Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
15 Cards in this Set
- Front
- Back
|
Population growth: causes and consequences
|
|
|
|
IPAT model
|
The IPAT model: I = P A T
Our total impact (I) on the environment results from: Population (P): individuals need space and resources Affluence (A): per capita resource use Technology (T): increases use of, or protects, resources Sensitivity (S): a fourth factor showing how sensitive an area is to human pressure Further model refinements include the effects of education, laws, and ethics on the formula |
|
|
Demography
|
applying the principles of population ecology to the study of change in human populations
|
|
|
Demographers
|
Demographers study:
-Population size -Density and distribution -Age structure -Sex ratio -Birth, death, immigration, and emigration rates |
|
|
Age structure affects population size
|
Age structure: describes relative numbers of individuals in each age class
Shown by age structure diagrams (population pyramids) Wide base: has many young that haven’t reproduced yet Population will soon grow rapidly Even age distribution: Remains stable Births = deaths |
|
|
Factors in population change & Natural rate of population change
|
Rates of birth, death, and migration determine whether a population grows, shrinks, or remains stable
Birth and immigration add individuals Death and emigration remove individuals Technological advances cause decreased deaths The increased gap between birth and death rates resulted in population expansion *Natural rate of population change: change due to birth and death rates alone, excluding migration |
|
|
Factors affecting total fertility rate
|
-Total fertility rate (TFR): the average number of children born to each female during her lifetime
-Replacement fertility: the TFR that keeps the size of a population stable (about 2.1) Causes of decreasing TFR: Medical care reduces infant mortality Urbanization increases childcare costs Children go to school instead of working Social Security supports the elderly Educated women enter the labor force |
|
|
Demographic transition
|
a model of economic and cultural change
Explains the declining death and birth rates in industrializing nations |
|
|
The demographic transition
|
As they industrialize, nations move from a stable pre-industrial state of high birth and death rates
To a stable post-industrial state of low birth and death rates Industrialization decreases mortality rates So there is less need for large families Parents invest in quality of life, not quantity of kids Death rates fall before birth rates Resulting in temporary population growth |
|
|
The 4 stages of the demographic transition
|
-Pre-industrial stage: low population growth
High death (disease, starvation, few medicines) and birth (compensation for mortality) rates -Transitional stage: industrialization, increased food and medical care reduce mortality rates High birth rates cause population to surge -Industrial stage: women get jobs and use birth control Kids do not need to help get food -Post-industrial stage: low birth and death rates stabilize populations |
|
|
Is the demographic transition universal?
|
It has occurred in Europe, the U.S., Canada, Japan, and other nations over the past 200–300 years
But it may or may not apply to developing nations The transition could fail: If the population is too large to allow the transition In cultures that place greater value on childbirth or grant women fewer freedoms |
|
|
Family planning: key to controlling growth
|
-Family planning: efforts to plan the number and spacing of children
The greatest single factor slowing population growth Clinics offer advice, information, and contraceptives -Birth control: controlling the number of children born by reducing the frequency of pregnancy -Contraception: deliberate prevention of pregnancy through a variety of methods Hindered by religious and cultural influences Rates range from 10% (Africa) to 86% (China) |
|
|
reproductive window
|
Women need control over their reproductive window:
The time in their lives when they can become pregnant Educating women reduces fertility rates, delays childbirth, and gives them a voice in reproductive decisions |
|
|
Wealth also impacts the environment
|
Affluent societies have enormous resource consumption
With severe, far-reaching environmental impacts Ecological footprints are huge |
|
|
Conclusion
|
-The human population is larger than it has ever been
Rates are decreasing but populations are still rising -Most developed nations have passed through the demographic transition -Expanding women’s rights slows population growth How will the population stop rising? :The demographic transition, governmental intervention, or disease and social conflict? -Sustainability requires a stabilized population to avoid destroying natural systems |
