The Role Of Hybridization In Speciation Biology Essay

The Role Of Hybridization In Speciation Biology Essay Charles Darwin had published, The origin of species by natural selection, using his lifes discoveries and analysis to define what a species is and how species originate follow through as a contentious debate especially in the study of evolutionary biology. The study of evolution helps us to understand what species are by loosely idealizing it as alien till one feeds on their hunger to gain knowledge about what has created the world and the extant and extinct varieties that have claimed it, including man. Many different species are discussed and debated continuously, with each one being weighed by pros and cons which can also be seen as the strong point to either validate the concept or a short -fall to nullify it. The most accepted definition of current is Mayrs biological species concept, according to Coyne Orr (2004) who have accepted nine species concepts (Claridge et al, 1997). Mayrss biological species concept places the evolution of complete reproductive isolation as the focal point of the process and nature of speciation (Mayr, 2002), the biological species concept was the solid basis of which he based his belief in gene flow being absent in some species, a decreased fitness level to certain hybrids. It is believed that the emergent species would infrequently form from the process in question according to Mayr (2002). Hybrid speciation implies that hybridization has had a principal role in the origin of a new species, hybrid species that have doubled their chromosome number (Mallet, 2007), the definition applies: 50% contributions from each derived species initially contain exactly one genome from each parent, although, in older polyploids, recombination and gene conversion may eventually lead to unequal contributions (Mallet, 2007). The factor which is critical in hybrid speciation is due to being reproductively isolated with a decreased fitness-level; therefore these progeny formed are of transitional then it is more likely to be more weakly reproductively isolated. Speciation can also be influenced by hybridization by the factor of reinforcement, this means that obstacles in reference to mating because of unfit hybrids being chosen, even-though progeny from this relationship does not form from the courtship, the scenario is questionable as to whether reinforcement can be looked at as hybrid spe ciation. An example of this that can be discussed is the diploid or triploid frog Rana esculenta which is complete heterozygous for Rana lessonae and Rana ridibunda genomes (Mallet, 2007; TunnerNopp, 1979). Poly-, Allopoly- and Homoploidy, is it all just about how you do It? Plants use the means of polyploid evolution; these species are reproductively isolated due to the process of mating with diploid mates which give rise to uneven ploidies of progeny like triploids. These progeny may be able to reproduce but these progeny would cease to exist due aneuploidy (Stebbins, 1971; Grant, 1981; Ramsey Schemske, 2002) polyploidy is a simple way of creating speciation. Bisexually polypoid speciation is highly prevalent in plants as compared to animals due to: plants usually have indeterminate growth and somatic chromosome doubling can lead to germline polyploidy, germline refers to the sex cells that an organism contains which is sperm, egg and pollen in plants. Plants are often perennial or temporarily clonal which allow multigenerational persistence of hybrid cells within which polyploid mutations occur; plants are more often hermaphrodites, in rare polyploids self-fertilization allows a means of sexual reproduction (Mallet, 2007). Gene flow is weaker in pla nts as compared to animals with local populations which have unusual ploidy ( Bullini, 1994; OttoWhitton, 2000; Astaurov, 1969). Speciation can occur by the process of duplication of chromosomes within a species or duplication of hybrids (Mallet, 2005) between an autopolyploidy and allopolyploidy, respectively. Allopolyploid speciation follows self-fertilization and gives rise to a tetraploid; this can be seen from studies on Primula kewensis which was a result of Primula verticillata and Primula floribunda which had cultivated diploid hybrids. Speculation had lead to the belief that fusion of unreduced gametes had caused this due to the failure in reduction divisions during meiosis. A triploid species, known to be sterile, may add to the production of tetraploids by progeny being back-crossing triploid gametes; this was used to produce the first bisexual self-sustaining animal in a laboratory which was a polypoid strain hybrid between silk moths: Bombyx mori and Bombyx mandarina (Astaurov.B.L, 1969; Mallet.J, 2005). Homoploid hybrid speciation is well known to angiosperms, also known as flowering plants. Speciation