O—S The blue graph shows the apparent percentage not the absolute number of marine animal genera becoming extinct during any given time interval. It does not represent all marine species, just those that are readily fossilized. The labels of the traditional "Big Five" extinction events and the more recently recognised End-Capitanian extinction event are clickable hyperlinks; see Extinction event for more details. Non-avian dinosaurs, for example, are known from the Maastrichtian of North America, Europe, Asia, Africa, South America, and Antarctica,  but are unknown from the Cenozoic anywhere in the world.
How Did Dinosaurs Become Extinct? Want to know more information about dinosaur extinction? We ask "How did dinosaurs become extinct?
Based on different research we outline some theories about why they became extinct. Share them with your kids and see which they think really happened.
Sponsored Links Dinosaurs became extinct about 65 million years ago at the Dinosaurs extinction of the cretaceous period see what cretaceous dinosaurs were around at this time. Having existed for million years, why did dinosaurs die out?
There are many different theories about why this happened. We will probably never know exactly what happened, which means that scientists will continue to disagree and come up with different dinosaur extinction theories.
Here are some of them: Asteroid Impact A massive asteroid hit the earth at Chicxulub on the Yucatan Peninsula in Mexico about 65 million years. The meteor crater is km from rim to rim and scientists Dinosaurs extinction worked out that the asteroid must have been 10 km across. It is thought that the impact would have caused massive damage, including a giant dust cloud which lead to massive changes in the climate.
This would have destroyed lots of the cretaceous plantsso herbivorous dinosaurs starved and the meat eating ones were left with nothing to eat either.
Ice Age Theory Now and again, the earth cools into periods we call ice ages. As dinosaurs were thought to be cold blooded, it would have been hard for them to cope with such cold conditions.
For example, if large parts of the planet were covered in ice, then there would have been little or no plants for herbivorous dinos to eat. However, there is no real evidence of an ice age at this time.
Volcano Theory There was massive volcanic activity between 63 and 67 million years ago, particularly on the Deccan Plateau in western India. This, again, would have caused a massive change in climate, which dinosaurs would have found hard to adapt to. Disease It is possible that a disease spread through the dinosaur population causing their extinction.
Competition from Other Animals Fossils of small mammals have been found from 65 million years ago. It is possible that these small cretaceous animals started to compete with dinosaurs, for example stealing and eating dinosaur eggs.
However, no-one is sure whether mammals caused dinosaur extinction, or they thrived because dinosaurs were no longer around. Gradual Extinction The number of dinos declined throughout the cretaceous period. Maybe a number of factors contributed to their eventual extinction and they just died out.
Dinosaur extinction is a big mystery, as although dinosaurs died out at this time, many species survived, including similar animal types like crocodiles. New Discoveries Scientist have come up with some strange ideas but none of the theories really explains everything, so we will probably never be sure what happened.
To help you keep up with the news and discoveries about this, I have set up a news page on Why are Dinosaurs Extinct?
So what do you think? Have you got a theory?
Why not invent a story about how you think dinos became extinct and share it with us here at Kids-dinosaurs. You can even upload a drawing to go with it!The fifth extinction, the one that doomed the dinosaurs, occurred just as one of the largest volcanoes in history seethed in the Deccan Traps.
Did a collision with a giant asteroid or comet change the shape of life on Earth forever? It is widely agreed that such an object -- 10 kilometers across -- . Dinosaurs are a diverse group of reptiles of the clade caninariojana.com first appeared during the Triassic period, between and million years ago, although the exact origin and timing of the evolution of dinosaurs is the subject of active research.
They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction . Ranging in size from large chunks to tiny beads, impact ejecta are common at or near the Cretaceous/Tertiary (KT) boundary, the geological layer that defines the dinosaur extinction.
That has made the identity of the dinosaurs’ true killer — an impact, volcanism or both — less clear, says Paul Renne. He is a geoscientist at the Berkeley Geochronology Center in California. He is a geoscientist at the Berkeley Geochronology Center in California.
Mar 24, · Watch video · The Cretaceous-Tertiary extinction event, or the K-T event, is the name given to the die-off of the dinosaurs and other species that took place some million years ago.