energy than 

liquid particles, which have less energy than gas particles. 

2. Melting point—temperature at which a solid becomes a liquid; example: ice 

melting 

3. Boiling point—temperature at which a liquid becomes a gas; example: water 

becoming steam 

C. Metallic properties can include luster, malleability, ductility, and magnetism. 

D. Physical properties can be used to identify, classify, and separate substances. 


What are the four states of matter? solid, liquid, gas, and plasma 

Matter and Its Changes 8

3 

Section 2 



Chemical Properties and Changes 

Matter and Its Changes 





A. Chemical property—characteristic that gives a substance the ability to undergo 

a change that results in a new substance 

1. Flammability 

2. Reacts with oxygen, light, water, or other substances 

B. Chemical change—change in the identity of a substance due to its chemical 

properties 

1. Signs of a chemical change can include production of bubbles, heat, light, 

smoke, sounds, or color change. 

2. Chemical changes are not reversible using physical means. 

C. Law of conservation of mass—mass is never lost or gained in a chemical reaction. 

1. When material is burned, residue is less massive than original material. 

2. Ash, smoke, and gases escaped into the air. 

3. Their mass was not lost, only relocated. 


What are some signs of a chemical reaction? bubbles, heat, light, smoke, 

sounds, or color changes 

Matter and Its Changes 9

4 

Section 1 



Structure of Matter 

Atoms, Elements, 

and the Periodic Table 





A. Matter—anything that has mass and takes up space 

1. The atom—a small particle that makes up most types of matter 

2. Lavoisier introduced the law of conservation of matter—matter is neither 

created nor destroyed,but only changes form. 

3. Before Lavoisier, people used to think matter could appear and disappear. 

4. Dalton introduced an early atomic theory of matter. 

a. Atoms are too small to be seen by human eye. 

b. Each type of matter is made of only one kind of atom. 

5. Thomson discovered that atoms are made of even smaller subatomic particles. 

a. Electrons—tiny, negatively charged particles with mass 

b. Proposed that an atom was a ball of positive charge with electrons 

embedded in it 

6. Rutherford suggested a new model of the atom. 

a. Nucleus—the positively charged central part of the atom 

b. Protons—the positively charged particles in the nucleus 

c. Electrons are scattered in the mostly empty space around the nucleus 

7. Chadwick introduced neutrons—particles that come from the nucleus and 

have no charge. 

8. Electron Cloud Model — Electrons are so small and fast that they move in a 

cloud. 


According to the law of conservation of matter, what happens to wood when it “burns 

up”? Matter is neither created nor destroyed, but only changes form. Wood and the oxygen 

from the air that it combines with during burning have the same mass as the ash, water, and 

carbon dioxide produced. 

Atoms, Elements, and the Periodic Table 10

4 

Section 2 



The Simplest Matter 







A. Elements—matter made up of only one kind of atom 

1. There are 115 known elements. 

2. 90 naturally occurring elements, plus synthetic elements—made by scientists 

B. Periodic Table—Chart that organizes and displays information about the 

elements 

1. Atomic number—the top number in the element’s periodic table block 

a. Tells the number of protons in the nucleus of each atom of that element 

b. The number of protons remains constant in every atom of an element. 

2. Isotopes—atoms of the same element that have different numbers of neutrons 

3. Mass number—number of protons plus number of neutrons 

4. Atomic mass—the number found below the element symbol 

a. The weighted average mass of an atom of an element 

b. The unit used for atomic mass is the atomic mass unit,which is given the 

symbol u. 

C. Elements fall into three general groups characterized by similar properties 

1. Metals—most of the elements 

a. Shiny luster 

b. Good conductors of heat and electricity 

c. Most are solids at room temperature. 

d. Malleable,or can be shaped 

e. Ductile,or can be drawn into wires without breaking 

2. Nonmetals—found on the right side of the periodic table 

a. Dull in appearance 

b. Poor conductors of heat and electricity 

c. Many are gases at room temperature. 

d. Brittle, cannot change shape without breaking 

e. 97 percent of the human body is made up of nonmetals. 


4 



Atoms, Elements, and the Periodic Table (continued) 

3. Metalloids—found between the metals and nonmetals on the periodic table 

a. Have characteristics of both metals and nonmetals 

b. Do not conduct heat and electricity as well as metals 

c. All are solids at room temperature. 


What do you know about chlorine, based only on the fact that it is a nonmetal? It is 

probably a gas at room temperature. It probably does not conduct heat and electricity very 

well. It is probably dull in appearance. It cannot change shape without breaking. 


4 

Section 3 



Compounds and Mixtures 







A. Substance—Matter that has the same composition and properties throughout 

B. Compound—Substance whose smallest unit is made up of atoms of more than 

one element 

1. Chemical formula—tells which elements make up a compound as well as how 

many atoms of each element are present 

a. The subscript number tells how many atoms of the preceding element are 

in the compound. 

b. No subscript is used when only one atom of the element is present. 

2. A given compound is always made of the same elements in the same 

proportion. 

C. Mixture—two or more substances mixed together which don’t make a new 

substance 

1. Unlike in compounds, the proportions of the substances in a mixture can be 

changed without changing the identity of the mixture. 

2. Examples: air, blood 

3. Can separate mixtures easily 

4. Homogeneous mixtures—the same throughout 

5. Heterogeneous mixtures—you can see the different parts 


What is the difference between compounds and mixtures? Compounds are single 

substances; mixtures are two or more substances mixed together. Compounds always contain 

the same elements in the same proportion; the proportions of the substances in a mixture can 

be changed. Mixtures can be easily separated; compounds cannot. 


5 

Section 1 



Motion 

Motion, Forces, and 






A. Speed involves distance and time. 

1. Average speed—calculated as total distance traveled divided by travel time 

2. Instantaneous speed—an object’s speed at a particular moment 

3. When instantaneous speed does not change, an object is moving at constant 

speed; average speed and instantaneous speed are the same in this situation. 

4. Distance can be calculated if an object is moving at constant speed over a particular 

time period; total distance traveled equals average speed times time. 

B. Speed and direction of motion is velocity. 

C. Acceleration is the change in velocity divided by the time needed for the change 

to occur. 

1. Acceleration can be calculated using a formula: acceleration equals change in speed 

divided by time. 

2. Acceleration can be shown on a speed-time graph. 


What two variables are involved in velocity? speed and direction of motion 

Motion, Forces, and Simple Machines 14

5 

Section 2 



Newton’s Laws of Motion 







A. Force—a push or a pull 

1. When a force acts on an object, it changes the object’s acceleration. 

2. Two or more forces that cancel each other out are balanced forces. 

3. Two or more forces that do not cancel each other out are unbalanced forces. 

4. The combination of all forces acting on an object is the net force. 

B. Newton’s laws of motion—explain how forces cause motion 

1. Newton’s first law—a moving object moves in a straight line with constant 

speed unless a force acts on it. 

a. Friction—a force that resists movement between two surfaces in contact 

b. An object’s tendency to resist a change in motion is inertia; the more mass 

an object has, the greater its inertia. 

2. Newton’s second law—if an object is acted upon by a net force, the change in 

velocity will be in the direction of the net force; acceleration can be calculated 

as acceleration equals net force divided by mass. 

3. Newton’s third law—forces always occur in equal but opposite pairs; the equal 

and opposite forces act on different objects, so they are not balanced forces. 


How are mass and inertia related? The greater an object’s mass, the greater its 

inertia. 


5 

Section 3 



Work and Simple Machines 







A. Work 

1. Occurs when a force causes an object to move in the same direction that the force is 

applied 

2. Calculated as work equals force times distance 

B. A simple machine uses only one movement; a compound machine is a combination 

of simple machines. 

1. Mechanical advantage is the number of times force is multiplied; calculated as 

mechanical advantage equals output force divided by input force. 

2. An ideal machine would experience no friction, so work in would equal work out. 

3. Real machines experience friction, so work out is always less than work in. 

C. Pulley—an object with a groove, like a wheel, with a rope or chain running through 

the groove; changes the direction of the input force 

D. A lever is a rod or plank that pivots about a fixed point called the fulcrum. 

1. The fulcrum is between the input force and the output force in a first-class lever. 

2. In a second-class lever, the output force is between the input force and the fulcrum. 

3. The input force is between the output force and the fulcrum in a third-class lever 

4. The wheel and axle provide a mechanical advantage greater than one. 

E. An inclined plane or ramp allows an object to be lifted over a greater distance using 

less force. 

1. A wedge is a moving inclined plane with one or two sloping surfaces. 

2. Screw—inclined plane wrapped around a post 


What is mechanical advantage? the number of times force is multiplied by a 

machine 


6 



Energy 





Section 1 

Energy Changes 

A. Energy—ability to cause change 

B. Energy transformation—energy changes from one form to another without any 

being lost or gained 

C. Energy due to motion is kinetic energy. 

1. An object’s kinetic energy depends on its speed and mass. 

2. When objects collide, kinetic energy can be transferred. 

D. Potential energy—stored energy due to an object’s position 

E. Potential energy can be transformed to kinetic energy and kinetic energy can be 

converted to potential energy. 

