Chapter 9Chapter 9

The Human PopulationThe Human Population

9.1: Studying Human Populations 9.1: Studying Human Populations

Describe how the size and growth rate of Describe how the size and growth rate of the human population has changed in the the human population has changed in the last 200 yearslast 200 years

Define four properties that scientists use Define four properties that scientists use to predict population sizesto predict population sizes

Make predictions about population trends Make predictions about population trends based on age structurebased on age structure

Describe the four stages of the Describe the four stages of the demographic transitiondemographic transition

Explain why different countries may be at Explain why different countries may be at different stages of the demographic different stages of the demographic transitiontransition

2 Categories for Countries:2 Categories for Countries:

Countries are often grouped by Countries are often grouped by demographersdemographers into 2 general into 2 general categories:categories: DevelopedDeveloped countries—higher average countries—higher average

incomes, slower population growth, and incomes, slower population growth, and diverse industrial economies.diverse industrial economies.

DevelopingDeveloping countries—lower average countries—lower average incomes, simple and agriculture-based incomes, simple and agriculture-based economies, and rapid population growth.economies, and rapid population growth.

Human Population GrowthHuman Population Growth

1800’s: exponential growth due to…1800’s: exponential growth due to… Increases in food productionIncreases in food production Improvements in hygiene (eg. clean Improvements in hygiene (eg. clean

water and safe sewage disposal)water and safe sewage disposal) Industrial and scientific revolutions Industrial and scientific revolutions Discovery of vaccines in the 20Discovery of vaccines in the 20thth century century

Cannot continue…Cannot continue…limited resources, limited resources, competition, carrying capacitycompetition, carrying capacity

Predicting Population Sizes (4)Predicting Population Sizes (4)

1.1. Age structureAge structure• The distribution of ages in a specific population at a The distribution of ages in a specific population at a

certain time.certain time.• Graphed in a Graphed in a population pyramid population pyramid (lab!)(lab!)• High growth rate High growth rate more young than oldmore young than old• Slow or no growth Slow or no growth even distribution of ages even distribution of ages

2.2. SurvivorshipSurvivorship• The percentage of members of a group that are likely The percentage of members of a group that are likely

to survive to any given age.to survive to any given age.• Survivorship curves: type I (most live to be very old), Survivorship curves: type I (most live to be very old),

II (similar death rates at all ages), III (very poor, many II (similar death rates at all ages), III (very poor, many children die)children die)

Predicting Population Sizes (4)Predicting Population Sizes (4)

3.3. Fertility rates: the number of babies born Fertility rates: the number of babies born each year per 1,000 women in a each year per 1,000 women in a population.population.

• Also can calculate total fertility rateAlso can calculate total fertility rate• Considers “replacement level”: the avg. Considers “replacement level”: the avg.

number of children each parent must have in number of children each parent must have in order to “replace” themselves.order to “replace” themselves.

4.4. Migration: mvmt. of individuals btwn. Migration: mvmt. of individuals btwn. areas.areas.

• Immigration (in) vs. Emigration (out)Immigration (in) vs. Emigration (out)

Reasons for Increases in Human Reasons for Increases in Human Population Growth (or decline)…Population Growth (or decline)…

Death rates decreased more rapidly than Death rates decreased more rapidly than birth rates…causes???birth rates…causes???

Life expectancy (most affected by infant Life expectancy (most affected by infant mortality); survivorship curvemortality); survivorship curve 1900 = age 40 w/ a high infant mortality rate1900 = age 40 w/ a high infant mortality rate 2000 = >age 67 (developed = 80+) w/ infant 2000 = >age 67 (developed = 80+) w/ infant

mortality at < 1/3 of the rate in 1900 mortality at < 1/3 of the rate in 1900 Infant health is affected by…Infant health is affected by…

-parents’ access to education, food, fuel, and clean water -parents’ access to education, food, fuel, and clean water Other threats?: density Other threats?: density increases in contagious increases in contagious

diseases (e.g. AIDS, tuberculosis, Ebola)diseases (e.g. AIDS, tuberculosis, Ebola)

HW!!HW!!

Read through chapter 9 Read through chapter 9 Pg. 239: The Demographic Pg. 239: The Demographic

TransitionTransition Take notes Take notes over the “over the “stages of stages of

transitiontransition” ” andand “ “women and fertilitywomen and fertility”” Checked in Checked in and discussed/questions and discussed/questions

tomorrowtomorrow

9.2 Changing Population Trends9.2 Changing Population Trends

Describe three problems caused by Describe three problems caused by rapid human population growthrapid human population growth

Compare population growth problems Compare population growth problems in more-developed countries and less in more-developed countries and less developed countriesdeveloped countries

Analyze strategies countries may use Analyze strategies countries may use to reduce their population growthto reduce their population growth

Describe worldwide population Describe worldwide population projections into the next centuryprojections into the next century

3 Problems…cause: rapid human 3 Problems…cause: rapid human population growthpopulation growth

Primary Problem: environmental; over Primary Problem: environmental; over consumption of resources; consumption of resources; infrastructure.infrastructure. 1. vegetation…ex.: fuelwood1. vegetation…ex.: fuelwood 2. water…used for drinking, washing, 2. water…used for drinking, washing, &&

sewage disposalsewage disposal: waterborne diseases : waterborne diseases such as dysentery, typhoid, and cholera; such as dysentery, typhoid, and cholera; ex. Lima, Peru.ex. Lima, Peru.

3. land…shortage of 3. land…shortage of arable (A.V.)arable (A.V.) land land (land that is used to grow crops); (land that is used to grow crops); urbanization (A.V.)urbanization (A.V.); “suburban sprawl”.; “suburban sprawl”.

Managing Development and GrowthManaging Development and Growth

StrategiesStrategies used include: family planning used include: family planning programs, economic incentives, legal programs, economic incentives, legal punishments, public advertising, punishments, public advertising, improvements in women’s status.improvements in women’s status.

ResultResult: worldwide fertility rates are : worldwide fertility rates are droppingdropping! Demographers predict that by ! Demographers predict that by 2050, most countries will have 2050, most countries will have replacement level fertility ratesreplacement level fertility rates world world population growth will population growth will _____(?)_____(?)

World population = >7 billion and is still World population = >7 billion and is still increasing.increasing.