DinosaursDinosaurs: How they became extinct Something happened 65 million years ago, atthe end of the Cretaceous period, something so devastating that it altered thecourse of life on earth. It seems like it happened so sudden, as geologic timegoes, that almost all the dinosaurs living on earth disappeared.
So how didthese dominant creatures just die off? Was it a slow extinction, or did ithappen all of the sudden? These questions bring rise to many different beliefson how the dinosaur disappeared over 65 million years ago. Extinction itself iseasily defined: When the birth rate fails to keep up with the death rate, it iscalled extinction. But, the definition does not answer the question about thenature or causes of extinction. Paleontologists generally divide extinctionsinto two types, for that of different causes arose. The first is calledbackground extinctions, isolated extinctions of species due to a variety ofcauses.
Included is out competition, depletion of resources in a habitat,changes in climate, the development or destruction of a mountain range, riverchannel migration, the eruption of a volcano, the drying of a lake, or thedestruction of a forest, grassland, or wetland habitat. The second type ofextinction is called mass extinctions. There are four main components involved:Large numbers of species go extinct; many types of species go extinct; theeffects must be global; and the effects must occur in a geologically shortperiod of time. 1 The dinosaur could not have lived for ever.
No creatures, noplants, no tiny bacteria are forever, not even Homo sapiens. Extinction is thefate of all species. One theory on how the dinosaurs became extinct is that ofcarbon dioxide, and the ?greenhouse effect?. Volcanoes produced the proposedconditions. A massive volcanic eruption could have saturated the atmosphere withcarbon dioxide so that it caused a sharp rise in temperatures worldwide. Theexcessive carbon dioxide would have permitted solar energy to enter theatmosphere but would have blocked the radiation of most surface heat back outinto space, therefore causing the ?greenhouse effect?.
Rising temperaturescould have killed off or reduced the activity of plankton, disrupting foodchains and also messing up the plankton?s normal role in converting carbondioxide to oxygen through photosynthesis. From there it would not have been longfor all the dinosaurs to have been suffering, and then to become extinct.
