The Milestones and Major Developments in the Early Paleozoic Era Essay Example for Free

The Milestones and Major Developments in the Early Paleozoic Era Essay Understanding the diversity and complexity of life as observed in the current modern days may seem as difficult as defining life itself. The changes, developments, and evolution of the earth and the life forms it holds are all varied and sundry enough which makes it hard to understand without looking back to when, where, and how it all started. History, Geology, Paleontology, and many other branches of Science play a significant role in aiding people to better understand the roots and beginnings of the life seen today. These fields of studies help and serve like windows to the past which make it easier to know what it was like back when the Earth was young and life was primitive. These various disciplines draw attention to where life originated. Knowing the evolution of the earth and life forms can help make people understand what the modern life is made of. While some would see this study as a lame and monotonous venture, it can never be denied that knowledge about the origins of life and the world addresses very common issues like confusions as to how the modern human beings got their form and the very controversial issue as to where actually life came from. Debates and ideological arguments will always be inevitable, but Science got the only factual proofs and pieces of evidence about where life actually started and how it came to its present form from the simplest and most primitive elements. All these can only be understood by studying and looking back at the beginning. Thus, this paper shall discuss one of the most important and most highlighted eras in the history of life and the Earth—the Early Paleozoic Era. The Paleozoic Era The term â€Å"Paleozoic Era† literally equates to the term â€Å"time of ancient life† (Farabee). This is the bracket of time between 544 and 245 million years in the past. The Online Biology Book written by Michael Farabee and sponsored by Estrella Mountain Community College summarizes the major highlights of the Paleozoic Era. A section of the book explains meticulously about this prehistoric period. The Paleozoic era is from the general period when life forms began to spring known as the Phanerozoic Eon. This period has been known to exist about 542 million years ago (Farabee). Phanerozoic Eon consists of three specific eras such as: 1) Paleozoic Era—also known as the â€Å"ancient life† which existed 542 to 251 million years ago; 2) Mesozoic Era—also regarded as the â€Å"middle life† which existed 251 to 65. 5 million years ago; and 3) Cenozoic Era—dubbed as the â€Å"recent life,† which has existed since 65. 5 million years ago up to the present time (Gore 1). The Paleozoic Era appears to be the first period from the Phanerozoic Eon when the earliest complex life forms first existed. The Early Paleozoic specifically can be further divided into three periods such as the 1. ) Cambrian, 2. ) Ordovician, and the 3. ) Sulirian periods. It was during the earlier parts of the Paleozoic era when major advances in biological evolution were dated. The first of such developments and evolutions was that of the Cambrian Explosion. After this highlight came the developments of some group of green algae from the Ordovician period. This development in the early forms of primitive plants led to the evolutions of vertebrates since most plants during that time were found to move from water to land (Farabee). The Cambrian Explosion (544-505 million years ago) The Cambrian explosion during the earliest years of the Paleozoic era has been considered as the most interesting zoological myth there is about the origin of life (Dawkins and Wong 436). This is because this was the period when the earliest known animal and plant life sprang and had left very remarkable pieces of fossils which served as their memoirs for the modern scientists of today. It was during the Cambrian period when primitive life such as Coelenterates, protozoa, poriferans, molluscans, worms, echinoderms, trilobites, tribitmorphs, achaocyathids, and brachiopods were found to rule the animal kingdom (Balisteri et al. ). However, these primitive life forms were seen only in bodies of water. The Early Cambrian period was also tagged as a â€Å"wild time† for animal evolution (Farabee). This was because within the relatively short period of time, a wide variety of body plans among animals have already developed. One of the most prevailing groups of primitive animals during that time was the trilobites. These shallow-marine dwelling organisms lived during the Cambrian period, and through the rest of the period, this group has diversified into other more complex forms of organisms (Balisteri et al. ). However, due to the massive cooling and freezing on most of the Earth’s land during this time, extinction was found very distinct in this period. As to primitive plant life during the Cambrian period, algae was found to be the major group of plant life that existed in this period. These plants were known to have secreted lime-like substances which aid in the development and formation of rocks (Balisteri et al. ). Also, plants were found to have inhabited the lands first before the animals did during the Cambrian period. It was also during this period when the world’s primitive supercontinent, Pangaea, was believed to start breaking apart (Balisteri et al. ). During the Cambrian period, the large continent of the North America moved upward the globe through the equator. Gondwana, which is the largest remaining land mass of Pangaea during that time, divided into what we know today as India, Australia, Antarctica, and South America. The Ordovician Period (505-440 million years ago) The Ordovician period was characterized by the emergence of the