Age-Structure Population grouped by age/gender High growth rate - more young than old Slow or no growth - even distribution of ages
Survivorship Percentage of newborns expected to survive to a given age. Demographers study people born in same time period and record when each member dies.
Survivorship Type I survivorship - Developed countries Type II – Emerging countries. Type III - Developing countries
Survivorship What do the different lines show about the relationship between survival and age? Type I Type II Type III
Fertility Rate No. of live births per 1,000 women Demographers also use total fertility rates - average number of births per woman Replacement level - average no. of offspring necessary for each parent to “ replace ” their number in population 2.1
Migration Movement of individuals from one location to another Population increases in developed countries – due to immigration
Life Expectancy Average length of time an individual is expected to live Affected by infant mortality death rate of infants < 1 year old determined by parents ’ access to education, food, and clean water
Talk to your partner Explain the 5 ways demographers study populations to predict future trends. Be prepared to answer!
Demographic Transition Change from high birth/death rates to low birth/death rates Theory: industrial development affects population growth rates
Stages of the Transition First stage: pre-industrial society: birth rate and death rate are similar Second stage: population explosion: Death rates decline; birth rates stay high
Stages of the Transition Third stage: birth rate decreases Population size stabilizes Population is much larger than before Fourth stage: birth rate drops below replacement level Population decreases Takes 1-3 generations for demographic transition to occur
Women and Fertility Decline in birth rates - due to increase in women ’ s: education economic independence Lower death rate in second stage - due to increased education
Changing Population Trends Global environmental issues caused by countries with large populations Strain community resources Firewood Clean water Land
Shortage of Fuelwood Main fuel source in many countries Deadwood is used when populations are stable
Shortage of Fuelwood With growing populations, living trees are used reduces amount of wood available the next year.
Water Used by developing countries for drinking, washing, sewage disposal Supply becomes tainted parasites, disease Treatment systems cannot be developed quickly enough to match explosive growth
Land Growing populations have a shortage of arable land. Natural ecosystems destroyed for land housing, agriculture
Urban Sprawl Urbanization - increase in density of people living in urban areas. Leads to gridlock, development, loss of natural habitats.
Urban Sprawl Housing within cities becomes more dense, supply decreases Demand increases; what happens to cost?
International community is focusing on least developed countries Lowest incomes and resources Most eligible for foreign aid and development programs to help reduce population and related environmental problems Demographic Diversity
Some countries may never become developed, due to population growth rates. China, Thailand, and India have incentives to reduce fertility rates. Development and Population Growth
1994 - United Nations held International Conference on Population and Development (ICPD) in Cairo, Egypt Discussed relationships between population, development, and environment Many countries want to stabilize population growth by developing infrastructure improvement women ’ s status Development and Population Growth
ICPD Goals for 2015 Provide access to family-planning methods Reduce infant mortality below 35 deaths per 1000 births Increase life expectancy to 75 years Provide access to primary education to all Provide access to secondary+ education to females
ICPD goals are impacting worldwide fertility rates Development and Population
Slowing Growth Demographers prediction: trend will continue worldwide population growth will be slower this century than last century. If trends continue, world population growth will stabilize by 2050 World population will be 9 billion