occurs by mean of sympatry, a hybridization which requires gene flow. This is hybrids need to overcome challenges such as chromosome and gene incompatabilies with the lack of reproductive isolation, this often renders the process unlikely. There are approximately twenty plant species which are known for being a good example of homoploids however, this plant is hardly detected due to prevalence. Helianthus anomalus, Helianthus deserticola and Helianthis paradoxus are the best documented desert sunflowers which come from hybrids between mesic-adapted Helianthus annuus and Helianthus petiolaris (Buerkle et al, 2000; Gross Rieseberg, 2005; Mallet, 2007). Synthetic hybrid populations are re-created; being similar to those of wild species due to selection continuously favors combinations of compatible chromosomal rearrangements. In Helianthus recombinant genotypes and spatial separation hav e enabled the hybrids to flourish where their parents are absent (Mallet, 2005). In animals, bisexual polyploids are often excluded, the homoploid hybrids are less prominent in animals yet there is no given reason. The number in animals is growing rapidly (Dowling Secor, 1997; Gross Rieseberg, 2005). A recent example is the invasive sculpin, a hybrid fish derived from the Scheldt River (compare Cottus perifretum) and upper tributaries of the Rhine (compare Cottus rhenanum) (Mallet, 2007). Upper river tributaries of Europe have normal conditions of clear, cold waters, which make them oxygen-rich, for Sculpins. Earlier canal building became connected and these are a result of The Rhine and Scheldt rivers, but invasive sculpins appeared in the warmer water and muddier lower Rhine only in the past fifteen years. Morphologically the invasive sculpin is intermediate and its mitochondrial DNA, as well as nuclear single nucleotide polymorphisms and microsatellites, are characteristic of b oth Scheldt and Rhine forms (Mallet, 2007; Nolte et al., 2005). This provides evidence of adaptive hybrid origin hence communicating that hybrids are displaying positive selective pressure. Hybrid speciation in the animal kingdom results thus far by data based on the respective genome. The disadvantages is that many homoploid hybrids fail to be present in the parent, secondly a decreased level of being reproductively isolated, however, contributing to maintaining or expanding ecologically with latest forms (Mallet, 2007). Importance of a future Innumerable discussions and journals of speciation have stressed the importance of reproductive compatabilities and isolation that occur due to physical and geological barriers; from this essay one can see that polyploidy is more dominant in plants but found to be rare in animals. Furthermore, at the root of many animal and plant groups ancient polyploidy has been found. Genome duplications probably facilitated the evolution of complex organisms (although this is debated) (Mallet, 2007; Otto Whitton, 2000), and we can infer that successful genome duplications were mostly allopolyploid, provided that limited plant community data are reliable (Grant, 1981; Brochman et al., 2004; Mallet, 2007). In my opinion, hybridization can be viewed as an effective catalyst for speciation to occur as it creates variation as in the case of the liger, apart from mutations, which according to the Molecular Clock hypothesis, occurs at a constant rate over time. The process of natural selection includes the need for gene variety which can then be complemented with hybridization also, the compatibility of species more suitably in more noticeably growing groups; suggesting that enough suspected animal homoploid hybrid species exist. A need for in depth genomic analyses is required, it is already possible for hybrid species, like the Helianthus, which can be developed and made accessible via the laboratory or grown naturally, making it hard to find another speciation mode documented historically and can be used experimentally easily. If hybrid species can adapt to survive, showing positive selection pressure, regardless of the challenges which are faced and to survive in competition with the parent organisms by completely new adaptations then will hybridization truly demonstrate the power of evolution through the years, starting a completely new train of thought which will spark more questions hence more research into this wide unknown. The ability of hybrid species to invade hitherto unoccupied niches also means that hybridization can contribute to adaptive radiations such as African cichlid fish and Darwins finches (Mallet, 2007). Humans have come up with uses of genetically modified crops and other ways in which to manipulate the gene and species of not only plants but animals too, therefore it can be said that Homo sapiens are in fact the invaders of Earth, not hybridization of species.

