Essay from the year 2002 in the subject Biology - Ecology, grade: 1.1 (A), Oxford University (New College), language: English, abstract: Biological invasion happens when an organism, any sort of organism, arrives somewhere beyond its previous range. Nowadays, most invasions come from human actions, deliberate or accidental. But natural invasions happen too, from minor changes of range to major invasions across continents. One reason for studying invasions...