What Is the Founder Effect

From an evolutionary perspective, populations change over time. The size and composition of a populations gene pool is key to maintaining genetic diversity. Gene pool change in a small population because of chance is known as genetic drift. The founder effect is a case of genetic drift in which a small population of a limited number of individuals breaks off from a larger population. The effect on the genetic makeup of a population can be quite profound, as the prevalence of disease can increase. The lower the number of individuals involved, the more that the breakaway population may be impacted. This effect continues until the population size is large enough for errors from generation to generation to become minimal. If the population continues to be isolated, the effects can persist. Key Takeaways Change in a small populations gene pool due to chance is known as genetic drift.The founder effect is a case of genetic drift caused by a small population with limited numbers of individuals breaking away from a parent population.The occurrence of retinitis pigmentosa in the British colony on the Tristan da Cunha islands is an example of the founder effect.The prevalence of Ellis-van Creveld syndrome in the Amish in Eastern Pennsylvania is another example of the founder effect. Founder Effect Examples If a small population breaks off from a larger population to colonize an island, for example, the founder effect can occur. If some of the colonizers are carriers or homozygous recessive, the prevalence of the recessive allele can be quite dramatic in the small population versus the larger parent population. When a new generation has alleles distributed at random, with a large enough sample size, we can expect that the gene pool of the new generation will roughly represent the gene pool of the prior generation. Wed expect a certain distribution of traits in a given population, when that population is sufficiently large. When a population is small, the gene pool from generation to generation might not be accurately represented. This is due to sampling error because of the small size of the population. Sampling error refers to the disproportion of results in a small population or sample. Retinitis Pigmentosa Example Not all genes have a simple dominant recessive occurrence. Others are polygenic traits and can be due to changes in a number of genes. For example, in the early 1800s a number of individuals migrated to the Tristan da Cunha islands to form a British colony. At least one of the colonists appears to have been a carrier and had a recessive allele for retinitis pigmentosa. Retinitis pigmentosa is a relatively rare disorder where the cells in the retina are lost or break down resulting in loss of sight. Individuals who are homozygous for the allele have the disease. By some estimates, in the 1960s, of the 240 residents in the colony, four had the disorder and at least nine others were carriers. This is much more prevalent than would be expected based on the rarity of retinitis pigmentosa in larger populations. Amish Example Eastern Pennsylvania is home to the Amish, who provide a striking example of the founder effect. It is estimated that about 200 individuals that immigrated from Germany founded their community. The Amish typically marry from within their own community and are isolated, so genetic mutations tend to persist. For example, polydactyly, possessing extra fingers or toes, is a common symptom of Ellis-van Creveld syndrome. The syndrome is a rare disorder that also is characterized by dwarfism and sometimes congenital heart defects. Due to the founder effect, Ellis-van Creveld syndrome is much more prevalent among the Amish.  Ã‚   Founder effect in animals and plants While the movement of human populations can provide examples of the founder effect, the effect is not limited to humans. It can occur in animals or plants as well, whenever small populations break off from larger ones. The founder effect can have a profound impact on small populations due to genetic drift. The impact can persist when the population remains isolated so that genetic variation is minimal. Inherited diseases like retinitis pigmentosa and Ellis-van Creveld syndrome are examples of the consequences of the founder effect. Sources â€Å"Genetic Drift and the Founder Effect.† PBS, Public Broadcasting Service, www.pbs.org/wgbh/evolution/library/06/3/l_063_03.html.Reece, Jane B., and Neil A. Campbell. Campbell Biology. Benjamin Cummings, 2011.

Life, Death and Samples of an Analysis Essay with Stakeholders/sides

Life, Death and Samples of an Analysis Essay with Stakeholders/sides Samples of an Analysis Essay with Stakeholders/sides Options Custom writing services can supply you with research and writing services that will guarantee you have an outstanding essay. It's also important to look at your work for plagiarism. There may be numerous reasons due to which you are unable to do your essays and assignments yourself. If you're not able to do so, you always have the option to find helpful crucial essay writing service. The Samples of an Analysis Essay with Stakeholders/sides Cover Up There's no overall pattern of the way to compose a literary analysis, as it greatly depends upon the part of work you want to talk about. After considering all key facets of the job, it is the right time to proceed to the outline. It is an impossible task to develop a good, impressive introduction before you know the remainder of the paper's content. The debut of textual analysis is, in a way, the mai n area of the paper. Life, Death and Samples of an Analysis Essay with Stakeholders/sides The analysis ought to be restated, and you ought to point out its significance to the subject accessible. You could make 1 claim with plenty of evidence, or five claims to back up your topic sentence. The evidence may take the kind of a criticism. Your evidence might be different from what it is that you're utilised to. Understanding Samples of an Analysis Essay with Stakeholders/sides Don't neglect to make and use your literary analysis outline. Writing a literary analysis paper expects that student examine specific elements of literature work. Locate an ideal sample literary analysis outline before you begin. Writing a case of rhetorical analysis isn't your worst nightmare any longer! Analysis essays are known to be among the hardest to write. They are your best friends. An analysis essay is a sort of persuasive essay. An analytical essay isn't a summary! The introduction must allow the reader to receive hooked to your topic. To learn to compose a character analysis essay you must note 1 thing. An essay linked to literary criticism may be a pleasant adventure if you understand how to write it! Apparently, writing an essay on the subject of marijuana is too general. You might decide to compose a book analysis as a way to think critically about the bit of literature and determine your literary preferences. Therefore, an analytical essay is a bit of writing that offers an informative observation about the particular topic or idea. Although you may think that such paper might be used only in a negative meaning, you ought to know that it may be used as a positive evaluation of a particular book, poem, article or something of the type. When you compose the outline and the book analysis paper, you've got to spell out the qualities of the primary characters within the book. Samples of an Analysis Essay with Stakeholders/sides - the Story You've got to present arguments in support of a specific opinion. When you own a topic accessible, the next issue is to produce a thesis statement. The principal or topic sentence is going to be the very first line in your essay. Following that, it's about convincing your reader in the principal body. The pri mary goal of the body paragraphs is to fully demonstrate the thesis statement. The number of the human body paragraphs could vary based on the topic available. If you don't wish to lose your way, make an outline. Occasionally you might be asked to produce your topics. Topics can change depending on your majors. It is crucial to pick a fantastic topic from the start if you aren't pre-assigned one with your instructor.

