The Neolithic Revolution
Starting around 12000-9000 BCE, our ancestors began to shift from a hunter-gatherer lifestyle to an agrarian one. This Neolithic Revolution happened sporadically across the globe over the coarse of a few thousand years. But compared to the depth of our pre-history, this was a blink of an eye. While many factors were at play, agriculture first developed in those places that were resource constrained. It's when a species is pushing the carrying capacity of it's environment that the evolutionary pressure to change becomes the strongest. Those on the outskirts, where human populations were thin and game was still plentiful, could continue their hunter gatherer lifestyles without being forced to shift. Geography also played a significant factor. For agriculture to take hold it needed a temperate climate, and local plants and animals suitable for domestication.
The earliest archeological evidence of agriculture points to the Fertile Crescent, at the intersection of Africa, Europe, and Asia. It began with the growing of cereal grasses like wheat and barley. Due to the long dry season of the Mediterranean climate, these plants had evolved large seeds that were rich in protein. Rather than spreading centrally from that point outward, agriculture arose independently elsewhere across the globe. Within Asia rice & millet were the first to be domesticated, and within the Americas we began to grow corn, squash, and beans.
Animal Domestication & Artificial Selection
Through Artificial Selection, we began selectively choosing to replant those crop strains with the greatest yields, those that were easier to harvest, and that were better tasting. In doing so we were guiding the process of evolution. Instead of letting the gradual drift of Natural Selection determine which traits were to be passed on, this intentional process of Artificial Selection relied on human intelligence. Eventually conscious selection became another one of the fundamental shaping forces of life on Earth. It's a shift as profound as the evolution of Selection Selection millions of years prior. Human's were now a powerful variable in a complex natural law, morphing species to our wills, and speeding the process of evolution.
This reshaping of nature also applied not just to plants, but also to the animals that had evolved along side of us. The first species that humans domesticated were dogs. They descended from wolves, which were pack hunters, and had already evolved to be intelligent, social animals. Throughout the Paleolithic era over 15,000 years ago, they had learned to follow our ancestors' camps, scavenging for scraps. Those less timid were rewarded. In time they became skilled in the art of begging, and were fully habituated to humans. A bond was formed between our two species. But the relationship was a symbiotic one. While dogs benefited from a more stable food source, humans were warned of predators, and aided by the dogs' keen sense of smell during hunts.
The next to be tamed and domesticated were livestock species of goats, sheep, cows and pigs. All were native to the middle east, and had the right temperament, size, and lifespan for our needs. While they provided food and milk, they also gave us materials like leather, wool, and fertilizer. We soon learned to keep the most impressive males for selective breeding, consciously choosing for desired traits. Horses and oxen were also domesticated, and used to transport goods and to plow the land, increasing our productivity. Cats came to live in close proximity to humans during this period too, as they were useful in protecting our granaries from rodents.