The History of Earth's Mass Extinctions
The four billion year history of earth has witnessed five mass extinctions, and some scientists believe that we are on the verge of the sixth.1[1] If we are in the midst of the next mass extinction, we are in the very early stages of an evolving, and escalating process. The most recent, or fifth mass of the extinctions occurred 65 million years ago at the boundary between the Cretaceous and Tertiary periods. Images of an asteroid colliding with the planet, decimating the dinosaur population have been in circulation since the early 80’s.2[2] Being the most recent mass extinction, thousands of scientists around the world have investigated it, and elementary school children are familiar with it.
While the asteroid-collision hypothesis has not been proven concretely, it has been widely assimilated into, and accepted by the popular culture. Palaeontologists, sedimentologists, palaeoceanographists, geochemistrists, and experts in numerous other related fields have recently stepped up investigative efforts concerning the mass extinctions.3[3] Knowledge about these previous mass extinctions would not only give us a better understanding our past, but it could be vital in the study and recognition of a sixth mass extinction.
Geologists studying basalt flats in Siberia are discovering evidence that a massive lava eruption in that region 250 million years ago may have been more devastating than previously believed. In their latest figures, the investigating scientists believe that 85% of all aquatic species, and 70% of all species living on land became extinct at this juncture in time. Figures three times that of the Cretaceous-Tertiary extinction.4[4] The belief is that the lava ...
... middle of paper ...
... Post, 21 April 1998, p. A-4.
[10] Virginia Morell. “The Sixth Extinction,” National Geographic.
[11] http://www.amnh.org/museum/press/feature/biofact.html. American Museum of Natural History.org
[12] http://www.amnh.org/museum/press/feature/biofact.html. American Museum of Natural History.org
[13] http://www.newscientist.com/news/print.jsp?id=ns99994797. NewScientist.com
[14] http://www.newscientist.com/news/print.jsp?id=ns99994797. NewScientist.com
[15] http://www.amnh.org/museum/press/feature/biofact.html. American Museum of Natural History.org
[16] Ayres, Ed. “Worldwatch Report: Fastest Mass Extinction in Earth History,” 16 September 1998.
[17] http://www.geol.umd.edu/~tholtz/G331/331extin.htm.
[18] http://www.mdgekko.com/devonian/opportunity/massExtinction.html. Devonian Times.
[19] http://www.ucmp.berkeley.edu/paleozoic/paleozoic.html.
“...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.
The eradication of species numbers average at a toll close to one hundred percent of earths total living creatures. “It is the Earth's most severe known extinction event, with up to 96% of all marine species and 70% of terrestrial vertebrate species becoming extinct” (Sahney, and Benton 759). Not only where marine and terrestrial species effected but this catastrophic event is the only recogni...
Throughout history, the world and its inhabitants have been subject to great change. Whether these changes are biological, ecological or geological they are all influenced by certain factors at play. Great changes take time to observe, usually longer than one's life would allow. The longer the change, the harder to identify the exact cause. When it comes to the species that inhabit the earth, it is notable that some species that lived and thrived long ago are now simply gone. The extinction of entire species of birds, mammals and amphibians occurs throughout time here on earth but the exact cause for their disappearance has been debated. In chapter two of "Twilight of the Mammoths" written by Paul S. Martin, the theories of extinction are challenged.
Throughout history our world has undergone and experienced all sorts of changes that have shaped the world into what we see it today. The most significant events included disasters like the extinctions of organisms. Out of all the extinctions, the most influential was the Permian Mass Extinction. During the Paleozoic era roughly eighty five percent of living species died and became extinct due to the Permian mass extinction. This illustrates how severe an event like the Permian mass extinction actually was. With such a prodigious magnitude, it’s important to note the consequences and results that aroused. In this case the most devastating consequence was its influence and alternation on the history of life. In addition, it is crucial to see the factors responsible for causing such immense extinctions, ultimately leading to what we call the Permian Mass Extinction.
In the book Metaphors We Live By, authors George Lakoff and Mark Johnson address the traditional philosophic view denouncing metaphor's influence on our world and our selves (ix). Using linguistic and sociological evidence, Lakoff and Johnson claim that figurative language performs essential functions beyond those found in poetry, cliché, and elaborate turns of phrase. Metaphor permeates our daily experiences - not only through systems of language, but also in terms of the way we think and act. The key to understanding a metaphor's effect on behavior, relationships, and how we make sense of our environment, can be found in the way humans use metaphorical language. To appreciate the affects of figurative language over even the most mundane details of our daily activity, it is necessary to define the term, "metaphor" and explain its role in defining the thoughts and actions that structure our conceptual system.
The poem says that "since feeling is first" (line 1) the one who pays attention to the meaning of things will never truly embrace. The poem states that it is better to be a fool, or to live by emotions while one is young. The narrator declares that his "blood approves" (line 7) showing that his heart approves of living by feeling, and that the fate of feeling enjoyment is better than one of "wisdom" (line 9) or learning. He tells his "lady" (line 10) not to cry, showing that he is speaking to her. He believes that she can make him feel better than anything he could think of, because her "eyelids" (line 12) say that they are "for each other" (line 13). Then, after all she's said and thought, his "lady" forgets the seriousness of thought and leans into the narrator's arms because life is not a "paragraph" (line 15), meaning that life is brief. The last line in the poem is a statement which means that death is no small thi...
