What Caused the Dinosaurs To Die?
How Did Dinosaurs Become Extinct?
The extinction of the dinosaur is one of the world's mysteries that we will never truly know. Most of what scientists believe to have caused the destruction of an entire species is just theories, at best. The theories are formed from the limited knowledge we have of our solar system and our planet's history. Even with this knowledge many of the hypotheses are just wild guesses. Some are ludicrous and involve the idea that the dinosaurs became extinct because their brains were too small, which caused them to be unable to adapt to a changing world. Since things with even smaller brains have survived, there had to be more than just small brains at work. There are also more plausible theories as well. One thing that most scientists agree upon is that there was one catastrophic event that caused many animals, not just dinosaurs, to die at the same time. Here are some of the most popular theories about what led to the extinction of the dinosaurs.
A Meteor Hitting the Earth
Did a Meteor Kill the Dinosaurs?
One of the most well respected theories is the Asteroid Collision Theory that was brought to attention by Walter Alvarez in 1980. He believed that an asteroid impacted the Earth 16.5 million years ago. There are many beliefs surrounding this idea, although there is still a discrepancy as to how the asteroid affected the Earth, and what truly caused the dinosaurs to become extinct.
Dust: Some scientists believe that when the meteor hit the earth, a huge dust cloud blocked the sun's rays for several years. Due to the lack of direct sunlight, many of the vegetation died off. Since dinosaurs were losing their primary food source, they were unable to survive. Although some scientists believe that the dust caused more than just the vegetation to die. It is unknown whether the dust would have settled after a few months or a few years. Since there are animals who did survive the Cretaceous Period, we know that not all the vegetation died off. What would account for some animals dying, but not others?
A Deep Chill: One theory is that the dust caused a deep chill. When the meteor hit the earth and caused dust to raise, the dust blocked the sun. Since the sun was blocked, not only did the vegetation die off, but the entire world began to cool down, leaving earth a very dark, cold place. Dinosaurs were not built to withstand long periods of cold, because most were cold-blooded. Consequently, they were not able to regulate their body heat, and essentially froze to death.
Greenhouse Effect: Ironically, although some scientists state that the earth cooled, others argue that the whole earth warmed up rapidly as a result of the meteors hitting the earth. The dust surrounding the earth along with a sudden volcanic eruption triggered a greenhouse effect, which ultimately led to the earth becoming overheated. Since cold-blooded creatures cannot regulate their own body temperatures, overheating is just as dangerous as freezing to death. This may have also killed off some of the warm-blooded creatures, since many warm-blooded creatures can only survive in certain climates.
Did Dinosaurs Die in a Flood?
The Great Flood: Not all scientists agree that the earth was hit by a meteor. They believe that there was a different catastrophic event such as a flood. Many people assume it was by the Great Flood, which Christians attribute to the story in the bible about Noah's Arc and other religions attribute to their own corresponding story. They believe that all animals except dinosaurs were protected. Although there is evidence that a Great Flood really did occur, many scientists believe that the flood that killed off the dinosaurs was more gradual.
A Gradual Flood: Over time the continents began to separate, slowly becoming the land masses we know today. As this occurred sea levels rose, this began to flood out the low-lying land, limiting vegetation and shelter for many of the dinosaurs. They believe when this occurred; flowering plants became more abundant, which made way for mammals to flourish. This is partly believed because the animals most related to the dinosaurs are birds and marine life; a gradual flood would not have hindered the existence of either of these creatures, but may have hindered land roaming dinosaurs, since birds would have been able to find homes even with a flooded floor, as well as marine life like lobsters, turtles, and sharks, which are still around today.
Many Questions Go Unanswered: Although not all sea creatures were as lucky during this event, and did become extinct, while there were also some land animals, who somehow survived this period. What we do know is that a gradual flooding truly did occur around the same time as the dinosaurs, which is believed to be before the Great Flood. This suggests a more gradual decline in dinosaur's extinction, while the evidence shows that dinosaurs were killed off abruptly, by some unknown event.
Did a Sudden Severe Weather Change Kill the Dinosaurs?
We do know the earth went through some major changes around the time the dinosaurs died that had nothing to do with a flood or meteors. They believe that the event that occurred was a natural solar cycle of our own world. It is interesting that many of these theories contain many similar attributes, despite the fact that these theories have little to do with floods or meteors.
The Parting of the Seas: It is known that that there has definitely been a change in land mass and that seas developed over time. It is believed that due to the rapid shift in land and water, a build up of Carbon Dioxide (CO2) abruptly occurred in the atmosphere. If the earth were to have increased levels of CO2, then the earth's temperature would rise, and the earth would become extremely hot. As stated in many of the theories, it was their cold-blooded nature that essentially killed off the dinosaurs. This would have affected many of the animals both in the sea and earth, who cannot survive in a carbon dioxide rich atmosphere.
Volcanic Activity: There is also a belief that a sudden surge of volcanic activity occurred around this time, unlike any we have seen. Some theorists believe that this was triggered by a meteor shower, while others believe it was a natural event that could happen again. If many volcanoes were to erupt at the same time, this would cause massive destruction to the earth's ozone layer. Once the ozone layer was destroyed, the atmosphere would allow an unhealthy level of ultraviolet radiation to reach the earth's surface. The ultraviolet radiation ultimately would kill the dinosaurs. Yet the question remains, then how come there are some remaining animals from that period?
No one will ever truly know how the dinosaurs became extinct. One fact remains clearer than the rest; many of these theories coincide with one another. The truth probably lies somewhere, where all of these theories collide.
What do you think caused the extinction of dinosaurs?
Gibbons, Gail. Dinosaur Discoveries: Holiday House; New York. 2005
National Wildlife Federation. Ranger Rick's: Nature Scope: Digging Into Dinosaurs: Chelsea House Publishers, Philadelphia. 1997.
Norman, David, Ph.D., and Angela Milner, Ph.D. Eyewitness Books: Dinosaur:Alfred A Knopf; New York. 1989.
© 2012 Angela Michelle Schultz