During your study of the prehistoric world, you examined how the earliest humans evolved from nomadic clans into settled builders of ancient cities. The development of agriculture led to the emergence of permanent settlements, and had a huge impact on the health, activities, and needs of early humans. In the Paleolithic Era, people hunted, gathered, and migrated based on the availability of food. The agricultural revolution of the Neolithic Era eliminated Paleolithic humans' need to move from place to place in order to survive. In fact, Neolithic people learned to cultivate the land, domesticate animals, and invent new technologies that enabled them to overcome limits set by the environment. This encouraged a rise in population and the development of more complex religious and governmental traditions.
The new settled way of life for early humans still had problems, however. For example, natural disasters like droughts and floods could destroy settlements. In addition, diseases easily spread among people who lived in close proximity to one another. Despite these problems, the ancient settlements constitute the foundations of a much more complex way of life, the world's first civilizations.