Quaternary Period
Modern Singapore
The Quaternary period, which began about 1.8 million years ago (1,800,000 years ago), is still going on today - we live in the Quaternary period. So far, it's a much shorter period than the others.
At the beginning of the Quaternary period, early people in Africa were already using stone tools. The climate was mostly on the cooler side, with ice ages coming and going every forty thousand years or so. There were big ice caps at the North and South Poles, as there are today. Among the bigger mammals were saber-toothed tigers, mammoths and mastodons, small ancestors of horses, and wolves.
A million years later, about 800,000 years ago, people began using fire to cook their food. These people probably gathered berries and roots and grains, and scavenged meat left over by other animals. By about 400,000 years ago, people had divided into two or more groups - one was the Neanderthals, and another was our own ancestors, homo sapiens. By 350,000 years ago, some Neanderthals had left Africa and were living in West Asia and Europe.
By about 75,000 years ago, people may have been beginning to wear clothes. About 60,000 years ago, probably drawn by changing climate at the end of an Ice Age, some modern people left Africa and traveled along the coast of South Asia into India and then over to Australia. A little later, other people moved out of Africa into West Asia and then into Europe, Central Asia and China. These people lived alongside the Neanderthals for a while, but by about 30,000 years ago all the Neanderthals had died out, perhaps killed off by our ancestors.
About 12,000 years ago, the end of the most recent Ice Age left Earth in a time when it was warmer than usual and wetter, and everything grew really well. Many large mammals that were adapted for the cold died out, including saber-tooth tigers, mammoths, and mastodons. In North America, horses, camels, and cheetahs died out too. Other animals like cattle, goats, wolves, and dogs did fine. Some people used the land bridge that appeared at this time to cross over from Asia into North America. Probably because of the warmer, wetter climate, there was plenty of food everywhere in West Asia, and some nomadic hunter-gatherers settled down in one place and just got their food there. Soon afterwards, these people began to grow their own food - that was the beginning of farming.
Once people in West Asia were settled farmers, they could feed a lot more people, so they began to have a lot of children, and by 6000 years ago people in West Asia were living in cities. Farming and cities also developed independently in China and in South America. Since then, farming and cities have gradually spread around the world, first to India and Africa, then to Europe, then to North America, and finally to Australia. Today more than half the people in the world live in cities, and the proportion is growing every day.
To find out more about geology, check out these books from Amazon.com or from your library:
