The Hardy-Weinberg theorem states that the frequency of alleles and genotypes in a population’s gene pool remain constant over the generations unless acted upon by agents other than sexual recombination. For example, take a population of mice that consists of 1,000 members. A specific allele, albino allele, is recessive within this species. 80% of the population expresses the normal phenotype- brown coloring, while the remaining 20% are albino. 640 members of the population have the genotype AA, 320 have Aa, and 40 have aa. If completely random mating were to occur, there would be an 80% chance that a gamete would bear the normal allele, A, and a 20% chance that the gamete would bear the albino allele, a. The resulting offspring will display the following genotype ratios: AA will have 64%, Aa 32% (the chance of the offspring having the A allele is 96%), and aa 4%. The offspring have the same genotype ratio as their parents. This example was one of Hardy-Weinberg equilibrium. The next generation will express the same genotype ratio as their parents, and so on. But what exactly is needed to create Hardy-Weinberg equilibrium? (Basically, a population in Hardy-Weinberg equilibrium s not evolving in any way.) Five specific factors are needed to create Hardy-Weinberg equilibrium within a population- a very large population, isolation from other populations, no net mutations, random mating, and no natural selection.
The first element needed to create Hardy-Weinberg equilibrium is a very large population size. The larger the population, the less likely it is for genetic drift to occur. Genetic drift is a chance fluctuation in the gene pool that may change the frequencies of alleles. A large population can better represent the gene pool of the previous generation than a small one. In order to completely eliminate all chances of genetic drift, a population would have to be infinitely large. Thus, we can see here that perfect Hardy-Weinberg equilibrium, which has no changes in the frequency of alleles, would require no genetic drift at all, and genetic drift itself is only possible in a population of infinite size. There are two types of genetic drift- the bottleneck effect and the founder effect. Both severely decrease the variability within a population, altering the frequencies of alleles and thus making Hardy-Weinberg equilibrium impossible. If a disaster occurs in a population, killing off many members, the surviving members will not be representative of the original population.
Why is genetic variation necessary in a population in order for natural selection to occur?
Vestigial females will be crossed with equal numbers of vestigial males and wild type males. I this population is at Hardy-Weinberg equilibrium we would predict an equal number of wild type and vestigial offspring in the next generation. However, according to Bastock and Manning An equal number of females and each type of male were introduced into each test tube, but in my own sample and those of others in the class there were mortalities throughout the experiment.
largely inferior to men at the time when this story was written. The story revolves around a couple Delia and Sykes, who have been unhappily married for 15 long years. It focuses on the turning point in Delia’s life when her husband wants her to go away from his life but eventually falls in his own trap and dies.
The major topic of this experiment was to examine two different crosses between Drosophila fruit flies and to determine how many flies of each phenotype were produced. Phenotype refers to an individual’s appearance, where as genotype refers to an individual’s genes. The basic law of genetics that was examined in this lab was formulated by a man often times called the “father of genetics,” Gregor Mendel. He determined that individuals have two alternate forms of a gene, referred to as two alleles. An individual can me homozygous dominant (two dominant alleles, AA), homozygous recessive, (two recessive alleles, aa), or heterozygous (one dominant and one recessive allele, Aa). There were tow particular crosses that took place in this experiment. The first cross-performed was Ebony Bodies versus Vestigle Wings, where Long wings are dominant over short wings and normal bodies are dominant over black bodies. The other cross that was performed was White versus Wild where red eyes in fruit flies are dominant over white eyes.
Gregor Mendel was born into a German family, as a young man Mendel worked as a gardener and studied beekeeping. In his later life Mendel gained his fame as the founder of the modern science of genetics. The research that was his claim to fame was his pea plant experiment. Mendel looked at seven different characteristics of the pea plants. For example with seed colors when he bred a yellow pea and green pea together their offspring plant was always yellow. Though, in the next generation of plants, the green peas reemerged at a 1:3 ratio. To explain what he had discovered, Mendel put together the terms “recessive” and “dominant” in reference to specific traits. Such as, in the previous example the green peas were recessive and the yellow peas
According to Klug, &Ward (2009), members of a certain population from another are distinguished by the presence of unique genetic characteristics. It is believed that large populations have greater diversity of alleles, compared to the small populations. In most cases, the diversity of alleles designates a greater potential for any evolution of new genes combination. This also shows greater capacity for evolution in adapting different environmental condition. On the other hand, individuals in small populations are possible to be hereditarily, anatomically as well physiologically more consistently than in large populations.
