Theory Of Natural Selection By Darwin

Theory Of Natural Selection By Darwin This paper gives an explanation of Darwins theory of natural selection. As well, the paper fully gives a description of natural selection in terms of modern evolutionary synthesis of the 20th century. The paper also gives application of the principles of natural selection to explain the current problem of antibiotics resistance in bacteria. Finally the paper gives a summary of scientific theories about evolution before Darwins discovery of natural selection. Generally this is a very important theory which has been greatly adopted by students and teachers of genetics presently. Outline Introduction Summary of Scientific Theories about Evolution before Darwins Discovery of Natural Selection Description Of How The Discovery Was Made By Darwin. Natural Selection In Terms Of the Modern Evolutionary Synthesis Of the 20th Century Natural Selection and Its Relationship to Antibiotic Resistance in Bacteria Conclusion Introduction Charles Darwin is known to be the father of evolution and heredity and came up with principles that govern heredity. His one outstanding principle is that of natural selection that dictates that if evolution was elucidated as a car, and then the theory of natural selection would be its engine. The theory categorically states that its the nature that controls and select organisms, which tend to have favorable characteristics for survival while at the same eliminating species that are inferior (Fairfield, 2000). Darwins theory is significantly a very important landmark in the process of evolution and origin of species. The principle is regarded as the key to the formation of new and superior species from old and existing ones. This is to say that nature selects superior traits, which are transmitted to the offspring in a manner that is independent on the other. The major explanation behind the theory is that one superior allele tends to be dominant over the others, blending a genetic make up and traits that influence a certain trait segregate during organism growth and development. Therefore, this research paper looks at all principles of natural selection, its relationship to the current problem of antibiotics resistance in bacteria, and its description in terms of modern evolutionary synthesis of the 20th century. Summary of Scientific Theories about Evolution before Darwins Discovery of Natural Selection Darwins theory of Natural Selection is generally regarded as a significant landmark in the origin of organisms and evolution process. Before Darwin, many scientists like him alleged that species evolved from other species or antecedent. Mostly during those times there was no any scientific evidence to prove that concept hence many theories went unnoticed. Prior to Darwins theory especially in medieval times, the concept of evolution was not much appreciated for the reason that origin of organisms was regarded as Gods creation. This idea claimed that organisms came into existence in a way that they were unchanged, hence going against the notion of evolution. Many scientists like Immanuel Kant established a notion of descent that was close to modern view; were he suspected that organisms may have originated from a common ancestor .His analysis emerged from studies of Orang Utang which he claimed had capacity to develop structures similar to those of man. Despite the fact that his theory is currently linked with modern views; the theory never gave any plausible mechanism that would drive changes in organisms.Carolus Linnaeus is another scientist who is viewed as the father of contemporary taxonomy in relation to his work of hierarchical classification in both plants and animals. In his theory, he viewed hybridization in plants as a process that could produce new plant species. However, he still supported the theory of creation that goes against the theory of evolution. Erasmus Darwin (Charles Darwins grandfather) was also a very illustrious naturalist who believed that life could have originated from a common ancestor. His theory states th at the disuse of organisms parts could in their own mechanism make the parts grow or shrink. Jean-Baptiste Lamarcks theory of evolution is another medieval theory that has been discredited by modern experimental evidences. His theory concentrated on the idea that living organisms could transfer certain traits acquired during natural life to its offspring. He saw organisms as immutable and not permanent (Zirkle, 1941). Another theory about Evolution before Darwins Discovery of Natural Selection is the theory of population growth that was coined by Thomas Malthus between 1766-1834. According to the theory, Malthus claimed that populations could produce large number of offsprings that could have capacity to stay alive on the available limited resources available. He viewed diseases, famine, and poverty to be the consequence of overpopulation. He never believed on the concept of evolution and he viewed the natural calamities as the wrath of God. Description of How the Discovery was Made By Darwin Charles Darwin started formulating his world-renowned theory of Natural Selection in late 1830s and early 1840s, but the process went on silent for about 25 years. Darwin conducted widespread research on animals and plants in order to learn the critical process of evolution. It was during his research work in Galà ¡pagos Islands that made him understand the theory of evolution. In his studies, he observed that birds dwelling in different islands displayed minor differences in their physical features .On one occasion he found out that different species of Finches birds had different beak sizes and shapes. After analysis, he discovered that the difference in beak sizes and shape was because of food available in particular islands (Fairfield, 2000). Contrary to this results, Darwin results showed that their was only one specific Finches