When did dinosaurs become extinct?

Answer

Dinosaurs became extinct about 65 million years ago. This extinction event occurred between the Cretaceous and Tertiary periods and wiped out about 50 percent of all other organisms then living on the planet.

Because the dinosaurs died out in a relatively short period of time, scientists surmise that some sort of global disaster had caused this massive extinction event. Some extinction theories include an increase in volcanism, a change in the climate, the movement of continents and the consumption of dinosaur eggs by evolving mammalian species.

In the 1980s, Luis Alvarez proposed one of the most probable theories for the extinction. He believed that an extraterrestrial object such as an asteroid or meteorite crashed on Earth, throwing up debris into the atmosphere. This debris effectively blocked out much of the sun's light, causing plants to die worldwide, which led to the extinction of many species unable to cope with this climate change.

Q&A Related to "When did dinosaurs become extinct?"
Dinosaurs became extinct from one or a combination of circumstances. These include a meteorite impact in Mexico, many or a super volcano, global climate change and sickness.
http://www.ask.com/web-answers/Science/Nature/how_...
The dinosaurs are thought to have been wiped out by a giant comet colliding with the Earth somewhere around the gulf of New Mexico around 65 million years ago, near the end of the
http://wiki.answers.com/Q/What+are+the+stages+of+d...
No one knows for certain exactly why and how the dinosaurs became e...
http://www.chacha.com/topic/climate-change-scienti...
Hi Doug! Thanks for your question. A meteorite impact was almost certainly involved in the dinosaurs' extinction. A huge crater, 160 miles across, was found a few years ago in the
http://en.allexperts.com/q/Paleontology-Dinosaurs-...
Explore this Topic
There is not sufficient proof as to why dinosaurs went extinct, but experts believe it is related to geological events, diseases, climate change and lack of plant ...
Brachiosaurus dinosaurs became extinct with the rest of the dinosaurs. This happened because they gradually ran out of food sources, as well as water, and things ...
The extinction of Triceratops is believed to have come from the same reason as all the other dinosaurs, but no one really knows how they became extinct. Some people ...
About -  Privacy -  Careers -  Ask Blog -  Mobile -  Help -  Feedback  -  Sitemap  © 2014 Ask.com