Human Population

Human Population

How has human population grown?Slowly over timeScarce food and incurable diseaseDeath rate highFamilies had many childern500 years agoRapid growthWhy?Agriculture, industrial; revolution, better food supply, shipping methods improved, improved sanitation, healthcare, improved medicineLed to expanded human growth

Science Behind Human PopulationThomas MalthusEnglish EconomistHuman population cannont grow exponentiallyLimits: Famine, disease, war

DemographyScientific study of human populationStudy a variety of social and economic factors that effect human populationExamines characteristics of human population and attempts to explain how and why human population changes over time

Things that help predict different population growth ratesBirth rate Death rateAge structure

HypothesisThese countries have completed a demographic transition, a dramatic change in birth and death ratesHistorically: humans have high birth and death rates500 years ago a change began: High birth rate and LOW death rateBecause of better conditions of living

Demographic TransitionDramatic change in birth rates and death ratesLow Death rate, High Birth rateFrom 1760 to 1910Society modernizesIncrease level of educationRaise standars of livingFamilies have fewer childrenBirth rate decreasesPopulation growth slowsDemographic transition complete when:Birth rate falls to meet death rate and population growth stopsOnly complete in a few countriesIndia and China high birth rate

Age StructurePopulation depends partly on how many people of different ages make up a populationAge-structure diagramsPopulation profiles used to predict future population growthShow population of a country broken down by gender and age group

Age structure in USEqual # of people in each age groupSlow and steady growth rate for near future

Age Structure in Nigeria More young children than teenagersMore teenagers than adultsPopulation will double in 30 years

Controlling Human PopulationIndiaCompulsory sterilizationChinaFamily planning programBenefits and bonusesForced abortions

Predicting Future Population GrowthMany factorsAge structure of countriesPrevalence of life threatening diseasesBy 20509 billionGrowth will level off or decrease if countries growing rapidly go through demographic transition

Lower growth rate means population growth is slowing by it is STILL growingHow does this effect environment?Ecologists predict that if this growth does not slow even more there will be Serious damage to EnvironmentGlobal economyOther ecologists predict that science, technology, and changes in society will control those negative impacts on economy and environment