Tree of Life in Evolution: A Discussion

Tree of Life in Evolution: A Discussion Introduction The tree of life in science describes the relationships of all life on Earth in an evolutionary context. Charles Darwin talks about envisioning evolution ; however, the books sole illustration is of a branched diagram that is very tree-like. The evolutionary relationships of the tree of life were refined using genetic data by the great American microbiologist Carl Woese, the discoverer of the domain Archaea and a pioneer in genetic methods in evolutionary biology. Homology and homoplasy are two aspects of evolution. Homology is the concept where two similar structures have the same functions and they are derived through descent from a common ancestor. The two other external factors affecting genetic variation Vertically generated and horizontally acquired variation. Vertically generated and horizontally acquired variation Vertically generated and horizontally acquired variation are the yin and the yang of the evolutionary process. They are very important to make evolution possible. Each of them is different in evolutionary impact. Vertically generated variation is highly restricted in character, it amounts to variations on a lineages existing cellular themes. Whereas for horizontal transfer, it can call on the diversity of the entire biosphere and systems that have evolved under all manner of conditions, in a great variety of different cellular environments. Thus, horizontally derived variation is the major evolutionary source of true innovation in novel enzymatic pathways and novel membrane transporter. Vertically generated variation is not very easy to manage and use. Vertically generated variation hold the key to the evolution of biological complexity and specificity. The essence of vertically generated variation on a lineages existing themes is the principal way in which biological specificity and cellular integration evolve. A horizontal acquisition of true novelty and a predominantly vertical generation of complexity and functional differentiation, and integration are the two forces whose interchange propels the evolution of the cell. Although horizontal transfer and vertical inheritance generally have very different evolutionary consequences, there are conditions important in the present context under which their effects copy one another, like two peas in a pod. Horizontal gene transfer is any process which an organism incorporates genetic material from another organism without being the offspring of that organism. By comparing with vertical transfer, it occurs when an organism receives genetic material from its ancestor like its evolved parent. Most scientists have focused on vertical transfer, but there is a awareness that horizontal gene transfer is a highly significant phenomenon, and amongst single-celled organisms are the dominant form of genetic transfer. Artificial horizontal gene transfer is a form of genetic engineering. The Cambrian explosion The Cambrian explosion or radiation was the seemingly rapid appearance of most major groups of complex animals around 530 million years ago, as evidenced by the fossil record. This was accompanied by a major diversification of other organisms, including animals, phytoplankton, and calcimicrobes. Before about 580 million years ago, most organisms were simple, composed of individual cells occasionally organized into colonies. Over the following 70 or 80 million years the rate of evolution accelerated by an order of magnitude in terms of the extinction and origination rate of species and the diversity of life began to resemble today. The Cambrian explosion has generated extensive scientific debate. The seemingly rapid appearance of fossils in the Primordial Strata was noted as early as the mid 19th century,and Charles Darwin saw it as one of the main objections that could be made against his theory of evolution by natural selection. The long-running puzzlement about the appearance of the Cambrian fauna, seemingly abruptly and from nowhere, centers on three key points: whether there really was a mass diversification of complex organisms over a relatively short period of time during the early Cambrian; what might have caused such rapid evolution; and what it would imply about the origin and evolution of animals. Interpretation is difficult due to a limited supply of evidence, based mainly on an incomplete fossil record and chemical signatures left in Cambrian rocks. The Cambrian explosion can be viewed as two waves of metazoan expansion into empty niches. Firstly, a co-evolutionary rise in diversity as animals explored niches on the Ediacaran sea floor, followed by a second expansion in the early Cambrian as they became established in the water column. The rate of diversification seen in the Cambrian phase of the explosion is unparalleled among marine animals: it affected all metazoan clades of which Cambrian fossils have been found. Later radiations, such as those of fish in the Silurian and Devonian periods, involved fewer taxa, mainly with very similar body plans. Although the recovery from the Permian-Triassic extinction started with about as few animal species as the Cambrian explosion, the recovery produced far fewer significantly new types of animals. Whatever triggered the early Cambrian diversification opened up an exceptionally wide range of previously-unavailable ecological niches. When these were all occupied, there was little room for such wide-ranging diversifications to occur again, because there was strong competition in all niches and incumbents usually had the advantage. If there