Business Intergration Essay

New IT developments are important to all business disciplines because they trigger changes in marketing operations, e-commerce, logistics, human resources, finance, accounting, and relationships with customers and business partners. Nothing about business or corporate strategy is untouched by IT (Turban & Volonino, 2011). The five elements of an IT-enabled business strategy Business strategy| * Contains the mission, vision, and objectives of the organization * States the company’s market strategy * Describes the unique value proposition the company offers customers * Provides the distinct value configuration of the organization| Business expectations of IT| * Describes how the company might expect IT to contribute to the success of the * business * Possible business expectations of IT include delivering better value, reducing costs, * or improving products and services| IT strategy| * Provides information on IT applications * Describes how to develop the competencies of the people who work in IT * States how IT is to be organized and controlled within the company * Describes the technical infrastructure| IT assessment| * Aims to reveal how technology helps or hinders a business * Can include network and systems performance reviews, software audits, and * concept testing and development * Can include strategic evaluations, technical reviews, and risk management * Should recommend how to use technology to meet business goals| IT plans| * Outlines a company’s long-term IT plans * Is concerned with how IT should be deployed, managed, and implemented in the * future * Should be cost effective and in line with business goals| What are the advantages of aligning business and IT strategies? There are many advantages when an organization IT strategies are aligned with the organizations business strategies. Information technology is a key business function in almost every successful organization. An effective IT strategy will enable businesses to: * Reduce cost; * Standardize processes; * Enhance productivity; * Improve risk control mechanism; * Implement new business strategies; * Facilitate organic and acquisition driven growth; * Gain competitive advantage by exploiting new technology; Other benefits of the alignment of IT and business strategy is automation, knowledge, organizational improvements, and innovation. Automation can result in increased efficiency while decreasing cost. Knowledge in IT is the ability of an organization to collect, store, process, and disseminate information. The benefit of knowledge gained from IT is cost reduction, greater efficiency, and increased revenues. IT also leads to organizational improvements which usually lead to more decentralized leadership structure which improves the overall effectiveness of the organization. Proper alignment of IT and business strategy can make an organization stand out and look different from its competitors. This alignment can provide a competitive advantage for an organization. How does IT deliver business benefits that are related to the business strategy? IT delivers business benefit by performing high-speed, high volume, and numerical computation. IT provides fast, accurate communication and collaboration unrestricted by time and location. IT gives organizations the ability to store huge amounts of information that is accessible via private networks and the internet. In addition it enables automation of routine decisions making and help facilitate complex decision making. IT also improves the ability to make informed decisions. IT also helps to facilitate collaboration, enhance customer relationships, develop new analytic capabilities, and provide feedback on performance. Reference Turban, E., & Volonino, L. (2011). Information Technology for Management (8th ed.). Hoboken, NJ: John Wiley & Sons, Inc..

Passing of Risk

In all legal system the passing of risk in sold goods is a big problem and an important event in the sale of goods. Once the buyer acquires risk, he become liable for the price even if the goods are lost or damaged. The financial risk of and responsibility for damage or destruction when property is being transferred between a buyer and a seller. The risk includes Peril, danger, the chance of loss or injury. Liability for injury, loss, or damage, by statute placed upon the manufacturer rather than the consumer, should it happen from normal use of a product. The Uniform Commercial Code uses a contractual approach in allocating the risk of loss and assumes that the risk is upon the seller until some event occurs that shifts the risk to the buyer. Where the goods are identified and the contract authorizes the seller to ship the goods by carrier, the event necessary to shift the risk of loss is dependent upon whether the contract is a â€Å"shipment† or â€Å"destination† contract. Where the contract does not require the transfer of the goods by carrier, risk of loss passes to the buyer upon the taking of physical possession if the seller is a merchant, otherwise risk passes on tender of delivery, unless an agreement to the contrary is made. The phrase is also an insurance term denoting the hazards and perils that an insured is protected against, i. e. , the contingencies or unknown events that are contemplated by the insured and that are covered by the insurance policy. Under English law that is the sale of goods, act 1979 