Chapter 7

Question 1

Describe what I=PAT is, and what each letter stands for.

Answer 1

• I=PAT stands for Environmental Effects of Population

• I= Environmental Impact
• P= Population Size
• A= Affluence
• T= Technology

Question 2

Please define crude birth rate, total fertility, zero population growth, crude death rate, natural increase of a population, and total growth rate:

Answer 2

• Crude Birth Rate: Number of births in a year per thousand. (Not adjusted for population characteristics such as number of women of childbearing age.)
• Total Fertility: number of children born to an average woman in a population during her life
• Zero Population Growth: Occurs when births plus immigration in a population equal deaths plus emigration. ZPG Is a rate of 2.1 children per couple, not 2.0, because some people do not have children and some children do not survive to reproductive age.
• Crude Death Rate: number of deaths per thousand persons in a given year. Poor countries average about 20 while wealthier countries average about 10.
• Natural Increase of a Population: Crude birth rate minus crude death rate.
• Total Growth Rate: Total growth rate includes immigration, emigration, births and deaths

Question 3

How do age structure graphs appear for rapid growth, stable growth and declining growth countries? How different do age categories( young, middle age, old) appear for each of those countries?

Answer 3

• Rapid Growth: Many people who are young, not very many people who are old
• Stable Growth: about the same percent of young people as there are middle aged and old
• Declining Growth: Less youth than middle aged, and even less old people. Implies that the rate of older people will continue to rise in proportion to younger and middle age

Question 4

Please explain demographic transition. What each stages I, II, III, and IV indicates with regard to crude birth rate and crude death rate, as well as the state of population growth(stable, declining, increasing?).

Answer 4

• Demographic Transition: Pattern of falling death rates and birth rates due to improved living conditions accompanying economic development.
• Stage I: Pre-Modern Society - Poor conditions keep death rates high; birth rates are correspondingly high
• Stage II: Economic Development brings better standard of living thus death rates fall. Birth rates stay constant or even rise.
• Stage III: In a mature industrial economy, birth rates begin to fall as people see that most of their children survive
• Stage IV: Developed Countries - Transition is complete and both death and birth rates are low and population is in equilibrium.