Extinction of Dinosaurs due to Asteroid Impact
Nobody knows for sure exactly how the dinosaurs became extinct. However scientists have speculated for decades about possible events that caused the dinosaurs to die out. Possibilities range from asteroids, to volcanoes, to climate changes. One of the more popular or well-known extinction theories involves the belief that an asteroid struck the Earth, causing devastating effects, and triggering mass extinctions around the end of the Cretaceous period.
The asteroid impact extinction theory began in 1980 with Luis and Walter Alvarez, a father and son team. They theorized that an asteroid struck the Earth at the close of the Cretaceous period, causing devastating effects and mass extinctions (Botzer 2004). Then, in the early 1990s, Alan Hildebrand, an associate professor at the University of Calgary, discovered the Chicxulub crater on the Yucatan peninsula in Mexico. This crater was 186 miles in diameter and six miles deep, and it was created when an asteroid hit the Earth approximately sixty-five million years ago. This asteroid is said to have strike the Earth with a force of 100 million to 300 million megatons of TNT (Recer 1993). With the discovery of the crater came the theory that this particular asteroid killed the dinosaurs and caused other mass extinctions. It was believed that the impact of the asteroid increased temperatures to above 20,000 degrees, sent massive tidal waves and earthquakes across the Earth, and filled the atmosphere with dust and chemicals, which blocked the sun. It was then hypothesized that the blocking of the sun led to drastic climate changes, allowing the Earth to cool, and creating a climate too cold for the warm-blooded dinosaurs (Re...
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...me 300,000 years after the impact. We still don’t know for sure what happened to the dinosaurs, and there is a possibility that we never will know. However, several signs indicate that the Chicxulub asteroid probably created conditions that begin the decline of the dinosaurs. This was most likely followed by a second large impact, or several smaller impacts that caused drastic changes in the environment and resulted in the mass extinction.
Works Cited
Botzer, Angela. “That Asteroid Didn’t Kill Dinosaurs, Study Says.” National Geographic News. 9 Mar 2004. 31 Mar 2004 http://news.nationalgeographic.com/news
Keller, Gerta, et al. “Chicxulub Impact Predates the K-T Boundary Mass Extinction.” PNAS Online. 2 Mar 2004. 5 Apr. 2004 http://www.pnas.org/cgi
Recer, Paul. “Crater Theory: Big Space Rock Did in Dinosaurs.” Times 17 Sep. 1993: National.
“...99.9 per cent of all [species] that have ever existed are now extinct.” (Benton 1) After one hundred and sixty million years of domination, the reign of the dinosaurs ended in fire and ice. Sixty five million years ago, the largest volcanoes in the history of the Earth erupted across what is now India, effectively annihilating the dinosaurs by spewing out noxious gas and ash, that effectively blocked out the sun killing off most vegetation and breaking the food chain, leaving the dinosaurs to starve. Compared to other groups of animals the dinosaurs were the most vulnerable to such a climatic event and the result was the end of the dinosaurs’ glorious evolutionary history.
Pterosaurs were not dinosaurs but were closely related, and existed for 150 million years beginning in the late Triassic period through the Jurassic and Cretaceous periods until eventually becoming extinct along with the rest of the earth’s population at what is now known as the KT boundary event. The KT boundary event was the mass extinction that occurred at some point in time between the Cretaceous (K) and the Tertiary (T). This is famous because it marks the end of the 160 million years of dinosaur life. The theory is that asteroid rock hit the earth and caused the mass extinction. 1
Through this scheme, the whole food industry are disseminated with the best practice and informed with the latest state-of-the-art technology. Also, they only follow a single specification which can already be applied to different markets. Consumers also benefit from standardization procedures since it ensures the safety and quality of the products they use. Appendix B shows the other standardization programs under ISO: 22000.
"A Rose for Emily" is a wonderful short story written by William Faulkner. It begins with at the end of Miss Emily’s life and told from an unknown person who most probably would be the voice of the town. Emily Grierson is a protagonist in this story and the life of her used as an allegory about the changes of a South town in Jefferson after the civil war, early 1900's. Beginning from the title, William Faulkner uses symbolism such as house, Miss Emily as a “monument “, her hair, Homer Barron, and even Emily’s “rose” to expresses the passing of time and the changes. The central theme of the story is decay in the town, the house, and in Miss Emily herself. It shows the way in which we all grow old and decay and there is nothing permanent except change.
