¶ … Dinosaurs Became Extinct

Why Dinosaurs Became Extinct

There are many possible explanations for the extinction of dinosaurs, and scientists have proposed many theories regarding their demise. One of the most common theories is that an asteroid from outer space collided with the earth about 65 million years ago. If a large asteroid had collided with the earth in this manner, then it is believed that such a cloud of dust would have entered the air that the sunlight would be unable to penetrate the dust cloud.

Therefore, all of the plants and animals would die, because the entire ecosystem on earth depends on the sunlight to provide warmth and energy. Without the sun, plants would be unable to produce their own food through photosynthesis, and they would die. Without plants, the herbivores would have no food supply and also perish. As a result, even the carnivores that ate other animals would have no food, as all of their food sources would disappear. (It is also believed that excessive volcanic activity may have caused a similar dust cloud that would have resulted in planetary changes very much like those described in the asteroid theory.)

It is also believed that under a thick dust cloud it would become very cold without any penetrating sunlight, which could have even resulted in an ice age, where a large portion of the water on earth would have been frozen and the atmosphere changed drastically. Therefore, it is also possible that all of the dinosaurs could have perished due to an ice age or similar atmospheric change. Another theory is that the dinosaurs became extinct when the earth gradually changed atmospheric conditions. If the earth had changed from being extremely warm and humid to being colder and less wet, then the dinosaurs may not have been able to adapt to the new earth climate and therefore died out. Gradual changes in the climate or many other factors may also have brought serious disease to the dinosaurs. If a plague-like illness circulated among the dinosaurs, then this could be another explanation for their disappearance because they would have had no medical knowledge such as humans posses today with which to combat the disease.