the general rule is that risk passes along with property though there are exceptions to this. The U. N. Sale of Goods Convention, 1980, is silent on the role of the parties' intention in the passing of risk; nevertheless, the same rule emerges from the whole tenor of the Convention. The civil law applies the rule that the risk falls on the owner of the goods. The U. C. C. provides that risk of loss passes to the buyer when the goods are delivered to the carrier: sect. 2-509(1)(a). In the case of CIF or FOB (vessel) contract, the seller need only put the goods into the custody of the carrier and at that point the risk of loss during carriage passes to the buyer. The Vienna convention also contains provisions relating to passing of risk. The consequence of the passing of risk from seller to buyer are passing of risk from seller to buyer are no different from those found in English domestic law. Article 66 of Vienna convention is substantively similar as Article 96 of ULIS. The UNCITRAL adopted to provide a uniform law for the international sale of goods. It focuses on the function of the contract between parties. And also addresses the issue of who bears the risk of loss on a simple point-to-point sale. The multiple sales creates problem in transfer goods. A solution is needed for the problem. In the context of risk, the principal aspect of the problem of risk is whether the buyer is bound to pay the price although the goods are lost or damaged. In German jurisprudence this aspect of the risk problem is called preisgefahr. In Art 96 of ULIS where the risk has passed to the buyer, he shall pay the price notwithstanding the loss or deterioration of the goods. The provisions on the passing of the risk in INCOTERMS are said to be founded on the same concept, but do not contain an express reference to the price. The UCC and Comecon conditions refrain from defining the risk as denoting price risk. The true character of the concept of risk is not treated as the meaning price risk. In another cases the reference to risk cannot denote the price risk because the defaulter, if he is the buyer, will rarely have to pay the price; the normal remedies against him are of compensatory character such as damages, compensation or a penalty. It’s something really confusing. The trade terms developed by international usage, such as the Comecon conditions, the ECE conditions, and the UCC, treat the concept of the risk in that general manner. In the ULIS, already observed in Art96 refers to the price risk. This obeisance to antiquated doctrine does not, howevre, imply a real, substantial difference between ULIS and the other international formulations, it only reveals an inelegantia juris in the draftsmanship of ULIS. A number of developing countries objected strenuously to the retroactive passing of risk provisions, and proposed that the risk pass at the conclusion of the contract. CONCLUSION However, the exact moment of the passing of risk under a contract of sale is of prime importance to the parties to a contract of carriage, because, in most cases, it determines who will suffer the consequences should loss or damage ensue. There are some exceptions also for this rule. When the seller fails to deliver the goods within the delay specified, they become at the seller's risk once the buyer gives notice to the seller of the latter's default. Another point is that the parties themselves can agree to detach the passing of risk from the passing of title.

Grade Grades The Most Important Predictors Of Future Math

Methodology Introduction As described in Chapter 1, the purpose of this study is to analyze which 5th grade teacher math inputs are the most important predictors of future math outcomes of 8th grade students. The research will be seen through the lens of an education production function. The research questions are as follows: †¢ To what extent do 5th grade teacher instructional practices predict 8th grade gains in mathematics of their students? †¢ To what extent do 5th grade teacher qualifications predict 8th grade gains in mathematics of their students? †¢ To what extent do 5th grade teacher professional development hours and perception of quality predict 8th grade gains in mathematics of their students? The purpose of this study is to explore and analyze which 5th grade teacher inputs are the most important predictors of future achievement of 8th grade math students in classrooms as measured by cognitive exam test scores. The theoretical framework of which this study will be looked at is an education production function. In looking at a study through the lens of an education production function, a trend in the research has emerged in using regression analysis to answer questions. Data Source Data from this dissertation comes from ECLS-K data set released by the National Center on Education Statistics. Their sponsor is the United States Department of Education. The data set, which follows the progress of over 21,260 students over the course of their K-8 academicShow MoreRelatedPredictors Of Academic And Academic Motivation1153 Words   |  5 PagesPredictors of Academic Persistence in Higher Education EDPS 189H Section 001 Term 1 Alex McKinney â€Æ' Abstract Accurately predicting academic persistence for incoming and returning college students is constant problem for all involved. Multiple predictors currently exist to help determine the academic motivation of students. Traditional predictors cover the cognitive aspects of students. The most common predictors are standardized tests and high school GPA. Noncognitive predictors are difficult toRead MoreThe Mathematics Of Math Education929 Words   |  4 PagesWhen in math class many students say, â€Å"What is the point of math I am never going to use it.