Primate Evolution Essay Example for Free

Primate Evolution Essay The theory of evolution began when man first noted his distinct similarity to apes. The possibility of a common ancester with the modern apes had been discussed since the mid 1800’s, but it wasn’t until Charles Darwin published his book, On the Origin of Species in 1859, that the idea was considered legitimate. Since that time, fossil records have helped us to deliniate and define our evolutionary history and to describe the many human-like species that have lived on the earth over the last 8 million years. Charles Darwin studied a population of finches that had been isolated on the Galapogos Islands, and described the theory of natural selection, whereby over time, each finch had changed in ways that made it more successful in a particular niche. He observed fourteen different species of finches, all who were very similar, except for the size and shapes of their beaks. He noted how each type of beak was shaped very specifically for the type of food the bird ate and explained that the changes were due to the natural selection of the characteristics in a species that made it more successful at obtaining food and at reproducing. If a finch with a slightly longer beak was more efficient at eating termites from holes in trees, he would survive longer and reproduce more than his short beaked counterparts who ate termites. His offspring that inherited his slightly longer beak would also survive longer and reproduce more. Over time, the longer beaked finches would be more prolific than the shorter beaked version within that particular niche and the adaptation would flourish while the shorter beaked finches would die out. Eventually, speciation occured (the development into reproductively separate species), as the termite eaters with longer beaks became more distinctly separate within their environment and became reproductively isolated. This gradual change of a segment of a population into reproductively different species, in response to an environmental pressure (competition) for survival factors is called adaptive radiation. Although Darwin mentioned nothing about human evolution in his first book, his science minded peers were able to understand how his theory applied to humans. Initially there was much debate by the general population over the idea that humans could have evolved from the same lineage as an ape, but by 1870s, the scientific community had already come to the general conclusion that a fossil record would be found in Africa, where our great ape relatives were found. In the 1920’s, as predicted, Raymond Dart found bones from Australopithecus africanus, a hominid who lived between 2-3 million years ago in the Pliocene Era. They were discovered in a cave in Africa. From the skeletal structure he was able to determine that the specimen was bipedal; a defining trait of humans, and the size of its braincase was between that of modern humans and apes. Since that time, paleoanthropologists have been able to trace the evolutionary history of the primates including hominids, for some 85 million years and can determine many facts about their lifestyle through the study of fossils and other artifacts (O’Neal, 2006). There is not a complete record, and although paleoanthropologists have presented us with many pieces of the puzzle, we do not know exactly how man evolved into the species we are today. Some researchers have speculated that many of our developed traits were due to adaptations for an aboreal life. The premise of this idea is that as angiosperms became prevailant, an overlapping canopy developed that allowed cross movement from tree to tree. The canopy was a niche that had little competition and provided advantages for primates. Over time and through natural selection, primates took to the trees. They developed opposable thumbs and short finger nailed, grasping hands for holding onto branches, binocular vision for depth perception, and more complex brains to be able to better deal with balance and complex navigation (Simons, 1992). The difficulty with this idea is determining why, since there are other aboreal animals without these characteristics, primates developed them. There had to be some other factors that added the pressure for choice of these characteristics in primates. A primary characteristic of hominids is bipedalism. We likely developed from a chimpanzee-like, knuckle walking ancestor. The reason for the change from using all four limbs for locomotion to standing upright, on two limbs is unknown. There are several theories that focus on environmental conditions as being the motivating factor. One such theory is called the Savannah Hypothesis which proposes that due to drier conditions, the African forests thinned and disapeared. Bipedalism developed both as an adaptation to facilitate movement across the grasslands and as a way to give early hominids use of their hands for food cultivation and tool use since