Thi_Thing

Section One: Research a) Using your own words briefly outline the Darwin/Wallace Theory of Evolution by Natural Selection and Isolation. The theory of evolution by natural selection and isolation was proposed jointly by Charles Darwin and Alfred Russel Wallace in 1858 to account for observations made on their extensive voyages. The theory outlines that characteristics favourable to the reproduction and survival an organism in their environment will be selected for, and over time, new species will appear in response to environmental changes. Some organisms possess characteristics more suited to the environment than others. These organisms are therefore more likely to survive and more likely to reproduce passing their characteristics onto their offspring. Gradually, over many generations, new organisms better adapted to the environment will evolve. The theory of natural selection is simply “the survival of the fittest” with fitness not only referring to being healthy, but to being well adapted to the environment but also to the reproductive capacity of the individual. The core of Darwin's theory is natural selection, a process that occurs over successive generations and is defined as the differential reproduction of genotypes. The theory is based on five important factors: 1. All organisms produce more offspring than can actually survive. 2. Each organism must face a constant struggle for survival. 3. The individuals of a given species have varying characteristics as a result of sexual reproduction. 4. Those individuals with characteristics best suited to the selective pressures of the environment will survive and reproduce. 5. Over many generations these characteristics will increase in the population. [pic][1] The Process of Natural Selection A new species will develop if members of the same species are subjected to different environmental pressures. This requires some form of isolation. The commonest type is geographic isolation. When two populations of the same organism become separated by geographical barriers, for example, mountain ranges or stretches of water, different selection pressures operate in the two areas. The populations may start to vary in their appearance and behaviour. After several generations, members from these two areas may not be able to interbreed and therefore at least one, and possibly two, new species would have evolved. The best example of this theory can be seen in the Galapagos finches. The Galapagos Islands finch species has been found in no other part of the world, though similar to the ones that exist in South America. The birds are slightly different from one island to another in terms of beak structure. The differences in the beak structure are associated with the differences in diet due to the types of food available on each island. [pic] [2] The different finches found on the Galapagos Islands were believed to have originated from the species found in South America 600 miles east of the Islands. The above picture shows the different shapes of the beaks of the finches Darwin observed in the Galapagos Islands [3] Darwin concluded that when the original South American finches reached the islands, they dispersed to different environments where the different environment pressures selected the different finch beak characteristics.  Over many generations, they changed anatomically in ways that allowed them to get enough food and survive to reproduce. [pic][4] b) Analyse information from secondary sources on the historical development of theories of evolution. Leonardo Da Vinci contributed to the theories of evolution through his observations of the rock formations, mountains, rivers and fossils in his native north Italy. He gasped the principle that rocks can be formed by deposition of sediments by water, while at the same time the rivers erode rocks and carry their sediments to the sea, in a continuous grand cycle. Leonardo appeared to have grasped what is known today as the law of superposition. He also appears to have noticed that distinct layers of rocks and fossils could be traced over long distances, and that these layers were formed at different times. Nearly three hundred years later, the rediscovery and elaboration of these principles would make possible modern stratigraphy and geological mapping. There were many hypotheses that attempted to explain how the shells came to be at the top of a mountain, but Leonardo discarded these and wrote, “Such an opinion cannot exist in a brain of much reason.” [5]Leonardo’s answer was remarkably close to the modern one: fossils were once-living organisms that had been buried at a time before the mountains were raised. It was possible, Leonardo thought, that some fossils were buried by floods. [pic][6] Charles Darwin's grandfather, Erasmus Darwin, was one of the leading intellectuals of eighteenth century England, a man with a