world’s earliest volcanoes. This caused the formation of igneous rocks from the produced ash and lava from eruptions (Balisteri et al. ). This period was also marked by the continental submergence. The most highlighted part of this event was the Late Ordovician Flood which caused continents to contract and moved closer to each other. The most popular remain of this great flood as of today is the Atlantic Ocean (Balisteri et al. ). It was also noted that sea levels were generally high during the Ordovician period. However, there were still shallow waters that have been dated and found to have depositions of shallow water carbonated rocks. These were eventually traced through the presence of mudcracks and stromatolites nowadays (Gore 6). When it comes to life form evolution, diversification will best describe the action by the survivor organisms among the many life forms that became extinct from the Cambrian period (Farabee). During this period, the earliest forms of sea vertebrates, such worm-like creatures, evolved (Christian and McNeill 123). These are the creatures were found to be the ancestors of the sharks and common fishes today. These Ordovician marine vertebrates were complete with backbone, limbs, and a nervous system which formed mainly the head. Also, the remaining species that the Cambrian period left like the brachiopods, trilobites and mollusks were reported to undergo a Jurassic evolution. Thus, the first Ordovician marine vertebrates were reported to be armored, jawless, and covered with hard shells (Balisteri et al. ). On the other hand, the development of plants from the earlier group of green algae was also a milestone during this period. Scientific studies of fossils and biochemical proofs show that modern plant species rooted from the multicellular green algae that prospered during the Ordovician period (Cartage. org). Among these green algal groups, Charophytes were found to be most dominant at that time. These algae with the rest of the other algal groups were known to reside within the cool waters of the ocean, but between 500-400 million years ago, some algal groups were found to transfer to land through various levels of adaptations and evolutions which aided them to live outside the waters (Farabee). The Sulirian Period (440-410 million years ago) This period was characterized by the evolution of scorpion-like creatures as large as modern human beings (Christian and McNeil 123). These creatures were known as Euyperiods which were known to root from the extinct family of marine arthropods (Balisteri et al. ). These creatures were averagely 3 meters long and these were known to reside in the seas. Moreover, various other creatures that were abundant in the Cambrian and Ordovician periods have decreased in number during the Silurian period. Some of these animals were the Trilobites. However, the Silurian period was also distinct for the abundance of coral reefs, cephalopods, and jawed fishes that colored up and made the waters alive during this period. The said reefs have covered what people now know as the sea floors of Wisconsin, Illinois, Ohio, New York, Lake Michigan, Lake Huron, and Lake Erie (Balisteri et al.). This period was found to be dominated by the early vascular plants—which developed tiny tubes within their structures to support the transport of nutrients—as well as varieties of insects (Paull). However, both these plants and animals went through specific challenges which threatened their early extinction during that time. These challenges were that of 1) Drying out—plants and animals would have to take sometime to adapt to a new environment like when they transfer from water to land; 2) Gas exchange—respiration also takes sometime to adapt to the change in environment these creatures had to go through; 3. ) Weight support; 4. ) Conduction; and 5. ) Reproduction—the change in environment also has great effects on the reproduction process of organisms. More often than not, the change of environment tends to slow down their reproduction ability (Farabee). In addition, the Caledonian Mountain which is currently found in Canada was found to have started to form through the collision of European and North American plates (Paull). These were the major highlights and developments during the Early Paleozoic era of life and world history. This field of study may appear too complicated and boring for most people to study. However, by going through the facts and amazing discoveries of the life forms of the past and discovering how they come to produce what life is like today, it may seem that studying where the modern life rooted from is indeed an interesting and adventurous ride through both history and science. Works Cited Balisteri, Alex, Ulrike Balisteri, Bernd Bickel, Ron Schumacher, Beate Steger, and Sarah Young. â€Å"History of the Earth.† Think Quest. 1998. 04 December 2008 http://library. thinkquest. org/20886/. Christian, David and William H. McNeil. Maps of Time: An Introduction to Big History. California: University of California Press, 2004. Dawkins, Richard and Yan Wong. The Ancestor’s Tale: A Pilgrimage to the Dawn of Evolution. New York: Houghton Mifflin Books, 2004. Farabee, Michael J. â€Å"The Early Paleozoic. † On-Line Biology Book. 07 October 2002. Estrella Mountain Community College. 04 December 2008 http://www. cartage. org. lb/en/themes/sciences/Paleontology/Paleozoology/EarlyPaleozoic/EarlyPaleozoic. htm. Gore, Pamela J. W. â€Å"Early Paleozoic Events. † The Earth Through Time. 10 November 2005. Georgia Perimeter College. 04 December 2008 http://higheredbcs. wiley. com/legacy/college/levin/0471697435/chap_tut/chaps/chapter10-01. html. Paull, Gene J. â€Å"Early Paleozoic. † University of Texas at Brownsville. 20 August 2008. 04 December 2008. http://blue. utb. edu/paullgj/geol1404/lectures/early_paleozoic. html.

