




Page
1

Science Safari

Teacher’s Instruction
Learning Objectives
This activity should be complete in
one 55 minute class period.
Students will be able to calculate area.
Students will be able to utilize the formula for population density and calculate the
asked for number.
Students will be able to work in groups and stay on task for the allotted time.
Background
The purpose of this activity is to practice using the formula for population density. The
problems show, by pictures, a population that is more dense in order for students to see what
they are working with. The student should have prior knowledge of the population density
formula and also about the factors that shift the population numbers. This activity can be used
to summarize a unit or section on population density, or review what has been learned.
Getting Ready
Materials Needed:
Stop watch or clock
Metric sticks (enough for each group of two students)
Calculators
1. Distribute the papers. The front cover shows the clock. Each problem is on a different page
to keep students from working ahead. This activity is timed so that students stay on task while
working in groups selected by the student. Explain to students about setting up appointments
with people at each time slot. If Student A is at 2:00 for student B, then Student B must also be
at 2:00 for Student A. Each student should have five different people to work with.
2. Once the appointments are set up, begin with problem one. The problems go from easy to
more difficult so you can judge time allotment accordingly. Once you feel that every group
has completed the problem, switch to next appointment. The students will stop work after
each page is complete and should not go on until you tell them to switch.
3. When you finish with problem 5, time allotment to students may be given for the student to
finish up problems not finished.
Assessment
Page
2
Grade according to answer sheet.
Science Safari
Student Activity

Practice problems to calculate population density
Page
3
Complete the clock by setting up appointment times with other students in the room. If you are
Person A’s 4:00, then Person A is your 4:00. You need to have five different people – one for
each time.
Science Safari
Student Activity

The first practice problem with be with your
person on the clock. Meet with that person and
begin the practice problem when your teacher tells you to begin.

Directions: Use the information below to answer the following questions.
30 meters
60 meters
1) Write the mathematical formula for calculating population density:
2) What are the units in a population density calculation? ____________________________________
Why squared and not cubed? ____________________________________________________
3) What is the population of crickets, according to the information above?
Show work:
Page
4
Answer: ______________________ (Don’t forget to include the units)
 - Do not go on until instructions are given.
Science Safari
Student Activity

The second practice problem with be with your
person on the clock. Meet with that person
and begin the practice problem when your teacher tells you to begin.

A
B
3 meters
6 meters
6 meters
What do you notice about the sea lions in the above drawings?
_____________________________________________________________________________________
_____________________________________________________________________________________
Which box, A or B, would be more dense? _________________________. Why did you pick your
answer? __________________________________________. What is consistent about both boxes?
____________________________________________________________________________________.
Let’s practice calculating population density with the problems below.
Remember: Population Density = Total number of individuals / unit area
1) If the unit area is 700 m2 and the total number of sea anemones is 3500, what is the population
density of the sea anemones?
Show work:
Answer: __________________
2) What is the population density of sea urchins in an area that is 150 meters squared and 35 total sea
urchins in the area?
Show work:
Answer: __________________
3) The area that is being used for counting turtles is 35 meters squared and has 40 turtles. What is the
population density of the turtle population?
Page
5
Show work:
Answer: __________________
 - Do not go on until instructions are given.
Science Safari
Student Activity

The third practice problem with be with your
person on the clock. Meet with that person and
begin the practice problem when your teacher tells you to begin.

1.) Sally, an ecologist with the U.S. Fish and Wildlife Service, is studying the impact of the invasive
honeysuckle plants on deciduous forest ecosystems in Indiana. Her study area is 200 square
kilometers. She has determined that there are approximately 105 honeysuckle plants in every
kilometer squared. What is the estimated total population size?
Show work:
Answer: ____________________
(Don’t forget the units!)
2.) John, a marine biologist at the University of Florida, is studying the impact that hurricanes are
having on the health of coral in an area off the coast of Miami. The area is approximately 60
kilometers by 13 kilometers. If John counts, on average, 70 individual coral organisms in every
square kilometer, what is the estimated total population of coral in this area?
Page
6
Show work:
 - Do not go on until instructions are given.
Science Safari
Answer: _____________________
Student Activity

The fourth practice problem with be with your
person on the clock. Meet with that person
and begin the practice problem when your teacher tells you to begin.

