New saplings that were trying to replenish the supply were eaten by goats. Also, there were more people to feed because agriculture allowed mothers to have more babies. These additional humans meant that field size had to expand to meet the demand. These field were eventually drained of nutrients from the soil. In order for these civilizations to survive they had to move, adapt, or die. Humans changed the environment by domesticating sheep, goats, pigs, and wolves.
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