Presentation on theme: "T HE H UMAN P OPULATION Ch. 9, Section 1: Studying the Human Population Standards: SEV5a, b."— Presentation transcript:
T HE H UMAN P OPULATION Ch. 9, Section 1: Studying the Human Population Standards: SEV5a, b
W HAT IS DEMOGRAPHY ? Demography- study of populations, especially human populations. Includes study of: Historical size of population Make up of population Economics Social structure Demographers use this info. to make comparisons & predictions about populations.
W HAT 2 CATEGORIES DO DEMOGRAPHERS GROUP COUNTRIES INTO ? 1. Developed Countries Have higher avg. incomes Slower pop. growth Diverse industrial economies Ex: US, western Europe
W HAT 2 CATEGORIES DO DEMOGRAPHERS GROUP COUNTRIES INTO ? 2. Developing Countries Lower avg. incomes Simple, agricultural based economies Rapid population growth Ex: India, China, countries in Africa
H OW HAS THE HUMAN POPULATION CHANGED OVER TIME ? Population grew slowly for 1000’s of years In 1800’s (Modern Age) population grew exponentially Due to increase in food supply & better hygiene thanks to industrial & scientific revolutions Human population continues to grow exponentially… will it ever reach its carrying capacity?
H OW CAN A POPULATION BE PREDICTED ? Demographers look at many properties of populations to predict: Will community need more schools? Will community need more retirement homes Will population increase to point where we need more roads & utilities?
H OW CAN A POPULATION BE PREDICTED ? Demographers use numerous tools and graphs to predict populations: Age structure graphs Survivorship curves Fertility rates Migration patterns
A GE S TRUCTURE G RAPHS Graph that shows the distribution of ages in a specific population at a certain time. A.K.A. population pyramids Parts of an age structure graph: Bars = ages Colors = gender Numbers on bottom= percentage of the population 3 Categories of Age Structure Graphs Rapid growth Slow growth Declining/zero growth
A GE S TRUCTURE G RAPHS Rapid growth Young people dominate population Has population momentum - more children will move up to become reproductive Rapid increase in birth rates once the youngsters reach reproductive age. EX: Developing countries- many countries in Africa, Mexico, S. America
A GE S TRUCTURE G RAPHS Slow Growth Birth rates = death rates All age groups are about equal EX: Most Western European countries, U.S.
A GE S TRUCTURE G RAPHS Declining Growth (Zero growth) Birth rates are lower than death rates Many more older people who are not reproducing Fewer younger people Population will become much smaller when they die. Ex: Germany, Russia
S URVIVORSHIP C URVES Percentage of members of a group that are likely to survive to any given age. Follows a group of organisms from the time they were born to the time they die to see trends. 3 Types of Survivorship curves: Type I Type II Type III
S URVIVORSHIP C URVES Type I Lots of offspring survive and live to old age. Ex: Developed countries- US, Japan Ex: Zebras, Bears, etc. Type II Populations have a similar death rate at all ages Ex: birds Type III Lots of offspring die young & very few survive to old age. Ex: Developing countries- Africa, Asia Ex: insects, clams
F ERTILITY R ATES Fertility rate- number of babies born each year per 1,000 women in a population. Total fertility rate- avg. number of children a woman gives birth to in her lifetime. Replacement level fertility- avg number of children each parent must have in order to “replace” themselves in the population. RLF = approximately 2 children Compare Zambia to Europe using the chart to the right. What conclusions can you draw based on this data? Highest (Zambia) Lowest (W. Europe) Lowest (E. Europe) Total Fertility Rate 188.8.131.52 GNP/capita/ year $225$19,000$3108 Life expectancy 47.6 yrs77.6 yrs68.9 yrs Birth Rate per 1000 184.108.40.206 Death Rate per 1000 17.610.013.0 Infant Mortality Rate per 1000 120722 Annual Growth Rate 2.9%0.1%-0.4%
F ERTILITY R ATES Keeping total fertility rate below replacement level fertility will help populations decline. This graph shows US population change since 1920. Who are the baby boomers? Lots of babies were born post WWII…when soldiers returned home from war ;) Why did population start rising in the 1990’s? Children of baby boomers were growing up & having kids
M IGRATION P ATTERNS Immigration- movement into an area Emigration- movement out of an area US experiences lots of immigration… would our population decline if we didn’t have immigration?
W HAT FACTORS AFFECT A COUNTRY ’ S DEATH RATE ? Life expectancy- avg. number of years members of a population are likely to live. Most affected by infant mortality- death rate of infants less than a year old. Infant mortality (death rates) have decreased and life expectancy has increased due to access to adequate food clean water safe sewage disposal vaccines (around beginning of 20 th century) access to education Worldwide Infant mortality rates
W HAT FACTORS AFFECT A COUNTRY ’ S DEATH RATE ? Threats to life expectancy : As populations increase, population becomes denser Disease can spread quickly thru dense populations. Ex: AIDS, tuberculosis This will increase death rate and decrease life expectancy. Sign located in South African village.
W HAT FACTORS AFFECT A COUNTRY ’ S BIRTH RATE ? Birth rates typically are lower in areas where: Women are educated Academically Family planning techniques Women are economically independent Have jobs So less time for raising many children. Pensions are available for elderly no need for kids to help take care of elderly
W HAT FACTORS AFFECT A COUNTRY ’ S BIRTH RATE ? Large families are common when children are needed to work and take care of older family members As countries modernize, there is less need for lots of kids. This can decrease birth rates.
W HAT FACTORS AFFECT A COUNTRY ’ S BIRTH RATE ? Factors that can increase a population’s birth rate: Lack of birth control due to availability or religion Need to have children b/c have poor health care and children can die easily Women are uneducated, repressed, with no rights to make decisions about their own bodies.
W HAT IS THE DEMOGRAPHIC TRANSITION ? Pattern of falling death rates & birth rates due to improved living conditions. All countries should experience this trend in population change.
W HAT ARE THE STAGES OF DEMOGRAPHIC TRANSITION ? Preindustrial societies- Higher birth rates- due to need for kids to help on farm; have lots of kids because many will die from disease/malnutrition. Higher death rates- due to food shortages, malnutrition, lack of sanitation & medicine, accidents, other hazards Population is low because of high death & birth rates.
W HAT ARE THE STAGES OF DEMOGRAPHIC TRANSITION ? Industrialization - Decreasing death rates- due to improved health care and sanitation. Continuing high birth rates- people still having lots of kids because healthcare is not widespread and may be ignorant about birth control People have better jobs, more income, more people surviving due to rise in standard of living. Population grows exponentially.
W HAT ARE THE STAGES OF DEMOGRAPHIC TRANSITION ? Mature Industrial Death rates continue declining Birth rates begin declining Women realize they don’t need as many kids Women realize how expensive kids are Women may have jobs so less time for kids
W HAT ARE THE STAGES OF DEMOGRAPHIC TRANSITION ? Postindustrial societies- eventually BR & DR level out & population is at equilibrium. W. Europe saw this in 19 th & 20 th century