ABSTRACT
Everyone has seen popular articles that lament the scourge of invasive species. A recent issue of Newsweek carried a typical story entitled, ‘Attack of the Aliens: Migrating species may be the biggest threat to plant and animal life on the planet’. 1 Since any species may migrate and because more and more plants and animals are travelling in the wake of human activity, one may wonder if the biggest threat to plant and animal life on the planet is plant and animal life on the planet. What does all this planetary mixing mean for us?