had continued to be a wide range of empty niches, clades would be able to continue diversifying and become disparate enough for us to recognise them as different phyla when niches are filled, lineages will continue to resemble one another long after they diverge, as there is limited opportunity for them to change their life-styles and forms. There is a similar one-time explosion in the evolution of land plants: after a cryptic history beginning about 450 million years ago, land plants underwent a uniquely rapid adaptive radiation during the Devonian period, about 400 million years ago. Different Historical Fossil Records Of Plant And Animal Life Plant life during the cambrian and ordovician which are the first two periods of the paleozoic era was confined to the water. Algae of immense size several hundred feet in length dominated the seas. Land plants came into existence in silurian time in the form of strange little vascular plants named the psilophytes. In the carboniferous period, imposing spore bearing trees lepidodendrids and calamites, and primitive naked seeded plants pteridosperms and cordaites reached their peak of development. The end of the paleozoic era marked the extinction of the majority of the luxuriant trees of the carboniferous coal swamps. The mesozoic era was the age of gymnosperms as evidenced by the abundance of cycads, ginkgoes and conifers. Flowering plants in the form of angiosperm rose to ascendancy toward the close of the mesozoic era and established themselves as the dominant plant group on the earth. In animal life, many of the invertebrate groups were already highly diversified and abundant in the cambrian the first period of the paleozpic era 600 million years ago. The paleozoic era called the age of invertebrates with its multitude of nautiloids, eurtpterids and trilobites. Brachiopods with hinged valves were the commonest shellfish of the paleozoic seas. In the mesozic era, the air breathing insects and vertebrates in the shape of the widely distributed reptiles held the center of the stage. Birds and mammals became prominent in the cenozoic era and the human species arrived on the scene in the closing stages of this era. Paleontologist study the fossil record based on boundaries between strata where one mix of fossils gives way to another. Transitional links are intermediate between major groups. Archeopteryx has features intermediate between primitive reptiles and birds. Eustheopteron is fish ancestral to amphibians. Seymoria is amphibian ancestral to reptiles. Therapsids are reptiles ancestral to mammals. Data are understandable assuming humans and chimpanzees share a more recent commn ancestor than do humans and ducks or yeast. Biochemical evidence is generally consistent with anatomical similarity of organisms. Tortoises, lizards, sunflower trees and other unqiue plants and animals on the islands were similar to forms on the mainland of south american as they were descended from those organisms. The differences between each island group resulted from the inhabitants of each island having been isolated from each other and changing slowly and separately in response to the conditions on their own island. Factors Affecting The Pace Of Species Evolution The factors affecting species who had evolved significantly overtime while other species did not evolve as much are due to biological factors like point mutation and viruses infection where DNA is easily attacked and attracted by viruses. There are also one other important factor that support it. Natural selection, in the form of overproduction of offspring, constancy of numbers, struggle for existence where members of a species were constantly competing with each other in an effort to survive and only a few will live long enough to breed. There were also variation among the offspring, survival of the fittest where only the strongest will survive the tough condition. Like produce like and last but not least, the formation of new species where individuals lacking favourable characteristic are less likely to survive long enough to breed. The inheritance of one small variation will not by itself produce a new species. However, the development of a number of variations in a particular di rection over many generation will gradually lead to the evolution of a new species. Conclusion The prokaryotes, the bacteria and archaea have the ability to transfer genetic information between unrelated organisms through Horizontal gene transfer (HGT). Recombination, gene loss, duplication, and gene creation are a few of the processes by which genes can be transferred within and between bacterial and archael species, causing variation that is not due to vertical transfer. There is emerging evidence of HGT occurring within the prokaryotes at the single and multicell level and the view is now emerging that the tree of life gives an incomplete picture of lifes evolution. It was a useful tool in understanding the basic processes of evolution but cannot explain the full complexity of the situation. Ultimately, i concluded that tree of life is correct and accurate to a certain extent but the informations obtained was not enough and completed. REFERENCE HTTP://shiva.msu.montana.edu/courses/mb437_537_2004_fall/docs/uprooting.pdf HTTP://www.pnas.org/cgi/reprint/97/15/8392.pdf Futuyma, D. J. (1998) Evolutionary Biology. 3rd edn. Sunderland, Massachusetts: Sinauer Assiociates, Inc. Long, J. A. (1995) The Rise Of Fishes: 500 million years of evolution. Australia, Sydney: University of New South Wales Press. Solomon, E. P, Berg, L. R Martin D. W. (2002) Biology. 6th edn. Thomson Learning, Inc.

