ABSTRACT
Any significant change in conditions, whether natural or man-made, has the potential to reduce biodiversity at one or more of these levels. The geological record contains numerous examples of events that caused sudden or progressive loss of biodiversity. Examples of the former include the impact of large meteors; the extinction of the dinosaurs is commonly attributed to such an event. Examples of the latter include climate change, which among other effects has caused a succession of ‘ice ages’ during which glaciers have advanced over major portions of the Earth’s surface. However, although these events may have been catastrophic at the time, the palaeontological record also indicates that each drastic loss of biodiversity is followed by a major and, in geological terms, rapid evolution of new species. It is as if the creation of new areas available for colonization provides the impetus for renewed competition, involving rapid adaptation and a proliferation of new species.