A Weird Experiece :: Personal Narratives Violence Crime Essays

A Weird Experience We were a threesome that late winter. Friday afternoons when Thomas got home at a decent hour he called on the intercom and I went down the hall to their apartment for drinks. Sometimes when he was late Krystal knocked on my door and asked me to come on down and keep her company. Later we might go out to dinner. Or we skipped dinner and just talked and listened to music. Sometimes on Saturdays he took his car and we drove down the Jersey shore or up the Hudson Valley or to Connecticut. Once we went out to The Hamptons where they were looking for a vacation house. Our friendship lasted exactly three months. A lucky number, Krystal said of the three of us. The perfect number. Thomas Milton was an investment banker. After getting his Masters from Harvard Business School, he'd returned to New York to a major firm and at 32 years old had already made $100 million, or close to it. Thomas was tall, handsome, charming—and Jamaican. His beautiful photo model wife, Krystal, was Dominican and rich in her own right. The Miltons had just bought and were remodeling a penthouse in a nearby Central Park West apartment building and would soon be moving from the cooperative. :: Inevitably we ended up talking about what I was calling in those days the great American divider—the color line. Not that Thomas and Krystal initiated our discussions; they said race didn't matter. No, it was I, the white liberal for whom race does matter, who turned an everyday conversation into a social study. I think they were embarrassed at my endless talk about such an immutable situation—they were black and basta, as Thomas once said soon after we met. And in general, he said, people are racists. That's just the way things are. Yet with each racial affront encountered, with each new racist attack reported on TV, with each new case of police humiliation, I returned to the attack. Relentless, I forced them to participate. How long, I asked piously, this chasm between whites and blacks? Why the fears? Why the silence? I often asked that winter why race had to change our relationship? Change everything? And deprive me of what I above all needed—their respect. One evening after a number of cocktails in the sprawling salon of their big 10th floor apartment I asked them point blank what it was like being black here in the city.

