Unit: Ch. 9 The Human Population

How do we study the human population? Demography – study of human populations historical size and makeup of populations of countries in order to make comparisons and predictions Population Size-total number of individuals Population Density-number of individuals per given unit of area 2 categories for countries Developed – higher average income, slower birthrate, diverse industrial economies Developing – lower average income, agriculture-based economies, rapid population growth

Human population over time Grew slowly up until 1800 1800’s – went through exponential growth Population growth increases every decade Due to increases in food production, better hygiene, industrial and scientific revolution Not likely the earth can sustain this growth Current population size is 7.6 BILLION!!

Human population over time

Forecasting population size Age structure – distribution of ages in a pop – shown in a pop pyramid Survivorship – percent of members of a group that are likely to live to a certain age – shown with line curves Fertility rates - number of babies born each year per 1,000 women Replacement level – average of children a parent must have to replace themselves, about 2 because not all babies survive Migration – movement of individuals between areas Immigration – entering, into Emmigration – exiting, leaving

Declining death rates Dramatic increase in population in the last 200 years due to drop in death rates More access to adequate food, clean water, and safe sewage disposal Life expectancy – average number of years a member of a population is likely to live Most affected by infant mortality – death rate of infants under 1 year old 1900: 40 years old world wide with high infant mortality 2000: 67 years old world wide and infant mortality decreased to less than 1/3 of 1900 rate

The Demographic Transition The populations of most developed countries have stopped growing Model that describes how economic and social changes affect population growth rates (within a country) Process takes 3 – 4 generations Stages 1. Preindustrial – birth rate and death rate are high, little change in population size 2. Transitional – population explosion, death rate lowers due to education, hygiene, nutrition, birth rates remain high 3. Industrial – birth rate declines and gets close to the death rate so the population stabilizes 4. Postindustrial – birth rate below replacement level so population decreases

Studying Human Populations Chapter 9

Problems of rapid population growth 1. Overwhelming the infrastructure Infrastructure – basic services and facilities that support a community (water supplies, roads, sewer lines, schools, etc.) Symptoms: Suburban sprawl Overcrowded schools Polluted rivers Barren land Inadequate housing Poor sanitation

Problems of population growth Resources used faster than they can be replenished or wastes overwhelm water sources -vegetation, land, and water are the most affected 3. Fuelwood shortage – wood gathered from fallen limbs to burn as fuel - when population rises trees are cut down for fuel Fuel allows people to boil water and cook No fuel leads to malnutrition and disease

Problems of population growth Unsafe water – in cities where there is no infrastructure local water source may be used for drinking, washing, bathing and sewage disposal Water becomes breeding ground for organisms that cause diseases like cholera, typhoid, and dysentery

Problems cont. Impacts on land – different uses for land are in competition with each other (agriculture, housing, natural habitats) Arable land – used for growing crops Urbanization – movement of people from rural areas to cities for work Suburban sprawl – leads to traffic jams, inadequate infrastructure, and reduction of land for farms and wildlife

Demographic diversity in the world Countries can be developed or developing, more developed or less developed Least developed countries are identified by United Nations and are given priority for foreign aid and development programs

Demographic diversity in the world Less developed countries suffer more from rapid population growth because they are less likely to have the family planning methods to support the population Educating women worldwide has lowered birthrates because they may learn family planning techniques

Managing Development and population growth Government focus is on reducing birth rates Public advertising Family planning programs Economic incentives Tax breaks Legal punishments China’s one child policy(70’s) Now-2 children

Growth is slowing Population is now 7 billion and increasing Fertility rates are declining in both developed and less developed regions Most countries predicted to have “replacement level” fertility rates by 2050 UN predicts world population to grow to 8.5 billion by 2030, driven by growth in developing countries