Dinosaur Theory

What really
killed the dinosaurs?

Contents

Page 1: The age of the dinosaurs
Page 2: The theory of an asteroid collision
Page 3: The theory of volcanic activity
Page 4: The theory of low and high oxygen levels
Page 5: The theory of global winter
Page 6: The Theory of Disease
Page 7: for and against
Page 8: Evaluation  
Page 9: Conclusion
Page 10: Bibliography

                        The Age of Dinosaurs

About 230 million years ago, a group of animals called dinosaurs ruled the earth. They lived in many different habitats, from open plains to forests to the edges of swamps, lakes, and oceans.
Dinosaurs were reptiles and most of them hatched from eggs.
Some dinosaurs were as tall as a five-storey building, and there were others no bigger than a chicken. In between the largest and the smallest, there were dinosaurs of all shapes and sizes. The dinosaurs had tough skin covered in scales. Some were armor-plated and covered with spikes. The name 'dinosaur' means 'most fearsome lizard'. However, dinosaurs were not lizards, though related to them. Some scientists think that dinosaurs were more closely related to birds.
Dinosaur diets
some dinosaurs were carnivores, which means they ate meat. They had sharp teeth and claws. Tyrannosaurus Rex, Allosaurus and Baryonyx were carnivores.
Most dinosaurs were herbivores and ate plants. They had teeth designed to grind their food. They had larger intestines than carnivores because plants are harder to digest than meat, so they had to eat huge quantities. Their large heavy stomachs meant they had to walk on all fours most of the time so as not to overbalance. The largest dinosaurs may have grown as long as 45 m and weighed as much as 77 tones.
Later on, some herbivores developed with their stomachs between their hind legs, and these were able to move around on two legs. Iguanadon is one such herbivore. Other herbivores developed armor plating and moved about on all fours, for example, Stegosaurus, Triceratops and...