BRAINCAKEHuman Population Explosion
For most of history the human population grew slowly, held back by famine, disease and high infant mortality. It reached about 1 billion around 1800, 2.5 billion in 1950 and passed 8 billion in 2022. A graph of population against time is J-shaped, showing exponential growth.
A population grows when the birth rate is greater than the death rate. Death rates fell sharply because of:
• improved agriculture (machinery, fertilisers, pesticides and high-yield crop varieties), giving more food;
• better sanitation and clean water;
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Key terms in this lesson
- exponential growth
- Growth in which the rate of increase is proportional to the size of the population, producing a J-shaped curve.
More in Human Influence on Ecosystems
- Climate Change
- Depletion of Biological Resources
- Loss of Biodiversity
- The Burden of Proof
- Evaluating Studies
- Greenhouse Effect
- Evidence for the Global Temperature Increase
- Analysis of Ice Cores
All 29 lessons in Human Influence on Ecosystems · All Edexcel A-level Biology topics