Field Trip Report: Arbi Falls Essay

The second field trip for Batch No: 1 on 30.01.2013 was to a water fall named â€Å"Arbi water-falls†. Our bus left us on the top of the plateau of Dasrath Nagar from where we had to walk down the steep slope of the plateau to get to the fields. We had to cross a swift stream of water which was very transparent and cold. We walked through the dykes, sort of no-man’s land made out of mud marking the boundary of two fields. Adjacent to the farmer’s house, which our sir described to over a hundred years old, was a well and a temple which was a special temple as there were big trees and people pray lord Vishnu in his cobra incarnation. It was also said to us that the people over there worship ‘Nagaraj’. We crossed a large number of bamboo barricades to visit the surrounding paddy fields, anywhere my eyes went I could only see greenery spread. The fields were quiet dense and we walked inside the canopy of large trees. After examining the nature around the place we headed towards the falls by the same way from which we entered. In few minutes we could cross the stream and reached the small road which headed us to the foothills of the falls. We had to cross the slippery rocks and thorny bushes to reach the top. We could also see the natural pores on the ground from where the water was oozing out very quickly and the natural water was really very pure and cold. We crossed the small valleys full of bushes and slippery rocks. Algae had grown on all the sharp edges and corners of the rocks, making it much more slippery. At last we reached the top of the falls to land on a barren field. There were houses all around that place. We took few pictures and left that place to board our bus. OBJECTIVE:- â€Å"To study a wetland ecosystem and observe the flora and fauna around Manipal.† LOCATION:- Co-ordinates: 13 °20’11†³N 74 °47’36†³E FLORA AND FAUNA:- Having a wide range of flora and fauna, the southern side of Manipal, frankly, is full of greenery. With a host bird species, butterflies, insects, snakes, cattle and other such animal species, the Dasrath Nagar area of Manipal can also boast about its variety in flora with a range of trees, ‘Acacia’, ‘Cashew’, etc. being the primary ones. PROBLEMS FACED BY LOCAL FARMERS:- Lack of labour Pests destroying their products Insufficient water supply Not much profitable farming PROBABLE SOLUTIONS:- Government should give machines and more mechanized products to the farmers in less cost so that they can use those and produce efficiently without the labour present. Pesticides and similar products should be given to the farmers in less costs so that they can use it efficiently on their fields, water supply can be enhanced by making well, use of motors to suck water from the falls and distribute to their fields. CONCLUSION:- It is a recently discovered waterfall near Manipal Lake. This waterfall is active only through the months of August to November, during the monsoon season. Recently this waterfall has come in the spotlight. Hence, a lot of people and Manipal University (MU) students have started coming here. Due to this increase of people, the waterfall and the nearby areas have started getting polluted. People living near the waterfall complain that visitors come and throw plastic bottles, chips wrappers and garbage near the fall.

