Existence, Lives, and Eventual Extinction

¶ … existence, lives, and eventual extinction of dinosaurs have intrigued scientists and public alike for many years. Because of the vast periods of time between when dinosaurs walked the earth and the present time, the development of precise arguments regarding each of these issues has been a taunting task. Reliance upon fossil and bone evidence has been the standard measuring device and it has been only recently, with the improvements in x-ray, DNA, and carbon dating technology that any real support has been found for developing theories about dinosaurs.

There is little doubt as to the existence of dinosaurs. There is a considerable body of physical evidence including nearly complete skeletal remains of various different species of dinosaurs that categorically establish not only that dinosaur lived but also where they lived. Fossilized remains from the area around where the dinosaur skeletons were retrieved have provided scientists with information regarding their diet and environment but the big mystery remains: what caused the dinosaur to become extinct?

A variety of theories exist that offer an explanation for the extinction of the dinosaur population. None of the offered theories have been established as controlling among all scientists in the field but support for several is stronger.

The first such theory suggests that a giant asteroid or other heavenly object such as a comet struck the earth as some point causing not only traumatic damage to the dinosaur but also caused climatic changes that endangered the dinosaur's environment. The impact of the heavenly object on the earth's surface resulted in large masses of dust to develop which blocked the sun's rays causing the plant life to die and for temperatures to fall below comfort levels for the dinosaur. A large portion of the dinosaur population was decimated by this process and when the dust finally cleared and temperatures began rising quickly in the opposite direction the remainder of the population died as well. According to this theory, in just a brief period of time, perhaps as short as two or three years, the entire dinosaur population was eliminated as well as most of the plant life that supported them.

The evidence for this theory is considerable. A large crater lies just off the Yucatan peninsula in Mexico that scientists speculate was caused by the collision of an asteroid or comet. The timing of the creation of this crater corresponds with the estimate of when dinosaur would have occupied the world and so the existence corroborates the collision theory. Also, scientists have found a more concentrated amount of a rare earthly metal known as iridium in areas around where dinosaur fossil and skeletal remains have also been found. Iridium is more commonly found deeper within the earth's surface and on other planets and scientists believe that is being concentrated near dinosaur remains supports the collision theory as well.

The fossil records of dinosaur also support the collision theory. Contrary to what one would expect if the extinction were gradual, the existing history of fossil records indicates that dinosaur were doing quite well up and that there were no factors threatening their extinction but that suddenly there is a complete loss of fossil history; a sudden extinction?

The collision theory is likely the most popular of the available approaches but there are several others including one that involves the idea that massive volcanic eruptions throughout the world caused the extinction of the dinosaur. The theory is that volcanic activity became so widespread as to cause a severe buildup in gas, ash, and dust to accumulate in the atmosphere to the point that the sun's rays were eventually lessened to the point that temperatures plummeted, plant life died, and the dinosaur could not adapt to their new environment and gradually died off as a result. The physical evidence for this theory is very similar to that offering support for the collision theory and, as a result, many scientists split their opinion between the two theories.

There is body of evidence that supports the theory that the emergence of mammals on the earth contributed to the extinction of dinosaur. The appearance of mammals created an environment of competition that the dinosaur had not been forced to encounter before and when mammals began competing for the same food stuff and, more importantly, began seeking dinosaur's eggs the dinosaur were ill-equipped to compete.

It would be nice if the fossil records would support one of the above stated theories over the other but this is not the case. In certain areas of dinosaur discovery, fossil records indicate a sudden extinction as there is virtually no fossil records after a specified time but in other areas the fossil records indicate a gradual decrease. This divergence may indicate that the extinction occurred for various reasons throughout the areas occupied by dinosaur activity.