Now, the ideas of Thomas Malthus generally do not apply to the world today. It is important to understand that Malthus wanted to create a theory that explained the success of people in a population. Like Darwin’s theory of evolution (which was helped formed by Malthus doctrine) it is survival of the fittest. I do bel...
131). This has happened because of modern methods of farming of wanting animals or crops that is genetically similar and easier to care for. It has become easier to produce food because of the large scale that is now used for farming. (Roberge 2015). With this low diversity, the resistance to a disease is reduced or gone, and it is harder to find a gene that can stop the disease (Roberge 2015). The industry having low genetic differences in a species makes the impact from an attack worse, increasing the damage it does to everyone. A person could launch an attack at fewer points since the disease could easily spread because the resistance is
Lowe’s should renew its efforts to acquire Rona since opting to enter the Canadian market as a green-field is more costly. By acquiring Rona, an already established company operating 79 big box locations and 700 smaller stores, Lowe’s would avert the costs of producing French ads and signage for Quebec customers, building French website as well as changing its weight metrics and measurement units. This will also give the company a chance to penetrate the Canadian market and strengthen its distribution network and cost-effectiveness and thus boost its operating efficiency. Moreover, gaining a chunk of
External Analysis Macroenviorment Analysis: · Economic- The home improvement industry is below their normal state with the present economic status. Consumers are putting their wants such as adding new appliances or redoing their bathroom on hold. Construction companies are also in a slump; with the building of new homes on a downward slope the large orders of construction companies are not being made · Technological- Technological advances have played a huge role in the home improvement industry with advancements in appliances and power tools.
Haas and Flower created an interesting point when I read “Rhetorical Reading Strategies and the Construction of Meaning “. In the reading, Haas and Flower, provided multiple propositions to apply, however a key one certainly caught my eye. Haas and Flower proposed various arguments, yet their main idea implied that there needs to be an increase in rhetorical reading. I came to the conclusion that increasing rhetorical reading was their main point due to a statement in the text. “We would like to help extend this constructive, rhetorical view of reading, which we share with others in the field…” [Haas and Flower, 167] the following statement blandly states their intention to spread an important strategy, reading rhetorically, among community.
In this experiment, Mendelain Models are observed. The purpose of the experiment is to understand how traits are passed from one generation to the other as well as understanding the difference between sex linked and autosomal genes. One particular trait that is observed in this experiment is when a fly is lacking wings, also known as an apterous mutation. In this experiment, we will determine whether this mutation is carried on an autosomal chromosome or on a sex chromosome. The data for this experiment will be determined statistically with the aid of a chi-square. If the trait is autosomal, then it will be able to be passed to the next generation on an autosomal chromosome, meaning that there should be an equal amount of male and
Genetics has given us important results with regards to knowing why certain organisms and their expressions are the way they are and how some expressions are suppressed due to those particular expressions being recessive. The reason is because genetics is the study of genes and the effects of it to organisms.
Natural selection is the process by which random modifications (mutations), related to a distinct individual’s chance of survival by adapting to its environment (food, predators, environmental features), are selected by nature in a total logical way (lecture). Basically, natural selection functions like this: the individuals among a community with the most advantageous characteristics regard to the survival and reproduction rate will spread on these inherent genetic traits to their offspring (Futuyma, 2004). Over time, these traits will become more frequent in the genetic basis of future generations and eventually all the living species within a population will gain those features (lecture). There are three preconditions for natural selection to exist (lecture). The first one is variation. It simply means that there will be changes in the DNA and those modifications are the reason why we vary in a population. The second one is differential reproductive success. This condition suggests that some individuals have more offspring than others and it generally has to do with competition between species. The third one is heredity which supports that we inherited the genetic basis of our creators, half of each parent. In brief, natural selection is broadly associated with the capacity of species to adapt in their environment and occurs only through three primordial preconditions: variation, differential reproduction and
stress is built, and finally, the body enters a stage of exhaustion, a sort of aging "due to wear and tear" (Andrews, Cromwell, Fries & Hodge, 2008).