Non-Invasive Diagnostic Techniques

Non-Invasive diagnostic techniques| | X-rays| An X-ray machine is essentially a camera. Instead of visible light, however, it uses X-rays to expose the film. X-rays are like light in that they are electromagnetic waves, but they are more energetic so they can penetrate many materials to varying degrees. When the X-rays hit the film, they expose it just as light would. Since bone, fat, muscle, tumors and other masses all absorb X-rays at different levels, the image on the film lets you see different (distinct) structures inside the body because of the different levels of exposure on the film. Ultrasound| Ultrasound or ultrasonography is a medical imaging technique that uses high frequency sound waves and their echoes. The technique is similar to the echolocation used by bats, whales and dolphins, as well as SONAR used by submarines. | Thermography| | MRI| MRI scanners vary in size and shape, and some newer models have a greater degree of openness around the sides. Still, the basic des ign is the same, and the patient is pushed into a tube that's only about 24 inches (60 centimetres) in diameter.The biggest and most important component of an MRI system is the magnet. There is a horizontal tube — the same one the patient enters — running through the magnet from front to back. This tube is known as the bore. But this isn't just any magnet — we're dealing with an incredibly strong system here, one capable of producing a large, stable magnetic field. The strength of a magnet in an MRI system is rated using a unit of measure known as a tesla.Another unit of measure commonly used with magnets is the gauss (1 tesla = 10,000 gauss). The magnets in use today in MRI systems create a magnetic field of 0. 5-tesla to 2. 0-tesla, or 5,000 to 20,000 gauss. When you realize that the Earth's magnetic field measures 0. 5 gauss, you can see how powerful these magnets are. Most MRI systems use a superconducting magnet, which consists of many coils or windings of wire through which a current of electricity is passed, creating a magnetic field of up to 2. 0 tesla.Maintaining such a large magnetic field requires a good deal of energy, which is accomplished by superconductivity, or reducing the resistance in the wires to almost zero. To do this, the wires are continually bathed in liquid helium at 452. 4 degrees below zero Fahrenheit (269. 1 below zero degrees Celsius) [source: Coyne]. This cold is insulated by a vacuum. While superconductive magnets are expensive, the strong magnetic field allows for the highest-quality imaging, and superconductivity keeps the system economical to operate. |

Relationship Between Childhood Sexual Abuse And Eating...

The Relationship Between Childhood Sexual Abuse and Eating Disorder Symptoms Mallory Holt PSYC 401 Introduction Some studies have shown a correlation between physical, sexual and/or emotional abuse and eating disorders, but there appears to be no casual link. (Tripp, 2001). Between 30 to 50% of adult women report an unwanted sexual experience in either childhood or adulthood. This paper explores the connection between sexual abuse, specificity during childhood, and eating disorders. Eating disorders include anorexia nervosa, bulimia nervosa, binge eating and over exercising. Because of the complex nature, factors such as family interactions, self-esteem, core beliefs, body mass, depression, body image and laxative†¦show more content†¦(Jenkins, 2013). The desire for an idealized body shape may develop as a coping mechanism to compensate for an underlying fear of being taken advantage. This fear may have be established due to growing up where abuse occurs. There is some support for the hypothesis that bulimic behaviors act as blocking mechanisms to painful thoughts and experiences. Emotional abuse predicted drive for thinness, whereas sexual abuse predicted symptoms of bulimia nervosa (BN). Mistrust and abuse beliefs were found to fully mediate relationships between childhood abuse and drive for thinness and bulimia scales. Abandonment beliefs were also shown to be partial mediators of the relationship between sexual abuse and symptoms of BN. In a sample of nonclinical women, beliefs pertaining to abandonment and mistrust or abuse appeared to be important in the explanation of the relationship between recollections of childhood abuse and adult eating disorder symptoms. Laxative Abuse and Body Image Research has examined the relationship of physical and sexual abuse and distortion of body image. (Treuer, 2005). 63 patients with eating disorders were interviewed about their experiences of physical and sexual abuse. The Body Attitude Test was also used to examine laxative use and body image. Sexual abuse occurred in 29%, physical abuse occurred in 57% and laxative abuse occurred in 46%. Sexual abuse