they were no longer needed for locomotion (Simons, 1992). The pressures that fuel evolutionary trends are those that are required for the species improved survival. We immediately think of food and shelter, but perhaps the most critical in insuring the continuation of a species is reproductive strategy. Primate reproductive strategies today include those that are monogmous (one male and one female), those that are polygynous (one male and multiple females), those that are polandrous (one female, multiple males), and those that are promiscuous (multiple males, multiple females). Eighty percent of primates practice polygyny, eighteen percent practice monogomy, with polandry seen only in some of the Callitrichids, the marmosets and tamarins, and promiscuity seen in chimps. The evolution of polygyny can be easily rationalized. In polygynous strategies, the egg has a high energy cost and the female puts her energy into childcare. Males may help with childcare as well, but females have a long period of gestation and then a period of lactation, so childcare is their primary focus. Females must focus also on food, not only for themselves, but for their offspring, whether directly or as an energy source for lactation. Therefore, female primates will naturally search for food sources. It is advantageous for females to congregate for childcare, for shared food sources and for safety. Reproductive success for a female primate is through the focused care of each individual offspring. Males do not have the same enforced biological costs throughout the reproductive process. Sperm are easily produced in large quantities at a low energy cost. Reproductive success for males is through the number off offspring he can produce. Under these circumstances, polygyny is the most efficient reproductive strategy for species survival (O’Neal, 2006). Mongomous primates have a different environment. Monogomy is driven by the spacial arrangements of females or when the male’s role in childcare is critical. When females do not gather, it is logistically not feasible for the male to obtain additional mates. Gibbon females will not tolerate another female in her claimed territory. The males might have the tendancy toward polygyny, but the females won’t allow it. Monogomy in tamarins is necessary because of the relative size of the offspring to parent size. The young, although still dependent on parental care, quickly grow to near adult size. It is nearly impossible for a single female to raise her offspring alone. Although reproductive strategy is varied among primates, each species’ tendancy is based on the evolutionary pressure for their survival and success. Recent fossil discoveries have been able to describe an evolutionary history that dates back as far as 4. million years ago to the Autraliopitecines. An almost complete skeleton was found in 1974 in Hadar, Ethiopia and adopted the name Lucy. This was the first human –like homonid. Lucy was bi pedal and had a large brain for her body size of 48 inches. Since that time, other fossils of Australopitecines have been uncovered, but Lucy remains the most complete, and is the standard for the species (Primate Info Net, 2008). Homo habilis is thought to have descended directly from a species of Australopithecine hominid and lived from approximately 2. 2 to 1. million years ago. Fossils found in Tanzania in 1962 by Louis and Mary Leakey show that Homo habilis was short and had long arms, like the Australipithecines, but had a decrease in facial protrusion, giving it a more human-like appearance. They used rudimentary tools in their hunting and gathering (Primate Info Net, 2008). Homo erectus had a larger brain case than Homo habilis and stood slightly more erect. They also had more sophisticated tools that were able to cut and slice. They had discovered the use of fire and were the first actual hunter-gatherer society. They lived approximately 2. 2 to 1. 1 million years ago and were the first to leave Africa and travel throughout the Great Rift Valley (Primate Info Net, 2008). . Homo sapiens archaic or Neanderthal Man inhabited Europe and parts of Asia approximately 1. 2 million years ago. They were a fairly sophisticated society. They buried their dead, had fire, ate meat and had modern tools like hand axes and knives. They were adapted to a colder climate with short, robust statures and large noses. Their brain capacity was greater than modern humans and they had language. There were probably only about 10,000 Neanderthals and they slowly disappeared as modern man, Homo sapiens sapiens began to appear 200,000 years ago (Primate Info Net, 2008). . Throughout man’s evolutionary history there has been a trend toward greater intelligence, mobility and refined physical and mental control. We are evolving each day towards a better version of ourselves. Are we the final model? Or will we eventually be replaced by a more efficient, successful hominid? In all likelihood, we will.

