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Effects of species extinction
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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.
The possibility if a meteor strike as the cause of extinctions is discarded, something that most specialists agree on. There is no evidence of any meteor crater big enough or recent enough to be accountable for it; there are no “elements that are common extraterrestrially but less so on Earth, such as iridium, and no sign of a tsunami or other phenomena following the impact.” The extinctions where also very selective and occurred over a very long period of time. If a “one shot” catastrophe had been the cause it would have affected all species at the same time and in similar
“Sex, Drugs, Disasters, and the Extinction of Dinosaurs” is written by Stephen Jay Gould, professor of geology and zoology at Harvard. This essay is one of more than a hundred articles on evolution, zoology, and paleontology published by Gould in national magazines and journals. It tells about scientific proposals for the extinction of dinosaurs – a confusing but an exciting problem that humanity tries to solve. By analyzing and describing each of the claims for the reptiles’ demise – sex, drugs, and disasters – Gould differentiates bad science from good science and explains what makes some theories silly speculations, while the other, a testable hypothesis.
The question of what caused the extinction of megafauna during the Late Pleistocene period is one that archaeologists have struggled to answer for decades, but why should it matter? Discovering with certainty the cause of megafaunal extinction would simultaneously prove or disprove any of the proposed implications of each existing theory regarding this massive extinction.
He explores the theories that a rise in temperature could have made the reptiles of old infertile, or that the dinosaurs ate flowering plants that acted as drugs, causing the beasts to overdose. He goes on to examine a third theory, that of an asteroid hitting the earth and causing a cloud of smoke and dust to cover the sun, dropping temperatures and killing not only the dinosaurs, but much of the life that was present on the Earth at the time. Gould himself leans toward the last theory, citing evidence and research to back his point. All of this, he delivers with an air of humor, saying things such as “How can we possibly decide whether the hypothesis of testicular frying is right or wrong?” (par 21). While the theory of infertility of dinosaurs comes from the idea of rising heat, Gould’s wording here brings to mind a funny image rather than a worldwide epidemic. Using humor again, Gould says “If you talk just about asteroids, dust, and darkness, you simply tell stories no better and no more entertaining than fried testicles or terminal trips” (par 26). Not only does he cast aside the first two theories as useless frivolities, he sets the stage for proving why the asteroid theory is better, using humorous language to do so. A humorous essay such as Gould’s is fun to read, while keeping a basis in
The Permian Triassic extinction was an event of cataclysmic disaster and almost the extinction of all species on planet earth. The Permian Triassic extinction is said to have occurred millions of years ago, geologist have estimated that its occurrences happened about 248 million to 286 million years ago. This rare occurrence of events proceeded the Triassic geologic periods and the Paleozoic and Mesozoic eras. This mass disaster was the largest dissipation of living life on planet earth; it is believed to be even superior to other crises such as the Ordovician and Devonian events and the conclusion of the cretaceous era that came upon the dinosaurs.
... 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.
We use dinosaurs to represent the changes in nature that have occurred throughout time. Studies found that although the “oldest rock did not show evidence of life, the progression of plant and animal life that changed in recognizable intervals, from ancient life, age of reptiles to the age of mammals” (Dino Nature Metaphor, slide 6), measured the age of the earth. When we think of dinosaurs in relation to nature, we think of that very powerful force that controls the cycle of life. Nature was able to yield such magnificent ferocious creatures that walked the earth and then take them back when they served nature’s purpose. Dinosaurs fit perfectly in nature’s constant
To begin, what constitutes abnormal behavior in Mr. Hughes’s case? As early as the 1930s, Hughes demonstrated signs of obsessive-compulsive disorder. Obsessive compulsive disorder is identified by DSM as having recurrent obsessions (persistent thoughts, ideas, impulses or images that seem to invade a person’s consciousness) or compulsions (repeated and rigid behaviors or mental acts that people feel like they must perform in order to prevent or reduce anxiety) (Cormer, 2008). Close friends reported that Hughes was obsessed with the size of peas, one of his favorite foods, and used a special fork to sort them by size.
A Rose for Emily is a southern gothic short story about an elderly woman stuck in her ways. When we are first introduced to Emily it is at her funeral where the entire town has come to falsely pay their respects. The men only went to Emily’s funeral because they viewed her as a fallen monument and the women only went out of curiosity to peer inside Emily’s house, which had been closed up to the world and shrouded in mystery for decades. Throughout the story, the narrator gradually describes Emily’s descent into madness and her unwillingness to accept the change happening around her. The central theme of A Rose for Emily focuses on the never-ending battle between tradition and change, which is expertly portrayed by William Faulkner’s use of
seems like it happened so sudden, as geologic time goes, that almost all the dinosaurs
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 Jurassic period is known as one of the most interesting periods of time in earth’s history, mainly for the awe-inspiring creatures many of which have gone extinct, the most remarkable being the dinosaurs. Life in the ocean during this time was also extremely diversified and amazing for the creatures it beheld. The Jurassic occurred from 199.6 to 145.5 million years ago, following the Triassic Period and preceding the Cretaceous Period within the Mesozoic Era. The supercontinent of Pangea began to drift apart during this time. Right before the Jurassic period began, a major extinction event occurred wiping out much of the life on earth. The events that unfolded afterwards gave life to a new planet.
Erdman, Shelby Lin. "Scientists Reaffirm Theory That Giant Asteroid Killed Dinosaurs." CNN. Cable News Network, 09 Mar. 2010. Web. 07 Mar. 2014.
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...