species in South America, which summed up the idea that Finches species in Galà ¡pagos could have developed from species found in central parts of South America. Further research work showed that this Finches species reproduced and survived, while those that could not familiarize themselves with environment died. As a result, Darwin concluded that organisms belonging to similar species illuminated some unique variations among them (Sober, 1984).Organisms possessing favorable characteristics showed capacity to live and reproduce, consequently passing the acquired trait genetic material to the offsprings from one generation to another. With the help of Alfred Russel Wallace, would had also similar results for the birds he used in his studies, established similar theories which then led to development of the book On the Origin of Species, which was published in 1859 (Zirkle, 1941). Natural Selection In Terms Of the Modern Evolutionary Synthesis Of the 20th Century Modern Evolutionary Synthesis is defined as an amalgamation of concepts or ideas from different evolution and biological area of expertise, which gives an extensively accepted explanation of evolution. The concept of Natural Selection generally relies on the idea of heredity, which developed before the fundamental models of genetics. Evidence of natural selection in relation to Modern Evolutionary Synthesis Of the 20th Century relates to Mendels theory and research work. Despite the fact that Gregor Mendel, known to be the father of heredity who came up with principles that govern heredity, was a modern concept of Darwin work, his work became appreciated in early years of the of 20th century (Hasan, 2005). This came because of integration of Darwin theory and Mendels work which one outstanding principle is that of independent assortment which dictates that the allele pairs will separate in an independent manner during gamete formation. This is to say that the traits would be transmit ted to the offspring in a manner that is independent of the other. The major explanation behind this notion relies on the Natural Selection strategy where alleles that are dominant over the others are passed over to the next generation, where the hereditary units then influence a certain trait to segregate during gamete formation. Another evidence of natural selection in relation to Modern Evolutionary Synthesis Of the 20th Century relates to T. H. Morgan research work on Drosophila melanogaster. The concept of Natural Selection has helped establish a relationship between Chromosomal Theory of Inheritance and the Mendelian Theory Genetics, which has established that instead of mutations creating species in single steps, it creates variations in genetic makeup that varies among populations. Other modern evolution advances relates to research works of W. D. Hamilton and John Maynard Smith, which have led to development of Gene-Centric View of Evolution in the mid 1960s. This synthesis has increased the extent of Darwinian Theory of Natural Selection to include consequent scientific advances that include genetics and DNA analysis. The work of G. Ledyard Stebbins, a botanist, is another most important contributor to the natural selection in relation to Modern Evolutionary Synthesis (Sober, 1984). His work has extended the concept of natural selection where the effects of polyploidy and hybridization shows dihybrid cross involving linkage of two genes which have no crossing over. From the Law of Independent Assortment, alleles from genes assort in an independent manner during formation of the gametes. Natural Selection and Its Relationship to Antibiotic Resistance in Bacteria In recent past, some bacteria species have showed extraordinary ability to develop resistance to certain types antibiotics, which are commonly used to treat most common illnesses. An antibiotic refers to a natural matter or material that is released by fungi or bacteria to kill competing micro organisms for limited available resources. In recent past scientists have discovered that some bacteria strains have started showing resistance to certain antibiotics through different mutations, or alterations in the organisms genetic material (DNA). This resistance results in situation where changes occur in the bacteria molecular material and mostly results from events such as antibiotic over and under prescription, poor hygiene, and environmental changes. If the target bacteria obtain changes in its molecular material for genes coding a specific protein, the antibiotic then cannot bind to affected protein hence the mutant bacterial organism survive (Purdom, 2007). Under the effects of antibiotics, the process of Natural Selection occurs, thus favoring the growth, development, reproduction, and survival and of the mutant or malformed bacteria. Concept of natural selection also plays part when bacteria obtain mutated genetic material from other micro organisms, where they swap genetic material from each other. This allows transfer of DNA into the bacteria, thus altering its structure making them transfer new DNA to its offsprings.Presence of new DNA makes the next generation resistant to antibiotic. The concept of natural selection and mutation supports bacteria populations to become resistant to antibiotics. On the other hand, these changes through natural selection also lead to emergence of strains with defective proteins that tend to have abnormal functions. Conclusion Charles Darwin is known to be the father of evolution and heredity and came up with principles that govern heredity. His one outstanding principle is that of natural selection, which categorically states that, nature controls and selects organisms that have favorable characteristics for survival while at the same eliminating species that are inferior. In conclusion, it is agreeable that Charles Darwin theory of natural selection is very important in respect to heredity and evolution.

