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Humanity originated in Africa and subsequently migrated to Asia and Europe. Estimates suggest that the human population hovered around 2 million in 10,000 BC and gradually grew, reaching 5 million by 8,000 BC. However, this growth wasn't linear; various factors led to periods of decline caused by famine, disease, and conflict. It wasn’t until the advent of agriculture and animal husbandry that population numbers began to increase significantly. Humans transitioned from hunter-gatherers to agriculturalists, facilitating the growth of population centers around the globe.