Download Populations

Name
Class
Date
Populations
Interdependence In Nature
Q: What factors contribute to changes in populations?
Chapter Summary
The diagram below shows what you will read about in this chapter and how the chapter is
organized. Study the diagram. Then answer the questions that follow.
Describing populations
5.1 How Populations
Grow
Population growth
Exponential growth
Logistic growth
5.2 Limits to Growth
Limiting factors
Density-dependent limiting factors
Density-independent limiting factors
5.3 Human
Population
Growth
Historical overview
Patterns of human population growth
1. What is the focus of this chapter? populations and factors that contribute
to changes in populations
2. What are the three major topics? how populations grow, limits to population growth,
and human population growth
3. In Lesson 1, what is the first topic that will be covered?
describing populations
4. In Lesson 3, what do you think "historical overview" means? the way that the human
population has changed over time
Chapter 5 • Workbook B • Copyright © by Pearson Education, Inc., or its affiliates. All rights reserved.
61
Name
Class
Date
5.1 How Populations Grow
Lesson Objectives
List the characteristics used to describe a population.
Identify factors that affect population growth.
Describe exponential growth.
Describe logistic growth.
BUILD Vocabulary
A. The chart below shows key terms from the lesson with their definitions. Complete the chart
by writing a strategy to help you remember the meaning of each term. One has been done
for you.
Term
Definition
How I’m Going to Remember
the Meaning
Age structure
Number of males and females
of each age group in a
population
Structure is the makeup of something. Age structure is a count of the
people of certain ages that make up a
population.
Carrying capacity
Maximum number of
individuals of a particular
species that an environment
can support
When something is “filled to capacity,” it is
full. The carrying capacity is the number of
individuals that "fill" an environment.
Emigration
(em uh GRAY shun)
When individuals move out of
a population
Emigration means exiting.
Exponential growth
Growth where the larger a
population gets, the faster it
grows
Exponential growth is explosive.
Immigration
(im uh GRAY shun)
When individuals move into a
population
Immigration means moving in.
Logistic growth
Growth that takes place when a
population’s growth slows and
then stops following a period of
exponential growth; forms an
S-shaped curve on a graph.
Within the word logistic is the letter S,
and logistic growth forms an
S-shaped curve.
B. As you work through this lesson, you may find these terms in the activities. When you
write a key term or a definition, highlight the term or the definition.
Note: Students should highlight terms and definitions used throughout the chapter.
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62
Name
Class
Date
BUILD Understanding
Concept Map A concept map can help you organize information and show how ideas are
connected. The concept map below shows the relationship between vocabulary terms in this
lesson.
As you read the lesson, place the terms from the box in the correct location in the concept map.
age structure
exponential growth
carrying capacity
immigration
emigration
logistic growth
Number of individuals per area
Population density
Population
Growth
is described by
Number of males and
females of certain ages
Age structure
is affected by
Immigration
with unlimited
resources is
Emigration
with limited
resources is
Exponential
growth
Logistic growth
Population grows
until reaching
Carrying capacity
Answer the questions.
1. Immigration and emigration affect population growth .
2. Exponential growth occurs when resources are
3. Logistic growth occurs when resources are
unlimited
limited
.
.
Lesson 5.1 • Workbook B • Copyright © by Pearson Education, Inc., or its affiliates. All rights reserved.
63
Name
Class
Date
Population Growth
Population size is the number of individuals that make up a population. Immigration and
births increase population size. Emigration and deaths decrease population size. The table
below shows how different populations changed over a one-year time span.
Follow the directions.
1. Study each population. Determine whether the overall population size has increased
or decreased.
2. If the population size has increased, draw an arrow that points upward in the last column.
3. If the population size has decreased, draw an arrow that points downward. The first one
has been done for you.
Population
Births
Deaths
Number of
People Who
Emigrated
Number of
People Who
Immigrated
A
200
100
0
0
B
10
10
100
0
C
1
1
1
50
D
10
100
100
10
E
100
200
0
0
F
50
1
1
50
G
10
10
0
100
Population
Size
Answer the questions.
4. Study population G. What would happen to the population size if 100 people emigrated?
The population size would not change.
5. A food shortage causes many members of a population to leave an area. What type of
population movement does this describe? Circle the correct answer.
emigration
immigration
6. What caused the population size of population C to increase?
immigration
Lesson 5.1 • Workbook B • Copyright © by Pearson Education, Inc., or its affiliates. All Rights Reserved.
64
Name
Class
Date
5.2 Limits to Growth
Lesson Objectives
Identify factors that determine carrying capacity.
Identify the limiting factors that depend on population density.
Identify the limiting factors that do not depend on population density.
