Name __________________________
Date _________
Hour ______
Lab ___: Population Growth
Part A: Reindeer Population
In 1911, 25 reindeer (also known as caribou)—4 males and 21 females—were introduced onto St.
Paul Island, one of the Pribolof Islands in the Bering Sea near Alaska. St. Paul Island is
approximately 106 km2 in size (41 square miles), and is more than 323 km (200 miles) from the
mainland. On St. Paul Island, there were no predators of the reindeer, and no hunting of the reindeer
was allowed. Study the graph below and answer the questions.
Reindeer population on St. Paul Island between 1911 and 1950
Analysis
1. What was the size of the population at the beginning of the study? _______
a. in 1920? _______
b. What was the difference in the number of
reindeer between 1911 and 1920? ______
c. What was the average annual increase in the
Average annual change between Year A
and Year B=
Population in Year B - Population in Year A
÷
number of reindeer each year between 1911
and 1920? (Show your work below.)
number of years between Year B and Year A
___________
2. What was the difference in population size between the years 1920 and 1930? _______
a. What was the average annual increase in the number of reindeer between 1920 and
1930? (Show your work below.) ___________
3. What was the average annual increase in the number of reindeer between 1930 and 1938?
(Show your work below.) ____________
4. During which of the three periods, 1911-1920, 1920-1930, or 1930-1938, was the increase in
the population of reindeer greatest? __________________
5. What was the greatest number of reindeer found on St. Paul Island between 1910 and 1950?
_______ In what year did this occur? _______
6. In 1950, only eight (8) reindeer were still alive. What was the average annual decrease in the
number of reindeer between 1938 and 1950? (Show your work below.)
Discussion
1. Could emigration or immigration have played a major role in determining the size of the
reindeer population? ______ Explain your answer. __________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
2. What might explain the tremendous increase in the population of reindeer between 1930 and
1938, compared to the rate of growth during the first years the reindeer were on the island?
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
3. What effect might 2000 reindeer have on the island and its vegetation? __________________
______________________________________________________________________________
______________________________________________________________________________
4. Beginning in 1911, in which time spans did the population double? ______________________
______________________________________________________________________________
5. How many years did it take each of those doublings to occur? _________________________
______________________________________________________________________________
______________________________________________________________________________
6. What happened to the doubling time between 1911 and 1938? ________________________
______________________________________________________________________________
______________________________________________________________________________
7. If some of the eight reindeer that were still alive in 1950 were males and some females, what
do you predict would happen to the population in the next few years? Why? ______________
______________________________________________________________________________
______________________________________________________________________________
8. What evidence is there that the carrying capacity for reindeer on this island was exceeded?
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
9. What does this study tell you about “unchecked” population growth? ____________________
______________________________________________________________________________
______________________________________________________________________________
10. What difference might hunters or predators have made? ______________________________
______________________________________________________________________________
______________________________________________________________________________
Part B: Human Population
Analysis
1. On your graph paper, plot the growth of the human population using the data in the data table.
Date (AD)
Human Population
1940
2300
(in millions)
1950
2500
1
250
1960
3000
1000
280
1980
4450
1200
384
1985
4850
1500
427
1990
5300
1650
470 (black death)
1995
5670
1750
694
2000
6070
1850
1100
2005
6450
1900
1600
2010
6970
1920
1800
1930
2070
2. Use your graph to determine the doubling times for the human population between 1 AD and
2010 AD. How much time elapsed before the human population of 1 AD doubled the first
time? ____________
3. Is the amount of time needed for the human population to double increasing or decreasing?
_____________________________
4. Extend your graph to the year 2025. What do you estimate the human population will be in
that year? ____________________
Discussion
1. What similarities do you see between the graph of the reindeer population and your graph of
the human population? ________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
2. What are the three or four most important factors required to sustain a population? _________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
3. In what ways is the earth, as a whole, similar to an island such as St. Paul? _______________
______________________________________________________________________________
______________________________________________________________________________
4. Does the earth have a carrying capacity? Explain. __________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
5. What might happen to the population of humans if the present growth rate continues? ______
______________________________________________________________________________
______________________________________________________________________________
6. What methods could be used to reduce the growth rate? ______________________________
______________________________________________________________________________
______________________________________________________________________________
7. Where in the world is population growth a problem today? ____________________________
8. Where in the world is population growth not a problem today? _________________________
9. What problems in the U. S. are related to the human population? _______________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
10. What are the most important three or four factors to think about with regard to the world
population? _________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________