11.1 – Human Numbers Through Time
Name:
from http://www.pbs.org/wgbh/nova/earth/global-population-growth.html
For most of human existence our ancestors led precarious lives as
scavengers, hunters, and gatherers, and there were fewer than 10 million
human beings on Earth at any one time. Today, many cities have more than
10 million inhabitants each, and populations continue to skyrocket. In this
activity you will trace the dramatic growth of human populations over
recent centuries.
Follow the link above to the NOVA website and click on “Launch
Interactive”. As you read through each slide, fill in table at right and answer
the questions below IN COMPLETE SENTENCES.
In 1000 AD, why did the population numbers fail in Europe?
Black Death (bubonic plague), many died from the plague, but also it
reduced the birth rates because there were less people.
What was happening in the late 18th century that increases living conditions
and population growth?
Industrial Revolution
What was the growth rate during this time?
.86 million/yr, or 0.15%
In 1800, what percentage of the population lived in North America?
Year
0
1000
1650
1750
1800
1927
1956
1960
1974
1987
1991
1999
2012
Today
Population
.3 billion
.31 billion
.5 billion
.7 billion
1 billion
2 billion
2.5 billion
3 billion
4 billion
5 billion
5.5 billion
6 billion
7 billion
7.2 billion
Less than 1%
In which two countries did most of the population live?
India and China
What was the growth rate in the early 1900s?
Approximately 1%
What began happening around the 1950s that significantly increased life expectancy?
Advances in agriculture, medicine, and sanitation in developing countries
Besides medicine, sanitation and agriculture contributed to increasing population growth during this time.
Explain the effect that each of these factors would have on population growth.
Medicine would treat disease, which would lead to longer lives. Sanitation would help prevent disease, which would
lead to longer lives. Agriculture would increase the amount of food available, which would allow for more people.
What was the population growth rate in 1960?
Approximately 2.04%
The rate of population growth was soon curbed by reproductive technologies. Give an example of a reproductive
technology that could slow population growth.
Any type of birth control or contraceptives
Why was the population still “exploding”?
There were already too many people in the world, so even though family sizes shrunk, the sheer number of people
was high enough that even having three children caused large population increases.
In what parts of the world was the population growing most rapidly?
Developing nations
Where does most of the world’s population live today (and what percent of the population live there)?
Asia (61%)
What percent live in North America?
5%
What percent live in each Europe and Africa?
12%
Where does 9% of the population now live?
Latin America
What is the population predicted to be by 2050?
9 billion
Why will most of this growth be in developing countries?
No family planning, the culture still exists to have large families even though children are surviving longer.
Why is this such a problem?
These areas are already stressed past the carrying capacity and are running out of food and water.
Go to the website of the United States Census Bureau and record the world’s population as of today (this minute
even!) in your data table.
Now you will create a graph of the human population using the data you collected in your table. BE SURE TO SCALE
YOUR GRAPH PROPERLY, LABEL EACH AXIS (with units), AND GIVE YOUR GRAPH AN APPROPRIATE TITLE.
Human Population Growth
8
7
Population Size (Billions)
6
5
4
3
2
1
0
0
500
1000
Year
1500
2000
Analysis & Conclusion Questions
1. It took 1649 years from the world population to double, going from .25 billion people to .50 billion people. How
long did it take for the population to double once again?
150 years (1650-1800)
2. How long did it take for the population to double a second time? 127yrs (1800-1927) A third time? 47yrs (1927-74)
3. Based on your graph, in what year will the population reach 8 billion? Approximately 2025
4. Based on your graph, how many years will it take for the population of 2004 to double? Approximately 2075
The Earth's Carrying Capacity
Prior to 1950, the death rate was high, which kept the numbers of humans from increasing rapidly. In the 19th
Century, the agricultural revolution increased food production. The industrial revolution improved methods of
transporting food and other good. In the 20th Century, advances in medicine, sanitation and nutrition have
decreased the death rates further. These factors combined to produce the rapid growth of the human population in
the 20th century.
As with any population, humans are also limited by factors such as space, amount of food and disease. The carrying
capacity is the number of individuals that a stable environment can support. Authorities disagree on on the
maximum number of people that the earth can support, though the numbers generally range for 8 to 10 billion. As
the population approaches its limit, starvation will increase. Some countries have a much higher growth rate than
others. Growth rate is the number of people born minus the number of people that die. Compare the growth rates
of the following countries
Most countries are trying to reduce their growth rate. Zero population growth means that as many people are being
born as there are dying - to achieve zero population growth, each couple would need to have no more than two
children (to replace the parents). Even if this number is achieved, the population will continue to grow because the
parents will still live on for decades, as their children have children and their children have children and so forth. The
United States reached zero population growth in the 1980's, and yet the overall population of the US still increases.
Analysis
1. What factors contributed to the world's overall population growth in the last 150 years.
Advances in agriculture (agricultural revolution), methods of transportation (industrial revolution), medicine,
sanitation and nutrition
2. Why does a population not level off during the same year it reaches zero population growth?
Even though family planning allows for replacement (2 children for every 2 adults), the population is still so bottom
heavy (more younger people than older) that the amount being born is greater than the amount dying.
3. If the carrying capacity of the earth was 9 billion people, when would this number be reached (USE YOUR GRAPH
and SHOW THIS ON YOUR GRAPH)?
Approximately 2030
4. What will happen when the human population exceeds the earth's carrying capacity?
Starvation, wars over resources, etc.