F. Law of conservation of energy—energy cannot be created or destroyed; it can 

only change form 

1. Total amount of energy in the universe never changes. 

2. Kinetic energy can be converted to heat energy. 


What does an object’s kinetic energy depend on? its speed and mass 

Energy 17

6 



Energy 





Section 2 

Temperature 

A. Temperature—measure of the average kinetic energy of an object’s atoms 

B. Temperature is measured with a thermometer. 

1. Fahrenheit scale—freezing point of water is 32° and boiling point is 212° 

2. Celsius scale—freezing point of water is 0° and boiling point is 100° 

C. Heat—transfer of energy from one object to another due to a difference in temperature 

1. Heat moves from warmer objects to cooler ones. 

2. Flow of heat stops when the temperature of two objects is the same. 

D. Water is unusual because it takes a large amount of heat to raise its temperature; 

water’s temperature does not change as much as surrounding air or land. 

E. Heat can be transferred in three ways. 

1. Conduction—transfer of energy by collisions between atoms; usually occurs 

in solids 

2. Convection transfers heat when particles move between objects or areas that 

differ in temperature; most common in gases and liquids. 

3. Energy transferred by waves is radiation. 


How is the kinetic energy of an object’s atoms measured? As temperature, 

using a thermometer 

Energy 18

6 



Energy 





Section 3 

Chemical Energy 

A. Chemical reactions transform energy. 

1. Compounds are broken down or new compounds are formed in a chemical 

reaction. 

2. Energy in chemical bonds is a form of potential energy called chemical energy. 

3. In every chemical reaction, energy transformations occur. 

B. To break chemical bonds, energy must be added; when chemical bonds form, 

energy is released. 

1. Endothermic reactions—chemical reactions that absorb energy 

2. Exothermic reactions—chemical reactions that release energy 

3. Chemical reactions occur at different rates; a catalyst changes the rate of 

chemical reaction without its own structure being changed. 


How do endothermic and exothermic chemical reactions differ? endothermic—absorb 

energy; exothermic—release energy 

Energy 19

7 

Section 1 



Electric Charge and Forces 

Electricity and Magnetism 





A. Atoms contain protons and electrons. 

1. The two types of electrical charge are positive and negative. 

2. Electrically neutral —Total positive charges and negative charges are equal. 

3. If the total positive and negative charges are not balanced, and object is electrically 

charged. 

B. Electrically charge particles exert a force on one another. 

1. Like charges repel one another 

2. Opposite charges attract one another 

3. Electric force increases with increased charge and decreases with increased distance. 

C. Electric field—surrounds a charged particle and exerts a force on other electrical 

charges. 

1. Charging by contact—electrical charges are transferred by movement of electrons. 

2. Charging by induction—rearrangement of electrons caused by movement of electrons 

within an object in an electric field. 

3. Materials in which electrons do not move easily are called insulators. 

4. Materials in which electrons do move easily are called conductors. 

D. Static charge—an imbalance of electric charge on an object. 

1. The movement of a static charge from one place to another is an electric discharge. 

2. Lightning is a static discharge between two clouds or between clouds and the 

ground. 

3. Providing a path for lightning to the Earth is called grounding. 


If an atom is made of charged particles, why does it not have an electric 

charge? An atom has an equal number of particles with positive and negative 

charges. 

Electricity and Magnetism 20

7 








Section 2 

Electric Current 

A. Electric current—the flow of electric charge. 

1. As a current flows in a wire, the number of electrons and protons in the wire 

remains balanced. 

2. The SI unit of electric current, the ampere, is designated by the symbol, A. 

B. Electric circuit—a closed path through which electric charges can flow. 

1. The measure of how difficult it is for electrons to flow is the electric resistance 

of a material. 

2. The unit of electric resistance is the ohm. 

3. In a series circuit, devices are connected so that there is only one path for 

current to follow. 

4. In a parallel circuit, there is more than one path for current to follow. 

C. Voltage—a measure of the electrical energy transferred by electrons flowing in a 

circuit. 

1. A battery transforms chemical energy into electrical energy. 

2. Ohm’s law—voltage, current and resistance in a circuit are related by the formula 

V IR. 


All of the lights in a string go out when one bulb burns out. What can you 

conclude about the electric circuit of the string? The string of lights is a 

series circuit because the burned out bulb breaks the circuit. 


7 








Section 3 

Magnetism 

A. Magnets exert forces on objects made of magnetic materials. 

1. Magnetic poles, labeled north and south are the two ends of a magnet. 

2. Like magnetic poles repel one another. 

3.Opposite magnetic poles attract one another. 

4. A magnetic field surrounds every magnet and exerts a force on other magnets. 

B. Magnetic materials—metals, containing certain elements such as iron that are 

affected by a magnetic field. 

1. A group of atoms that have their magnetic poles aligned in the same direction 

are called a magnetic domain. 

2. In a permanent magnet, the magnetic domains line up with one another. 

C. Electromagnet—a temporary magnet formed by wrapping a current-carrying 

wire around a magnetic material. 

D. Electromagnetic induction—the production of an electric current by moving a 

magnet and a wire loop relative to one another. 

1. An electric generator converts mechanical energy into electrical energy. 

2. The kinetic energy of moving steam or water is converted to electrical energy 

by huge generators in power plants. 


How can a fossil fuel such as coal be converted to mechanical energy to drive 

a power plant? Heat from the burning of the fuel is used to boil water and 

produce steam. High-pressure steam is directed at the blades of a turbine, 

causing the turbine to spin. 


8 



Waves 





Section 1 

What are waves? 

A. Rhythmic disturbances that carry energy without carrying matter are called 

waves. 

B. Molecules transport wave energy without themselves moving, like a line of people 

passing a ball. 

C. Mechanical waves use matter to transfer energy. 

1. Transverse wave—wave energy causes matter in the medium to move up and 

down or back and forth at right angles to the wave. 

2. Compressional wave—matter in the medium moves forward and backward 

in same direction as the wave. 

D. Sound waves—compressional waves caused by colliding air molecules 

E. Electromagnetic waves—transfer energy without using matter; the Sun emits 

electromagnetic waves that travel through space to Earth. 


What is the difference between a mechanical wave and an electromagnetic wave? 

Mechanical waves use matter to transfer energy; electromagnetic waves use electrically 

charged particles to carry energy. 

Waves 23

8 



Waves 





Section 2 

Wave Properties 

A. Amplitude—the measure of how high the crests are or how deep the troughs 

are; or the distance between the particles in a compression and rarefaction 

B. Wavelength—distance from the top of one crest to the top of the next crest or 

from the bottom of one trough to the bottom of the next trough; or the distance 

from compression to compression or rarefaction to rarefaction 

C. Frequency—number of wavelengths passing a given point per second 

1. Longer wavelengths result in smaller frequencies. 

2. Larger frequencies result in shorter wavelengths. 

3. Color and pitch result from wavelengths and frequencies of light and sound. 

D. Wave speed—how fast a wave travels through a medium 

1. Mechanical waves travel faster in a medium in which atoms are closer 

together. 

2. Electromagnetic waves travel faster in a medium with fewer atoms in it. 


Name four properties of waves. amplitude, wavelength, frequency, and speed 

Waves 24

8 



Waves 





Section 3 

Wave Behavior 

A. Reflection—when a wave strikes an object or surface and bounces off 

B. Refraction—when a wave bends and changes speed as it moves from one 

medium to another 

C. Diffraction—the bending of waves around a barrier 

D. Interference—two or more waves combine and form a new wave. 

1. Constructive interference—the crest of one wave overlaps the crest of another 

wave, making a larger wave. 

2. Destructive interference—the crest of one wave overlaps the trough of another 

wave, making a smaller wave. 

3. If waves with equal amplitude meet crest to trough, they cancel each other 

out. 

4. Interference can be used in hearing protection. 


How are refraction and diffraction similar and different? Similar—both involve wave 

bending; different—refraction’s bending is caused by a medium change while diffraction’s 

bending is caused by a barrier. 

Waves 25

9 

Section 1 



Minerals–Earth’s Jewels 

Rocks and Minerals 





A. Mineral—inorganic solid material with a particular chemical makeup 

and orderly arrangement of atoms 

1. Rocks are usually composed of two or more minerals. 

2. Minerals form from magma or lava or through evaporation or precipitation. 

3. Mineral formation clues include size and how mineral crystals fit together. 

B. Properties—characteristics used to identify minerals 

1. Solid materials with a repeating pattern of atoms are called crystals. 

2. Some minerals have cleavage,splitting into thin sheets; other minerals have 

fractures,breaking into rough edges. 

3. Color or streak (color of a powdered mineral) helps identify minerals. 

4. Luster describes how light reflects from a mineral’s surface. 

5. Mohs scale uses hardness to classify minerals from 1 (softest) to 10 (hardest). 

6. Specific gravity—compares weight of mineral with weight of an equal volume 

of water. 

7. Other properties of minerals include magnetism,double refraction, taste, or 

reactions with acid. 

C. Common minerals—most rock-forming minerals are silicates or carbonates. 

1. Rare minerals which can be cut and polished are gems. 

2. Diamonds are produced under pressure beneath Earth’s surface and brought 

to the surface by special volcanic eruptions. 

3. An ore contains enough useful mineral to be sold at a profit. 

4. Ores must be processed to extract the mineral. 


What makes gems valuable? They are rare. Not only are gems produced under unusual circumstances, 

these minerals usually need to be clear with no blemishes or cracks to be considered 

gem quality. Gems must also have a beautiful luster or color, and they must be a 

material that can be cut and polished. Very few minerals meet all these qualifications. 