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.
"since feeling is first" is a free verse poem and the speaker is specific persona created by the author. The persona that Cumming created is a man deeply in love. This poem has 16 lines in total and is structured in stanzaic form. The stanzas are grouped together with syntax errors. There is no proper punctuation which makes the reader confused of making pauses. There is enjambment; where the lines are broken after a completion of thought. For instance, stanza one contains four lines and those four lines have no proper punctuation. To make sense of that stanza, it should be read together. The author has purposely made this syntax error because he compares life to a paragraph (line 15). He had to show that life is not structured like a paragraph. Life lacks the logical order the paragraph contains. The speaker of this poem is a man who is in love and believes that there is nothing better. The tone of the speaker is romantic and realization. Literally, the speaker is in love and he thinks nothing is greater than love. There is nothing that can come among love. Figuratively, the poem is about the people forgetting to realize the great things in life because they pay attention to trivial matter and tend to lose something prom...
A metaphor can be defined as “a figure of speech in which a word or phrase that ordinarily designates one thing is used to designate another, thus making an implicit comparison” (dictionary.com). We use metaphors in our everyday language more than most people realize. But metaphors are also vital in the field of Information Systems, especially in the design of user interfaces. To the “Average Joes” of the world, or those people who have difficulty understanding the complicated concepts of digital storage, information transmission, and processing, metaphors provide them with relevant concepts to which they can easily relate. Therefore, metaphors allow a significantly larger amount of the worldly population to use many of the common technologies that we take for granted today.
Earth has gone through five fully major extinctions before. We currently are in the process of Earth’s sixth mass extinction. This mass extinction is closely related in severity to the extinction of the dinosaurs. Earth’s extinctions are broken into three different areas. The first area was the large number of animals caught by hunter-gathers. The discovery of agriculture led to the second area of extinction, wildlife habitats. These wildlife habitats were destroyed due to humans starting to stay in one area.
The most significant event of the Cretaceous era came at its end. Nearly 65 million years ago, the second most severe mass extinction in earth’s history occurred. This resulted in the loss of around 80% of species living at the time. Though nowhere near as severe as the end-Permian mass extinction, the end-Cretaceous extinction is the most well known mass extinction event. This is due to the violent event that caused it the extinction, as well as the chapter of earth’s history that it closed: the Dinosaurs. The Cretaceous Event ( often shortened to K-T event) Of the animals that were killed off were the flying reptiles (pterosaurs) and the last few mosasaurs and plesiosaurs, both early marine reptiles. Many mollusks and species of microscopic plankton were killed. Terrestrial plants suffered mass extinction as well. Almost 60% of terrestrial plants were lost. This led to high extinction rates among insect populations, especially insects that were highly specialized to feed on just a few types of plants had it the worst. It took approximately 9 million years for the global insect populations to recover from the Cretaceous extinction. Immediately after the extinction, the earth saw an explosion of short term species who respond well to fire, or other external disturbance. Evidence of the catastrophe comes from a thin rock layer deposited worldwide just after the impact. It is dominated by fossil plants whose descendants recover quickly after fires of other disturbances, such as Fire Weed in Alaska. The causes of the Cretaceous extinction are still being debated by paleontologists. Scientists agree that the main cause of the extinction was a...
Our literal understandings of a word are twins in constant opposition with one another, twins in constant competition to receive the most love from their mother and father. Let us pretend the parents are the literary community that demonstrates love frequently by showing a preference for one of their twins. Donald Davidson's theory expressed in What Metaphors Mean is a tragic, intellectual miscarriage; it is a theory of language that brings forth a stillborn child, a dead metaphor.
The Jurassic Period of our earth’s history was one of great change. It began with a major extinction even, bounced back, and was yet again the victim of an extinction event. The Jurassic was a flourishing time of new species adapting, changing, and modernizing to suit the ever-changing world they
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 most popular theory of dinosaur extinction, the asteroid theory, says that dinosaurs died out because of a single, giant asteroid. They say that the asteroid that struck the earth near the Gulf of Mexico went 43,000 mph and spanned six miles wide (Erdman). When it hit the Earth the asteroid it left an enormous crater that measured 24 miles deep and 125 miles wide (Erdman). Just the impact of the asteroid destroyed the forests and landscape of the majority of North America due to its massive shock wave (Erdman). Many species went extinct when the asteroid hit, these species include dinosaurs, ammonites (certain ocean dwelling creatures), pterosaurs, and some plant groups dinosaurs, ammonites (mollusks related to the octopus and the chambered nautilus), pterosaurs, and certain plant groups. Although devastating, the asteroid did not wipe out all of the animals on Earth, it didn’t exterminate fish, frogs, turtles, birds, mammals and croco...