The Characters Of Samson And Dalila in Miltons Samson Agonistes Essay

The Characters Of Samson And Dalila in Milton's Samson Agonistes      Ã‚   The character of Dalila is first described by Samson, in his opening dialogue with the Chorus, as "that specious Monster, my accomplish'd snare." He also later describes her as "fallacious, unclean, unchaste". Thus when she finally appears in person, the reader is perhaps surprised to hear the Chorus uses a simile of a pulchritudinous ship to describe Dalila, "so bedeck'd, ornate and gay". It is the first mention of her physical beauty. Neither does the Chorus merely mention it in passing; the chorus takes a total of eleven lines to describe the full extent of Dalila's beauty. The Chorus continues this extended simile, admiring her "tackle trim . . . and streamers waving". She even smells sweet, being followed by a damsel train and "amber scent of odorous perfume". It seems as if the Chorus has fallen under Dalila's spell as Samson had.    Samson, however, is under no such illusions. Perhaps his blindness prevents him from capitulating to her beauty, in the same way that in Greek mythology, sailors, having blocked up their ears, saw the Sirens for the evil creatures that they were, rather than be charmed to their deaths by their beautiful singing. His blindness is perhaps the reason that he has made no reference to Dalila's beauty - her seemingly only asset he is no longer able to appreciate. Unlike the Chorus, Samson is not so welcoming. He calls her a "Traitress" and bids the Chorus not to let her go near him. The Chorus, however, seems powerless to act against Dalila, as "yet on she moves". They appear to still be under the spell of Dalila's captivating beauty, this time assimilating her beauty with that of "a fair flower". ... ...le Milton. New York: Penguin, 1977 [1949]. Erskine-Hill, Howard. Poetry and the Realm of Politics. Oxford: Oxford University Press, 1996. Fish, Stanley. How Milton Works. Cambridge: The Belknap Press of Harvard University Press, 2001. Hale, John K. "Milton's Preface to 'Samson Agonistes.'" The Explicator. Vol. 52. No. 2. P. 73. (Winter 1994): 3 pp. Online. Internet. 20 April. 1997. Lewalski, Barbara. The Life of John Milton. Malden: Blackwell Publishers Inc, 2000. Martindale, Charles. John Milton and the Transformation of Ancient Epic. Totowa: Barnes and Noble Books, 1986. Milton, John. Samson Agonistes.   In John Milton: Complete Poems and Major Prose. Ed. Merritt Y. Hughes. New York: Macmillan, 1957. 531-93. Radzinowicz, Mary Ann. Towards Samson Agonistes: The Growth of Milton's Mind. Princeton:   Princeton University Press, 1978.

How Effective Are Various Methods in Reducing Recidivism Essay

Prison, non-custodial sentences and rehabilitation seem all failed in reducing recidivism; however, there is little and limited evidence to support non-custodial sentences, as well as some people think if rehabilitation could be implemented effectively, it would work. Although the advantage of prison is keeping our society from dangerous people, when it comes to reducing recidivism rate, the effect of prison is disappointing. The public usually think that imprisonment is safer for communities; however, it appears powerless to deter inmates from committing crime again. In the article, â€Å"Study shows building prisons did not prevent repeat crimes†, Fox Butterfield (2002) cites a large-scale study of recidivism from the Bureau of Justice Statistics, which investigated up to 272,111 former prisoners in 15 states during the first three years after being released. It found that 67% of inmates broke the law again in three years right after their release in 1994. It is surprised that it does not make any difference to recidivism rate which was studied in 1960’s, and it is even 5% higher than the study done in 1983. In addition, it indicated that the more rearrest records a criminal has, the higher recidivism rate he has. The inmates who have more than 15 prior arrests have 82. 1% of recidivism rate. Nevertheless, according to Emily Kingham’s article (2006), she believes that prison forces offenders to regret and reflect on their behaviour; as for the reason that criminals cannot reject the temptation of committing new crime is because of inadequate provided support. In spite of this, some experts have admitted that prison does not work in terms of reducing recidivism rate (Considering the alternatives 1978; Finckenauer 1988). Some limited evidence has shown that non-custodial sentences may decrease recidivism; regardless of some experts being sceptical about their desired achievements. On the one hand, alternative sentences can help government save money and alleviate over-cramped number of criminals in prison (Considering the alternatives 1978). On the other hand, Kingham(2006) points out that alternative sentences do nothing but return prisoners to their original circumstances, which result in unawareness of their crimes and the onsequences. One study indicated that through one of alternative sentences, intensive probation, recidivism rate is less than 20%; however, the evidence maybe weak as the study has not been completely put into practice (Considering the alternatives 1978). Furthermore, in the Minnesota, alternative sentences have been successfully adopted to keep criminal rate not increasing, but it may not be convinced because of the source not being confirmed (Considering the alternatives 1978) . While some people argue rehabilitation is also failed in reducing recidivism rate, some authors counter that if government could support rehabilitation, recidivism rate would decrease. According to the article, â€Å"Prison†, James O. Finckenauer (1988) cites some studies, which shows that even though the government has already provided with good rehabilitation programmes, they cannot achieve reformatory of inmates. On the other hand, this position is contested by Joan Petersilis (cited in Butterfield 2002), a professor of criminology at the University of California at Irvine and an expert on parole, who says that state governments spent such little money on rehabilitation programs that inmates do not receive sufficient help with drug addition, work skill and preparation for a new life, which may lead increasing recidivism rate. Butterfield (2002) further cites the statement by Mr. Travis, who also argues that criminals return to crime.