Population Density in Your Space
1) Record the classroom dimensions and population of students below. Then, calculate the area and
amount of classroom space per person.
Length: __________________________
Width: ________________________
Area (length x width) = __________________________ square meters
Population: _____________________ people in the classroom.
How much space does each person have? ___________________ square meters.
Hint: space = area (length x width) divided by (# of people).
2) How much space would each person have if the number of people in the class doubled?
_____________________________________________________________________________________
3) Calculate the population density:
Population density: ___________________________
Hint: population density = (# of people) divided by area (length x width)
4) Calculate the population density of the class in previous years. Fill in the answers on the chart below.
Year
# of Students
Area
Population Density
(square meters)
1990
35
1994
25
1999
32
2004
45
2009
16
What would be two reasons that the population of students changed in these given years?
a.
 - Do not go on until instructions are given.
Page
7
b.
Science Safari
Student Activity

The fourth practice problem with be with your
person on the clock. Meet with that person and
begin the practice problem when your teacher tells you to begin.

There are four factors that affect any given population. Two will increase the population. They are
______________________________ and ___________________________. The other two will decrease
the population. They are _________________________________ and
___________________________________. By keeping these four factors in mind, complete the
following problem:
Black-tailed prairie dogs are generally found on the plains from Canada to Mexico. One of the largest
populations is found in South Dakota. In January 2001, a population of black-tailed prairie dogs of South
Dakota was counted. There were 50 prairie dogs. Since this animal is an endangered species, it is
highly protected. The population is constantly being monitored. In 2000, 4 prairie dogs died and 10
were born. The field area measures 210 square meters.
1) If there are no predators or diseases in this area, what would the expected population be at the end
of December 2002?
2) What was the initial density of the prairie dog population?
3) Twenty-five black-tailed prairie dogs were released in this area in 2003. Due to environmental
conditions, predators of the black-tailed prairie dog did not have enough to eat and began to eat the
prairie dogs. The loss of 12 prairie dogs brought the population down. However, there were 10 born.
What is the expected population at the end of 2003?
4) Disease spread over the habitat of the prairie dog in 2004. 40% of the population was wiped out. The
birth count was down to 5 new prairie dogs. What would the expected population be at the end of
December 2004?
Page
8
5) In the four year period described, predict what might happen to the population of black-tailed prairie
dogs in 2005.
Science Safari
Answer Key

The first practice problem with be with your
person on the clock. Meet with that person and
begin the practice problem when your teacher tells you to begin.

Directions: Use the information below to answer the following questions.
30 meters
60 meters
1) Write the mathematical formula for calculating population density:
Population Density = # of individuals / unit area (length x width)
2) What are the units in a population density calculation? Measurement
Why squared and not cubed?
squared
You multiply length x width
3) What is the population of crickets, according to the information above?
Show work:
8 / 60 x 30 meters
8 / 1800 m2 = 0.004444 individuals / m2
Page
9
Answer:
0.004 individuals / m2
(Don’t forget to include the units)
 - Do not go on until instructions are given.
Science Safari
Answer Key

The second practice problem with be with your
person on the clock. Meet with that person
and begin the practice problem when your teacher tells you to begin.

A
B
3 meters
6 meters
6 meters
What do you notice about the sea lions in the above drawings? There
are more in picture B than in
picture A
Which box, A or B, would be more dense?
20 in box B and 10 in box A .
Both areas are the same size.
B.
Why did you pick your answer?
Counted each box:
What is consistent about both boxes?
Let’s practice calculating population density with the problems below.
Remember : Population Density = Total number of individuals / unit area
1) If the unit area is 700 m2 and the total number of sea anemones is 3500, what is the population
density of the sea anemones?
Show work:
PD = 3500 sea anemones / 700 m2 Answer: 5 sea anemones / m2
2) What is the population density of sea urchins in an area that is 150 meters squared and 35 total sea
urchins in the area?
Show work:
PD = 35 sea urchins / 150 m2
Answer: 0.23
sea urchins / m2
Page
10
3) The area that is being used for counting turtles is 35 meters squared and has 40 turtles. What is the
population density of the turtle population?
Show work:
PD = 40 turtles / 35 m2
 - Do not go on until instructions are given.
Science Safari
Answer: 1.14
turtles / m2
Answer Key

The third practice problem with be with your
person on the clock. Meet with that person and
begin the practice problem when your teacher tells you to begin.

