over a large area. According to Lenski, the difference between horticultural and agrarian societies is the use of the plow. Increases in food supplies due to improved technology led to larger populations than in earlier communities. This meant a greater surplus, which resulted in towns that became centers of trade supporting various rulers, educators, craftspeople, merchants, and religious leaders who did not have to worry about locating nourishment. Greater degrees of social stratification appeared in agrarian societies. For example, women previously had higher social status because they shared labor more equally with men. In hunting and gathering societies, women even gathered more food than men. However, as food stores improved and women took on different roles in providing food for the family, men took an increasingly dominant role in society. As villages and towns expanded into neighboring areas, conflicts with other communities inevitably occurred. Farmers provided warriors with food in exchange for protection against invasion by enemies. A system of rulers with high social status also appeared. This nobility organized warriors to protect the society from invasion. In this way, the nobility managed to extract goods from "lesser" members of society. Industrial Between the 15th and 16th centuries, a new economic system emerged. Capitalism is marked by open competition in a free market, in which the means of production are privately owned. Europe's exploration of the Americas served as one impetus for the development of capitalism. The introduction of foreign metals, silks, and spices stimulated great commercial activity in European societies. Industrial societies rely heavily on machines powered by fuels for the production of goods. This produced further dramatic increases in efficiency. The increased efficiency of production of the industrial revolution produced an even greater surplus than before. Now the surplus was not just agricultural goods, but also manufactured goods. This larger surplus caused all of the changes discussed earlier in the domestication revolution to become even more pronounced. Once again, the population boomed. Increased productivity made more goods available to everyone. However, inequality became even greater than before. The breakup of agricultural-based societies caused many people to leave the land and seek employment in cities. This created a great surplus of labor and gave capitalists plenty of laborers who could be hired for extremely low wages. Post-industrial Post-industrial societies are societies dominated by information, services, and high technology more than the production of goods. Advanced industrial societies are now