Rocks and Minerals 26

9 

Section 2 



Igneous and Sedimentary Rocks 






A. Igneous rocks—form from melted rock that cools 

1. Extrusive igneous rocks form when melted rock cools on Earth’s surface. 

2. Intrusive igneous rock forms when melted rock cools beneath Earth’s surface. 

3. Light-colored often intrusive igneous rocks containing a high percentage of silica are 

called granitic. 

4. Dark-colored often extrusive igneous rocks containing iron, magnesium, or calcium 

are called basaltic. 

5. Lava is melted rock that reaches Earth’s surface and forms extrusive igneous rock 

when it cools. 

a. Volcanoes can erupt, bringing a lava flow to Earth’s surface. 

b. Large cracks or fissures can allow lava to ooze out in a lava flow. 

6. Magma is melted rock that does not reach Earth’s surface; intrusive igneous rocks 

form as magma slowly cools under the surface. 

7. Crystal size is the main difference between intrusive and extrusive igneous rock. 

a. Intrusive igneous rocks have large crystals. 

b. Extrusive igneous rocks do not have large crystals. 

B. Sedimentary rocks form in layers from broken rock, shells, plants, and other materials. 

1. Detrital rocks—made of grains from minerals or other rocks that have been compressed 

2. Chemical rocks—form when mineral-rich water evaporates and from other chemical 

processes 

3. Organic rocks—form from dead plants and animals that have been compressed 

a. If the rock is produced from layers of plants, it is called coal. 

b. If the rock is produced from organic sediment in the ocean, it is usually classified 

as limestone. 

c. Chalk is a kind of limestone made from the fossils of tiny animals and algae. 


How are lava and magma similar and different? Similar—both melted rock; different— 

lava flows to the surface while magma does not reach the surface. Lava forms extrusive 

igneous rock, and magma forms intrusive igneous rock with large crystals. 


9 

Section 3 




Metamorphic Rock and the Rock Cycle 





A. Time, pressure, and heat, and events such as erosion and moving land masses, 

make new rocks out of old rocks. 

1. Metamorphic rocks—form when existing rocks are heated or squeezed; they 

recrystallize and might change chemically. 

a. Rocks having visible layers or elongated mineral grains are called foliated 

rocks. 

b. Nonfoliated rocks do not have layers or bands. 

B. Rock Cycle—rocks change from one type to another over millions of years. 

1. The model, or diagram,shows each rock on a continuing journey. 

2. A rock in any part of the cycle could become any other kind of rock. 


What forces can form metamorphic rocks? Thousands of meters under Earth’s surface, 

high temperatures and great pressure will, over millions of years, squeeze rocks into new 

forms, called metamorphic rocks. These can be formed from sedimentary rock and igneous 

rock as well as other metamorphic rock. For example, sandstone can become quartzite, granite 

can change to gneiss, and limestone can change to marble. 


10 

Section 1 



Earth’s Moving Plates 

Forces Shaping Earth 





A. Geologists use earthquakes and surface rocks to indirectly observe Earth’s interior. 

1. Seismic waves change speed and direction depending on the density and 

material they travel through. 

2. Forces bring rocks formed deep within Earth to the surface. 

3. Evidence suggests that Earth is formed of different materials in layers. 

B. Earth has four layers. 

1. Inner core—dense iron core; very hot and dense 

2. Outer core—molten metal above the inner core 

3. Solid layer that flows slowly like putty is the mantle. 

4. Outermost layer is the crust. 

C. Earth’s structure—theories based on physical properties of density, temperature, 

and pressure that change with depth 

D. Earth’s moving plates are sections of the lithosphere, the rigid upper part of the 

mantle and crust. 

E. Plate boundaries are edges where plates meet. 

1. Tension can pull plates apart,resulting in new lithosphere forming in the gaps. 

2. Colliding plates could cause mountains to form as rock crumbles and folds. 

3. Subduction occurs when a denser plate sinks underneath a less dense plate. 

4. Shearing causes faults and earthquakes as two plates slide past each other. 

F. Plate movement theory—convection in the mantle circulates material and 

moves plates. 

1. Ridge-push at mid-ocean ridges causes plates to slide down the slope. 

2. Slab-pull happens as plates move away from mid-ocean ridges and become 

denser. 


Name Earth’s four main layers. inner core, outer core, mantle, and crust 

Forces Shaping Earth 29

10 

Section 2 



Uplift of Earth’s Crust 

Forces Shaping Earth 





A. Mountains form in different ways. 

1. Fault-block mountains—form from huge tilted blocks of rock separated from 

surrounding rock by large faults 

2. Folded mountains—form by compression forces folding rock layers 

3. Upwarped mountains—forces push up Earth’s crust and allow the sedimentary 

rock to erode, leaving igneous or metamorphic rock. 

4. Over time, layers of lava can form a cone-shaped volcanic mountain. 

5. Hot spots formed by plumes of magma in the mantle can cause underwater volcanic 

mountains. 

B. Isostacy principle indicates Earth’s crust and lithosphere float on the upper 

mantle. 

1. Earth’s crust is thicker under mountains. 

2. When mountains erode, the crust rises because the weight has been removed. 


Name four types of mountains. fault-block, folded, upwarped, and volcanic 

Forces Shaping Earth 30

11 

Section 1 



Weathering and Soil Formation 

Weathering and Erosion 





A. Natural process that causes rocks to break down is called weathering 

B. Mechanical weathering—breaks rocks into smaller pieces without changing 

them chemically 

1. Ice wedging is the freezing and thawing cycle that breaks rocks apart. 

2. Plant roots and burrowing animals exert pressure on rocks. 

C. When the chemical composition of rock changes, chemical weathering has 

occurred. 

1. Carbonic acid,from water and carbon dioxide, reacts chemically with many 

rocks. 

2. Tannic acid,formed from a plant’s release of tannin, dissolves some rock minerals. 

3. Oxygen can cause rocks containing iron to rust in the process of oxidation. 

D. Soil—mixture of weathered rock, organic matter, water, and air that supports 

the growth of plant life. 

1. The parent rock affects what kind of soil develops. 

2. Topography influences soil development. 

3. The climate in tropical regions increases the rate of weathering forming soil 

more quickly than in deserts. 

4. Rocks take time,perhaps thousands of years, to weather into soil. 

5. Plant materials impact soil development. 


What are the factors influencing soil development? parent rock, topography, climate, time, 

and plants 

Weathering and Erosion 31

11 

Section 2 



Erosion of Earth’s Surface 

Weathering and Erosion 





A. Erosion—wearing away and removal of rock, occurs because of gravity, ice, 

wind, and water 

B. Mass movement—gravity pulls rock or sediment down slopes. 

1. Creep—sediments move downhill slowly. 

2. Slump—rock or sediment moves downhill along a curved slope. 

3. Rock layers break loose and slide downhill in a rock slide. 

4. Mudflows—mass of wet sediment that flows downhill over the ground surface 

C. Ice forms continental and valley glaciers. 

1. Glacial erosion can occur as glaciers remove loose pieces of rock or as dragged 

rock scratches rock underneath the glacier. 

2. Glaciers can form cirques and steep peaks in mountains, create lakes, or totally 

remove rock from the surface. 

3. Glaciers deposit sediment. 

a. Till,amixture of different sized particles ranging from clay to boulders, is deposited 

directly from the bottom of a glacier. 

b. Outwash includes sand and gravel deposits moved by rivers from melting glaciers. 

D. Wind—blows small particles from Earth’s surface in a process called deflation 

1. Abrasion forms pits in rocks or polishes surfaces smooth as sediments are 

blown by strong winds. 

2. Dunes can form as the wind is slowed as it blows around irregular features 

such as rock or vegetation and deposits the sediment it carried. 

3. Loess,or fine silt, often collects downwind of large deserts or near glacial 

streams. 


11 



Weathering and Erosion (continued) 

E. Runoff—water flowing on Earth’s surface causes erosion. 

1. Sheet flow—when water flows downhill as a thin sheet often carrying loose 

sediment grains 

2. Rills and gullies are channels cut into Earth’s surface and are formed as runoff 

carries sediments along. 

3. Streams have water flowing through them continuously; they eventually flow 

into the ocean or a large lake. 

4. Moving water in streams is the most important agent of erosion, they shape 

more of Earth’s surface than ice, wind, or gravity. 


Name and describe four types of mass movement. creep—slow downhill movement; 

slump—movement downhill along a curved surface; rock slide—rocks break loose and fall 

downhill; mud slides—wet sediment flows downhill 


12 



The Atmosphere in Motion 





Section 1 

The Atmosphere 

A. The atmosphere,alayer of gases surrounding Earth 

B. The atmosphere is composed of a mixture of gases, water and other liquids, and 

microscopic particles of solids. 

1. Many gases are in the atmosphere. 

a. Nitrogen makes up 78%. 

b. Oxygen makes up 21%. 

c. Water vapor is responsible for clouds and precipitation. 

d. Carbon dioxide keeps Earth warm and is used by plants to make food. 

2. Aerosols—solids such as dust, salt, pollen, and tiny acid droplets in the 

atmosphere 

C. The atmosphere is divided into layers. 

1. Troposphere—from Earth’s surface to about 10 km 

a. Contains most clouds and weather 

b. Most of the troposphere’s heat is from Earth. 

c. Temperature cools about 6.5 degrees Celsius per kilometer of altitude. 

2. Stratosphere—from 10 km to 50 km above Earth’s surface, this layer contains 

ozone that absorbs much of the Sun’s ultraviolet radiation. 

