Degradation of flora and fauna habitats

Prior to about 40,000 BC humans were probably confined to the 'great world island' of Africa and Eurasia, together with Australia and parts of the Indonesian archipelago. Migration into the Americas began about that time, across a land link on the site of the present Bering Strait. The crossing of wider ocean passages to remote islands took place last of all. Over the centuries, the impact of man on terrestrial biota—the natural living resources of the continents—changed not only as a result of this progressive spread, but also as man's tools and technologies advanced and his needs escalated.