Population Models Describe the nature and discuss the implications of exponential human population growth Calculate and explain from given data the values of crude birth rate, crude death rate, fertility, doubling time, and natural increase rate analyse age sex pyramids showing demographic transition models discuss the use of models in predicting the growth of human populations Population Clock

Population changes Changes in population size occur through births, deaths, immigration and emigration. The factors affecting global human population are very simple: They are birthrate, mortality, initial population, and time.

Population Terms Crude death rate, CDR: The number of deaths per 1000 people. Crude death rate, CDR: The number of deaths per 1000 people. Crude birth rate, CBR: The number of births per 1000 people. Crude birth rate, CBR: The number of births per 1000 people. Natural rate of increase = Percent rate of increase Natural rate of increase = Percent rate of increase

Rate of natural increase calculations How rapidly a population grows depends upon the difference between the crude birth rate (CBR) and the crude death rate (CDR). Natural Rate of increase, NIR is a percentage. NIR = CBR - CDR 10

Calculate the NIR for the following countries: countryCrude birth rate (CBR) Crude Death Rate (CDR) Natural Rate of Increase, NIR (%) Uganda4713 Pakistan307 Chile156 China127

Natural rate of increase, % countryCrude birth rate (CBR) Crude Death Rate (CDR) Natural Rate of Increase, NIR (%) Uganda % Pakistan % Chile % China1270.5%

Doubling time One of the simplest approaches to making population projections is to calculate doubling time. One of the simplest approaches to making population projections is to calculate doubling time. The doubling time is the length of time required for a population to double in size. The doubling time is the length of time required for a population to double in size. Rule of 72 = 72/NIR = Doubling time Rule of 72 = 72/NIR = Doubling time

Calculate the Doubling time for each of the following countries countryNatural Rate of increase, NIR % Doubling Time / Years Uganda3.4 % Pakistan2.3% Chile0.9% China0.5%

Doubling time: The time it takes the population to double its size countryNatural Rate of increase, NIR % Doubling Time / Years Uganda3.4 %21 Pakistan2.3%33 Chile0.9%80 China0.5%144

Calculate the NIR and doubling time for the world The crude birth rate, CBR, is 20 births per 1000 population The crude birth rate, CBR, is 20 births per 1000 population The crude death rate, CDR, is 8 deaths per 1000 population The crude death rate, CDR, is 8 deaths per 1000 population Calculate NIR and doubling time for the human population! Calculate NIR and doubling time for the human population!

Based on the previous data % increase 1.2 % increase Doubling time = 60 years Doubling time = 60 years So, if the NIR does not change, the world population will double from 7 billion to 14 million by 2072! So, if the NIR does not change, the world population will double from 7 billion to 14 million by 2072!

Population Changes Birthrate Mortality Initial population Time. Can be Changed Cannot be Changed Affected by…

Fertility ulation/animations/fecondity/

Total Fertility Rate, TFR The average number of children that a woman will have in her lifetime. The average number of children that a woman will have in her lifetime. Uganda: 6.5 children per woman Zimbawe: 3.8 children per woman Chile: 1.9 China: 1.5 Japan: 1.4 World average: values from Population Reference Bureeau

data/worldpop/table_population.php

Replacement-level Fertility Replacement -level fertility is the number of children that a couple must have to replace themselves. Replacement -level fertility is the number of children that a couple must have to replace themselves. 2.1 in MECD’s 2.5 in some LEDC’s

Useful indicators of the health of a country Life expectancy: The average number of years that a newborn infant can expect to live. Infant mortality rate, IMR: The number of babies out of 1000 born that die before their first birthday. High infant mortality rate usually indicates malnutrition, disease from contaminated drinking water, poor prenatal care, few doctors at births.

Life Expectancy g_about_population/animations/ life_expectancy/

Infant Mortality Rate, IMR The number of children who die before their first birthday per 1000 live births. The number of children who die before their first birthday per 1000 live births. Uganda: 76 Uganda: 76 USA: 6.4 USA: 6.4 Chile: 8.3 Chile: 8.3 China: 21.0 China: 21.0 Japan: 2.1 Japan: 2.1

Average Life expectancy The average number of years a person is expected to live. The average number of years a person is expected to live. Afghanistan: 43 years Afghanistan: 43 years China: 74 years China: 74 years Chile: 79 years Chile: 79 years USA: 78 years USA: 78 years Japan: 82 years Japan: 82 years

Mortality In MEDC’s, the death rate has dropped, more or less continuously, since the start of the industrial revolution. In LEDC’s CDR have also decreased, but at rates lower than in MEDC’s.

More about Mortality The downward trend of the death rate is common to most countries. The downward trend of the death rate is common to most countries. Personal hygiene Improved methods of sanitation Modern medicine AntibioticsVaccinations Improved Food Supply