3. Upper layers include the mesosphere (from 50 km to 85 km above Earth’s surface), 

thermosphere (from 85 km to 500 km above Earth’s surface), and the 

exosphere. 

a. Mesosphere—coldest layer with little ozone 

b. Thermosphere—warms as it filters out X-rays and gamma rays from the 

Sun 

c. Exosphere contains few atoms and extends into space without a clear 

boundary. 

The Atmosphere in Motion 34

12 



D. Water—makes up about 70% of Earth’s surface 

The Atmosphere in Motion (continued) 

E. Water cycle—water is in constant motion. 

1. Sun provides water cycle’s energy. 

2. Water on the surface absorbs heat and evaporates,entering the atmosphere. 

3. Condensation—water vapor changes back into liquid. 

4. Clouds of water become heavy and water falls to Earth as precipitation. 

5. The cycle repeats itself continuously. 


In which layer of the atmosphere does most of Earth’s weather occur? Troposphere 


12 








Section 2 

Earth’s Weather 

A. Weather—the atmosphere’s condition in terms of temperature, cloud cover, 

wind speed and direction, humidity, and air pressure 

1. Temperature—a measure of how fast air molecules are moving 

a. When molecules are moving rapidly, temperature is high. 

b. Celsius and Fahrenheit thermometers measure air temperature. 

2. Energy is transferred between fast-moving molecules and slower-moving molecules. 

a. Conduction—transfer of energy when molecules collide 

b. Convection occurs when warm air rises and cool air sinks. 

3. Air pressure—air weight that varies over Earth’s surface 

a. Warmer air is less dense and exerts less pressure. 

b. Cooler air is more dense and exerts more pressure. 

B. Humidity—the amount of water vapor in the air 

1. Temperature affects how much moisture is in the air. 

2. Dewpoint—when the air is holding as much water vapor as it can 

3. Relative humidity—a measure of the amount of water vapor present compared 

to the amount that could be held at a specific temperature 

C. Clouds—form when air rises, cools to its dew point, and becomes saturated 

1. Low clouds—form at 2,000 m or less in altitude 

a. Cumulus—puffy clouds formed when air currents rise and carry moisture 

b. Stratus—layered dull, gray sheets that can cover the entire sky 

c. Nimbostratus—low, dark, thick layers that hide the Sun 

2. Middle clouds—form between 2,000 m and 8,000 m in altitude 

a. Most are layered. 

b. Names have alto- prefix (altocumulus and altostratus) 

c. Can produce light precipitation 


12 



The Atmosphere in Motion (continued) 

3. High and vertical clouds 

a. Cirrus—wispy, high-level clouds 

b. Cirrostratus—high, layered clouds that can cover the sky 

c. Cumulonimbus—known as thunderstorm clouds; produce heavy precipitation 

D. Precipitation—falling water in the form of rain, freezing rain, sleet, snow, or 

hail 

E. Wind—air moving from one temperature or pressure area to another 

1. Coriolis effect—deflected air moves to the right in the northern hemisphere 

and to the left in the southern hemisphere 

2. Surface winds include the trade winds near the equator, the prevailing westerlies 

from about 30 degrees to 60 degrees latitude north and south of the equator, 

and the polar easterlies near the poles. 

3. Jet streams—bands of strong winds near the top of the troposphere at the 

northern and southern boundaries of the prevailing westerlies 


What factors influence weather? Temperature, cloud cover, wind speed and direction, 

humidity, and air pressure 


12 

Section 3 



Air Masses and Fronts 






A. Air mass—large body of air that develops over a particular region; it acquires 

the characteristics of the area over which it occurs 

B. Front—boundary between different air masses 

1. Cold front—cold air mass pushes under a warm air mass and can cause a narrow 

band of violent storms; temperatures drop 

2. Warm front—warm air mass slides up over a cold air mass; widespread precipitation 

develops 

3. Stationary front—warm air mass and cold air mass meet but neither advances; 

cloudiness and precipitation result 

4. Occluded front—fast-moving cold front overtakes a slower-moving warm 

front or vice versa; cloudy weather with precipitation 

C. Centers of pressure 

1. High pressure—air sinks and spreads away from the high-pressure center; 

moisture cannot rise and condense; usually dry with few clouds 

2. Low pressure—air rises and cools forming clouds and precipitation 

D. Severe weather—causes strong winds and heavy precipitation; can threaten 

property or life 

1. Thunderstorms—develop from cumulonimbus clouds that form along cold 

fronts; can have strong wind, dangerous hail, lightning and thunder 

2. Tornado—violent, whirling wind that moves in a narrow path over land 

3. Hurricane—large storm that begins as an area of low pressure over tropical 

oceans; heat energy from moist air is converted to wind that can reach speeds 

of 250 km/h 

4. The National Weather Service monitors weather and issues watches when 

severe weather is a potential threat and warnings when severe weather is an 

actual threat. 


Why do hurricanes form only over the tropical oceans? Hurricanes need warm, moist air 

to supply them with energy. 


13 



Oceans 





Section 1 

Ocean Water 

A. Oceans are important because they provide homes to many 

organisms; provide resources such as food, salt, transportation; provide 

water for precipitation; and provide oxygen produced by ocean organisms. 

B. Billions of years ago oceans formed from volcanic water vapor that collected in the 

atmosphere and then fell as torrential rains. 

C. Ocean water contains many dissolved substances that make it taste salty. 

1. Salinity—measure of the amount of salts dissolved in seawater 

2. Gases enter the ocean from the atmosphere. 

a. Oxygen—enters from the atmosphere and photosynthesis of ocean organisms 

b. Carbon dioxide—enters from the atmosphere and from respiration of ocean 

organisms; forms carbonic acid, which controls ocean acidity 

c. Nitrogen—provides nutrients for plants and is used in plant and animal tissues 

D. Water temperature and pressure vary with depth. 

1. Three layers of water temperature 

a. Warm surface layer—found near the equator 

b. Thermocline—begins at about 200 m with temperatures rapidly dropping 

with increasing depth 

c. Deep-water layer—extremely cold 

2. Pressure or force per unit area increases about 1 atmosphere (atm) for every 10 m 

increase in depth. 


How did the oceans form? Water vapor from volcanoes collected in the atmosphere and 

then fell as rain. 

Oceans 39

13 

Section 2 



Oceans 

Ocean Currents and Climate 





A. Surface currents—wind that moves only the upper few hundred meters of 

seawater 

1. Gulf Stream—100-km-wide current of warm water flowing east across the North 

Atlantic Ocean 

2. Surface currents influence climate. 

a. Warm currents keep northern climates mild. 

b. Cold currents prevent excessive summer warming. 

B. Density current—forms when more dense seawater sinks beneath less dense 

seawater 

1. North of Iceland a density current flows along the ocean floor toward the 

Atlantic Ocean and spreads into the Pacific and Indian Oceans; warm Gulf 

Stream water replaces this cold current. 

2. Density currents help regulate global rainfall patterns and temperatures. 

C. Upwelling—current bringing deep, cold water to the ocean surface; occurs 

where winds blow surface water away from land 

1. Cold water brings nutrients to enrich fishing grounds. 

2. Affects climate of coastal areas 


How do surface currents differ from density currents? Surface currents are caused by 

wind; density currents are caused by dense seawater sinking below less dense seawater. 

Oceans 40

13 



Oceans 





Section 3 

Waves 

A. Formed by wind, a wave is a rhythmic movement the carries energy through 

water. 

1. Waves have parts. 

a. Crest—highest point of a wave 

b. Trough—lowest point of a wave 

c. Vertical distance between crest and trough is height. 

d. Wavelength—horizontal distance between crests or troughs of two successive 

waves 

2. Wave motion—water particles do not move forward unless the wave is breaking 

on shore. 

3. Breakers—collapsing waves near the shore caused by the wave bottom being 

slowed by friction with the ocean floor 

B. Tides—rising and falling of sea level caused by gravity from Earth, the Moon, 

and the Sun 

1. Spring tides—high tides higher and low tides lower than normal due to 

Moon, Earth, and Sun lining up 

2. Neap tides—high tides lower and low tides higher than normal due to Sun, 

Moon, and Earth forming a right angle 

C. Wave erosion—wears away both rocky shores and beaches 


What are the four parts of a wave? crest, trough, height, wavelength 

Oceans 41

13 



Oceans 





Section 4 

Life in the Oceans 

A. Types of life are classified by where organisms live. 

1. Tiny marine animals that float in the upper ocean layers are called plankton. 

a. most are one-celled organisms 

b. examples—eggs of ocean animals, young adult fish, and larval jellyfish and 

crabs 

2. Nekton—animals that swim rather than drift in the currents 

a. some feed on plankton and others remain in deeper water 

b. examples—fish, whales, shrimp, turtles, and squid 

3. Bottom dwellers—can burrow in sediments, walk or swim on the bottom, or 

be attached to the seafloor 

a. vary greatly 

b. examples—anemones, crabs, coral, snails, and starfish 

B. Ocean ecosystems—community of organisms and nonliving factors such as 

sunlight, water, nutrients, sediment, and gases 

1. Producers—organisms that make their own food through photosynthesis or 

chemosynthesis 

2. Consumers—eat producers to get energy 

3. Decomposers—break down tissues and release nutrients and carbon dioxide 

back into the ecosystem 

4. Energy is transferred from producers to consumers and decomposers through 

food chains and complex food webs. 

C. Ocean nutrients—recycled through the ecosystem, particularly in coral reefs 


How do plankton differ from nekton? Plankton float and drift in ocean currents; nekton are 

able to swim. 

