Human Populations Chapter 9. Studying Human Population Human populations have grown faster in the 20...
Transcript of Human Populations Chapter 9. Studying Human Population Human populations have grown faster in the 20...
Studying Human Population
Human populations have grown faster in the 20th century than it ever has before.
Demography: the study of populations, usually human populations. Study history of population growth: the makeup,
the size, economy at the time, and social structure.
Separate developing countries and developed countries.
Human Population over Time
During the 1800s the human population grew exponentially Grew due to improvements in food production and
hygiene that came with industrial and scientific revolution
It is unlikely the earth can sustain such a rapid growth
Forecasting Population Size
Demographers look at properties of populations to predict what a community will face in the coming years. Age Structure: the
distribution of ages in a specific populations at a certain time.
Forecasting Population Size
Survivorship: the percentage of members of a group that are likely to survive to a given age. Wealthy developed
countries have a higher survivorship than developing countries
Forecasting Population Size
Migration: the movement of individuals between areas. Immigration: movement into an area Emigration: movement out of area Populations of many developing countries might be
decreasing if not for immigration.
Forecasting Population Size
Fertility Rates: number of babies born each year per 1,000 in a population. Total fertility rate is the average number of
children a women gives birth to in her lifetime
Declining Death Rate
One of the reasons for rapid population growth is due to the fact that death rates have declined more than birth rates. Declined because people have access to
adequate food, clean water and safe sewage disposal.
Life Expectancy: average number of years a person is likely to live
Men: 74 years (born today) Women: 79 years (born today)
• Life expectancy changes as you get older and depends on a number of other factors.
Declining Death Rate
Life expectancy is most affected by infant mortality: the death rate of infants less that a year old. In 1900 worldwide life expectancy was 40 years
and the infant mortality was very high. By 2000 the infant mortality was one-third of the
1900 rate. Infant death is most affected by the parents
access to education, food, fuel, and clean water. In developing countries diseases such as AIDS and
tuberculosis have affected the life expectancy.
Women and Fertility
Decline in birth rate is directly correlated to the education and independence of women Educated women find that they do not
need to have more children to ensure that some will survive.
The total fertility rate in developed countries is 1.6 children per woman, while in developing countries it is 3.1 children per woman
Changing Populations Trends
A rapidly growing population uses resources at an increased rate and can overwhelm the infrastructure of a community Infrastructure: the basic facilities and
services that support a communityPublic water supplies, sewer lines, power
plants, roads, subways, schools, and hospital.Symptoms of overwhelming populations
growth include suburban sprawl, overcrowded schools, polluted rivers, barren land and inadequate housing
Problems of Rapid Growth
A rapidly growing population can use resources faster than the environment can renew them, unless resources come from elsewhere.
Vegetation, water and land are the resources most critically affected by rapid growth
Problems of Rapid Growth
Shortage of Fuelwood – wood is the main fuel source in many developing countries.
Unsafe Water – in places that lack infrastructure, the local water supply is used for drinking and washing but also for sewage Many diseases are carried in water
supplies
Problems with Rapid Growth
Impacts on the Land – Arable land: land that can be used to
grow crops Urbanization: more people are living in
cities than in rural areasLeads to suburban sprawl
A demographically diverse world
More developed countries vs. less developed countries vs. least developed countries Least: countries show few signs of
development and in some cases have increasing death rates, while birth rates remain high
United Nations identifiedQualify for foreign aid and development
programs