Changing Populations Key Concept Builder LESSON 2 Key Concept

Name
Date
Class
C21L2
Key Concept Builder
LESSON 2
Changing Populations
Key Concept How do populations change?
Directions: Answer each question in the space provided.
How Populations Change
Question
Answer
1. How does a population of spiders
change when a large group of
eggs hatches all at once?
2. What will most likely happen to
many of the young spiders?
3. How will this change the
population?
4. What are a population’s birthrate
and death rate?
Directions: Use the graph to answer each question.
6. What type of growth is shown in
the graph?
pattern?
8. Why can’t this type of growth continue forever?
34
E. coli population
(thousands)
7. When does a population grow in this
1,200
Population
of E. coli Bacteria
800
400
0
2
4
6 8
Hours
10
Populations and Communities
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
5. How does the relationship
between birthrate and death
rate affect population size?
Name
Date
Class
C21L2
Key Concept Builder
LESSON 2
Changing Populations
Key Concept How do populations change?
Directions: Answer each question or respond to each statement on the lines provided.
1. State four reasons why a population might decrease in size. Then give a specific
example of each reason.
a.
b.
c.
d.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
2. What does it mean for a species to be extinct, endangered, or threatened?
3. Distinguish between migration and movement that is not migration. Give a specific
example of each.
Populations and Communities
35
Name
Date
Class
C21L2
Key Concept Builder
LESSON 2
Changing Populations
Key Concept Why do human populations change?
Directions: Use the graph to answer each question or respond to each statement.
Population
(in billions)
Human Population
Growth
10
8
6
4
2
75
0
10
00
12
50
15
00
17
50
20
00
22
50
0
Year
1. How has the human population changed in the past 150 years?
3. Compare the birthrate and death rate in the year 2000.
Directions: Answer the question on the lines provided.
4. How has carrying capacity affected the human population in the past? How might it
affect it in the future?
36
Populations and Communities
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
2. Compare the birthrate and death rate in the year 1000.
Name
Date
Class
C21L2
Key Concept Builder
LESSON 2
Changing Populations
Key Concept Why do human populations change?
Directions: Answer the question for each factor in the space provided.
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Factors That Result in
Population Growth
What advances have humans made?
Access to food
1.
Access to resources
2.
Sanitation
3.
Improved medical care
4.
Directions: Answer each question on the lines provided.
5. What are some causes of an increased death rate in human populations? Give specific
examples.
6. If birthrate and death rate in an area are equal, how can the size of the human
population in that area change?
Populations and Communities
37