Oceans 42

14 

Section 1 



Radiation from Space 

Exploring Space 





A. Electromagnetic waves—carry energy through space and matter 

1. Electromagnetic radiation includes radio waves, visible light, gamma 

rays, X rays, ultraviolet light, infrared waves, and microwaves. 

2. Electromagnetic spectrum—electromagnetic radiation arranged by wavelength 

a. Forms of electromagnetic radiation differ in their frequencies—the number 

of wave crests that pass a given point per unit of time. 

b. The shorter the wavelength, the higher the frequency. 

3. All electromagnetic waves travel at the speed of light,or 300,000 km/s 

B. Optical telescopes—use light to produce magnified images 

1. Refracting telescopes—have convex lenses 

2. Reflecting telescopes—use concave mirror 

3. Optical telescopes are often located in buildings called observatories, which 

often have roofs that can be opened for viewing. 

4. The Hubble Space Telescope, is located outside Earth’s atmosphere. 

a. Mistake made in shaping largest mirror. 

b. Once the mistake was repaired in 1999, the Hubble Space Telescope sent back 

images of a large cluster of galaxies. 

5. Active optics—computer helps correct poor images. 

6. Adaptive optics—laser relays information to computer to adjust telescope’s 

mirror and make images clearer 

C. A radio telescope—studies radio waves that travel through space 

1. Because radio waves pass freely through Earth’s atmosphere, radio telescopes 

are usually useful 24 hours a day. 

2. Scientists use information from radio waves to detect objects in space, map 

the universe, and look for signs of life on other planets. 


What is the main difference between an optical telescope and a radio telescope? 

Optical telescope uses visible light; and a radio telescope uses radio waves. 

Exploring Space 43

14 

Section 2 



Early Space Missions 






A. Early space missions allowed astronomers to study space in ways not possible using telescopes 

1. Special motors that don’t require air are called rockets 

a. Solid-propellant rockets cannot be stopped once they are ignited. 

b. Liquid-propellant rockets can be reignited after they are shut down. 

2. A satellite—any object that revolves around another object in an orbit, or curved path 

a. In 1957 the former Soviet Union launched first artificial satellite Sputnik I. 

b. Today thousands of communication, scientific, and weather satellites orbit Earth. 

B. A space probe gathers and transmits information to Earth 

1. Voyager 1 and Voyager 2 are Exploring Space beyond the solar system. 

2. Pioneer 10, first probe to travel through an asteroid belt 

3. Galileo, launched in 1989, studied Jupiter and two of its moons, Europa and Io. 

a. Gathered information about Jupiter’s composition,temperature, and atmospheric pressure. 

b. Studies of Europa indicate a possible ocean of water and the possible presence of life. 

C. United States began race for the Moon in 1960s. 

1. First step in program to reach the Moon began with Project Mercury. 

a. In 1961, Alan B. Shepard became first U.S. citizen in space. 

b. In 1962, John Glenn became first U.S. citizen to orbit Earth. 

2. Second step in the Moon race involved Project Gemini. 

a. Teams of astronauts met and connected with orbiting spacecraft. 

b. Effects of space travel on humans studied 

c. Unoccupied space probes also studied the Moon during Projects Mercury and Gemini. 

3. Project Apollo—final step in U.S. program to reach the Moon. 

a. On July 20, 1969, Apollo 11 landed on the Moon’s surface, and Neil Armstrong and 

Edwin Aldrin became the first two people to set foot on the Moon. 

b. Six lunar landings resulted from Project Apollo, which ended in 1972. 


What were the three main phases of the United States moon mission, and 

during what years did this moon mission occur? Phases: Projects Mercury, 

Gemini, and Apollo; years 1961 to 1972 

Exploring Space 44

14 

Section 3 




Current and Future Space Missions 





A. Space shuttle—reusable spacecraft for transporting people, satellites, and other 

materials to and from space. 

1. Launched standing on end 

2. Glides back to Earth like an airplane 

B. Space stations—permanent places in space for humans to live and work 

1. U.S. Skylab orbited Earth from 1973 to 1979. 

a. Crews performed experiments and collected data on the effects of living in 

space. 

b. Fell out of orbit and burned up as it entered Earth’s atmosphere. 

2. Former Soviet Union Mir housed one cosmonaut for more than a year at a time 

a. Crews from the former Soviet Union and American crews worked together 

aboard the Mir. 

b. Crews from the former Soviet Union spent more time aboard Mir than 

crews from any other country 

C. The United States and Russia have cooperated in nine joint space missions 

1. International Space Station (ISS)—cooperation and resources of 16 countries 

2. ISS to be completed by 2006. 

D. Several missions explore Mars. 

1. Mars Global Surveyor and Mars Pathfinder—scientists learned water may have 

covered planet in the past. 

2. In 2002, Odyssey confirmed that Martian soil contained frozen water. 

E. New Millennium Program (NMP)—purpose is to create advanced technology 

that will let NASA send smart spacecraft into the solar system 

Exploring Space 45

14 



Exploring Space (continued) 

F. Moon exploration—Lunar Prospector mapped the Moon’s structure and 

composition. 

1. Scientists wanted to know if water existed in craters at the Moon’s poles. 

2. Because no material was thrown up when Lunar Prospector was ordered to 

crash, more studies needed. 

G. Space probe Cassini will explore Saturn and its largest moon Titan. 

H. The Next Generation Space Telescope will study star and galaxy processes. 

I. Many people have benefited from research and technology developed for the 

space program. 


Why is space exploration becoming a more cooperative activity among 

nations? No one country has all the resources for complex space missions 

Exploring Space 46

15 

Section 1 



Earth’s Place in Space 

The Solar System 

and Beyond 





A. Earth moves,even though it appears that the Sun does. 

1. Rotation—spinning of Earth on its axis,which occurs once every 24 hours 

2. Earth moves around the Sun in a regular, curved path called an orbit. 

3. It takes one year for Earth’s revolution around the Sun. 

4. Seasons occur due to Earth’s tilted axis and its revolution around the Sun. 

B. The Moon revolves around Earth every 27.3 days. 

1. The Moon’s changing shapes are known as phases of the Moon. 

2. The Moon’s phases are caused by the position of Earth, the Moon, and the Sun. 

a. When the Moon changes from new to full, it is called waxing. 

b. When the Moon changes from full to new, it is called waning. 

3. A solar eclipse occurs when the Moon is between the Sun and Earth and the 

Moon’s shadow falls on Earth 

4. A lunar eclipse occurs when Earth is between the Moon and the Sun and 

Earth’s shadow falls on the Moon. 


How do lunar and solar eclipses differ? In a lunar eclipse Earth’s shadow falls on the Moon; 

in a solar eclipse the Moon’s shadow falls on Earth. 

The Solar System and Beyond 47

15 

Section 2 





and Beyond 





A. Solar system—the Sun, its nine planets, and other objects that orbit the Sun 

1. Distances in space are so vast they require different units of measurement 

than are used to measure things on Earth. 

2. An astronomical unit is about 150 million km, the mean distance from Earth 

to the Sun. 

B. Inner planets are solid,with minerals similar to those on Earth. 

1. Mercury—second-smallest planet and closest to the Sun 

a. Little atmosphere, resulting in extremes of temperature 

b. Heavily cratered surface 

2. Venus—second-closest to the Sun 

a. Heavy cloud layer 

b. Clouds trap solar energy, making the planet extremely hot—about 470° 

Celsius. 

3. Earth—third planet from the Sun 

a. Atmosphere allows life to flourish 

b. Water exists as a solid, liquid, and gas. 

4. Mars—fourth planet from the Sun 

a. Has seasons and polar ice caps 

b. May have water shaping its surface 

5. The asteroid belt separates the inner and outer planets. 

C. Outer planets—most are huge balls of gas 

1. Jupiter—fifth planet from the Sun and largest 

a. Has 61 moons 

b. Great Red Spot is a giant storm on the planet’s surface. 

2. Saturn—sixth planet from the Sun 

a. Has at least 31 moons 

b. Has several broad rings of ice and dust 

3. Uranus—seventh planet from the Sun 

a. Axis makes the planet spin nearly sideways 

b. Has rings and at least 21 moons 


15 



The Solar System and Beyond (continued) 

4. Neptune—eighth planet from the Sun 

a. A gas planet with rings and at least 11 moons 

b. Methane in its atmosphere gives planet a blue color. 

5. Pluto—smallest planet and farthest from the Sun 

a. Rocky and frozen crust 

b. One moon 

6. Comet—large body of ice and rock that travels toward the center of the solar 

system 

7. Meteorites—fragments of space material that land on Earth’s surface 

a. Pieces may be iron, rocky or both 

b. Age (4.5 billion years) provides a clue to the Solar System’s age 


What makes Uranus’ axis unusual? It is nearly sideways, while most planets’ axes are only slightly 

tilted. 


15 

Section 3 



Stars and Galaxies 


and Beyond 





A. Constellations—groups of stars that form a pattern in the sky 

B. A star has a life cycle that depends on its size. 

1. Stars begin as huge clouds of dust and gas that contract and heat up to the 

point of fusion. 

2. Small stars shine longer than larger stars. 

3. A medium-sized star ends up as a black dwarf, while a larger star explodes as a 

supernova that could eventually become a black hole. 

