Extinction is a natural part of biological history. Extinction events are just events that have a higher than normal extinction rate, for example we are going through a major extinction event at the moment, however, this one is due to us.
For the dinosaurs, there appears to be a number of factors that led to their downfall. Changes in the climate and possibly an increase in volcanic activity along with other environmental factors placed increased pressure on large animals for survival. So about 65 million years ago, the dinosaurs appear to have been in decline.
Then about that time, a 10 km wide meteorite smashed into the earth near the Yucatan peninsula. This put more pressure on large animals as this event killed off large amounts of vegetation, either through fire or through clouding out the sky.
Then what took place was a cascade of extinctions of animals over about 30 kg. When the vegetation disappears, the herbivores that need it to survive begin to disappear, then the carnivores, begin to die off because they cannot get the required amount of food. So in a very short space of geological time (thousands of years), you have a mass dying event.
But this is not conclusive, there are still many things about the event that are not accounted for. The most likely hypothesis is as I pointed to here, that it wasn’t just one single thing but a combination of factors.
Beware the reports of new things that killed off the dinosaurs that come out regularly. Often it is lazy journalism to make a headline. Last week dinosaurs farted themselves into extinction… http://news.discovery.com/animals/dinosaur-farts-120507.html
Hi Shadycactus,
Extinction is a natural part of biological history. Extinction events are just events that have a higher than normal extinction rate, for example we are going through a major extinction event at the moment, however, this one is due to us.
For the dinosaurs, there appears to be a number of factors that led to their downfall. Changes in the climate and possibly an increase in volcanic activity along with other environmental factors placed increased pressure on large animals for survival. So about 65 million years ago, the dinosaurs appear to have been in decline.
Then about that time, a 10 km wide meteorite smashed into the earth near the Yucatan peninsula. This put more pressure on large animals as this event killed off large amounts of vegetation, either through fire or through clouding out the sky.
Then what took place was a cascade of extinctions of animals over about 30 kg. When the vegetation disappears, the herbivores that need it to survive begin to disappear, then the carnivores, begin to die off because they cannot get the required amount of food. So in a very short space of geological time (thousands of years), you have a mass dying event.
But this is not conclusive, there are still many things about the event that are not accounted for. The most likely hypothesis is as I pointed to here, that it wasn’t just one single thing but a combination of factors.
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Beware the reports of new things that killed off the dinosaurs that come out regularly. Often it is lazy journalism to make a headline. Last week dinosaurs farted themselves into extinction…
http://news.discovery.com/animals/dinosaur-farts-120507.html
0