Dinosaur Extinction Research Paper

Carmen Whaley

Mr. Miller/Mrs. Dene’

Science/English 7B

23 April 2018

Why did the Dinosaurs Go Extinct?

What is extinction? Dinosaurs are the largest species to be extinct. There are many different theories of how the dinosaurs went extinct. Some of those theories are an asteroid hit earth causing massive amounts of iridium to fill the air, climate change very intense causing them to go extinct, mosquitos that contain malaria could have forced the dinosaurs into extinction, and a volcano could have erupted causing iridium to fill the air.

There are many different theories of how the dinosaurs went extinct, but the most popular theory is an asteroid hit earth. For about 150 million years, dinosaurs were the most dominant form of animal life on

earth, but the only dinosaur fossils are more than 65 million years old. This confused scientist until they found many other life forms that died at the same time, the lead scientist to believe there was a mass extinction. In 1979 a team from the University of California, Berkeley, led by Walker Alvarez, studied rocks that formed at the change from the Cretaceous to the Tertiary period (K/T Boundary). The rocks they found held massive amounts of iridium. Iridium is a metal that is rare on earth but common in meteorites and asteroids. This suggests that a meteor about 6 miles wide struck earth at about 12 miles per second. This impact would have been as powerful as 100 million H-bombs. Once scientist found out about the asteroid theory

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they started looking for the impact site. The presence of shocked quartz crystals showed that the collision must have been on or never land, but signs of giant waves also suggested that it was in the sea. Scientist found a creature off the Yucatan Peninsula in Mexico that was dated to 65 mya. If this was the impact site this would explain why an estimate 60% of marine life became extinct, but turles, ammonite shellfish, clams and related animals, and many species of fish survived. Large numbers of plankton died. Land extinction was more dramatic than in the ocean. All animals over 55 pounds went extinct, also many smaller species. All dinosaurs, flying reptiles, and many mammals died. Many animals survived too, like crocodiles, some birds, and land plants. When the asteroid hit it caused a temporary stop of plant growth from blocked sun rays. Lack of plant growth killed off plant eaters and that left no food for the meat eaters. It is also believed that smaller animals might have hibernated.
There is another theory that climate change killed the dinosaurs. A recent study makes a better estimate of how much sulfur and carbon dioxide gas was ejected into the earth’s atmosphere at the time of the impact of the asteroid. That gas was believed to have been released from vaporized rocks. Estimate more than 3 times as much sulfur may have entered the air as previously predicted. Causing a period of cool weather that may have been cooler than previously thought. When the asteroid hit it threw up massive amounts of dust, sulfur, and carbon dioxide into the atmosphere. The dust and sulfur form a cloud that reflected sunlight and dramatically reduced the earth's

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temperature.

The temperature dropped to 47°F and lasted for at least 3 years after impact.

There are two more theories of how the dinosaurs went extinct, one of them are malaria killed them. A fossil was recently found of a mosquito containing malaria that is at least 20 million years old. Earlier forms found in biting midges are at least 100 million years old. The type of Malaria found in the fossil was the first fossil record of Plasmodium malaria. The last theory is that a volcano killed the dinosaurs. The the theory is that 65 million years ago a volcano explodes with rich iridum and magama spewing out like flood waters. The iridum and magama piled up more than 1.5 miles thick over one million square miles. It spread iridium around the world. Also sunlight-blocking dust, soot, and greenhouse gases filled the air.

There are many different theories of how the dinosaurs went extinct. Some of those theories are an asteroid hit earth causing massive amounts of iridium to fill the air, climate change very intense causing them to go extinct, mosquitos that contain malaria could have forced the dinosaurs into extinction, and a volcano could have erupted causing iridium to fill the air. My favorite theory is the asteroid theory. The most significant part of this theory is when the asteroid hit earth because the asteroid collided with earth. The impact was so intense that it caused a whole species to go

extinct.

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Bibliography
American Geophysical union Dinosaur-killing asteroid impact cooled Earth’s climate
more than previously thought October 31,2017 3-7-18
https://www.sciencedaily.com/releases/2017/10/171031111446.htm
George Poinar Jr. Did malaria help kill off the dinosaurs? 3-7-18
https://cosmosmagazine.com/paloentology/did-malaria-help-kill-dinosaurs websit
National Geographic Dinosaur Extinction 3-7-18
https://www.nationalgeographic.com/sceince/prehistoric-world/dinosaur-extinctio
n/ website
Rupert Matthews End of the Dinosaurs Blackbirch Press United States 200 book