Evolutionary Biology BIO305 Exam 3, Exams of Evolutionary biology

Download Evolutionary Biology BIO305 Exam 3 and more Exams Evolutionary biology in PDF only on Docsity! BIO305 Exam 3 Due by 9pm on Tuesday, December 20, 2022 Instructions:  Answer using a different font (e.g., red font) so that your answers can be distinguished from the question.  Use FULL SENTENCES in your answers, with proper spelling, grammar, punctuation, and sentence structure. Points will be docked for improper writing style. This is a writing-enhanced course.  Species Latin (scientific) names MUST follow proper notation (capitalization and italicization) or else points will be docked. (You learned how to do this in BIO102, which is a prerequisite for BIO305.)  Everything must be in your own words. Plagiarized work will receive a grade of 0 and the incident will be reported to the Academic Conduct Committee and the report will remain on file in the Office of the Provost. Plagiarizing more than once will result in an F in the course, with the possibility of additional sanctions.  The maximum number of points awarded for each answer is listed for each question. This exam is worth 25% of your final course grade. 1. On Exam 2, you were asked to draw your predictions (in a graph) for an experiment in which researchers inserted a gene with deleterious alleles into the genome, but left the genes required for normal meiosis intact. The deleterious alleles decrease, but do not eliminate, the chance of survival. One strain (Stain A) had the gene inserted into a recombination hotspot, also known as a highly recombining region. Another strain (Strain B) had the gene inserted into a recombination coldspot where recombination is much less likely to occur. A control strain (Strain C) did not have any gene inserted. Only the benign environment was used. The change across mitotic generations is with respect to the starting point for each strains’ population – you are not comparing the strains to each other. Explain your answer (in words) to this question from Exam 2. That is, why did you draw the expectations that you drew for Exam 2? [3 points – one point per strain] Strand C’s fitness is shown by a horizontal line because it’s the control group, while strand A and B get rid of the deleterious allele by genetic recombination by the process of meiosis. Line A has a higher slope because it has a better chance of getting rid of the deleterious allele because it is in a recombination hotspot, but Strand B has a lower chance of getting rid of the deleterious allele because it is in a recombination cold spot. 4. Given the DNA sequence data in the table, which phylogenetic tree is the most parsimonious? [1 point] Correct Answer: A a. b. c. 5. The bullet points below describe two different approaches to conservation. Which one do you think would be more effective at conserving marine fish populations and explain WHY you think so, based on evolutionary principles. Be sure to include information on not only why you think that approach would be effective [2 points], but also why it would be MORE effective than the other approach [2 points]. [4 points total] a. Establishment of marine reserves where fishing is prohibited. Fishing is allowed outside of the reserve. b. Implementation of size restrictions such that only fish of a minimum size are allowed to be harvested. Fishing is allowed everywhere. Approach A would be more effective because if approach B was implemented then there would be no means of regulating what size fish were being caught because fishing is allowed everywhere, and people may not follow the size restriction. By establishing a reserve, people will only be able to fish outside of the reserve and inside the reserve, the fish will be protected, and specific favorable genes can be introduced to stabilize that populations growth and development without disruption. If there is a marine reserve then genetic drift could take effect and make favorable genes more frequent while if there is no marine reserve, there is more genetic variation available 6. Describe the role of each of the following two evolutionary mechanisms in conservation. [4 points – 2 points each] a. Genetic drift b. Gene flow a) Genetic drift is the random changes that occur in the allele frequencies of a population which decreases the number of alleles present in the population which therefore will decrease the genetic variation available in the population. This is harmful because it will increase the presence of one allele type in a population so without that variation, a population’s ability to evolve and adapt to change will reduce and decrease gene pool size. b) Gene flow maintains the genetic diversity in a population which is mainly beneficial in small populations because new alleles can be introduced which could counter the effects of deleterious genes. By introducing individuals with favorable gene to an area, it can produce conservation benefit because these favorable genes could become more frequent in this population. 7. Height is a quantitative trait meaning that genes at several loci contribute to the phenotype. a. Does this mean that any two individuals in a population that differ in height must also differ in the alleles they carry? EXPLAIN your answer. [2 points] Two individuals in a population that differ in height will not differ in the alleles they carry but the alleles that they express will be different. The individuals will differ in height because of the allele being expressed not the alleles they carry. b. Does this mean that any two individuals in a population that have identical height must also carry identical alleles at each locus? EXPLAIN your answer. Your answer must contain unique information that you didn’t include in part (a). [2 points] Individuals in a population that have identical height do not have to carry identical alleles because environmental aspects or factors can influence your height so the environment that an individual is exposed to can influence their height.