Presentation on theme: "By: Laura And Alice Jordan. No one really knows why the dinosaurs went extinct, but a lot of scientists have theories on how it might have happened. Here."— Presentation transcript:
No one really knows why the dinosaurs went extinct, but a lot of scientists have theories on how it might have happened. Here are some or their theories…
There is proof that an asteroid over 9 miles wide struck the earth on the tip of the Yucatan Peninsula, in the Gulf of Mexico. An asteroid that big would change the atmosphere all over the world. Massive forest fires would spread through countries, severe storms all over the world, poor air quality, ocean to ocean tidal waves, and probably the worst thing ever: It would eliminate ALL sunlight for longer than 6 months. This would definitely kill 70% of all life forms. The only life that would survive would be small animals hiding out through this demolition. This theory is probably the most likely out of the others.
Some Scientists think that a Supernova is to blame for dinosaur Extinction. A Supernova is a Star that explodes and sends a shockwave of the amount of energy of radiation that the Sun creates at an estimate of about 20 billion years. A supernova destroys everything in its path and anything far enough out of the path to not be impacted by the explosion may get stomped by mass radiation. This wouldn’t destroy the earth but it would kill just about every living thing that isn't buried and/or hiding in a hole for years.
There were many different types of caterpillars when dinosaurs roamed the earth. Many where much larger than today’s. It's believed that they were just like insects and reproduced in vast amounts. There is proof that they have gone through several stages of evolution during the cretaceous period. Scientists pose that its very possible that caterpillars could have exhausted the plant life creating a high demand for food to all of the herbivores that habited the world back then. The conclusion is that the herbivores became extinct and the carnivores were soon to follow. Most people don't believe that this really happened, though.
251 to 65.5 years ago the dinosaurs roamed the earth. The dinosaur age (also known as the Mesozoic Era) is split into three periods, the Triassic, the Jurassic, and the Cretaceous period.
The Triassic life is the time period of 250 to 203 million years ago. It is the first time area of which dinosaur fossils are dated to and the beginning of dinosaur evolution ladder for dinosaurs. Before the Triassic Era there was large reptiles, but none of them where considered a dinosaur. There was much changed with the worlds atmosphere and life forms. This is also the Era where mammals started to appear in the oceans as well. The dinosaurs of the Triassic era where much more smaller than in the later periods.
The Jurassic life is the time period of 203 to 135 million years ago. Evolution has begun to develop excessively. Not only for dinosaurs either. Flying creatures called Pterosaurs started to soar in the air. The dinosaurs of the Jurassic era were very large but there were a share of smaller ones as well.
The Cretaceous life is the time period of 135 to 65 million years ago. This was the last of the dinosaur evolution chain. For reasons unknown all dinosaurs became extinct at the end of this Era. There is a lot more Dinosaur Species in the Cretaceous Era than the other two dinosaur times. The fossil discoveries typically are in much better quality than the other two prehistoric time lines and due to evolution there was many more species. The most famous dinosaurs known are of the Cretaceous era like the massive Tyrannosaurus and the fearsome Velociraptor.