The following sample essay talks about a report from a population genetics lab. Read the introduction, body and conclusion of the essay, scroll down.
The data was found using a program called Popsicle (Heron 2002), which picked genotypes Mandalay, and showed the results after particular conditions were entered. Students took these numbers and visually displayed them in charts. They configured the predicted amount of adults for each genotype by using the Hardy- Weinberg mathematical equation pa + PC + q to figure out the expected adults for the genotypes AAA, AAA, and AAA.
The students also produced graphs showing allelic frequencies and genotype frequencies. They concluded that their original hypotheses were indeed correct.
Therefore, there was support that the Hardy- Weinberg Theory and the 5 cases for evolution were indeed accurate in their own particular cases (1 70 words). Introduction In this report, students conduct a laboratory procedure that exemplifies certain occurrences of genetics among populations. In other words, the students predict and observe the results in a population from generation-to-generation due to certain specific conditions, also known as a study called microinstruction (Pearson Education, Inc.
2002). In some cases, evidence supports evolution.
Evolution is defined as the changes that have transformed life on Earth from its earliest beginnings to the diversity that characterizes it today (Pearson Education, Inc. 2002). There are five known cases for evolution, known as selection, migration, on-random mating, genetic drift, and mutations. Selection is best described by the alteration of survival rates. For example, if a specific genotype (egg. AAA, or homozygous dominant) is lethal, there will be no (0) adults in the population.
Or perhaps there are limiting factors that limit a particular genotype to 50%, that case too is also selection.
Migration is also known as gene flow. When members of a population migrate or move away from their habitat, various genes enter different communities and other populations. Migration rates are originally 100% if there is no net movement. Non-random mating means that mates are selected individually, and that perhaps two organisms mate so that their offspring will have beneficial features, also changing the species’ possible features. Genetic drift occurs in small populations, and it is the change of the population’s gene pool due to chance (Pearson Education, Inc. 2002).
Due to small numbers in the population, results are inconsistent and therefore change is frequent. Lastly, mutations are a case for evolution in that the rare changes in DNA cause genetic diversity (Pearson Education, Inc. 2002). One of the reoccurring themes in the laboratory procedure is the Hardy- Weinberg Equilibrium Theory. Under this theory by these two popular scientists, they stated that gene pool frequencies are inherently stable, but that evolution should be expected in all populations all the time; they resolved this apparent paradox by analyzing the probable net effects of evolutionary mechanisms (O’Neil 2002).
The particular conditions that had to exist for this to apply were that the population had no mutation, had no natural selection, was a large population, had only random mating, and had no migration. For the cases to follow later in the lab, Cases 1 and 2 exemplify Hardy-Weinberg conditions. All of he others either have selection or not enough members in the population, which will be the most-closely observed conditions. In this lab, there are also mathematical aspects. Population genetics is known as the branch of biology that provides the mathematical structure for the study of the process of microinstruction (Wisped 2004).
An equation exists under the Hardy-Weinberg Equilibrium Theory. The equation (pa + PC + q) helps to determine the predicted amount of adults of a particular genotype under particular conditions. In the equation, p represents the dominant allele, noted by a capital letter, A for instance. Also, q in the equation represents the recessive allele, noted by a lowercase letter. And, as suspected, PC represents heterozygous. The equation was derived from when two alleles come to produce a genotype from p and q (VA 1996). Since the allele frequencies must add up to 1, q must equal 1 – p and p must equal 1 – q.
Therefore an individual is represented by p + q, and the offspring could be found by (p + q)2, which comes out to pa + PC + q (VA 1996). Essentially, the allele frequencies could be multiplied by 100% to find the chance that that particular allele will show up in he next generation, given that the conditions are of Hardy-Weinberg. The students next hypothesized what would happen in the 6 cases that follows. They concluded that Case 1 was the control group and that there would only be small fluctuations in the allele frequencies.
This is supported best by the fact that the conditions are under those described by Hardy and Weinberg. In Case 2, the students also hypothesized that there would be a small fluctuation in the allele frequencies, however they were different numbers due to the initial allele A frequency change. In Case 3, with the addition of selection, the students hypothesized that there would be no (O) adults with genotype AAA, and that therefore, the allele frequencies would have greater fluctuations. In Case 4, the students hypothesized that due to the selection rates, there would ultimately be a heterozygous advantage.