remarkable array of interests and pursuits. As a naturalist, he formulated one of the first formal theories on evolution in Zoonomia, or, The Laws of Organic Life (1794-1796). Although he did not come up with natural selection, he did discuss ideas that his grandson elaborated on sixty years later, such as how life evolved from a single common ancestor, forming "one living filament"[7]. He wrestled with the question of how one species could evolve into another. Erasmus Darwin also talked about how competition and sexual selection could cause changes in species. Erasmus Darwin arrived at his conclusions through an "integrative" approach: he used his observations of domesticated animals, the behaviour of wildlife, and he integrated his vast knowledge of many different fields, such as palaeontology, biogeography and comparative anatomy. Beginning in 1801, Jean Baptiste Lamarck began to publish details of his evolutionary theories. "Lamarckism" is now often used in a rather derogatory sense to refer to the theory that acquired traits can be inherited. What Lamarck actually believed was more complex: organisms are not passively altered by their environment. Instead, a change in the environment causes changes in the needs of organisms living in that environment, which in turn causes changes in their behaviour. Altered behaviour leads to greater or lesser use of a given structure or organ; use would cause the structure to increase in size over several generations, whereas disuse would cause it to shrink or even disappear. Lamarck also believed that all such changes were heritable. The result of these laws was the continuous, gradual change of all organisms, as they became adapted to their environments; the physiological needs of organisms, created by their interactions with the environment, drive Lamarckian evolution. While the mechanism of Lamarckian evolution is quite different from that proposed by Darwin, the predicted result is the same: adaptive change in lineages, ultimately driven by environmental change, over long periods of time. Yet despite these differences, Lamarck made a major contribution to evolutionary thought. He gave voice to the idea that species could change over time. He developed a theory that paralleled Darwin's in many respects. Charles Darwin and Alfred Wallace both worked independently of each other, travelled extensively, and eventually developed similar ideas about the change in life over time as well as a mechanism for that change: natural selection. Charles Darwin secured an unpaid position as ship's naturalist on the H.M.S. Beagle. The voyage would provide Darwin a unique opportunity to study adaptation and gather a great deal of proof through his many observations that he would later incorporate into the theory of evolution. Darwin spent much time ashore collecting plant, animal and fossil specimens, as well as making extensive geological observations. On his return to England in 1836, Darwin began to catalogue his collections and ponder the seeming "fit" of organisms to their mode of existence. Unlike the upper class Darwin, Alfred Russel Wallace (1823-1913) came from a different social class. Wallace spent many years in South America, publishing salvaged notes in Travels on the Amazon and Rio Negro in 1853. In 1854, Wallace set out on a collecting expedition to the Malay Archipelago. During his travels he decided that the geographical distribution of species results from evolutionary forces Alfred Russel Wallace, co-developer of the theory of evolution. In 1858, Charles Darwin received a letter from Wallace, in which Darwin's as-yet-unpublished theory of evolution and adaptation was precisely detailed. Darwin and his colleagues arranged for Wallace's paper to be read at the July 1, 1858 meeting of the Linnean Society, along with a letter on the same subject by Darwin. Wallace's paper, published in 1858, was the first to define the role of natural selection in species formation. Darwin rushed to finish his major treatise, the origin of species, which remains one of the most influential books ever written. To be correct, we need to mention that both Darwin and Wallace developed the theory, although Darwin's major work was not published until 1859. While there have been some changes to the theory since 1859, most notably the incorporation of genetics and DNA into what is termed the "Modern Synthesis" during the 1940's, most scientists today accept evolution as the guiding theory on which modern biology is based. Careful field observations of organisms and their environment led both Darwin and Wallace to the role of natural selection in formation of species. Neither Darwin nor Wallace could explain how evolution occurred: how were these inheritable traits passed on to the next generation' During the 20th century, genetics provided that answer, and was linked to evolution in Neo-Darwinism, also known as the Modern Synthesis. [pic][8] Selective pressures experienced by Wild Mustard to produce some food crops. c) Outline briefly creationism, which was the prominent view up until Darwin’s theory. Creation or Creationism is the belief system regarding origins holding that all material in the universe was created out of nothingness (ex nihilo) by a deity, or by one or more powerful and intelligent beings through supernatural, theistic, or mythological means. Many societies have creation stories that are not ex nihilo.