Coe Case Stydy Essay

The Coe’s company has been in business since the 1950’s when the founder Terry Windham invested $600 in 32 chairs to rent out to auction houses. From there on, the business expanded into party equipment and sickroom gear. The founder further shifted the business into household goods and residential furniture in the 1970’s. The company has since been growing. Stan Windham, Terry’s son who now is the CEO of Coe’s, recently opened its 1000th store in South Tucson and the company is taking over $2 billion a year in revenues. Unlike their competitors, Coe’s has had an advantage in the market by always emphasizing ownership and offering monthly payments schedules with shorter contract periods. They trained their managers to only approve lease agreements for people who they were sure they could afford the payments. Also, one of their strengths was to be able to identify and target the customers who never before were interested in renting-to-own but due to the state that the economy was in, they were afraid to commit to big-ticket items and instead decided to rent-to-own. They also attracted customers by offering free delivery and free repairs with an option to return the item if customer was not able to make payments but when their financial situation improved they could resume the contract with no penalties. A weakness of Coe’s I would say would be that the company did not diversify their risk and solely built growth strategy only in the U.S. Except for Mr. Rental, Coe’s dos not have any other direct competitors in South Tucson. Yes, Wal-Mart is there as well but neither Mr. Rental nor Wal-Mart are the same as Coe’s. To distinguish itself from Mr. Rental, Coe’s offers shorter contract periods, free delivery and free repairs and Wal-Mart is not a rent-to-own company. However, there are other external factors to be considered and those being both opportunities and threats. Coe’s has been considering entering into the Mexican market, which they believe would be a good strategic move for the company and help them diversify their portfolio. Taking into consideration the low transportation, labor and real estate costs, Mexico would be an inexpensive place to open a new Coe’s store. Of course where opportunities exist, threats exist also. With plenty of growth  opportunities in the U.S., an expansion to Mexico would add complications and risks to the company. The company had experienced this first hand when they tried to expand to Puerto Rico and due to shrinkage and not being able to find the right personnel that did not go to well. On top of everything, the consumer protection advocates are attacking the rent-to-own companies by claiming that the prices of the products are 60% to 90% higher than those of traditional retailers. While every investor is aiming towards growth, they also want to play it safe. Coe’s has been considering going international and building a growth strategy in other parts of the world for a while. By comparing the strengths and weaknesses, the company is holding a strong competitive position and it can continue to do business at its current pace. I also believe that they should expand their business in Mexico. An expansion to Mexico would offer a great potential. An in-depth market research will help analyze the patterns and habits of costumers. Doing business in Mexico will not only help the company grow but it will also benefit the U.S. economy. Ever since NAFTA took effect, both large and small American companies have expanded in Mexico. A range of locations in Southern USA have developed rapidly to keep up with the heavy trade between US and Mexico offering new jobs to U.S. Citizens and boosting the U.S. economy.

Why Dont Spiders Get Stuck in Their Webs

The spiders that make webs – orb weavers and cobweb spiders, for example – use their silk to ensnare prey. Should a fly or moth unwittingly wander into a web, it becomes instantly entangled. The spider, on the other hand, can rush across the web to enjoy its freshly captured meal without fear of finding herself trapped. Did you ever wonder why spiders dont get stuck in their webs? Spiders Walk on Their Tiptoes If youve ever had the pleasure of walking into a spider web and having silk plastered on your face, you know its kind of a sticky, clingy substance. A moth that flies full speed into such a trap doesnt stand much of a chance of freeing itself. But in both cases, the unsuspecting victims came in full contact with the spider silk. The spider, on the other hand, doesnt tumble willy-nilly into its web. Watch a spider traverse its web, and you will notice it takes careful steps, tiptoeing delicately from thread to thread. Only the tips of each leg make contact with the silk. This minimizes the chances of the spider becoming ensnared in its own trap. Spiders Are Meticulous Groomers Spiders are also careful groomers. If you observe a spider at length, you may see her pull each leg through her mouth, gently scraping off any silk bits and other debris that inadvertently stuck to her claws or bristles. Meticulous grooming probably ensures that her legs and body are less prone to sticking, should she suffer a misstep in the web. Not All Spider Silk Is Sticky Even if a disheveled, clumsy spider should trip and fall into its own web, its not likely to get stuck. Contrary to popular belief, not all spider silk is sticky. In most orb weaver webs, for example, only the spiral threads have adhesive qualities. The spokes of the web, as well as the center of the web where the spider rests, are constructed without glue. She can use these threads as pathways to walk around the web without sticking. In some webs, the silk is dotted with glue globules, not completely coated in adhesive. The spider can avoid the sticky spots. Some spider webs, such as those made by funnel-web spiders or sheet weavers, are constructed only of dry silk. A common misconception about spiders is that some kind of natural lubricant or oil on their legs prevents silk from adhering to them. This is entirely false. Spiders do not have oil-producing glands, nor are their legs coated in any such substance. Sources: Spider Facts, Australian MuseumSpider Myths: That Web Aint Normal!, Burke MuseumSpider Myths: Oily to Bed, Oily to Rise, Burke Museum