Osmosis and celery lab experiment Essay

Diffusion is simply the net movement of atoms or molecules from a region of higher concentration to a region of lower concentration. The force behind the movement is heat or kinetic energy (also called Brownian motion). Diffusion occurs when you spill water on the carpet floor and it spreads out, or when you open a bottle of perfume and it leaves the bottle and spreads throughout the air in the room. Osmosis is a similar phenomenon that moves water from a region of high water concentration to a region of low water concentration. Imagine that a cell from your body is placed in a solution of water. If the concentration of the water inside the cell is the same as the concentration of water in the solution, then we describe the water solution as being â€Å"isotonic† or having the same concentration as the water inside the cell. In this case, net movement of water will be zero and the cell will not swell or shrink. In other words, the same amount of water will move in the cells as will move out. On the other hand, if the cell is placed in a solution of water that has a higher concentration (of water) compared to the concentration of water inside the cell, then osmosis will cause more water to move into the cell than will move out and this will cause the cell to swell. In this case, we say that the solution of water is â€Å"hypotonic†. Now imagine that the cell is placed in a solution of water that has a lower concentration (of water) compared to the concentration of water inside the cell. In this case osmosis will cause more water to move out of the cell than will move in the cell and the cell will shrink. In this case, we say that the solution is â€Å"hypertonic†. Learn more about osmosis and diffusion from Chapter 3 of your textbook. CELERY EXPERIMENT We can place celery in three different water solutions to observe the effects of osmosis on the celery stalks. Salt will serve as our solute to mix with water to make the water either hypotonic, hypertonic or isotonic. The hypotonic solution will contain less salt so that the amount of water compared to salt will be greater than the amount of water inside the cells (compared to the salt and other solutes inside the cell.) The hypertonic solution will contain more salt so that the amount of water compared to the  salt will be less than the amount of water inside the cells (compared to the salt and other solutes inside the cell.) The isotonic solution will contain an amount of salt that will be similar to the amount of salt and other solutes inside the cells of the celery. Materials: knife measuring cup and spoon two stalks of celery (they should be fresh and firm, not bend like rubber) table salt three containers with lids (or something to cover the containers) to hold the solutions and the celery stalks filtered or soft water, distilled water works best, tap water will work if it the mineral content is not too high (tap water with high mineral content is called â€Å"hard† water) Procedures: 1. cut four pieces of celery that are each two inches long (be sure they are all the same length) 2. make four vertical slices or cuts into the celery but make the cuts only three fourths of the length or 1.5 inches; space the vertical cuts as evenly apart as possible 3. label the three containers A, B and C 4. add one cup of water to each container 5. add NO salt to container â€Å"A† 6. add  ½ teaspoon of salt to container â€Å"B† and stir well 7. add 2 teaspoons of salt to container â€Å"C† and stir well 8. place one of your 2 inch cut pieces of celery into each of the three containers and keep the fourth piece as a control for comparison 9. cover the three containers with the lid or cover that you are using, you could use a cling plastic wrap as well 10. wrap the fourth control celery piece tightly in plastic wrap 11. leave the celery pieces in the three containers and the fourth wrapped (control) piece for 6 hours or overnight at room temperature 12. remove the pieces from the containers and bend them while observing how firm or flexible they are 13. record your observations of each of the four pieces of celery below Observations: Solution Flexibility compared to the control stalk (less flexible, similar, more flexible) More water moved into or out of the cells? Indicate which solution was isotonic, hypotonic, and hypertonic A When the celery stalk was placed in solution A. The water moved through and in the cells of the celery which is an example of osmosis. Water moves through the cells. The stalk was firm and less flexible. More water moved into the celery’s cells. The celery stalk was nice and firm after the allotted time. More water and less to no solute, is an example of hypotonic solution. Which means there is â€Å"less† osmotic pressure. B In solution B the celery became a little more flimsy. Solution has a little salt. Slightly less water moved into the celery’s cells. The reason the water didn’t move as freely through the cells is due to the small amount of solute. This is an example of hypertonic, or greater osmotic pressure. This solution has a higher concentration of solute than the hypotonic solution. C In solution C the salt/ solute is very present. The celery became very flimsy after 4 hours. Even less water moving into cells. The celery became â€Å"very† flexible and very flimsy. The water was not moving through the cells even at a higher rate. This solution is a full example of osmosis. In osmosis the solute is of greater concentration of the solute. The diffusion of pure solvent across a membrane in response to a concentration gradient,