C. Galaxy—group of stars, gas, and dust held together by gravity 

1. Elliptical-shaped galaxies are most common. 

2. Spiral galaxies look something like a pinwheel. 

3. Irregular galaxies are smaller and less common than other galaxies. 

4. Earth is located in the Milky Way Galaxy. 

5. A light-year is the distance light travels in a year, approximately 9.5 trillion km. 

6. The universe,containing billions of galaxies, seems to be expanding. 


What does a star’s life cycle depend on? its size 


16 



Cells—The Units of Life 





Section 1 

The World of Cells 

A. Cells help living creatures with activities of life such as movement, growth, and 

reproduction 

1. the cell theory developed after Robert Hooke invented the microscope in 1665 

a. All living things are made of one or more cells. 

b. The cell is the basic unit of life. 

c. All cells come from cells that already exist. 

2. Bacteria are one-celled organisms; larger organisms are made of many cells, 

sometimes trillions of cells 

3. A microscope’s magnification is found by multiplying the powers of the eyepiece 

and the objective lens. 

B. Cells are composed of parts that do specific jobs. 

1. The flexible cell membrane is the boundary of the cell and helps control what 

enters and exits the cell; some cells have a cell wall that helps support and 

protect the cell 

2. Cytoplasm is a gelatinlike substance containing many chemicals the cell needs. 

3. Specialized cell parts called organelles do various jobs within a cell. 

4. The nucleus contains hereditary material called chromosomes. 

5. Vacuoles are storage organelles for food, water, and wastes. 

C. Inside the mitochondria,cellular respiration uses oxygen to convert food energy 

into a form the cell can use. 

1. Waste products of cellular respiration are carbon dioxide and water. 

2. Leaf cells in plants contain chloroplasts that help the cell make its own food 

through photosynthesis. 


What are organelles? specialized cell parts that do various jobs within a cell 

Cells—The Units of Life 51

16 

Section 2 



The Different Jobs of Cells 

Cells—The Units of Life 





A. The cells in many-celled organisms are specialized in shape and size for their 

function. 

1. Human specialized cells include fat cells, bone cells, nerve cells, and muscle 

cells. 

a. Fat cells can store so much fat that the nucleus is pressed against the cell 

membrane. 

b. A hard calcium and phosphorus material surrounds bone cells. 

c. Nerve cells have many long branches to send and receive messages. 

d. Muscle cells have fibers that can contract and relax. 

2. Plant cells in leaves, stems, and roots are specialized to move food and water 

or to support the plant. 

B. Cells are organized so they can work together to keep the organism alive. 

1. Tissues are groups of similar cells that do the same kind of work; two or more 

tissues that work together form an organ 

2. Groups of organs that work together to perform a job are called organ systems. 


In what two general ways are cells specialized according to their function? size and shape 

Cells—The Units of Life 52

17 



Invertebrate Animals 





Section 1 

What is an Animal? 

A. Animal characteristics—similar features 

1. Composed of many eukaryotic cells,must find and digest their own food,and 

usually can move 

2. Symmetry—arrangement of parts 

a. Radial symmetry—parts are arranged in a circle around a central point 

b. Bilateral symmetry—parts are mirror images of each other 

c. Asymmetrical—no definite shape 

B. Animal classification—placed into related groups 

1. Vertebrates—animals with a backbone 

2. Invertebrates—majority of animals which lack a backbone 


Why might an animal need to move? Find food, shelter, a mate, or escape from danger 

Invertebrate Animals 53

17 

Section 2 




Sponges, Cnidarians, Flatworms, and Roundworms 





A. Sponges—don’t move to find food since adults are sessile or stuck in one place 

1. Filter feeders—filter food out of water that flows through body 

a. Pores let water into central cavity. 

b. Flagella keep water moving through sponge. 

2. Soft sponge bodies are protected by sharp spicules or rubbery spongin. 

3. Sponges reproduce sexually and asexually. 

a. In asexual reproduction a new sponge grows from pieces of an old sponge. 

b. Most sexually reproducing sponges are hermaphrodites,producing both 

eggs and sperm. 

B. Cnidarians—have tentacles and hollow bodies 

1. Two body shapes 

a. Polyp cnidarians are usually sessile and have vase-shaped bodies. 

b. A medusa body is free-swimming and bell-shaped. 

2. Cnidarians reproduce both sexually and asexually. 

a. Polyp forms reproduce asexually by budding. 

b. Some polyps also reproduce sexually by releasing sperm or eggs. 

c. Medusa forms have a two-stage life cycle in which they reproduce both sexually 

and asexually. 

C. Flatworms—search for their food 

1. Have long, flattened bodies with organs and systems 

2. Most are parasites living off or in a host. 

3. Tapeworms—a type of flatworm 

a. Lack a digestive system and absorb nutrients from the host’s intestines 

b. Tapeworms reproduce sexually. 


17 



Invertebrate Animals (continued) 

D. Roundworms—very common animals 

1. Body is a tube within a tube. 

2. Digestive tract has both a mouth and an anus. 

3. Diets vary with some roundworms being decomposers, some predators, and 

some parasites. 


What are some differences between sponges and roundworms? Mobility, digestion, reproduction, 

symmetry 


17 

Section 3 



Mollusks and Segmented Worms 






A. Characteristics of mollusks—invertebrates usually with shells protecting their 

soft bodies, mantle, and muscular foot 

1. Mantle—tissue that covers a mollusk’s soft body and that may produce a shell 

2. Lungs or gills exchange carbon dioxide from the animal for oxygen in the air 

or water. 

3. Many mollusks use a radula,ascratchy tongue-like organ, to help them eat. 

4. Some mollusks have an open circulatory system which washes blood over 

organs and lacks blood vessels. 

B. Types of Mollusks 

1. Gastropods—most have one shell 

a. Live in water or on land 

b. Move by gliding their large muscular foot along a trail of mucus 

2. Bivalves—have two shells 

a. Large muscles open and close shell halves 

b. Water animals that filter feed 

c. Use gills to remove foot from water 

3. Cephalopods—have no shell 

a. Have a foot divided into tentacles with suckers 

b. Move by using a mantle to quickly squeeze water through a funnel-like 

siphon 

c. Have a closed circulatory system with blood vessels 

C. Segmented Worms—also called annelids,have repeating segments, a closed circulatory 

system, and digest food in a complete system with two openings 

1. Earthworms—have more than 100 body segments 

a. Use external bristle-like setae and muscles to move 

b. Eat organic material in soil 

c. Exchange carbon dioxide and oxygen through mucus-covered skin 


17 



Invertebrate Animals (continued) 

2. Leeches—have flat bodies with sucking disks at both ends 

a. Attach to animals and remove blood for food 

b. Can store enormous amounts of food for months 

3. Marine worms—use bristles or setae for moving 

a. Some marine worms are filter feeders. 

b. Some eat plants or rotting material. 

c. Some marine worms are predators or parasites. 


What is the difference between an open and closed circulatory system? Open has blood 

oozing around organs; closed contains blood inside vessels 


17 

Section 4 



Arthropods and Echinoderms 






A. Arthropods—have appendages such as claws, legs, and antennae plus an 

exoskeleton 

1. Insects—such as ants have three body regions called the head, the thorax,and 

the abdomen 

a. Open circulatory system transports food and waste but spiracles gather 

oxygen. 

b. Insects change body form in process called metamorphosis. 

2. Arachnids—such as spiders have two body regions called the cephalothorax 

and the abdomen plus four pairs of legs 

3. Centipedes and millipedes—long, thin, segmented animals 

a. Centipedes—predators with one pair of jointed legs per segment 

b. Millipedes—plant eaters with two pairs of jointed legs per segment 

4. Crustaceans—water animals such as lobsters usually having two pairs of 

antennae, three types of chewing appendages, and five pairs of legs 

B. Echinoderms—have radial symmetry 

1. Diets vary—some are predators, some are filter feeders, some eat rotting material 

2. Echinoderms have spiny skin covering an internal skeleton of plates. 

3. Echinoderms have a water-vascular system to help them move and eat. 

4. Some echinoderms can reproduce through regeneration from parts. 


How do arthropods differ from echinoderms in symmetry? Arthropods tend to be bilateral; 

echinoderms are radial 


18 



Vertebrate Animals 





Section 1 

Chordate animals 

A. Chordate—animal with a notochord, a nerve cord, and pharyngeal pouches 

sometime during its development 

1. Internal system of bones called an endoskeleton 

2. Ectotherms—cold-blooded animals whose body temperature changes as their 

surrounding temperature changes 

3. Endotherms—warm-blooded animals whose body temperature does not 

change with changes in their surroundings 

B. Fish—ectotherms living in water 

1. Gills that exchange carbon dioxide for oxygen 

2. Fins that help steer, balance, and move 

3. Scales that cover and protect skin 

C. Three groups of fish 

1. Bony—have a skeleton made of bone; 95% of all fish 

a. Swim bladder—air sac that helps control swimming depth 

b. External fertilization in reproduction 

2. Jawless fish—long, tube-like body without scales; a cartilage skeleton; mouth 

without a jaw; very few species 

3. Cartilaginous fish—cartilage skeletons, movable jaws, rough scales, sharp 

teeth, usually predators; sharks in this group 


What do all fish have? Gills; most also have fins and scales 

Vertebrate Animals 59

18 

Section 2 



Amphibians and Reptiles 






A. Amphibians spend part of their lives on land and part in water. 

1. Amphibian adaptions 

a. Hibernation—inactivity during cold weather 

b. Estivation—inactivity during hot, dry weather 

2. Characteristics of amphibians 

a. Endoskeletons that support body on land 

b. Lungs that breathe on land; also exchange oxygen and carbon dioxide through 

the skin 

c. Hearing and vision adapted to land life 

d. Long, sticky tongue captures insects for food 

3. Amphibian metamorphosis 

a. Hatched from eggs fertilized in water; larval forms live in water and breathe 

through gills 

b. Land-function structures such as legs and lungs develop for adult life 

B. Reptiles—ectothermic animals that generally live their whole lives on land 

1. Reptile types—body plans vary 

a. Some, such as turtles, use a hard shell for protection. 

b. Some, such as alligators or crocodiles, live in or near water. 

c. Some, such as lizards and snakes, use their tongues to smell their environment 

2. Reptile adaptations 

a. Thick, dry skin covered with scales protects and reduces water loss. 

b. Breathe through lungs 

c. Internal fertilization produces amniotic eggs that nourish and protect the 

young until they hatch, fully developed 


How is reptilian reproduction different from amphibian reproduction? Reptiles do not 

generally live around water and thus do not need water for fertilization. Reptiles have internal, 

rather than external, fertilization. Their eggs are amniotic and protected from drying 

out by an outer shell. 


