1. Infer Would a density-independent limiting factor have more of an effect on population size in a large ecosystem or in a small ecosystem?

  2. Compare and Contrast How is the relationship between parasites and their hosts similar to a predator-prey relationship?

  3. Apply Concepts How would a drop in the water level of a river affect a fish population living in that river?

5.3 Human Population Growth

Understand Key Concepts

  1. The scientific study of human populations is called

    1. immigration.

    2. emigration.

    3. demographic transition.

    4. demography.

  2. The demographic transition is considered complete when

    1. population growth stops.

    2. the birthrate is greater than the death rate.

    3. the death rate begins to fall.

    4. the death rate is greater than the birthrate.

  3. How can you account for the fact that the human population has grown more rapidly during the past 500 years than it has at any other time in history?

  4. What is the significance of the demographic transition in studies of human population around the world?

  5. How does the age structure of a population affect its growth rate?

  6. What factors did Thomas Malthus think would eventually limit the human population?

    Think Critically

  1. Compare and Contrast What shape population growth curve would you expect to see in a small town made up mainly of senior citizens? Compare this growth curve to that of a small town made up of newly married couples in their twenties.

  2. Pose Questions What questions would a demographer need to answer to determine whether a country is approaching the demographic transition?

solve the CHAPTER MYSTERY

An photo of a rabbit.

A PLAGUE OF RABBITS

Australia had no native rabbit population when the European rabbits arrived, so there were no density-dependent controls to keep their numbers in check. The rabbits' new environment provided many favorable conditions for survival, including fewer predators, parasites, and diseases. The initial small number of rabbits—which can reproduce rapidly—soon multiplied into millions.

High rabbit numbers caused serious environmental and agricultural damage. In an effort to manage the problem, many methods have been tried, including fencing, poisoning, the destruction of burrows, and the use of parasites and disease. In the 1950s, a rabbit virus that causes the fatal rabbit disease myxomatosis was deliberately introduced as a form of biological control. It killed countless rabbits. But the virus and rabbits soon reached an equilibrium that allowed host and parasite to coexist, and the rabbit population rose. Later, a new virus that causes rabbit hemorrhagic disease (RHD) was introduced, and the rabbit population dropped again. In several places, environmental recovery was dramatic: Native animals recovered, and native trees and shrubs thought to be locally extinct began to grow again. But the RHD virus and rabbits appear to have reached a new balance, and the rabbit population is rising again!

  1. Predict Populations of wildcats and foxes (both also introduced to Australia) have come to depend on rabbits as prey. How do you think wildcats and foxes would be affected by a crash in the rabbit population?

  2. Connect to the Why should people be cautious about introducing organisms into new environments?

End ofPage 149

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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