The Leaked Secret to English Essay Outline Discovered

The Leaked Secret to English Essay Outline Discovered English Essay Outline Secrets In the USA, there's a good deal of controversy surrounding the minimal legal drinking age of 21. Low-income areas can entice little businesses as a result of decrease cost of operation, and can grow economically as a consequence of the new jobs, improving the standard of life of the region. It's only feasible to create a synopsis in case you've got familiarity with the area. If you take a close look at research paper outline examples, you will observe we have several tactics to present the most important body. Lies You've Been Told About English Essay Outline A debate can be composed by purdue on-line essays online resume authors. What country would you like to reside in essay. You can rely on the ideal essay help online. Once you get your completed essay, make certain to tell all your friends what a wonderful service it is and what's the perfect place to get cheap essays. Nowadays it's quite difficult to locate a trustworthy essay writing service. There are numerous essay writing services that think they're the very best, and therefore don't be cheated and check the genuine collection of the very best. Get the Scoop on English Essay Outline Before You're Too Late You might also see speech outline. A consistent structure ought to be used in the key headings and the subheadings. Let's look at an excellent case of an outline. It is an impossible task to compose a persuasive research paper without having and very clear outline. The significance of the outline in the research paper is clear. An outline will help to learn the way a student will build other critical sections like Literature Review. By studying various outline samples, you're guaranteed to come up with the ideal research paper outline in virtually no time. Whether you do a very simple research or a complicated one for a larger project, a research outline can help you receive the best outcomes. Finding out how to compose a thorough outline for a research paper is a more complicated course of action. An outline is intended to help you set a structure for a paper you are likely to write. A comprehensive outline is essential for writing a very good research paper. But What About English Essay Outline? It is possible to also Speech Outline Template. A research outline template is readily gettable on the web. Though it might look difficult, as soon as you become familiarized with the rules and format, it is going to become easier. The perfect way to get a comprehension of the APA outline format is to have a look at examples. Completing an MLA outline will make sure your research paper format is accurate. APA format is usually utilized in the social sciences. The Hidden Gem of English Essay Outline There are more than a few reasons, but generally, it could possibly be valuable to make an outline if you want to demonstrate the hierarchical relationship or logical ordering of information. It's possible that you use quotes or paraphrase regions of the text to be able to add evidence. In the event of a lengthier project, it's challenging to imagine a successful writing process with no obstacles in the event the outline is missing. Additionally, among the crucial purposes of an outline is to clearly convey the link between the thesis and every one of the topic sentences. A graduate pa per outline isn't an exception, it must be done following the typical rules known to a lot of students but the primary difference could be in the content that it is going to carry. Example, on types of work that's a written you'll become 1 mistake students to compose a specialist. Every student demands help with homework from time to time. By time to time, even the best students realize it's problematic as the write-up must perhaps not comprise information regarding the topic matter but in addition significant research of selected issues to compose an article that's superb. Thus a sample might enhance the general performance and presentation of the paper which will assist them in future too. In order to start outlining the research paper, determine why you're researching the subject. For research papers, an outline may assist you in keeping an eye on considerable amounts of information. A well-made outline is crucial in locating considerable info and keeping track of conside rable amounts of information from a research paper. Who Else Wants to Learn About English Essay Outline? If you're thinking that you require someone to compose my essay at the moment, you can merely rely on our honest reviews. Employing an outline template can assist the student organize the paper and eliminate the ideas that aren't pertinent to the function of the essay. A systematic approach will definitely assist you to produce a brilliant research paper. The most frequently encountered paper writing service that the majority of our clients require is essay writing.