[9] While the term creationism in principle describes the belief that God created the world and all life, it is most often used for belief that this occurred literally as described in the book of Genesis (for Jews and Christians). The terms Creationism and Creationist have become particularly associated with beliefs conflicting with the theory of evolution by natural selection. Many faiths which believe in divine creation accept evolution by natural selection as well as, to a greater or lesser extent, scientific explanations of the origins and development of the universe, the Earth, and life – such beliefs have been given the name evolutionary creationism, though others call them "theistic evolution". Creationism grew as a result of the advancement of evolution that was evident after the publication of 1859 of Darwin’s Origin of Species. Within two decades, most of the scientific community had accepted some from of organic evolution. Many religious leaders, however, feared that a less-than-literal reading of the biblical story of creation would result in a loss of faith. One of the problems for Theistic Evolution has been something known as the “Neo-Darwinian Synthesis.” Begun in the 1940s, this was a synthesis of the work being done by field biologists on the one hand and experimental work performed by geneticists on the other. This process managed to eliminate many of the “mysteries” in how evolution and natural selection work. Traditionally, Theistic Evolution has relied on the idea that evolutionary theory hasn’t been able to explain how evolution works. These mysteries were gaps in our understanding of nature and, as has happened so often in the relationship between religion and science, religious belief relied upon gaps in scientific knowledge which have become all but filled. Once those gaps are indeed filled, what is the basis for continuing religious belief and continuing Theistic Evolution'[10] d) Outline and assess the social and political influences on the Historical development of the Theory of evolution. As the idea of evolution started to spread in the world, society became split in beliefs. Today the theory is more widely accepted but during the time of Darwin and his fellow contributors, society was outraged with this deplorable idea that questioned all of their beliefs. Social factors that influenced the historical development of the theory of evolution were: • Evolutionary Creationism – the prominent view in western cultures at the time of Darwin was creationism. This was the belief that living things were created for their environments at the same time by God in six days; the organisms have not changed and are not related. Darwin’s theory went against this belief stating that organisms have changed over millions of years. At a time of strong religious influence, society and the church protested against these ideas and campaigned against these anti-biblical ideas of evolution. • The prevailing view of the history of the earth was that a series of sudden catastrophes has shaped a world which was only about 6000 years old. A catastrophist would have held the view that not much, if any, biological evolution would have taken place between catastrophes. To them, catastrophes, such as the flood described in the Bible, represents the principle means of geological and biological change. The theory of evolution questioned this by suggesting that the earth was millions of years old. • God and Religion – in spite of the mountain of scientific evidence, Darwin’s theory of evolution was and still is rejected by many religious people. The idea that God did not create each species individually in their present form caused a furore among society. This theory questioned everything people believed in and based their lives upon. In response to the wide scientific acceptance of the theory of evolution, many religions have formally or informally synthesized the scientific and religious viewpoints. Several important 20th century scientists, whose work confirmed Darwin's theory, were also Christians who saw no incompatibility between their experimental and theoretical confirmations of evolution and their faith. Some religions have adopted a theistic evolution viewpoint, where God provides a divine spark that ignited the process of evolution and (or), where God has guided evolution in one way or another. • Basis