18 








Section 3 

Birds 

A. Characteristics—endothermic vertebrates that have two wings, two legs, a bill or 

beak, feathers, and lay eggs 

B. Adaptations for flight 

1. Strong, almost hollow bones 

2. High-energy diet 

3. Large, efficient heart 

4. Lungs with air sacs for efficiency and light weight 

5. Wing shape, movement, and surface area to enable flight 

C. Feather functions 

1. Contour feathers—give streamlined shape and coloring 

a. Barbs—parallel strands off the main shaft 

b. Help bird fly or swim 

c. Attract mates or protect from predators 

2. Down feathers—insulating layer of fluffy feathers under contour feathers 

3. Feather care—preening cleans and reorganizes feathers and may add conditioning 

oil 


What feature is unique to birds? Feathers 


18 








Section 4 

Mammals 

A. Characteristics—endothermic vertebrates with mammary glands and hair 

1. Mammary glands—produce milk that is used to nourish young 

2. Specialized teeth 

a. Herbivores—plant-eating animals with incisors that cut and flat molars that 

grind 

b. Carnivores—meat eaters with sharp canines that tear flesh 

c. Omnivores—eat both plants and animals using a variety of teeth 

3. Body systems 

a. Well developed lungs with millions of alveoli 

b. Large brain and complex nervous system that allows them to learn and remember 

c. Internal fertilization 

B. Mammal types 

1. Monotremes lay eggs and lack nipples on mammary glands. 

2. Marsupials give birth to immature young that finish developing in a pouch. 

3. Placentals develop from embryos connected to a placenta by an umbilical cord. 

a. Placenta provides food and oxygen to embryo and removes the embryo’s wastes. 

b. Time of development in uterus is called gestation period. 

C. Mammals today 

1. More than 4,000 species exist. 

2. Found on every continent and climate 

3. Have a role in maintaining environmental balance 

4. Many mammals are endangered due to destruction of their habitat. 


What does a mammal’s teeth reveal about it? Its diet 


19 



The Human Body 





Section 1 

Body Systems 

A. Bones provide structure. Muscles allow movement. 

1. All the bones in your body make up your skeletal system. The skeletal system 

gives shape and support to the body. 

2. The place where two or more bones come together is called a joint.Joints 

make movement possible. 

3. The skin forms a protective covering for the body, is a sense organ, helps control 

body temperature, and helps provide vitamin D. 

4. A muscle is an organ that can relax, contract, and provide force to move body 

parts. 

a. Muscles you can choose to move are voluntary muscles. 

b. Muscles that are not controlled consciously are involuntary muscles. 

B. Food is broken down in the digestive system. Undigested food is eliminated. 

1. Food travels through the mouth, esophagus, stomach, small intestine, and 

large intestine. 

a. Most digestion and absorption of food occurs in the small intestine. 

b. Water is absorbed in the large intestine. 

2. The six main kinds of nutrients are proteins, carbohydrates, lipids, vitamins, 

minerals, and water. 

a. Proteins, carbohydrates, lipids, and vitamins are organic nutrients. 

b. Minerals and water are inorganic nutrients. Your cells need water to carry 

out important chemical reactions. 

3. The kidneys are the main organs of the urinary system. Their function is to 

filter the blood and remove wastes. 

C. The respiratory and circulatory systems work together to supply oxygen to cells. 

1. The respiratory system helps move oxygen into the body and waste gases out 

of the body. 

a. The bronchi of the lungs branch into bronchioles,which end in alveoli. 

b. Air leaves the alveoli and enters tiny blood vessels called capillaries. 

The Human Body 63

19 



The Human Body (continued) 

2. The circulatory system is made up of the heart,blood vessels, and blood. The 

heart pumps blood to all the cells of the body. 

a. Red blood cells carry oxygen.White blood cells fight infections and heal 

wounds. 

b. The four major blood types are A, B, AB, and O. 

D. The lymphatic system collects tissue fluid and returns it to the blood. 

E. The body has many ways to defend itself against disease-causing organisms. 

1. The skin and respiratory, digestive, and circulatory systems block or destroy 

many disease-causing organisms. 

2. In specific immunity, the body makes antibodies that destroy disease-causing 

organisms. 

F. The nervous and endocrine systems control the body. 

1. The brain, spinal cord, nerves, and nerve receptors make up the nervous system. 

a. The nervous system sends messages to and from the brain to all parts of the 

body. 

b. A reflex is an involuntary, automatic response to a stimulus. Reflexes help 

protect your body by allowing your body to respond without you having to 

think about what to do. 

2. In the endocrine system, chemicals called hormones carry messages throughout 

the body. 


What are some examples of body systems working together to perform particular functions? 

Possible answers: The skeletal and muscular systems work together to allow movement. 

The digestive and excretory systems work together to process food. The respiratory and circulatory 

systems work together to deliver oxygen to body cells. Other examples are possible. 

The Human Body 64

19 

Section 2 



Human Reproduction 

The Human Body 





A. The male reproductive system has both internal and external organs. 

1. The testes produce the male hormone testosterone and sperm, the male reproductive 

cells. 

2. Fluid from the seminal vesicles mixes with sperm to form semen. 

3. Semen leaves the body through the urethra. 

B. The organs of the female reproductive system are internal. 

1. Ovaries are the female sex organs that produce eggs and the hormone estrogen. 

2. An egg is released from an ovary roughly every 28 days—a process called 

ovulation. 

3. The monthly cycle of changes in the sexually mature female reproductive system 

is the menstrual cycle. 

4. The menstrual cycle has three phases. Ovulation occurs at the end of phase two. 

C. Human development goes through many stages. 

1. Development begins with fertilization —the joining of a sperm and egg. 

2. Development from fertilization to birth is called pregnancy. During pregnancy 

the zygote becomes an embryo, then a fetus. 

D. The stages of development after birth are infancy, childhood, adolescence, and 

adulthood. 

1. During infancy the nervous and muscular systems develop rapidly and the 

infant interacts with the world. 

2. During childhood growth is rapid and the child learns many new skills. 

3. Adolescence includes puberty and a final growth spurt. 

4. During adulthood the muscular and skeletal systems stop growing. 


Unlike all other body systems, the reproductive system is not essential for an individual 

to live. Why is it still very important? Without the reproductive system there would be no 

new humans and the species would become extinct. 

The Human Body 65

20 

Section 1 



Continuing Life 

The Role of Genes 

in Inheritance 





A. Reproduction—transfers chemically coded hereditary information 

contained in DNA,deoxyribonucleic acid 

B. The nucleus divides into two new nuclei, each with the same DNA, a process 

called mitosis. 

C. Asexual reproduction—reproduction in which a new organism is produced 

from a part of another organism by cell division. 

1. One-celled organisms divide in half to reproduce. 

2. In a process called regeneration,some organisms replace lost parts by growing 

new ones. 

3. Some animals reproduce by budding,which results in a new organism that 

grows out of the old one. 

4. Cloning—making copies of an organism; the copy is termed a clone. 

D. Sexual reproduction—a new organism is produced from the combined DNA of 

two different cells called sex cells. 

E. Sex cells form by meiosis—a double cell division process that leaves the four 

newly formed cells with half the number of chromosomes of the original cell 

F. When fertilization occurs, each sex cell contributes one half of the new organism’s 

chromosomes. 

G. Plants also reproduce sexually when sex cells from the male and female parts of a 

flower combine. 


What is the difference between mitosis and meiosis? Mitosis is cell division with the two 

new cells containing the same DNA as the original cell; meiosis results in four new cells each 

with only half the chromosomes of the original cell. 

The Role of Genes in Inheritance 66

20 

Section 2 



The Role of Genes 

in Inheritance 

Genetics—The Study of Inheritance 





A. Heredity—passing traits from parents to offspring 

B. Genetics—study of how traits are passed from parents to offspring through 

small sections of DNA called genes 

C. What determines traits? 

1. A dominant allele will mask the other allele for a particular trait. 

2. Recessive alleles show when two copies of the recessive allele are inherited. 

D. Chance determines which traits an offspring will inherit from a parent. 

E. Differences in organisms result from variations in the ways a trait appears. 

1. Some traits result from multiple alleles and multiple genes. 

2. A mutation can create new variations. 

3. Selective breeding results in organisms with desired traits. 


What determines which traits an offspring will inherit from a parent? chance 

The Role of Genes in Inheritance 67

21 

Section 1 



What is an ecosystem? 