An opposing theory proposes that the impact of asteroid or comet caused catastrophic destruction of the environment, leading to the extinction of the dinosaurs. Evidence to support this theory includes the discovery of a buried impact crater (thought to be the result of a large comet striking the earth) that is 200 km (124 mi.) in diameter in the Yucatan Peninsula of Mexico. The spray of debris was blown from the edge of the crater. The debris has been found over large regions of North America. Comet enriched material from the impact's fiery explosion was spread all over the world. With radiometric dating, scientists have used the decay rates of certain atoms to date the crater, spray of debris, and fireball layer. Using similar techniques to date the dramatic changes in the record of microscopic fossils, they have found that the impact and the dinosaur extinction occurred nearly simultaneously.
The K-T Extinction is supported by 3 pieces of evidence. According to the EarthViewer app, the crater caused by the impact of the 10 km-diameter asteroid was identified in the Yucatán Peninsula of Mexico. This evidence proves the K-T extinction because there it is physical evidence that exists from the mass extinction event. Additionally, "Fossil Data by Era and Period" shows that during the Cretaceous period, there was evidence of a diversity of dinosaurs from the fossils. However, during the Tertiary period, there was no evidence of dinosaurs, seemingly nonexistent. This is another piece of evidence because the K-T extinction happened at the end of the Cretaceous period and the beginning of the Tertiary period. The Tertiary period wouldn't
... the patient. As a matter of situation and literature, I believe that the interpreters should not take an assignment which is related to the interpreter in medical setting. However, if the relationship with the patient is leading to successful consequences, the interpreters should take an assignment as the patient’s needed.
Cretaceous period, something so devastating that it altered the course of life on earth. It
Several mass extinctions have occurred during the Earth’s history. The Cretaceous – Tertiary Boundary (K-T) Extinction caused the loss of at least three-quarters of all species known at that time including the dinosaurs. The cause of this mass extinction is a controversial subject among scientists but the fossil evidence of it’s occurrence is abundant.
I write this clear and concise reflection to identify and evaluate an academic problem that I feel is negatively impacting my studies which is time management; otherwise, I find lot of difficulty to manage my time.
There are many different parts to time management, such as procrastination, strategy, organization, expectations and being prepared. All of them contribute equally in many ways. All of the things that we have spoken about in this paper are highly recommended. The best thing to do when it comes to time management is to set a strategy, become organized and do your best to avoid procrastination. When you manage your time make sure you include the following; studying, sleeping, eating, relaxing and other necessary things. No matter what our circumstances are, we can all use some time management skills in our lives.
Norell, Mark, Lowell Dingus, and Eugene S. Gaffney. "Why Did Nonavian Dinosaurs Become Extinct?" Discovering Dinosaurs: Evolution, Extinction, and the Lessons of Prehistory. Berkeley: U of California, 1995. N. pag. Print.
In the workplace, time management is an important factor in everyone’s day-to-day work. If a person’s time is well managed, it is possible to achieve a greater amount in a shorter space of time. How effectively people manage their time has a major influence on aspects of their working lives and their personal lives. Effective time management can have a hugely positive effect on a person, it can lead to a focused and disciplined mentality, giving a higher level of productivity, greater efficiency and an all round positive attitude in life. This benefits the individual, their team, the company they work for and also their friends and family. An example of this is an employee who prioritises their jobs at the start of the day; this gives them a structured day and ensures they have time to complete all of the important jobs. However, if time is poorly managed it can lead to inefficiencies, work overload and added pressure, this could eventually lead on to other issues such as stress.
The problem of time management can be said to be universal not only affecting students but also other people in careers. This problem is seen to transition from a person’s life from different cadres of his or her engagement specifically from home, school and at work. It is also a problem that is internal and not external.
(Claessens, Brigitte J.C.2004). adds that time “cannot be managed, because time is an invariable factor. Only the way a person deals with time can be”. Nevertheless, time management has become increasingly essential to businesses and organizations. This is especially true over the last two decades, as a result of expanding global competition and increased demands for the immediate availability of products and services. Given the increased pace of everyday life, people increasingly need to be more organized. Efficient time management practices support business students in acquiring key skills that will assist them both in their educatio...