What does biology teach you? 14
What does a microscope reveal? 25
How are living things classified? 34
What animals exist in the world? 45
What are the jointed-legged animals? 52
Which animals have backbones? 63
What plants exist in the world? 71
UNIT 1 Laboratory Activities 79
Projects 81 Using Computers 82
Suggested Reading 82
CAREER OPPORTUNITIES Insect Control 83
Landscaping and Gardening 83
How is the body built? 86
How do you breathe? 95
How is food digested? 107
Why must blood circulate? 119
How are wastes removed from cells? 137
How do ductless glands affect the body? 142
UNIT 2 Laboratory Activities 147
Projects 152
Using Computers 154
Suggested Reading 154
CAREER OPPORTUNITIES Blood Bank Technology 155
Respiratory Therapy 155
Food and life pages 156-195
What is in the food you eat? 158
What are good eating habits? 174
What is known about the basic food substances? 164
Where does your food come from? 183
UNIT 3 Laboratory Activities 191
Projects 193
Using Computers 194
Suggested Reading 194
CAREER OPPORTUNITIES Dietetics 195
Dentistry 195
What are reflexes? 198
How does a reflex work? 204
Can behavior be changed? 208
How do habits affect your life? 212
How do you learn? 217
How does the brain control behavior? 222
How do emotions affect behavior? 229
What problems do teen-agers face? 234
How do alcohol and drugs affect behavior? 239
UNIT 4 Laboratory Activities 247
Projects 251
Using Computers 252
Suggested Reading 252
CAREER OPPORTUNITIES Physical Therapy 253
Optometry 253
What are the causes of infectious disease? 256
How do bacteria affect your life? 263
What are the body's defenses? 267
How are microbes attacked today? 274
How do bacteria cause disease? 282
What diseases are caused by viruses? 290
What other agents may cause disease? 295
What diseases are not infectious? 298
How can community health be protected? 306
UNIT 5 Laboratory Activities 311
Projects 313
Using Computers 314
Suggested Reading 314
CAREER OPPORTUNITIES Laboratory Technology 315
Nursing 315
How do living things reproduce? 318
How do fishes and frogs reproduce? 322
How do birds hatch from eggs? 329
How do mammals reproduce? 333
How do flowering plants reproduce? 341
How can plants grow without seeds? 347
UNIT 6 Laboratory Activities 351
Projects 353 Using Computers 354
Suggested Reading 354
CAREER OPPORTUNITIES Fish Breeding 355
Poultry Farming 355
What controls your traits? 358
How are traits inherited? 366
Are chromosomes the same in males and females? 377
Do genes 6ver change? 382
How can heredity be improved in plants and animals? 392
How does heredity affect human beings? 399
UNIT 7 Laboratory Activities 406
Projects 407
Using Computers 408
Suggested Reading 408
CAREER OPPORTUNITIES Plant Breeding 409
Genetic Counseling 409
How do scientists know about ancient life? 412
What living things existed long ago? 421
How have living things changed through the ages? 432
What is the story of human history? 441
UNIT 8 Laboratory Activities 450
Projects 451
Using Computers 452
Suggested Reading 452
CAREER OPPORTUNITIES Museum Work 453
Fossil Hunting 453
What can be learned from the science of ecology? 456
How can natural resources be saved? 474
How does pollution affect the earth? 483
UNIT 9 Laboratory Activities 498
Projects 501
Using Computers 502
Suggested Reading 502
CAREER OPPORTUNITIES Air Pollution Control 503
Wildlife Conservation 503
Words and their meanings 504
Index 527
PHOTO CREDITS 543