Human’s ability to learn, communicate, make tools and control fire enabled invasions of environments not previously inhabitable to their earlier ancestors.

Nomadic wandering lifestyles of hunter-gatherers with no permanent residence placed biological and social restrictions on average family sizes.

Birth-rate low Death-rate high Small numbers...

Intentional planting of seeds had profound effect on human history as humans discovered that certain plants and animals were ideally suited for cultivation and domestication.

Larger families were now possible due to agricultural practices. These activities could support larger population densities

Not all humans needed to cultivate, leaving them to become specialized artisans, scholars and merchants

This lead to... ◦ The establishment of political organizations◦ Major advances in technology◦ Rapid growth in population...spreading across the

globe and displacing indigenous people...brought plants, animals, guns, steel & diseases with them.

Many epidemic diseases evolved where population densities were high...spread around the world as populations increased.

Example...14th Century ◦ Black Death (bubonic plague...bacteria Yersinia

pestis)

17th century... Science-based knowledge and technology became major influences in factors in European societies.

Populations became increasingly urbanized Increase in food production = less farming

needed Vaccines, medicine, sanitation!!

These changes allowed humans to avoid the natural limits to growth that had existed for years. The result was a dramatic decline in death rates and a rapidly growing human population.

YEARS ELAPSED YEARS HUMAN POPULATION

3,000,000 10,000 B.C.E. (Agricultural Revolution)

5-10 Million

10,000 1 A.D. 250 Million

1,800 1800 (Industrial Revolution)

1 Billion

130 1930 2 Billion

30 1960 3 Billion

15 1975 4 Billion

12 1987 5 Billion

12 1999 6 Billion

13 2012* 7 Billion

13 2025* 8 Billion