BUILD Vocabulary
A. The chart below shows key terms from the lesson with their definitions. Complete the chart
by writing a strategy to help you remember the meaning of each term. One has been done
for you.
Term
Definition
How I’m Going to Remember
the Meaning
Densitydependent
limiting
factor
A limiting factor that only
becomes limiting for a
population when the population
density reaches a certain level
I’ll focus on density-dependent. This
means that population growth is limited
by how dense the population is.
Densityindependent
limiting
factor
A limiting factor that affects
all populations in similar ways
regardless of population size
and density
I’ll focus on density-independent. This means
that population growth is not affected by how
dense the population is. These limiting factors
affect all populations the same way.
Limiting
factor
Something that controls the
growth of a population
My spending is limited by the amount of
money I have. A population’s growth is
limited by limiting factors.
B. As you work through this lesson, you may find these terms in the activities. When you
write a key term or a definition, highlight the term or the definition.
BUILD Understanding
Lesson Preview When you preview a lesson before you read, you learn the topics you will
study in the lesson. One way to preview a lesson is to read the headings. The lesson headings
let you know the topics in the lesson. The order of the headings tells you the order in which
the topics will be covered. As you preview the headings, you should also look at the key
questions.
Continued on next page ▶
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65
Name
Class
Date
Preview the lesson by looking at the main headings, the subheadings, and the key questions.
After you have finished, answer the questions below. If you don't know the answer, go back
and check the lesson again.
green
1. What color are the main headings?
Write the main headings in the order in which they appear.
Limiting Factors, Density-Dependent Limiting Factors, Density-Independent Limiting
Factors
2. Look at the question under the heading Limiting Factors. In your own words, what will
you learn in this part of the lesson? Sample answer: the things that determine how
many individuals can live in an environment
3. Look at the blue headings within the main heading Density-Dependent Limiting Factors.
What are the four subtopics covered in this part of the lesson?
Competition, Predation and Herbivory, Parasitism and Disease, Stress from
Overcrowding
Density-Dependent Limiting Factors
Density-dependent limiting factors become important when the population density of an
area reaches a certain level. The effect of predators on prey is one density-dependent
limiting factor.
A predator is an animal that eats other animals. Prey is the animal that is eaten. Predatorprey interactions can affect the population growth of both the predator and the prey.
Populations of predators and prey cycle up and down over time. In the graph below, the
wolves are the predators and the moose are the prey.
60
2400
50
2000
40
1600
30
1200
20
800
10
400
0
1955
0
1960
1965
1970
1975
1980
1985
1990
Number of Moose
Number of Wolves
Wolf and Moose Populations on Isle Royale
1995
Year
Wolves
Moose
Answer the questions.
1. Was the moose population increasing or decreasing from 1964 to 1974?
2. Was the wolf population increasing or decreasing from 1969 to 1980?
increasing
increasing
3. How might changes in the moose population from 1964 to 1974 relate to changes in the
wolf population from 1969 to 1980? An increasing number of moose provided a larger
food source for wolves. More food resources allowed the wolf population to increase.
Lesson 5.2 • Workbook B • Copyright © by Pearson Education, Inc., or its affiliates. All Rights Reserved.
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Name
Class
Date
Inquiry Into Scientific Thinking
How Does Competition Affect Growth? Organisms compete with one another for
resources. The competition can be between the same species or different species. The size of
one population can decrease because of an increase in the size of another population.
Read the description.
In 1970, no humans lived in the old field on Grassridge
Lane. By 1986, more than 100 homes had been built in
this location. An ecologist discovered a population of
mice living in the field in 1974. The ecologist studied
and sampled the mice annually from 1974 to 1982. The
chart on the right shows the data.
Year
Estimated number
of mice per 1000
square meters
1974
50
1975
44
Analyze and Conclude
1976
42
Answer the questions.
1977
31
1978
29
2. What limiting factor(s) could be affecting the mouse
1979
26
population? Sample answer: competition among
1980
23
3. How could competition be a limiting factor in this
1981
19
situation? Sample answer: The humans and mice
1982
15
1. Did the number of mice increase or decrease
between 1974 and 1982?
decrease
mice for resources; predators
competed for space and the humans were more
successful in this competition. As space became limited, the mice competed among
themselves for limited resources such as food.
CHAPTER
A Plague of Rabbits When an
Australian farmer released 24 wild
European rabbits on his farm, things
got out of control.
Design a logo and slogan that warn
people of the dangers of introducing
new species.
Students’ artwork and slogans
should warn of the dangers of
exponential growth and how rapid
population growth can affect
other species.
Lesson 5.2 • Workbook B • Copyright © by Pearson Education, Inc., or its affiliates. All rights reserved.
67