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 honestly know — most of what scientists believe in having destroyed an entire species is just theories, at best. Limited knowledge helps form the arguments 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 little 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. Many who agree, disagree about how the asteroid affected the Earth and what caused the dinosaurs to become extinct.
Dust: Some scientists believe that when the meteor hit the earth, a vast 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 rise, 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 the 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 ground. 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 body temperatures, overheating is just as dangerous as freezing to death. Freezing to death may have also killed off some of the warm-blooded creatures since many of them can only survive in certain climates.
Did Dinosaurs Die in a Flood?
The Great Flood: Not all scientists agree that a meteor hit the earth. 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 tale. They believe that all animals except dinosaurs were protected. Although there is evidence that a Great Flood 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 landmasses 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 happened; flowering plants became more abundant, which made way for mammals to flourish.
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. Marine life, like lobsters, turtles, and sharks, which are still around today, would have also been able to survive.
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 gradual flooding did occur around the same time as the dinosaurs, which is believed to be before the Great Flood. It is more likely that a more gradual decline in dinosaurs becoming extinct occurred than them being killed abruptly by some unknown event.
Did a Sudden Severe Weather Change Kill the Dinosaurs?
We do know the earth went through some significant 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 world. Interestingly, despite none of these theories being about floods or meteors, hey share many similar attributes.
The Parting of the Seas: Seas did develop over time, and there has been a change in landmass. 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 land would become extremely hot. As stated in many of the theories, their cold-blooded nature essentially killed the dinosaurs. Their extinction 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 destruction of the ozone layer occurred, 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 honestly know how the dinosaurs became extinct. One fact remains brighter 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