Dinosaur Extinction Theory Of Disease
There are many theories available that try to explain how dinosaurs became extinct. One such theory that tries to explain dinosaur extinction is the Theory of Disease that was made extremely popular by Dr Robert T Bakker through his book The Dinosaur Heresies. |
Sponsored Links :
|
According to Theory of Disease, the sea level started to lower towards the end of the Cretaceous period. This lowering allowed land bridges to form, linking continents that were previously isolated from one another and the bridges also facilitated the migration of large animals. The animals that were migrating already had their own diseases and parasites but had developed some level of immunity to them. The migration caused the animals that did not have the immunity to be exposed to diseases and parasites and this ultimately led to their demise and extinction.
Proponents of the Theory of Disease to explain dinosaur extinction opine that the smaller animals were not affected because they were unable to migrate long distances, while the marine animals were affected because the waters they were living in started drying up.
Opponents of Theory of Disease find Dr Bakker's assumptions completely unacceptable because towards the end of Cretaceous period, North America and Europe were much closer to each other and the Equator. In addition, Atlantic Ocean was too narrow; while the Pacific Ocean was too wide. Also, the critics say that small animals like opossums and armadillos migrated from South America to North America across the Panama land bridge, hence Dr Bakker's explanation on small animal migration is not acceptable. Opponents also opine that a disease can wipe large portions of animal population but can not cause extinction.
More Articles :
|
Many birds are facing extinction as their natural habitats are slowly getting destroyed because of global warming. In fact, birds and plants are slowly moving to higher elevations because of rising temperatures across the world. However, as the higher reaches are also affected because of global warming, these habitats will also disappear leading to extinction of birds. 