A top view of high rise housing complex.

FIGURE 5–14 A Growing Population This graph (from the U.S. Census Bureau, International Database) shows the projected age structure of the world population in 2050. As population numbers climb, cities face various challenges, such as housing. The photo above shows a housing complex in Hong Kong; each apartment building is home to thousands of residents.

A graph shows the projected age structure of the world population in the year 2050 compared to that in year 2002.d

Future Population Growth To predict how the world's human population will grow, demographers consider many factors, including the age structure of each country and the effects of diseases on death rates—especially AIDS in Africa and parts of Asia. Current projections suggest that by 2050 the world population will reach 9 billion people. Will the human population level out to a logistic growth curve and become stable? This may happen if countries that are currently growing rapidly complete the demographic transition.

Current data suggest that global human population will grow more slowly over the next 50 years than it grew over the last 50 years. But because the growth rate will still be higher than zero in 2050, our population will continue to grow. In the next chapter, we will examine the effect of human population growth on the biosphere.

5.3 Assessment

Review Key Concepts

    1. Review Describe the general trend of human population growth over time.

    2. Relate Cause and Effect What factors contributed to the pattern of growth shown in Figure 5–11?

    1. Review Why do populations in different countries grow at different rates?

    2. Explain Describe the demographic transition and explain how it could affect a country's population growth rate.

    3. Form an Opinion Are age-structure diagrams useful in predicting future population trends?

VISUAL THINKING

  1. Describe the changes in human population predicted by Figure 5–14. How do you think those changes will affect society?

End ofPage 145

Table of Contents

Miller & Levine Biology
About the Authors
Changing the World of Biology Education
Contents
Diversity of Life: A Visual Guide DOL•1–DOL•64
Labs and Activities
Features
UNIT 1 The Nature of Life
1 The Science of Biology
2 The Chemistry of Life
Unit Project
UNIT 2 Ecology
3 The Biosphere
4 Ecosystems and Communities
5 Populations
6 Humans in the Biosphere
Unit Project
UNIT 3 Cells
7 Cell Structure and Function
8 Photosynthesis
9 Cellular Respiration and Fermentation
10 Cell Growth and Division
Unit Project
UNIT 4 Genetics
11 Introduction to Genetics
12 DNA
13 RNA and Protein Synthesis
14 Human Heredity
15 Genetic Engineering
Unit Project
UNIT 5 Evolution
16 Darwin's Theory of Evolution
17 Evolution of Populations
18 Classification
19 History of Life
Unit Project
UNIT 6 From Microorganisms to Plants
20 Viruses and Prokaryotes
21 Protists and Fungi
22 Introduction to Plants
23 Plant Structure and Function
24 Plant Reproduction and Response
Unit Project
UNIT 7 Animals
25 Introduction to Animals
26 Animal Evolution and Diversity
27 Animal Systems I
28 Animal Systems II
29 Animal Behavior
Unit Project
UNIT 8 The Human Body
30 Digestive and Excretory Systems
31 Nervous System
32 Skeletal, Muscular, and Integumentary Systems
33 Circulatory and Respiratory Systems
34 Endocrine and Reproductive Systems
35 Immune System and Disease
Unit Project
A Visual Guide to The Diversity of Life
HOW TO USE THIS GUIDE
THE TREE OF LIFE
Bacteria
Protists
Fungi
Plants
Animals
Appendices
Appendix A Science Skills
Appendix B Lab Skills
Appendix C Technology & Design
Appendix D Math Skills
Appendix E Periodic Table
Glossary
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q, R
S
T
U
V
W
X, Y, Z
Index
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Credits
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