Definition and Examples of Semantic Entailment

In semantics  and pragmatics, entailment is the principle that under certain conditions the truth of one statement ensures the truth of a second statement. Also called strict implication,  logical consequence, and semantic consequence. The two types of entailment that are the most frequent in language, says  Daniel Vanderveken, are truth conditional and illocutionary entailments. For example, he says, the performative sentence I beg you to help me illocutionary entails the imperative sentence Please, help me! and truth conditionally entails the declarative sentence You can help me (Meaning and Speech Acts: Principles of Language Use, 1990). Commentary [O]ne statement entails another when the second is a logically necessary consequence of the first, as Alan lives in Toronto entails Alan lives in Canada. Note that the relationship of entailment, unlike that of paraphrase, is one-way: it is not the case that Alan lives in Canada entails Alan lives in Toronto. (Laurel J. Brinton, The Structure of Modern English: A Linguistic Introduction. John Benjamins, 2000) [M]any, if not all, assertive sentences (statements, propositions) of a language allow for inferences solely on the basis of their meanings. For example, when I say Ben has been murdered, then anyone who has understood this utterance and accepts its truth will also accept the truth of the statement Ben is dead. (Pieter A. M. Seuren, Western Linguistics: An Historical Introduction. Wiley-Blackwell, 1998) Entailment Relations An entailment can be thought of as a relationship between one sentence or set of sentences, the entailing expressions, and another sentence, what is entailed... We can find countless examples where entailment relations hold between sentences and countless where they do not. The English sentence (14) is normally interpreted so that it entails the sentences in (15) but does not entail those in (16). (14) Lee kissed Kim passionately. (15)a. Lee kissed Kim.b. Kim was kissed by Lee.c. Kim was kissed.d. Lee touched Kim with her lips. (16)a. Lee married Kim.b. Kim kissed Lee.c. Lee kissed Kim many times.d. Lee did not kiss Kim. (Gennaro Chierchia and Sally McConnell-Ginet, Meaning and Grammar: An Introduction to Semantics. MIT Press, 2000) The Challenge of Determining Meaning Semantic entailment is  the task of determining, for example, that the sentence: Wal-Mart defended itself in court today against claims that its female employees were kept out of jobs in management because they are women entails that Wal-Mart was sued for sexual discrimination. Determining whether the meaning of a given text snippet entails that of another or whether they have the same meaning is a fundamental problem in natural language understanding that requires the ability to extract over the inherent syntactic and semantic variability in natural language. This challenge is at the heart of many high-level natural language processing tasks including Question Answering, Information Retrieval and Extraction, Machine Translation, and others that attempt to reason about and capture the meaning of linguistic expressions.Research in natural language processing in the last few years has concentrated on developing resources that provide multiple levels of syntactic and semantic analysis, resolve context sensitive ambiguities, and identify relational structures and abstractions.... (Rodrigo de Salvo Braz et al., An Inference Model for Semantic Entailment in Natural Languages.  Machine Learning Challenges: Evaluating Predictive Uncertainty, Visual Object Classif ication and Recognizing Textual Entailment, ed. by  Joaquin Quià ±onero  Candela et al. Springer, 2006)