Human populations 0.0 / 5 ? BiologyHuman, animal and plant behaviourA2/A-levelAQA Created by: meganbradfield1Created on: 08-06-16 19:05 What factors affect grow and size of human populations? Birth rate, death rate, immigration, emmigration 1 of 16 What is the equation for population growth? (births + immigration) - (deaths + emmigration) 2 of 16 What is the equation for percentage pop growth rate? Population change during period divided by pop at start of the period x 100 3 of 16 What affects birth rate? Economic conditions, cultural/religious backgrounds, social pressures & conditions, birth control, political factors 4 of 16 Equation for birth rate? Number of births per year divided by total population of the same year x 100 5 of 16 Equation for death rate? Number of deaths per year divided by total population of same year x 100 6 of 16 What affects death rate? War, age, life expectancy, food supply, natural disasters 7 of 16 Characteristics of a stable population? Birth rate + death rate balanced; no increase or decrease in pop 8 of 16 Characteristics of an increasing population? High birth rate (wide base on pyramid); Few old people (narrow apex); LEDC 9 of 16 Characteristics of a decreasing population? Low birth rate (narrow base of pyramid); low mortality rate (wide apex); MEDC 10 of 16 Stage 1 of demographic transition? BR + DR high; small & stable pop 11 of 16 Stage 2 of demographic transition? BR high; DR low; early expansion 12 of 16 Stage 3 of demographic transition? BR + DR low; late expansion 13 of 16 Stage 4 of demographic transition? BR + DR low (balanced); large and stable pop. 14 of 16 How do you calculate average life expectancy? age at which 50% of individuals in a pop are still alive 15 of 16 What does a survival curve show? Number of people alive at a time 16 of 16
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