Theory That Shook The World Essay, Research Paper
Theory That Shook The WorldOther than Mendellson and his studies with genetics,Darwin has by far contributed the most to our modern science.From his theories on variation of species to his explanation ofnatural selection Charles Darwin has shocked the world by provingthe world older than previously thought and creatures notimmutable. In this present day these theories are as commonbelief as a simple mathematical equation such as two plus twoequals four; but in the year eighteen hundred and fifty nineDarwin not only risked his reputation with these far fetchedfindings but also the risk of being excommunicated from thechurch. Previous to Darwin the thought had been that the worlditself was only a few hundred years old and that all creatureswere made by God in those seven days as they lived exactly today(Campbell p 421). Aside from past resistance, Darwin also comesunder scrutiny still today as missing fossils which are to havebeen the bridge between a two familiar species are not yet found(Hitching p 3). Whatever the reason of belief or disbelief inDarwin’s theories, he astounded the scientific world as well asthe public and was able to convince many in the presence of amisguided past belief. This fact alone makes him one of the mostimportant people of science ever. Charles Darwin was born in Shrewsbury-Shropshire,England on Feb 12, 1809 (GEA & RBi p 42). He was the fifth childin a wealthy English family with a history of scientificachievement with his paternal grandfather Erasmus Darwin who wasa physician and a savant in the eighteenth century (GEA & RBi p42). As a young boy Darwin already showed signs of his love fornature. When he was not reading about nature and its quirks hewas out in the forest looking for wild game , fish, and insects(Campbell p 424). His father, although noting his son’s interestin nature, felt that all the discoveries of the natural branch ofscience had been accomplished so he sent his son to medicalschool at Edinburgh instead (Bowler p 62). While Darwin wasthere, he could not keep his mind on his medical studies anddecided to go and study at the University of Cambridge and becomea clergyman. It was here that he was to meet two people whowould change his future forever; Adams Sedgwick and John StevensHenslow. Out of these two, Henslow turned into his second fatherand taught him to be meticulous in his observations of naturalphenomena (GEA & RBi p 42). Upon graduating in 1831, Henslowsuggested that he go on the Beagle as an unpaid naturalist on thescientific expedition (GEA & RBi p 43). Darwin gladly tookHenslow’s advice and set out on his voyage to South America toanalyze and collect data that would later back up hisevolutionary theories (Campbell p 424). Even as Darwin collected his data pertaining to whatwould become his theory on natural selection, many pre-existingviews still had a hold on the scientific world as well as thepublic. The earliest recorded were those of Plato and Aristotle.Plato (427-347 BC) believed in two worlds; an illusionary whichwas perceived only through our senses and a real world which wasideal and eternal (Campbell p 422). Aristotle (384-322 BC), onthe other hand, believed in a “scala naturae” in which each beinghas its own rung on a ladder which was permanent (Campbell p422). Also, there were the present religious views that had tobe dealt with as well as the ancient ideals. At that time manybelieved that animals and plants did not evolve because they weremade holy and immutable by God on those seven days (GEA & RBi p43). A person who was widely respected and also took somebeliefs from Aristotle and present religion was Carolus Linnaeus(1707-1778). He believed species immutable and later becameknown as the father of modern taxonomy (Campbell p 422). Perhapsthe largest barrier Darwin had was to convince the present dayscientists of his findings in contrast to their pre-existingtheories. The most common of the time was the catatropisttheory. The definition of this theory was that “a violent andsudden change in the earth” had destroyed all creatures and eachtime this happened, God would come back down and recreate all thelife in a seperate seven days (Webster p 131). This theory initself seemed created for the soul purpose of covering up thereason for fossils existing and misled thought of the speciesbeing immutable (Campbell p 423). After Darwin’s voyage on the Beagle, he had begun todevelop his own theory of evolution. His personal definition ofevolution was “in biology, the complex of processes by whichliving organisms originated on earth and have been diversifiedand modified through sustained changes in form and function” (JWVp 20). In regards to his research he had not only foundevolution in the wild but in the domesticated sphere as well.Darwin held that all related organisms descended from a commonancestor and he found examples easily in common life (GEA & RBi p43). One of these such examples were the domesticated pigeon.Darwin studied the skeletal and the live forms of the pigeons hehad found. In doing so, he found them all to be related but for
