Human population

1. Human population In 1650, human pop. only 500 million In 2003, human pop, more than 6 billion Increases 90 million every year By 2050, could be 10 billion How does this impact Earth? History Thomas More, Utopia, 1500�s Said ideal state is constant population, controlled crops, distribute food in public markets and dining halls Thomas Malthus, 1798, Said populations grow quicker than food supply This leads to war, famine, human suffering To avoid this, Malthus suggested late marriages, and small families

2. Increases in Growth Rate Beginning humans were hunter-gatherers, living in small tribes, population not known Starvation, predation, and disease kept humans from living much older than 35 10,000-20,000 yrs ago, people began to settle These people stored food This reduced threat of starvation, and increased population size Agriculture-10,000 yrs ago began Agricultural revolution began-shift from harvesting wild food sources to producing food through techniques of farming and herding More food supply led to population growth Standard of living rose

3. Mortality (death) rate decreased Life expectancy increased Population about 5-10 million Industry-300 years ago began Industrial revolution began Technology advancements led to: Improved food production & distribution Work day shortened Safer work environments Improved health care and medicine Health Care 1800�s, germ theory occurred- identified bacteria and other microorganisms as the agents responsible for many diseases Before, people did not relate health and hygiene as being connected

4. Germ theory improved sterilizing, waste disposal, water treatment Also vaccines and antibiotics developed These increased birth rates, decrease death rate Declines in Growth Rate Plagues-decrease populations by large percentages Bubonic plague killed 25% of Central Europe and Asia Famine-lack of food for long time Irish Potato Famine of 1840�s killed 1 million War-many lives killed in short time 1/3 of Germany and Bohemia killed during Thirty Year�s War WWI killed 21.5 million, WWII, killed 35-60 million

5. Review Questions What was the estimated human population in 1650? What is the estimated human population today? What did Thomas More say humans should do to control the population? What did Thomas Malthus say humans should do to control the population? What kept the beginning humans from growing the population? How did the agricultural revolution change human population & standard of living? How did the agricultural revolution change mortality rates & life expectancy? How did the industrial revolution change the working environment and healthcare? What is the germ theory? How did it change healthcare? What types of things have decreased the human population?

6. Growth & Changing Needs Overpopulation is one of the most serious problems Measuring population growth is helpful to predict changes in the future Growth rate is calculated by: Birth rate (#births per 1,000 people) � Death rate (#deaths per 1,000 people) Ex: Egypt has birth rate 29/1,000 and a death rate 8/1000 29-8=21 people for every 1,000 or 2.1% Doubling time-how long it takes for a particular population to double its size Mexico City doubled in 10 yrs Honduras, Kenya, Syria, Iran, Guatemala doubled in less than 30 yrs

7. Doubling time indicates potential problems for a population Short doubling time means needing to double housing, food supplies, jobs, water, energy very quickly Immigration/Emigration also effects growth rate Immigration-movement of people into an area Emigration-movement of people out of an area But these do not effect overall earth�s population We can�t leave the planet, and we don�t count aliens!!

8. Demography Science of the changing vital statistics in a human population Demographics include: age, race, education level, income, # of children, gender Demographics help scientists, planners, and politicians make plans for populations Changing Needs Population size isn�t the only thing that determines the needs of people Changes in technology, lifestyles, standards of living affect needs Energy consumption increases in industrial areas b/c of machinery, not population size

9. Review Questions How do you calculate the growth rate of a population? Williston has a yearly birth rate of 15 births for every 1,000 people. We have a yearly death rate of 9 deaths for every 1,000 people. What is our growth rate? What is doubling time? What is the difference between immigration and emigration? What is demography? What are two examples of demographics studied? What things besides population size effects the changing needs of a people?

10. Challenges of Overpopulation Rapid growth affects the global ecosystem It places greater demand on available land space It strains resources: minerals, fuels, and food Human growth takes away land available for other wildlife Will humans give up land for wildlife? Humans must realize that all life on Earth is connected Problems with overpopulation One country�s overpopulation affects other countries They have to rely on other countries for energy and resources Pollution can travel from one country to another

11. Health problems are linked to overpopulation Crowding exposes more people to more sick people Malnutrition, poor hygiene, lack of medical facilities are greater problems in crowded areas Environmental effects are caused by overpopulation Exhaust fumes from millions of cars causes pollution Clearing large tracts of land destroys homes and breeding grounds of wildlife Controlling Population Size Obvious answer is to control birth rate This is difficult b/c many people do not have education and tools needed to control birth Even more difficult to convince them it is ethical and best to limit family size

12. Difficulties to control population Religion: many consider preventing pregnancy unacceptable Work: many families need large numbers to work on farms or care for aging parents Self-satisfaction: many people want children to fulfill a feeling of pride and joy in life Challenges of low birth rate Bulgaria, Hungary, Latvia have birth rates lower than death rate Now face difficulty finding youth for military, workforce Have begun to offer financial help to couples to have more children

13. Help from Technology Many think that more people means more brain power Technology will help humans New sources of energy, new farming techniques Still, the earth can only house a limited # of people comfortably before it runs out of resources