3.) Sally, an ecologist with the U.S. Fish and Wildlife Service, is studying the impact of the invasive
honeysuckle plants on deciduous forest ecosystems in Indiana. Her study area is 200 square
kilometers. She has determined that there are approximately 105 honeysuckle plants in every
kilometer squared. What is the estimated total population size?
Show work:
105 honeysuckle plants / 1 km2
105 plants x 200 = 21,000 honeysuckle plants / 200 km2
2
Answer: 21,000 honeysuckle plants / 200 km
4.) John, a marine biologist at the University of Florida, is studying the impact that hurricanes are
having on the health of coral in an area off the coast of Miami. The area is approximately 60
kilometers by 13 kilometers. If John counts, on average, 70 individual coral organisms in every
square kilometer, what is the estimated total population of coral in this area?
Show work:
60 km x 13 km = 780 km2
70 coral / 1 km2 70 coral x 780 = 54,600 coral / 780 km2
Page
11
Answer:
54,600 coral / 780 km2
 - Do not go on until instructions are given.
Science Safari
Answer Key

The fourth practice problem with be with your
person on the clock. Meet with that person
and begin the practice problem when your teacher tells you to begin.

Population Density in Your Space
Answers will vary depending on the size of your classroom and the number of students. I will give
the example of my classroom and student size.
1) Record the classroom dimensions and population of students below. Then, calculate the area and
amount of classroom space per person.
Length: _11
meters____________
Width: __6
meters________________
Area (length x width) = __66___ square meters
Population: ___30____ people in the classroom.
How much space does each person have? ____2.
2 ______ square meters.
Hint: space = area (length x width) divided by (# of people).
2) How much space would each person have if the number of people in the class doubled?
2
2
_______________66 m / 60 people = 1.1 m __________________________________________
3) Calculate the population density.
Population density: ___0.91
people / m2 _______________
Hint: population density = (# of people) divided by area (length x width)
PD = 60 people / 66 m2
4) Calculate the population density of the class in previous years. Fill in the answers on the chart below.
Year
# of Students
1990
35
1994
25
1999
32
2004
45
2009
16
Area
(square meters)
2
66 m
66 m2
66 m2
66 m2
66 m2
Population Density
0.53 people / m2
0.38 people / m2
0.48 people / m2
0.68 people / m2
0.24 people / m2
Page
12
What would be two reasons that the population of students changed in these given years?
a. Not as many students enrolled in this class
b. Not
as many students enrolled in the school.
 - Do not go on until instructions are given.
Science Safari
Answer Key

The fourth practice problem with be with your
person on the clock. Meet with that person and
begin the practice problem when your teacher tells you to begin.

There are four factors that affect any given population. Two will increase the population. They are
_birth_________________________ and ___immigration___________________. The other two will
decrease the population. They are ___death_________________________ and ____emigration______.
By keeping these four factors in mind, complete the following problem:
Black-tailed prairie dogs are generally found on the plains from Canada to Mexico. One of the largest
populations is found in South Dakota. In January 2001, a population of black-tailed prairie dogs of South
Dakota was counted. There were 50 prairie dogs. Since this animal is an endangered species, it is
highly protected. The population is constantly being monitored. In 2000, 4 prairie dogs died and 10
were born. The field area measures 210 square meters.
1) If there are no predators or diseases in this area, what would the expected population be at the end
of December 2002? 56
2) What was the initial density of the prairie dog population? 44
2
dogs / 210 m2 ==
0. 2 prairie dogs/m
3) Twenty-five black-tailed prairie dogs were released in this area in 2003. Due to environmental
conditions, predators of the black-tailed prairie dog did not have enough to eat and began to eat the
prairie dogs. The loss of 12 prairie dogs brought the population down. However, there were 10 born.
What is the expected population at the end of 2003? 79 prairie dogs
4) Disease spread over the habitat of the prairie dog in 2004. 40% of the population was wiped out. The
birth count was down to 5 new prairie dogs. What would the expected population be at the end of
December 2004? 52.4 prairie dogs or 52 prairie dogs
5) In the four year period described, predict what might happen to the population of black-tailed prairie
dogs in 2005. Answers will vary. Since it is a given area in a certain environment, chances are the
Page
13
population will remain constant unless some are immigrated, as in the case in the year 2003. It
might decrease due to death, for example, a disease might wipe out the population in that area.
Science Safari