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Mass extinction in the Permian and Cretaceous period
Mass extinction and its consequences
Short note on extinction of dinosaurs
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Hypotheses on the Extinction of Dinosaurs
In the early nineteen hundreds, dinosaur fossils were discovered and recognized around the globe. Greedy scientists and civilians, searching for their own prize skeleton, rushed to rip bones out of the ground, destroying the fossils as they went. It was not until later in the century that scientists and paleontologists began pondering how such widespread creatures disappeared. Currently, paleontologists debate the two main hypotheses of how the classic dinosaurs died: from volcanic activity or an asteroid impact. Although they result in the same outcome, the volcanic and asteroid hypotheses differ in key elements: the actual event, the environment's stress, and the impact on life.
Physical evidence left behind in each scenario supports each possible explanation for the massive extinction responsible for wiping out the dinosaurs. Scientists that support the volcanic activity hypothesis believe the massive volcanic activity lasted approximately 500,000 years eventually ending dinosaurs reign on earth. The lava flows filled over 480,000 cubic miles, devastating areas over the entire globe. For example, The Decan Trap, a famous site of Cretaceous tectonic activity, is up to 8,000 feet deep, and it averaged between thirty-three and 164 feet deep. Fires raged across the lands. Those that believe in the asteroid impact, on the other hand, project a six mile wide meteorite moved at speeds from 50,000 mph to 150,000 mph and busted into Earth's atmosphere at the end of the Cretaceous Period. The sudden impact near the present day Yucatan Peninsula ejected 5,000 cubic miles of debris into the atmosphere and created an earthquake of magnitude thirteen sending tidal waves, 250 to 300 feet high...
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...sms alike. Conversely, paleontologists backing the asteroid hypothesis guess the massive blast killed nearby animals instantaneously. Creatures on the opposite side of the world, however, were not so lucky. They were forced to dwell in freezing temperatures until vegetation withered. Herbivores quickly starved to death; consequently, carnivores lacked prey. Instead of gradually dying off, dinosaurs perished within one generation. Although the two hypotheses of the great extinction come from opposite occurrences, in the end the event proved fatal.
While paleontologists may never agree on the true cause of dinosaurs' extinction, many people are now speculating mankind's termination. Will mother nature be responsible for our destruction also? Only time will tell. Perhaps in the far future, another species will encounter human remains and search for our match maker.
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
The disaster theory, Gould claims, is an example of good science. It has testable evidence and has an impact on studies in other fields of science, it develops further and explains why the extinction of dinosaurs occurred simultaneously with other events. This theory suggests that a large comet hit the Earth sixty five million years ago, causing the cloud of dust to rise into the sky and to block sunlight. As a result, world temperatures went down significantly, the ice age bega...
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.
Youngblood, R. (1973). 20 years in the Secret Service: my life with five presidents. New York: Simon and Schuster.
However, asteroids are much more deadly. If over-sized meteor can wreck buildings and injure people, then a normal sized asteroid can easily wipe out species if it lands in the right place. As mentioned before, asteroids are much bigger than meteor and much more rare. According to the “Mail Online” 12,000 years ago some type of asteroid slammed into the Northern Canada and some scientist believe that wiped off the mammoths and caused the “Younger Dryas”. Another famous event of asteroids striking, that many scientist believe, was around 65 million years ago asteroids rained and killed of all the dinosaurs 75% of all the life on earth.
Lady Macbeth is a dominant character as soon as she is introduced into the play. A.C. Bradley wrote about her as “…the most commanding and perhaps the most awe-inspiring figure that Shakespeare drew” from his article titled Lecture X. She became a image known for her ambitious nature. Her thirst for power and disregard for life was shocking to the audience, as to her own husband. The moment she learns of the prophecies, she decides to stand behind Macbeth and see him to the throne. She is immediately set on her quest for more power. As it reads “Glamis thou art, and Cowador, and shalt be/ What thou art promised (1.5.13-14) This moment is crucial because it is the turning point where Lady Macbeth decides that she might have to kill to fulfill her quest for royalty. Macbeth is doubtful about their plan to kill King Duncan; however, she bombards him with comments that question his courage. She goes as far as telling him his love his worth nothing if he refuses, which proves her to be dominant and controlling using his own weakness against him. His love for her. The fact that she belittles his confidence, insults his abilities, and questions his manhood is so manipulative, but also wise because it worked in her favor. She said to him “Screw your courage to the sticking place” (1.7.60). She was confident that her ridicule could gain her control over her husband. There is no doubt that she manipulates her close relationship to Macbeth to get them both the power they covet.
Tobacco companies should be prevented from using advertising tactics that target teenagers. There has always been controversy as to how tobacco companies should prevent using advertising tactics to target teenagers. As controversial as this is tobacco companies shouldn’t advertise teen smoking. Many teens may be lured to believe cigarette advertising because it has been part of the American Culture for years, magazine ads and the media target young people, and these companies receive a drastic increase financially; however, the advertising by these cigarette companies has disadvantages such as having to campaign against their own company, limiting their cigarette advertising and becoming a controversial dilemma as to encouraging teenagers to smoke. From billboards to newspaper advertisements, cigarette promotions started becoming part of the American Culture.
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.
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
"Smoking Bans and the Tobacco Industry." Issues & Controversies. Facts On File News Services, 1 July 2013. Web. 4 Dec. 2013. .
Throughout Earth’s history there have been many changes. These changes have consisted of temperature fluctuations, atmospheric differentiations, extinctions of various plant and animal life, etc. Over time everything seems to have evolved in some way form or fashion. However, the Permian Era extinction was different from all the rest. This extinction affected every form of life, but especially the marine life. Researchers have stated that 93-97% of all Earths species went extinct during this period of time. This essay will explain how a once blossoming progressive era turned into Earths most catastrophic event.
seems like it happened so sudden, as geologic time goes, that almost all the dinosaurs
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.
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.
According to Gary Phillips, School culture is “beliefs ,attitudes and behaviors that characterize a school in terms of how people treat and feel about each other , the extent to which feel included and appreciated and rituals and traditions reflecting collaboration and collegiality”.