Studying Human Population Forecasting Human Population –Age Structure- distribution of ages of individuals in a population Young populations tend to increase. Evenly distributed populations are typically stable
Studying Human Population Survivorship- the % of individuals in a population that will survive at a given age.
Studying Human Population Fertility rate- the # of babies born per 1000 women each year. –Total fertility rate- average # of children per women in her lifetime. –Replacement level- average # of children that parents must have to replace themselves (a little above 2 in the US)
Migration- movement of individuals into and out of an area –Immigration- movement INTO –Emigration- movement OUT of (EXIT)
Studying Human Population Declining death rates- –Declining death rates are the main reason for the human population explosion Today people have access to adequate food, clean water, and safe sewage disposal –Life expectancy- average # of years a person is likely to live. Affected mainly by infant mortality rates Education, food, fuel, and clean water are keys New threats to life expectancy include disease such as AIDS
Studying Human Populations In 1900 the average life expectancy was around 40. By 2000 it has increased to more that 67 worldwide.
Studying Human Population The Demographic Transition- a model that describes how population growth changes my occur.
Changing Population Trends Problems with population growth –A rapidly growing population can overwhelm natural resources and infrastructure. Infrastructure- basic facilities and services that support a community. –Schools, roads, clean drinking water, sewage, garbage collection, police and fire protection, hospitals, etc. Standards of living decrease when resources become overwhelmed.
Changing Population Trends Problems with population growth –A shortage of fuelwood –Unsafe drinking water Dysentery, typhoid, cholera –Impacts on land. Arable land- land used to grow crops. Urbanization- development of cities Suburban sprawl- development of suburban areas around cities.
Changes in Population Trends Managing development and population growth –Some counties have tried to manage population growth with advertising, family planning programs, economic incentives, or legal punishments China, Thailand, India –In 1994, the United Nations’ conference on population set goals for managing population growth mainly through economic development and raising the status of women world wide.
Growth is slowing –World population = 6 billion people Grew by 87 million per year between 1985-1990 Grew by 81 million per year between 190-1995 Fertility rates have decreased since 1970 world wide It is predicted that by 2050 most countries will be at their replacement fertility rate. This would start to level off human population growth.