Exam #1 (50 points)
1a ) Natural selection is the process by which adaptive traits of species increases through generations. In Cadotte’s research, he had several combinations of the 17 kinds of plots and he found out that those which had the most variation, survived the most. These were the plants with the most distance from each other. The adaptive traits of these plants were inherited by its offspring. Since the plants with traits that survived the most produced more offspring then these were the ones that flourished the most. The reason, Codette explained was that these plants had different needs therefore they complement with each other and would be able to survive in specific environments.
1b) In Codette’s research he prepared several plots where the number of species planted together varied. Some had one kind only, others had two, three or four. The resulting species that survived in each of the plots with the multi-species present the diversification process. Adaptive radiation applies in the resulting species which, because related species are planted together those which survived would have certain differences. The species that survived in that particular environment would have different primary needs (e.g. one would need more phosphorous, while another more nitrogen) so that they do not compete with resources and would be able to continue thriving.
1c) The principle of “differential reproductive success” was illustrated with the plots which contained the most species. In this plot, the ones that have the adaptive traits—those being the most distantly related produced the most offspring. Over generations these adaptive traits strengthened as those ones which have poorer adapted do not produce much offspring . These traits are then inherited by the ones who adapt better, leading to the survival of only those who can adapt best to a particular environment.
2a) In this research, the kind of mutation that caused the Prader-Willi syndrome was called point mutation. The mutation occurred in the child and not from any of the parents’ genes. The gene from the father was deficient while that from the mother was silenced. In the case of the child, there was a frame shift mutation in his Chromosome 15.
2b) The mutations that were believed to cause Prader Willi syndrome were uniparental disomy and single base pair alteration. The first one is also known as deletions in the chromosome. The child does not inherit chromosome 15 from father, only from mother. The alteration of a single base pair of nucleotides also results in the mutation.
2c. The new finding is surprising because the mutation took place in the offspring and not in the parents.
3b) No, males and females would not be equally affected. Females would have a less severe form of the disease from the mutated PKD2 gene than those affected by the mutated PKD1 gene.
3c) ADPKD is a kidney disease that can be inherited by the offspring of someone who has it, therefore the parent of an ADPKD would likely show it too.
3d) Yes. It takes only one affected parent to pass on the mutated gene to the child.
4a) The main forces of evolution involved in this research are natural selection and gene flow. Natural selection refers to the process by particular species survive because they possess adaptive traits to a particular environment. Gene flow refers to the process by which mating and reproduction results in the passing of genes coming from a particular population going to another. In the case of the butterflies, the researchers pointed out that wing patterns contribute to mating and reproduction behaviors.
4b) These theories are in a tug of war because observations show that genetic changes would manifest in the early stages but not so much in the later part. In these different stages the findings would either be closely related to the natural selection process or with genetic changes. Thus, the term tug of war.
4c) Genetic mutations refer to changes in the DNA sequence. When this occurs there would be changes in the behavior and structure of the species. In the case of the butterflies, there were distinct changes in the wing’s patterns. Such wing pattern has an impact on the butterflies mating habits.
5a) Acclimatization is the human adaptation discussed in the study. This is a process involving physiological changes in the body resulting from prolonged exposure to environmental factors such as cold or heat. This process does not involve genetic changes to genetic mutations.
5b) This type of adaptation enables the body to perform productively and function efficiently even during prolonged exposure to cold, heat, or height in the environment. For example, people who have been accustomed to the conditions at sea level residence would typically experience oxygen deficiency or hypoxia when they reach places of high altitudes. Another example according to the Bergman’s rule is the bigger built of humans occupying areas that experience extreme cold while the slender body frame of those belonging to those in temperate climates
5c) Athletes who would be competing in races at sea levels do not need the high altitude training. The reason is that when they are at high altitudes, the heart exerts more to compensate for the greater oxygen need. Since the body requires more effort at high altitudes, training there then competing in sea level attitudes would bring about a de-training scenario.