of Power – in the 19th century in Britain and Europe man was considered to be at the pinnacle of a hierarchy of organisms, steadily increasing in perfection. This idea of evolution diminishes humans to the same level as every other organism, particularly the idea that humans are descendents from apes, and threatened the basis of power. By giving importance to scientific thought, it also threatened the power of the religious institutions that had long held political and social power. The theory was immediately and continuously criticised by these institutions as being degrading to the status of humans. Political factors that influenced the historical development of the theory of evolution were: • Passing of laws – in the USA the people campaigned against the publication and declaration of any anti-biblical ideas of evolution. This lead to several states passing laws banning teaching in Universities and all other public schools of the State which are “supported in whole or in part by the public school funds of the State, to teach any theory that denies the story of the Divine Creation of man as taught in the Bible, and to teach instead that man has descended from a lower order of animals.” [11] • Scope Trial – in 1925 John Scopes, a teacher from Tennessee, was arrested and put on trial for teaching the theory of evolution to his class. It was a confrontation between fundamental Christians and evolutionists and between opposing politicians and lawyers. Even though scopes lost the case, the media coverage of the trial brought the controversy to public attention. • Economics and Social Ideas – Some on political left, especially Marxists and communists have been critical of aspects of the theory evolution by natural selection (Darwinism). Some of this opposition appears for ideological reasons; the concept of "survival of the fittest" appears not to fit with economic or social ideals. e) Bibliography Aubusson, P and Kennedy, E 2000 Biology in Context: The Spectrum of Life Oxford Melbourne Victoria Australia Butler Tennessee Evolution Statutes 1925 http://www.law.umkc.edu/faculty/projects/ftrials/scopes/tennstat.htm Caddy, Rhonda and West, Jane 2003 Macquarie Revision Guides HSC Biology Macmillan Sydney NSW Australia Carroll, Robert Todd Creationism and creation science 2005 http://skepdic.com/creation.html Cline, Austin Theistic Evolution & Evolutionary Creationism: Combining Evolution & Creationism http://atheism.about.com/od/creationismcreationists/p/theistic.htm Creeper, John Natural selection May 1984 http://www.answersingenesis.org/creation/v6/i4/naturalselection.asp Encyclopaedia Britannica 2002 [CD – ROM] 2002 Britannica Sydney Australia Farabee, MJ Development of Evolutionary Theory 2001 http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookEVOLI.html Grohol, John M Social effect of evolutionary theory 1995 http://psychcentral.com/psypsych/Social_effect_of_evolutionary_theory Guralnick, Rob Erasmus Darwin (1731-1802) 1995 http://www.ucmp.berkeley.edu/history/Edarwin.html Kelly, N and Hatherly, J and Rosen, G 1989 Focus On Life McGraw-Hill Roseville NSW Australia Douglas Linder The Evolution Controversy 2000 http://jurist.law.pitt.edu/trials1.htm O'Neil, Dennis Darwin and Natural Selection 1998 http://anthro.palomar.edu/evolve/evolve_2.htm Regents of the University of Michigan 31/10/2004 Evolution and Natural Selection [On-Line] http://www.globalchange.umich.edu/globalchange1/current/lectures/selection/selection.html Schneider, Susie Evolutionary Creationism 1984 http://www.orot.com/ec.html Waggoner, Ben Jean-Baptiste Lamarck (1744-1829) 1996 http://www.ucmp.berkeley.edu/history/lamarck.html Waggoner, Ben Leonardo Da Vinci (1452-1519) 1996 http://www.ucmp.berkeley.edu/history/vinci.html Section 2: First Hand Investigation Experiment: Modelling Natural Selection Aim: To model natural selection. Hypothesis: the green toothpicks would be better camouflaged in the grass and therefore harder to find than the red toothpicks. Apparatus: 50 green toothpicks 50 red toothpicks Area of grass Plastic container Method: 1) 1000 toothpicks were purchased and 500 of them were painted red and the other 500 were painted green. 2) 10 students then counted out 50 of each colour, which were then placed in a plastic container. 3) A grassy area was selected and each of the students lined up in a line on the grass about a metre apart. 4) Each student then scattered the toothpicks in their area of grass. 5) The students were allowed 30 seconds to gather the toothpicks, each being picked up individually. 6) Once the 30 seconds was up, the red and green toothpicks collected were counted and the results of the 10 students were recorded in a table. 7) The method was then repeated and again the results were recorded. 