Are Skyquakes Real Science of the Mystery Boom

A skyquake or mystery boom is like an earthquake in the sky. If youve ever heard a sonic boom or cannon fire then youll have a good idea what a skyquake sounds like. Its a stupendously loud, window-rattling noise. While a sonic boom is caused by an object breaking the sound barrier, a skyquake is when a boom occurs with no apparent cause. Are Skyquakes Real? You can search YouTube for videos of skyquakes to hear what they sound like, but be warned: many of these videos are hoaxes (e.g., skyquake2012s channel). However, the phenomenon is real and has been reported for centuries. Locations reporting skyquakes include the Ganges river in India, the East Coast and Finger Lakes of the United States, the North Sea of Japan, the Bay of Fundy in Canada, and parts of Australia, Belgium, Scotland, Italy and Ireland. Skyquakes have their own names in various parts of the world: In Bangladesh, they are called  Barisal guns (referring to the Barisal region of East Bengal).Italians have several names for skyquakes, including balza, brontidi, lagoni, and marine.The Japanese name the sounds umimari (cries from the sea).In Belgium and the Netherlands, skyquakes are called mistpoeffers.In Iran and the Philippines, they are retumbos.In the United States, some recurring skyquakes are the Seneca guns (near Seneca Lake, New York) and Moodus noises in Connecticut. Possible Causes While sonic booms from aircraft might explain some skyquakes, the explanation doesnt account for reports predating the invention of supersonic flight. The Iroquois of North America believed the booms were the sound of the Great Spirit continuing creation of the world. Some people believe the sounds are produced by UFOs. Most scientists propose other possible explanations: Some modern skyquakes may be sonic booms from meteors or military aircraft.Earthquakes and volcanic eruptions may produce sounds that are heard far from their point of origin. There are well-documented accounts of booming sounds associated with earthquakes, particularly those with a shallow origin. For example, the quakes in Spokane, Washington in 2001 and New Madrid, Missouri in 1811-1812 were accompanied by reports resembling artillery fire.The sound may be distant thunder, with the sound focused by atmosphere. Some skyquakes may also result from clear-sky lightning (the bolt from the blue).  which occurs near mountain ranges or large open areas, such as plains, sounds, or lakes.Some skyquakes may be produced by coronal mass ejections (CMEs). A CME is a solar radiation storm that can accelerate protons to 40 percent of the speed of light, potentially generating shock waves that break the speed of sound and produce sonic booms.A related explanation is that the Earths magnetic fiel d produces the sounds, either by accelerating particles or from resonance. While skyquakes occur all over the world, most of them have been reported near a coast. Some explanations focus on the possible relationship between proximity to water and skyquakes. One disputed hypothesis is that the sounds may be produced when parts of the continental shelf fall into the Atlantic abyss. Problems with this hypothesis are the extreme distance from the ridge to the site of reported sounds and the lack of modern evidence. Another water-related explanation is that the sounds are produced when underwater caves collapse, releasing trapped air, or that trapped gas escapes from vents or from beneath decaying aquatic vegetation. Experts disagree about whether the sudden release of gas could produce a loud report. Scientists believe there are several occurrences which are not likely causes of skyquakes. There is no evidence booming sounds are associated with global warming, industrial disasters, tectonic plate shifts, the hole in the ozone layer, or ghosts revisiting past battles. Other Strange Sky Sounds The booming sound of a skyquake isnt the only incompletely explained atmospheric noise. Strange hums, trumpeting, vibrations, and wailing have also been reported and recorded. Sometimes these phenomena are called skyquakes, although the origin of the boom is likely quite different from that of the other eerie noises. Fast Facts A skyquake is a loud boom that has no apparent cause.While some videos of skyquakes are hoaxes, the phenomenon is real and has been reported all over the world.Scientists believe skyquakes have a variety of causes, including meteors, coronal mass ejections, escaping gas, and collapsing landmasses. References and Further Reading Dimitar Ouzounov; Sergey Pulinets; Alexey Romanov; Alexander Romanov; Konstantin Tsybulya; Dimitri Davidenko; Menas Kafatos; Patrick Taylor (2011). Atmosphere-Ionosphere Response to the M9 Tohoku Earthquake Revealed by Joined Satellite and Ground Observations. Preliminary results.K., Krehl, Peter O. (2008).  History of shock waves, explosions and impact a chronological and biographical reference. Springer. p. 350.T.D. LaTouche, On the Sounds Known as Barisal Guns, Report (1890-8) of the annual meeting By British Association for the Advancement of Science, Issue 60, pp. 800.