Population Part 2

Overpopulation

•Overpopulation is defined as the lack of necessary resources to meet the needs of the population of a defined area

•Resources include: food, water and shelter

Carrying Capacity

•Carrying capacity is the ability of the land to sustain a certain number of people

•The more people inhabit an area, the more likely they will reach the carrying capacity of the environment

•Once the carrying capacity is reached, the problems of overpopulation become apparent

•People can begin to starve and many deaths occur due to a lack of resources

•Certain factors can alter the environment's carrying capacity, such as technological innovations that can increase food production

CBR

•Crude Birth Rates- number of births per 1,000 in a population

•Average world CBR is 21 •Also known as natality rate

CDR

•Crude death rate- number of deaths per 1,000 people in a population

•Average CDR is 9 •Also known as mortality rate

Demographic Equation

•The demographic equation is global births minus global deaths

•Determines the population growth rate for the world

•Currently the inequity between birth and death rates means the global population is growing by about 80-100 million per year

Doubling Time • The time required for a population to double in size • 2,000 years ago, the world’s population was 250

million • More than 16 centuries passed before this total

had doubled to 500 million, the estimated population in 1650

• Just 170 years later, in 1820, the population had doubled again to 1 billion

• In 1930, it reached 2 billion (doubling time is now at 100 years and the population explosion is in full swing)

Infant mortality rate

•IMR is one of the leading measures of the condition of a country’s population

•Number of infant deaths (1 and under) per 1,000 live births

•child mortality is between the ages of 1-5

•Infant and child mortality reflect the overall health of a society

•High infant mortality has a variety of causes, the physical health of the mother being a key factor

•In societies where women bear a large number of children, the women tend to be inadequately nourished, exhausted from overwork, suffering from disease, and poorly educated

•Malnutrition is one of the leading causes of infant deaths

•Poorer, developing countries have high IMR

•Sierra Leone and Afghanistan have the highest IMR: 165

•Sweden has the lowest IMR: 2.8 •United States has an IMR of 6.8

Life expectancy •The number of years on average, someone in

a given country may expect to remain alive •Does not always take into account gender

(women outlive men by 4 years) •Average life expectancy for women world

wide is 68 and for men 64 •These levels are greatly exceeded in wealthy

countries • In sub-Saharan Africa the number is below

40 in many countries

Leading causes of Death in the U.S.

•1. Heart Disease •2. Cancer •3. Stroke •4. Lung Disease •5. Accidents