a small change in their phenotype. Phenotype being defined asfollows “the actual appearance of an organism” (GEA & RBi-2 p77). This small difference had been procured through the use ofbreeding and mutation. Perhaps the most notable would be thenumber of feathers in the fantail which ranged from twelve toforty feathers (Darwin p 42). Another example Darwin found inspeciation by domesticated breeding were cows and horses. By thedefinition of a gene pool, “large random assortment of genes thatmay be rearranged”, the farmers were able to produce a betterbreed of race horse or milk cow by breeding the best he hadtogether (JWV p 21). This sexual evolution was just seen by thepublic as a way to produce the necessary end but Darwin held itas important evidence of evolution accessible for all to witness.And to back up this finding in the domesticated breeds as well asthe wild he came up with his variability within a species. Thedefinition to variability within a species held that 1) theoffspring resemble the parents , but were not identical and 2)some differences in the parents were due solely to theenvironment but were often inheritable (JWV p 20). These twostatements as well as the backup with clinical data helped toshow that his theory was correct. Another area of variability was that of species in thewild. Perhaps Darwin’s most famed findings to back his theoryare “Darwin’s finches”. During his voyage on the Beagle he hadobserved thirteen different types of finches (Campbell p 425).These finches were found on seperate Galapagos Islands. Hereeach species of finch had at one time migrated to another island.In doing so the founder effect had been put into action. Thefounder effect being described as “when a few individuals of apopulation migrate and form a new colony having only a small genepool causing a new species” (JWV p 23). Due to the diversesurroundings and limited gene pool the thirteen species hadevolved from the original species that had migrated from themainland to the islands. Darwin also observed other animals onthese islands that were not found anywhere else in the world andbegan to doubt the churches teaching that species were immutable(Darwin p 29). The most controversial of Darwin’s theory was that ofnatural selection. The term evolution was so controversial evenDarwin did not use it but the phrase “origin of species” instead(Darwin p 27). Even though he did not term it evolution hisviews were definitely concrete and were laid out in a few simplesentences. These were the reasons why natural selection was away of life and always had been. First, Darwin proposed thatfood supply was too little to support the large population thuseliminating those who were not strong enough to find food andsurvive. Second, parents adapted to a certain environment wellwould pass on favorable traits that would help the nextgeneration survive, those without the trait would not survive.Third, each generation would become better adapted and ifremaining in the same environment would become more capable ofsurviving. Finally, even with all the above working there werealso factors of mutation, genetic drift, and bottle neck theorieswhich contributed to the survival of the fittest (GEA & RBi p43). Mutation being the most effective in changing a species hadfour factors by itself: 1) size of a population, 2) the length ofa generation’s life span, 3) the degree to which the mutation wasfavorable, and 4) the rate at which the same mutation appears indescendants (JWV p 21). Although most mutations are fatal, theyare key in changing the genetic make up of an individual.Genetic drift is described as when a species for some reasonbegins to drift apart or come together to create a new specie orspecies. This is typically seen in today’s fossil record when apresent species is related to an extinct animal. [see fig. 1] Another of the traits of natural selection is the bottle necktheory. Here a population has been destroyed to such an extentthat only a few survive. This limited population will recreate anew species based on its extremely limited gene pool and have ahigher chance of carrying a fatal gene. All these factorsworking together simultaneously create the phenomena of naturalselection. Darwin was not going to publish his findings but wasforced to by a young man Alfred Russel Wallace who had come tothe same conclusion after twenty years had passed. Although bothscientists names were on the original copies of the Origin ofSpecies Wallace regarded Darwin as the soul author. Within ayear of writing, Darwin published what would be twenty years ofresearch in 1859. Although, thoroughly backed up withpainstaking research, it was still refereed to as “the book thatshook the world” and in its first day of sales had sold out (GEA& RBi p 43). The immediate reaction in the science world was oneof disbelief. The leading scientists of the day said that Darwincould not prove his hypothesis and the concept of variation couldnot be proved. Darwin was to be doubted for the next seventyyears until the rediscovery of Mendel’s pea plant experiments(GEA & RBi p 43). With these new findings on genetics, manyscientists would take in account Darwin’s work. Some of thesepeople were to be a German zoologist named Ernst Mayr, a botanistG. Ledyard Stebbins, and paleontologist named George Simpson(JWV p 21).