The stone age is generally divided into three different eras, the Paleolithic, Mesolithic, and Neolithic. Mesolithic literally means middle stone and is the bridging era between the Paleolithic and Neolithic. The Mesolithic era is generally dated from 10,000 BCE to 5,000 BCE although the years change depending on what part of the world you are talking about. The early stone age is characterized by hunter-gatherers and nomadic living. It is also the earliest useage of stone tools by early humans. The late stone age is characterized by the emergence of agriculture, larger permanent settlements and polished tools. The Mesolithic era marks the change in both lifestyles and tools. Small settlements began to form that were the beginnings of domestication. More advanced chipped stone tools called microliths emerged for use in weapons and tools.