Components of Population Change

2.3

Recap

• Learning targets 2.1 and 2.2• Which measure of density is the best

indicator as to whether a country will have enough food to feed their people?– physiological

• Which measure of density would be the best indicator of a country’s level of development?– agricultural

Recap

• Computer lab activity– Population and migration

Terms/Concepts

• Natural Increase Rate (NIR)• Crude Birth Rate (CBR)• Crude Death Rate (CDR)

Population

• Why is it important to study?– 2 questions WHERE and WHY– 7 billion people alive, more than any

other time in history– Population increasing at faster rate than

ever in history– All global population growth is

concentrated in LDCs (more MDCs at 0 percent growth)

Population

• Demographics– Study of characteristics of the

population– Census statistics– Could be used in marketing, political

research and campaigning

Why does population growth vary among countries?

• What factors influence population growth – pair share– Amount of food– Birth / death rates– Life expectancy– Culture contraceptives – Others

Components of Population Change

• Depending upon births and deaths; populations can increase, decrease or stay constant

• 3 Indicators / Measures of Change– NIR– CBR– CDR

Natural Increase Rate

• Natural Increase Rate (NIR)– Percentage by which a population grows

in a year– Only uses birth and death rates–Migration excluded

(immigration/emigration)• Map: LDC vs. MDC– LDC = less developed country

(developing)– MDC = more developed country

• More then 97 percent of the natural increase is clustered in developing countries

Doubling Time

• Doubling time– Number of years needed to double a

population, assuming a constant rate of natural increase

– At a rate of 1.2% per year, world pop. would double in about 54 years

–With current rate global pop. = 24 billion by 2100

Crude Birth Rate

• Crude Birth Rate (CBR)– the total number of live births in a year

for every 1,000 people alive in society – Ex. A CBR of 20 means that for every

1,000 people in a country, 20 babies are born over a 1-year period

Crude Death Rate (CDR)

• Crude Death Rate- the total number of deaths in a year for every 1,000 people alive in the society

• NIR = CBR – CDR– Ex. 20 – 5 = 15 (1.5%)

CBR

CDR

Terms/Concepts

• Natural Increase Rate (NIR)• Crude Birth Rate (CBR)• Crude Death Rate (CDR)