Changes and Continuity in Western Europe Free Essays

During the period of 1492 to 1750, Europe experienced drastic changes during their Age of Discovery. As a result of contact and colonization, Western Europe’s economy, political, social, and military systems changed, but also maintained certain aspects that enabled them to build strong civilizations. Such changes include increased (international) trade routes, more centralized governments such as monarchies, decreased unifying influence of the Catholic Church, and increased interest in military conquest and expansion. We will write a custom essay sample on Changes and Continuity in Western Europe or any similar topic only for you Order Now In terms of the economy, industrialization and manufacturing drove the economy forward, catalyzing change and developments that would contribute to the economy. Advancements in metallurgy produced an increased demand for skilled blacksmiths and detailed metal work. State sponsored trading companies and colonial ventures were investments that had a lasting influence. The ventures were mainly directed at the Americas, which were rich sources of gold, silver, sugar, and other desired goods. This new international trade opened infinite possibilities for the economy to grow and expand. These ventures also brought American crops back to Europe, such as potatoes, which increased specialized agriculture. However, through these increased changes within the economic system, many aspects remained behind. Most notably was in agriculture, where farmers continued relying on the methods and techniques of the Middle Ages, such as the three-field system. Although there were innovations during the 18th century, they were not enough to noticeably improve the productivity, and many old crops were grown along with new crops, which resulted in a lower production of the old crops. Politically, important changes, mainly the Glorious Revolution, impacted Europe in such a way that there is a lasting impression to this day. The decline in feudal balance resulted in more centralized government states, therefore leading to absolute and parliamentary monarchies. When France, England, and the Netherlands gained power through international trade, Spain lost its dominance while slowly falling behind the new major powers of Western Europe. Parts of the European political systems that remained untouched included the feudal political forms that remained strong, even with introduction of monarchies. Since European states thirsted for expansion of their states, military remained a top priority in funding; therefore, the strong feudal forms remained, although with shifted balance. Furthermore, ordinary people were not highly affected by the political changes, because politics did not concern them; all they had to worry about was paying their taxes as usual, and the general economic life was not altered. In terms of the social system and structure, a main change that altered the social structure was commercialization, which created a new social class, the proletariats, who suffered from poverty. Other notable social changes include the emergence of a European-style family, which emphasized the nuclear family structure, and intensified links between family and individual property, and the decline of influence of the Catholic Church, which cause a separation of peoples’ religious and daily lives. However, women maintained their low statuses as inferiors to men, and have fewer alternatives when Protestants abolished convents. In addition, although the Catholic Church lost its influence, the elite remained powerful and limited cultural movements, mirroring that of the Dark Ages but to a lesser extent because of the Enlightenment. Militarily, the main advancements were evident in the navy, and skills in building stronger, bigger ships capable of sailing the Atlantic and Indian Oceans. The increased interest in military conquest supported state-sponsored expeditions and ventures. France formed a professional military, and Italy became more militarized, with majority of Western European states improving their navies. Similar to their ancestors, the European states used their dominating armies and navies to expand their boundaries and conquer neighbouring lands. The coastal states gained more territory as a result of having superior naval forces, notably Britain. Throughout the period of 15th to 18th centuries, the changes that occurred, heavily influenced the development of the states into independent, dominating forces with Western Europeans gaining their own unique identity. Although there were more changes than continuities, the aspects that did last through this period aided in the development of others, such as how the feudal political forms aided the emerging monarchies in becoming stronger, lasting till modern day. Europe’s Age of Discovery was a time for drastic and rapid changes, changes for the best, and not necessarily for the worst. Guns, Germs, and Steel. Dir. Jerad Diamond. National Geographic, 2005. DVD. Hoffman, Philip T. â€Å"Prices, the Military Revolution, and Western Europe’s Comparative Advantage in Violence. † Economic History Review, Feb2011 Supplement. Vol. 64. 2011. 39. Print. â€Å"Outline. † World Civilizations, AP Edition. Pearson Education, 2010. Web. 11 Dec. 2011. . â€Å"Transformation of the West. † World Civilizations. Pearson Education, 2010. Web. 11 Dec. 2011. . How to cite Changes and Continuity in Western Europe, Papers