The number of people in the world grew steadily from about 6000 BC until about 1800 AD, chiefly due to slow improvements in agriculture. In earliest times, human beings lived by hunting and gathering the available food over a large area, as the Bushmen and Inuit (Eskimos) still do in a few cases. The development of settled agriculture made larger populations possible.
Stages in the development of agriculture
|Way of Life||
|Sustainable Population Density|
|1 Hunter/gatherer, e.g. Arctic lnuit (Eskimoes) Bushmen (Southern Africa).||Live by hunting available wild animals, e.g. seals, or by gathering roots and berries (Bushmen). Fully integrated with local ecosystem. No attempt to increase the resources available by management, i.e. by agriculture.||Very low. Several hundred acres required to sustain each family.|
|2 Pastoralism, e.g. Lapps in Scandinavia, Masai in Kenya.||Live by herding, and managing animals so that their numbers are greater than in the wild, e.g. Lapps herd reindeer, Masai herd cattle. Local ecosystem can be temporarily damaged by over grazing No attempt at settled agriculture — animals are constantly moved from pasture to pasture.||Higher than hunter/gatherers, but still low. Each tribe requires a large area in which to keep its animals.|
|3 Rural/agricultural, e.g. peasant farmers in India, China, Africa.||Settled communities making serious efforts to increase the resources available by managing the land. Local ecosystem permanently changed.||Larger densities possible because feeding on plants is much more energy-efficient than feeding on animals.|
|4 Urban e.g. most British communities.||Urban populations exist by feeding off surplus food produced by efficient rural communities. Become specialists in making
machinery, etc. to exchange for surplus food. Local ecosystem may be in serious danger from pollution.
|igh densities now possible, as long as surplus food is available.|
CHANGES IN BIRTH AND DEATH RATES
1. The birth rate is the number of live births per 1000 people, per year.
2 The death rate is the number of deaths per 1000 people per year.
The reason for the huge increase in human population is that the death rate has been greatly reduced so that it is now well below the worldwide birth rate.
CAUSES FOR THE DECLINE IN DEATH RATE
The death rate has fallen because of the following.
1 Agriculture has greatly improved due to use of fertilizers, irrigation, removal of forests, and use of machinery. E.g. combine harvesters, and selective breeding of crops and animals to produce more food.
2 Increased food supplies have resulted in stronger growing children, who are better able to resist infection.
3 Standards of living generally have risen due to better agriculture and improved technology, so increasing national wealth. This has led to:
(a) better standards of housing, leading to less overcrowding and so less spread of infection;
(b) water supplies free from pathogens due to chlorination and water purification;
(c) hygienic sewage treatment, which has also reduced the spread of pathogens.
4 Medical Research has resulted in the discovery of better drugs, antibiotics the use of vaccination and aseptic surgery.