Human Population (Leaving Cert Biology): Revision Notes

Human Population

Factors Affecting Human Population Growth

1. Famine reduces population numbers.
2. Disease reduces population numbers.
3. War reduces population numbers, but the effect may be temporary. Birth rates often increase after a war, leading to a "baby boom" as societies recover.
4. Contraception reduces population growth by preventing fertilisation and, therefore, pregnancy.

Reasons for Increasing Population Numbers

1. Vaccination
2. Improved surgical methods
3. Improved sanitation: Better hygiene and waste management reduce the spread of diseases.
4. Drugs such as antibiotics
5. Insecticides: Chemicals applied to crops that kill harmful insects, leading to higher crop yields.