< Previous | Contents | Next >
♤ Have been caused due to several factors:
♤ continent drifting,
♤ climate change,
♤ tectonic activity
♤ increased volcanic activity
♤ The late Ordovician global glaciations (439 Mya).
♤ The late Cretaceous extinction assumed to be associated with an extra-terrestrial impact.
♤ Extinction in vascular plants has been more gradual compared with the loss of animals. It is believed that extinction among this group was due more to competitive displacement by more advanced plant forms, or due to a gradual climate change, than due to any sudden catastrophic event.