8) Once the results from the two trials were tabulated, the results from each student were averaged. Results: |Number of Toothpicks Retrieved | |Student |Red |Green | |1 |20.5 |17.5 | |2 |19 |13 | |3 |25 |11 | |4 |20 |17.5 | |5 |28.5 |13 | |6 |27.5 |22 | |7 |18 |15.5 | |8 |19 |18 | |9 |17 |16.5 | |10 |20 |16.5 | |Total |214.5 |160.5 | Conclusion: Results and Natural Selection The different coloured toothpicks represented two different forms of the same species. The green toothpicks were the form best suited to the environment as they were better camouflaged in the grass and hence harder to find, so they “survived” more often than the red toothpicks. If the population of toothpicks was able to reproduce, the green toothpicks would be able to pass on their genes and there would be more green toothpicks in the next generation. This trend would continue over several generations. However, if there was a change in the environment, for example, the background was changed to red, then the selection process would favour the red toothpicks and this from would become more common in subsequent generations. This activity models the theory of natural selection. Problems Encountered - Not all of the toothpicks were fully painted. - Some of the toothpicks were stuck together so two may have been picked up at the one time - In the first trial the toothpicks were thrown but because they did not scatter far enough they had to be recovered and the trial repeated. In doing this, some of the toothpicks could have been missed when recovering them. Evaluation of the Investigation Method in Terms of Conclusions Drawn The method used in the investigation is successful in demonstrating that the green toothpicks are harder to find because of their more favourable characteristic of camouflage which better suits them to the environment. The red toothpicks, on the other hand, are exposed to more selective pressures limiting their survival in the environment. The green toothpicks are shown to be better suited to the environment as supported by the averaged results of the two trials, with 214.5 of the red being found compared with 160.5 of the green being found. Validity and reliability Validity is how accurate the results found are. For all methods to be valid, we need to: - Test one variable at a time - Control all other variables - Be consistent in the methods used - Choose appropriate equipment and use correctly In the first trial, only one variable was tested – the gathering of the toothpicks. The number of toothpicks in both colours was controlled. However, there were some variables that were not controlled. Where the investigation was performed changed from trial one and trial two as well as the formation of the students. In the second trial, the students stood in a circle, which caused some of the toothpicks to be mixed with those of other students. The way in which the toothpicks were scattered changed according to the container used because of its size and shape. These variables were therefore not controlled, decreasing the validity of the investigation. The method was inconsistent over the two trials. There was a limited quantity of equipment that was used and for that reason it could be used correctly in both of the trials. For results to be reliable the experiment needs to be repeated several times, under the same conditions, and obtain the same results. The method used in this investigation was repeated by 9 other students and the results recorded allowed for comparison. Each person repeated the investigation twice increasing its reliability. This gives 20 separate results that were similar in each trial, demonstrating that the experimental results were valid and reliable. The investigation was replicated under the same conditions with the exception of the area of grass on which it was performed. Advantage of Group Results Group results allow a greater field for comparison as each individual scattered their toothpicks in different directions, at various distances and had a different size area in which to gather their toothpicks. By using a group the results are not bias. The group results were the best to use as they increased to reliability of the investigation by showing that similar results are gained by each trial. ----------------------- [1] http://www.globalchange.umich.edu/globalchange1/current/lectures/selection/selection.html [2] http://anthro.palomar.edu/evolve/evolve_2.htm [3] http://anthro.palomar.edu/evolve/evolve_2.htm [4] http://www.globalchange.umich.edu/globalchange1/current/lectures/selection/selection.html [5] http://www.ucmp.berkeley.edu/history/vinci.html [6] http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookEVOLI.html [7] http://www.ucmp.berkeley.edu/history/Edarwin.html [8] http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookEVOLI.html [9] http://skepdic.com/creation.html [10] http://atheism.about.com/od/creationismcreationists/p/theistic.htm [11] http://www.law.umkc.edu/faculty/projects/ftrials/scopes/tennstat.htm