The Human Population

Studying Human Population Objectives Describe how the size and growth rate of the human population has changed in the last 10 years Define four properties that scientists use to predict population sizes Make predications about populations trends based on age structure Describe 4 stages of the demographic transition Explain why different countries may be at different stages of demographic transition

Why should we care if our world population is growing?

More people means more environmental problems!

The Human Population over time Since the 1800’s are population has grown exponentially. Can the Earth sustain all these people indefinitely???

Forecasting Population Size Age Structure –Distribution of ages

Survivorship –% of members of age group that are likely to survive to any given age

Fertility rates in the US Fertility Rates

Migration –Immigration and emigration

Declining Death Rates Our population has increased because death rates are actually lower –Access to food, clean water, and safe sewage disposal

Life Expectancy –Most effected by infant mortality Angola has a rate of 180/1000 live births US has a rate of 6/1000 Singapore has a rate of 2/1000 –Life expectancy has increased dramatically from about age 40 in 1900 to

Demographic Transition A model that shows how changes take place in a population States that as a country because more developed it causes social and economic changes which effect populations

Stages of Transition 1 – Preindustrial. BR up, DR up 2 – Population Explosion - pop. Grows exp., DR down, BR up, pop. 2X

3 – BR slows BR almost equal DR 4 – Pop decreases DR drops below replacement level

Women’s fertility –Increased education of women leads to a decrease in the number of children Family planning No need for large families Increased cost –Developed country's have lower rate 1.6 as apposed to developing nations at 3.1

World Population Clock

Changing Population Trends Objectives Describe the three problems caused by rapid human population growth Compare population growth problems in more- developed countries and less developed countries Analyze strategies countries may use to reduced their population Describe worldwide population projections into the next century

What problems does a rapidly growing human population create??

Problems with rapid growth Shortage of fuel wood Trees are cut down to provide fuel –Helps provide basic needs to clean water and cook food –Results in malnutrition and disease

Unsafe water Lack of infrastructure causes people to use water sources as a place to dump sewage and waste water –Causes disease such as dysentery, typhoid, and cholera

Impacts on Land Growing populations reduce amount of arable land Urbanization –People moving from rural areas to cities to find jobs Traffic jams Inadequate infrastructure Reduction of land for farms Destruction of wildlife habitat Cost of living in cities goes up

Demographically Diverse World Many counties do not progress through each stage of demographic transition –Growing fast but infrastructure, economics, and education has not caught up with growth Birth rate is still high –Lease developed countries (show few signs of development and increases death rates) are the focus of international aid

Managing Development and Population Growth Many countries have established programs to limit the number of children –Advertising –Economic incentives –Legal punishments

Growth is actually slowing but the population of 2050 is projected to be over 9 billion people!!

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