land bridge hypothesis

The land bridge hypothesis suggests that during periods of low sea levels, such as ice ages, large areas of land connecting continents emerged, allowing humans and animals to migrate between them. For example, when sea levels dropped, a land bridge called Beringia appeared between Asia and North America, enabling the first humans to migrate into the Americas. This theory helps explain how populations spread across continents before modern seas made travel more difficult. It highlights how natural changes in Earth's climate and sea levels have influenced human migration and the distribution of species.