ABSTRACT
The history of the human species is a history of migration. From small centres in Eastern Africa, humans have migrated to all known places on the planet. Foods and pathogens have moved with people to create a global ecosystem, tied together by human activities. Massive migrations have affected all known land masses and all indigenous peoples, who were themselves prior migrants to sometimes empty lands. In all of these past cases, environmental conditions undoubtedly caused the migration streams, and were subsequently greatly altered by those streams.
