Human Population Growth

since peopie have the abifilty to change the environment, a population increase can have a significant impact on the ecosystem.

S5G3.00 To evaluate alternatives that can help limit population growth.

3.01 List methods of limiting population growth.
3.02 discuss viewpoints that favor and object to limiting population growth.

TIME REQUIRED:

100 minutes OUTLINE OF CONTENT:
1. Means of limiting population growth
A. Birth control
1. Voluntary
2. Mandatory
B. Problem enforcing birth control
II. Pros and Cons of population limitation
A. Why limit - growing exponentially
B. Decrease death rate
C. Gene pool altered - medicine keeping people alive
D. Increase birth rate
E. Natural limiting factors avoided by men
F. Infant mortality
G. Zero population growth
MATERIALS:
overhead projector, graph paper, transparency of bacteria population. This lesson addresses Instructional Objective 3.01
SET:
Pretend there is a town of 1000 people and due to new industry moving to town the population doubles every twenty years. How many people would be there after 100 years? How many would be there after 100 years if the population doubled every ten years? (Allow time for students to write their answers then give them time to share their answers with the class.) Today we will discuss whether human population should be limited.
INSTRUCTION:
The doubling time of population in Europe in 248 years, 98 in the United States, but is 39 years in Asia, 30 years in Latin America, and 24 years in Africa. In which is the population growing the fastest?

What would cause a population to grow? (birth rate, death rate, immigration, emigration) A town might grow due to jobs in the area, or decrease in population due to plant closing, etc. Should the growth of a town be controlled? (Show the graph of bacteria population in a closed system.) What happened to the bacteria? (The population decreased until all were dead.)

Why? (All the resources were used.) Do we live in a closed system? (The earth is a closed system but each town can get resources from other places as long as transportation is available.)

Prepare a graph of human population. (Put students in groups and let them brainstorm the answers to the following questions. Allow time for sharing of the answers.)

QUESTIONS:
1. Where are places on earth where people cannot live? (ice caps, oceans, deserts, some mountains, etc.)

2. What is the relationship between the carrying capacity of the earth and the population of the earth? (We cannot increase beyond our ability to acquire raw materials, acquire energy, or safely dispose of our waste materials. Interactions with other species and with other humans may be involved in determining our carrying capacity. Therefore there is a limit to the population the earth will support.)

3. What are some effects of the population growth on the world's environment? (Wastes generation, depletion of soils, overuse of land, depletion of nonrenewable resources, not enough time for renewable resources like air, water, soil, trees to recycle, use of land not meant for humans such as irrigation of deserts, draining wetlands, etc. are some effects. This puts humans in greater competition with other humans and wildlife for available resources.

4. What is the effect of population growth on the world's people? (Competition for space creates political and social tensions as we compete for resources.)

5. How does our population growth in this country affect the quality of life in other countries? (More people produce more need for goods which our country can afford to but from the rest of the world. It produces economic booms there but it puts pressure on people in the rain forest to sell us lumber, clear land for pet food, drugs, coffee, kill elephants for ivory and cats for fur. A baby in the U.S. uses more of the world's resources than a baby born in a poorer country because of the energy demands of our lifestyles.)

6. How does population growth in other countries affect the quality of life in the U.S.? (Overuse of land to raise food, improper wastes treatment pollutes oceans and rivers, over fishing and over hunting all affect the food chains of wildlife on which we depend. Cutting rain forest decreases oxygen production, draining wetlands puts stress on ocean food chain and other factors contribute to climate changes.)

7. Should the human population be limited? Whose population be limited? (Allow time for discussion and fill in the missing ideas.)

SUPPLEMENTAL ACTIVITY:
Students could report on a boom town.
CLOSURE:
We live in a "closed ecosystem." We can do some things to increase the carrying capacity of the earth. Write one reason for and one reason against controlling human population growth. (Share answers in class if there is time.)

This lesson addresses Instructional Objective 3.02

SET:
We have learned that the population of the world is growing at an astounding rate. The growth affects the future quality of life. Write one reason for limiting the population growth in your town.
INSTRUCTION:
Approximately one billion people live in China- one fifth of the world's population. Between 1950 and 1980 the population increased by 400 million people; this increase is nearly twice the size of the United States in 1980. They initiated a program in which the government established laws to regulate population growth. First they tried "Later, Longer, Fewer" (marry later, wait longer between children, and have fewer children). That did not work fast enough so they now have encouraged, by very strict economic and social pressure, the limiting of family size to one child. It has been very successful in the urban areas but has met with opposition in the rural areas where children are needed for labor. Some of the problems encountered in China are increased abortions, female infanticide, etc. What would be the reaction to people getting married today if the government asked them to have only one child? We need other ways of limiting our population. According to some studies, the status, the status of women in the society affects the birth rate. Why would you think women having a job would affect the birth rate? (Pause for answers.) Knowledge of and access to birth control devices controls the birth rate. (You might list pills, spermaticides, diaphrams, condoms, timing of intercourse (rhythm method). A third factor that affects the birth rate is later marriage. Why would this affect the birth rate?

Put students in groups to prepare an advertising brochure to encourage zero population growth for the United States and one for other countries. (Define Zero population growth for them.) Remember that some of these ideas for your brochure could be used to encourage teenage birth control. Include all three methods of decreasing the birth rate we mentioned.

CLOSURE:
List two ways to control population growth.
SUPPLEMENTARY ACTIVITY:
Debate voluntary or mandatory birth control.
SIGNIFICANT TERMS:
zero population growth, geometric growth, sterilization, birth control, natality, mortality, limiting factors
RESOURCES:
ARTICLES:
"Planet of the Year - Too Many Mouths." Time. January 2, 1989. Vol 133 No. 1 pp 48-50
"Population, Plenty, and Poverty" - National Geographic. December 1988. Vol 174 No. 6 pp 914-914

---

ceceone@utm.edu