† That statement is not true, math is used on a daily basis in our everyday life. â€Å"Mathematics is the queen of science, and arithmetic the queen of mathematics† (Carl Friedrich Gauss). Not only is math a tremendous part of everyday life but it is also a substantial part of education. Education is something that many people are passionate about, but many people overlook how much influence math has on otherRead MoreFactor s Contributing to Poor Math Performance1749 Words   |  7 PagesFactors That Contribute to Poor Math Performance â€Å"Nineteen comes before twenty all over the world,† as English teacher Mr. Newkirk would say. The meaning behind this saying is that no matter where someone goes in this world math and numbers are virtually the same. With the similarity throughout each culture, one would assume math would be a strong subject with the masses; however, a majority of people struggle with mathematics. Factors that contribute to poor performance can include, but are notRead MoreParents And Parents Essay1254 Words   |  6 Pagesand where they were most afternoons, were less likely to begin to use drugs (Steinberg et al., 1994). Hypothesis #3, which predicted that students performing better academically will report better physical health than those with worse academic performance, showed mixed results. There was a positive correlation between general health level and most recent grade in the subject of English. There was no correlation between general health and most recent scores in the subje ct of math. After being askedRead MoreStudent s Performance Gap Between Students And Students946 Words   |  4 PagesIntroduction Academic institutions are always trying to improve the grades of their students. They are researching if a smaller classroom setting will improve the grades of their students overall. This is important because these institutions want their students to graduate in the typical four years. In another study, a small classroom setting is important during adolescence because a child develops social behaviors which later affect his or her level of learning (Cappella, 2012). Another researcherRead MoreThe Big Fish Little Pond Effect For Academic Self Concept1424 Words   |  6 PagesMoshe Zeidner and Esther Schleyer article called The Big-Fish-Little-Pond Effect for Academic Self-Concept, Test-Anxiety, and School Grades in Gifted Children, they discuss the effect of putting gifted students into a classroom of likeminded students and the impact on the student s self-concept. As defined in Alder, Rosenfeld and proctor s textbook titled Interplay: the process of interpersonal communication, self-concept is the relatively stable set of perceptions you hold on yourself. Read MoreThe Importance of Extracurricular Activities1380 Words   |  6 PagesThe struggle is real. Maintaining the three most important aspects of teenage life - grades, sleep, and social life - is hard enough, but when you throw in the stress of having to add more onto your plate for a better future, it can be almost suffocating. It is possible to only have to worry about making the top grades to be automatically admitted into a college and then you’re free from having to add more to your plate, but does that have lasting benefits like branching out into extracurricularsRead MoreForeign Language : A Longitudinal Study2008 Words   |  9 PagesForeign Language: A Longitudinal Study I pledge my honor that this paper represents my own work in accordance with the University regulations. [Sarah Hirschfeld Gross] Introduction: The transition to adolescence can often be one of the most difficult periods in a person’s life. It is not only a period of rapid physical growth and change, but it is also a time in which interpersonal relationships often become more complex. Junior high school years have been identified as a critical developmentalRead MoreCollege And Career Readiness For College Students Essay1720 Words   |  7 Pagesand succeed without remediation—in a credit-bearing course at a postsecondary institution (Conley, 2010). Remediation education- also known as developmental higher education course to support a student, such as skill building in reading, writing, math, study, and test-taking strategies for students unprepared for credit-bearing college courses (Ulmer, Means, Cawthon, Kristensen, 2015). Review of Literature Background In 1955, the Advanced Placement program was first offered to high school studentsRead MoreHelping and Supporting Educational Systems by Starting a Foundation1165 Words   |  5 Pagesideation (even among children in lower elementary grades), (5) Vandalism and (6) Parental substance and child abuse. Magnitude of the Need for Services and Activities to be Carried Out There was another survey done on Rio Arriba County 66% of students, grades 6–8 participated, sufficient to generalize results. Although the grade level assessed addresses middle school, findings are indicative of target students’ behaviors and predictors of future behaviors: the children are from the same families