The change from a hunter-gatherer way of life to an agricultural way of life. About 10,000 years ago, sea-levels rose. In some places, rising sea levels forced people closer together, so close that they could no longer support themselves by hunting and gathering. Some people dispersed; probably some perished; in one place, along the Persian gulf, rising sea levels crowded people into a place that was especially hospitable to an agricultural way of life. So, along the Tigres and Euphrates Rivers, agriculture and cities began to be developed.
A very tiny little book by Colin Tudge, Neanderthals, Bandits & Farmers: How Agriculture Really Began, summarrizes how agriculture began.
In other places, rising populations of people and declining populations of edible wild animals, forced people to rely more and more upon domestic plants and animals--agriculture.
Obviously, there were many changes that occurred in human society in the course of 5500 years. However, since you start the time period in question 10,000 years ago, I will say that the most important transformation was the movement towards living in civilizations that depended upon agriculture.
It was around 10,000 years ago that we have the first evidence of people having domesticated crops. This meant that they could settle down and live in one place instead of wandering around as hunters and gatherers. In the milennia following the development of agriculture, it spread to many places (and was independently invented in others). This allowed civilizations to spring up around the globe.
The most important transformation that took place between 10,000 and 4,500 years ago in human society was that human beings gave up a life of hunting and gathering food and settled down to an agricultural mode of farming to grow crops.
The most important reason why Man gave up his hunting and gathering lifestyle to become an agriculturalist was security. Man realized that hunting for food and gathering whatever food was available was not only a risky and dangerous proposition but it was also a very uncertain one. It soon became obvious to him that farming and agricultural operations were a much more efficient means of easily feeding and supporting larger populations than the earlier hunting and gathering modes.
So, he decided to grow crops and rear animals for food. Later on dense populations which depended on farming became more and more complex which finally led to the birth of modern civilization.