Approximately how long ago did humans reach North America according to migration records?

Approximately how long ago did humans reach North America according to migration records?

• A. 6,000 years ago
• B. 75,000 years ago
• C. 22,000 years ago
• D. 15,000 years ago

Answer: (C)

Humans first reached North America by crossing from Asia over the Bering Land Bridge during the last Ice Age, when huge ice sheets lowered sea levels and exposed a land connection. This allowed people to move into Alaska and beyond. Based on archaeological dating and genetic evidence, the initial arrival is placed around twenty-two thousand years ago. As the ice sheets melted and climate warmed, groups spread south and east, eventually populating much of the continent. The other dates don’t fit the best-supported timing, since arrival around twenty-two thousand years ago aligns with the strongest archaeological and genetic signals, while the alternatives are either far too early, much too late, or less consistently supported.

Humans first reached North America by crossing from Asia over the Bering Land Bridge during the last Ice Age, when huge ice sheets lowered sea levels and exposed a land connection. This allowed people to move into Alaska and beyond. Based on archaeological dating and genetic evidence, the initial arrival is placed around twenty-two thousand years ago. As the ice sheets melted and climate warmed, groups spread south and east, eventually populating much of the continent. The other dates don’t fit the best-supported timing, since arrival around twenty-two thousand years ago aligns with the strongest archaeological and genetic signals, while the alternatives are either far too early, much too late, or less consistently supported.