Ecology 





A. An ecosystem is made up organisms interacting with one another and with nonliving 

factors to form a working unit. 

1.Afrog eating an insect is an example of two living things interacting in an 

ecosystem. 

2. A frog using a stream as shelter is an example of an interaction between a living 

thing and a nonliving part of an ecosystem. 

B. Ecology is the study of the interactions that take place among the living organisms 

and the nonliving parts of an ecosystem. 

1. Ecologists spend a lot of time outdoors,observing ecosystems up close. 

2. They also conduct experiments in laboratories. 

C. The biosphere is the part of Earth where living things can live. 

1. Ecosystems on Earth include: 

a. deserts, 

b. mountains, 

c. rivers, 

d. prairies, 

e. wetlands, 

f. forests, 

g. plains,and 

h. oceans. 

2. The organisms that make up the living part of an ecosystem are called biotic 

factors. 

a. An organism depends on other biotic factors for food, shelter, protection, 

and reproduction. 

Ecology 68

21 



Ecology (continued) 

D. The nonliving things found in an ecosystem are called abiotic factors. 

1. The abiotic factor soil is made of minerals, water, air, and organic matter. 

2. The abiotic factor temperature determines which organisms live in a particular 

place. 

3. Another important abiotic factor is water. 

a. Some organisms are adapted for life in water. 

b. Water helps all living things carry out life processes, such as digestion. 

c. Water can also serve as shelter and a way to move from place to place. 

4. The abiotic factor sunlight is also essential to an ecosystem. 

a. The Sun is the main source of energy for most organisms on Earth. 

b. Energy from the Sun is used by green plants to produce food. 

c. Humans get energy by eating plants and other organisms that have fed on 

plants. 

E. Ecosystems change over time. 


Think of a park near your home. What are some of the abiotic and biotic factors you 

would find in the park? Answers will vary. Students’ answers should include some of the following: 

abiotic—soil, rocks, water, items made by people, such as fences; biotic—animals, 

such as birds, insects, worms, people; plants, including trees, shrubs, and grass. 

Ecology 69

21 

Section 2 



Ecology 

Relationships Among Living Things 





A. Ecologists organize living things into groups to make it easier to study ecosystems. 

1. A population is a group of the same type of organisms living in the same place at the 

same time. 

2. All of the populations that live in an area make up a community. 

3. Ecologists want to know the size of a population, where its members live, and how it 

is able to stay alive. 

4. Ecologists determine population density by comparing the size of a population with 

its area. 

5. Ecologists use tags to study populations of animals that travel long distances. 

B. Populations do not have enough resources to grow larger and larger forever. 

1. Things that limit the size of a population are called limiting factors. 

2. Limiting factors include food, water, living space, and other resources. 

C. The most common interactions in a community are feeding interactions. 

1. Organisms will compete for any resource that is in limited supply. 

a. The greater the population size of an area, the greater the competition for resources. 

2. Predation is the act of one organism feeding on another. 

a. A bird of prey, such as a falcon, is an example of a predator. 

b. A facon’s prey is the organism it eats. 

3. When the African tickbird eats insects off a zebra’s skin, both organisms in the relationship 

benefit. 

4. A bird that builds its nest in a tree benefits but the tree is neither harmed nor helped. 

5. Insects biting a zebra’s skin harm the zebra but benefit themselves. 

D. Each type of organism has a different role to play in an ecosystem. 

1. The role of an organism in an ecosystem is called its niche. 

2. The place where an organism lives out its life is called its habitat. 


What factors might prevent a population of dandelions from overtaking a lawn? Answers 

will vary. Student responses should include competition for soil nutrients, availability of 

water, competition from other plant populations for space. 

Ecology 70

21 

Section 3 



Ecology 

Energy Through the Ecosystem 





A. Energy moves through an ecosystem in the form of food. 

1. An organism that makes its own food, such as a plant, is called a producer. 

2. Consumers, like grasshoppers, eat other organisms. 

3. Decomposers,such as bacteria and fungi, use dead organisms and the waste 

material of other organisms for food. 

B. A food chain models how energy from food passes from one organism to 

another. 

1. In an ecosystem, food chains often overlap. 

2. A food web is a series of overlapping food chains that shows all the possible 

feeding relationships in an ecosystem. 

C. In an ecosystem, matter cycles through food chains. 

1. The amount of matter on Earth never changes. 

2. Matter in ecosystems is recycled. 


Name the producers, consumers, and decomposers in the following list of organisms: a hawk, 

a grasshopper, a field mouse, grass, and a fungus. What are the feeding relationships among 

these organisms? The grass is a producer; the hawk, field mouse, and grasshopper are consumers; 

the fungus is a decomposer. The grasshopper eats the grass, the field mouse eats the grasshopper, 

the hawk eats the field mouse. 

Ecology 71

22 

Section 1 



Natural Resource Use 

Earth’s Resources 





A. Most of the things you buy or use are made of materials that come 

from natural resources. 

1. Natural resources are things found in nature that living things use. 

2. Organisms use natural resources to meet their needs. 

3. Natl resources include 

a. nutrients,which come from vegetables, 

b. trees,which provide lumber, and 

c. minerals,which can be used to make plastic and metal. 

B. Natural resources are used to make items,such as a CD player. 

1. The cardboard box the CD player comes in is made from trees. 

2. Plastic is made from crude oil,athick, dark liquid found underground. 

3. The metal screws are made from iron ore,which is also found underground. 

4. It takes energy to get natural resources and make them into the parts of a CD 

player. 

a. Energy also comes from natural resources. 

b. Trucks use gasoline or diesel fuel to take natural resources to factories. 

c. The electricity used to power the machines that make the CD player comes 

from coal. 

C. Resources that can be replaced in 100 years or less are called renewable 

resources. 

1. Energy from the Sun is a renewable resource because it gives off light energy 

every day and 

will continue to do so for millions of years. 

2. Trees are a renewable resource because most trees will grow back and be cut 

again in less than 100 years. 

3. Water is a renewable resource because the same water has been reused over 

and over again on Earth. 

4. Wind is a renewable resource because it can be used again and again to make 

electricity with the help of a wind mill. 

Earth’s Resources 72

22 



Earth’s Resources (continued) 

D. Nonrenewable resources are resources that cannot be replaced by natural 

processes within 100 years. 

1. Nonrenewable resources include 

a. coal, 

b. crude oil,and 

c. natural gas. 

2. Nonrenewable resources form slowly over long periods of time. 

3. When we use up nonrenewable resources, it can take millions of years for new 

ones to form. 

4. Conservation is the practice of protecting and preserving natural resources so 

they will always be available. 


Can the pollution created by nonrenewable resources be reduced? Yes. Alternative natural 

resources such as sunlight and wind can provide the energy we need reducing atmospheric 

and water pollution. 


22 

Section 2 



People and the Environment 






A. Human activities can destroy the habitats of other organisms. 

B. All of the things we use in our every day lives take some amount of land to 

produce. 

1. Houses, malls,roads, and factories take up land. 

2. Food, clothing, jobs,and homes all take land. 

3. Some laws protect against habitat loss and help us use land wisely. 

4. Most of our garbage is buried in landfills. 

a. A landfill is a hole in the ground where garbage is deposited. 

b. Any material that can harm a living thing by interfering with life processes 

is called a pollutant. 

c. Garbage that contains dangerous chemicals or other pollutants is called 

hazardous waste. 

5. Land is a nonrenewable resource. 

C. Only a small amount of Earth’s water can be used for drinking. 

1. Many human activities cause water pollution.This can happen when 

a. household cleaners, 

b. pesticides, 

c. fertilizers, 

d. oil or grease,or, 

e. litter reaches our water supplies. 

2. Countries are working to reduce water pollution. 

a. The U.S. and Canada agreed to clean up Lake Erie. 

b. The U.S. government passed the Safe Drinking Water Act,which sets standards 

for drinking water. 

c. The Clean Water Act gives money to states for building water-treatment 

plants. 


22 



Earth’s Resources (continued) 

D. Most air pollution results from the burning of fuels. 

1. The two biggest sources of air pollution are cars and factories. 

2. Acid rain happens when the gases released by burning oil and coal mix with 

water in the air to form acidic rain or snow. 

3. The best solution for air pollution is prevention. 

a. You can help protect the atmosphere by limiting the amount of energy you 

use at home. 

b. You can also support the use of renewable energy sources, such as sunlight. 


Can Earth’s water supplies be protected from pollutants? Yes. Developing dry systems for 

disposing of pollutants and developing biodegradable cleaning products can protect our 

water resources. 


22 

Section 3 



Protecting the Environment 






A. Solid waste is whatever people throw away that is in a solid or near-solid form. 

1. Most waste is produced when coal, oil, and other natural resources are taken 

from the ground. 

2. Most of the waste from home, school, and businesses is paper and cardboard 

products. 

3. Using items again, or reusing them, helps reduce solid waste. 

4. Recycling is a type of reuse that requires changing the material into another 

form. 

B. You can be part of the solution to solid waste by getting in the habit of reducing, 

reusing, and recycling. 


Can you reuse some of the objects that you use daily at home? Yes. Used paper can be 

reused as scrap paper. Shopping bags can be kept and taken to the grocery store to be reused 

many times. Earthenware and porcelain dishes can replace disposable plastic and paper 

dishes reducing the amount of trash you produce.

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