Communities were small during the Paleolithic Age because we didn't have time to settle down and build a community. There was usually about 20 to 60 people in a group so that we could easily move to find more food.
Since a more stable food supply was created, permanent housing was invented. Houses in the Neolithic age were often built with mud and wood or sticks put in the walls to make them stronger.
Having a permanent shelter is important to keep safe from weather and animals. It was also built for holding a larger community. It made our lives more comfortable. Due to the invention of permanent housing, communities were now growing stronger
Now that permanent housing was invented, we were now establishing large communities.
The more people that we had the safer we were from our enemies and animals that would try harming us. Now that we had more people, we could split work between each other from the new jobs we had.
During the Paleolithic Age, where ever you were staying, you had to use the resources that were around you. There was no other way to get resources that were not the immediate area.