1.6 Human Populations 0.0 / 5 ? BiologyHuman, animal and plant behaviourA2/A-levelAQA Created by: Isabel CookeCreated on: 09-02-14 13:40 Human population size For most of history governed by food availability, disease, climate etc. Development of agriculture, and the industrial revolution allows for population explosion. Therefore the exponential phase continues rather than a stable popluation forming. 1 of 5 Human population equations Population growth = (births + immigration) - (deaths + emigration) Percentage population rate = pop. change/ pop. at the start x 100 2 of 5 Factors affecting birth rates Economic conditions - LEDCs have higher birth rates. Cultural and religious backgrounds - Some cultures and religions oppose bith control and encourage large families. Lack of access to contraception - Causes higher birth rate. Political factors - Governments influence birth rates through tax policies. 3 of 5 Factors affecting death rates Medical care - better healthcare reduces the death rate. War - causes an immediate increase in death rate. Clean drinking water and sanitation - decreases death rate. Food supply - good balanced food supply decreases birth rate. Age profile - the higher proportion of old people, the higher death rate. 4 of 5 Population pyramids 5 of 5
Comments
No comments have yet been made