To a large extent, the environment has the most significant influence on a person's weight. This is because of the changes related to the environment that have been witnessed in the near past, most of which positively influence peoples' affinity to gain weight. Industrialization of food production, for example, can be used to support the assertion. With the drastic reduction of prices of energy-dense foods and an increase in the prices of healthy foods, people's options have been limited to energy-dense foods. Besides this, the current environment where individuals are more concerned with career and financial development and often overlook their diets, most individuals are increasingly consuming fast foods. This increases their likelihood of weight gain. Besides, the work environment, one which encourages a sedentary lifestyle contributes to weight gain. Today, most individuals sit behind their computers for extended periods. An example is a person who works as a teller for 12 hours and does not get time to move around. At the same time, in a bid to save time and ensure more productivity, they are likely to order prepared meals, groceries, and other items. Such a busy environment drastically reduce a person's physical activities, hence, predisposing them to weight gain. In addition to the above, the built environment does not encourage outdoor activities. The more people use elevators and other quicker means of transport and movement, the less they become active, and their likelihood of gaining weight increases. Weight is a quantitative trait because it is not only measurable, but it also varies from one person to another.
There are notable differences between artificial selection and genetically modifying organisms in that, artificial selection involves choosing organisms with particular highly desirable traits and interbreeding them, hence, reproducing the particular desirable traits. An example is the crosspollination of a high yielding maize type with another. On the other hand, genetic modifying of organisms involves the introduction of a new genome with specific genetic characteristics to another organism. An example is an introduction of a bacteria genome to cotton plants with the aim of making the cotton plant toxic to some pests, for example caterpillars.
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In stabilizing selection, a given population tends to stabilize around a given mean value, hence, ensuring a similarity in a given trait. In most cases, there is no drastic change of the feature in question over time. Pine trees that are tall do not do well as the average, an aspect that is also witnessed in shorter pines because they do not get light. This is stabilization selection because of the elimination of extreme values, in this case, the short and tall pines. By all being average, they favorably thrive.
The moth illustrates the first observation in that, initially, they were peppered, and hence, blended well with the environment they lived in, one that was dominated by lichen-covered tree trunks. This characteristic helped the mouths to evade predators. The second observation is the increase in the black colored moths during the industrial revolution. The explanation behind this is industrial melanism. As the environment changed because of the soot emitted from the burning of coal to power the industries, the black colored moths camouflaged better. Because they were prayed on less in comparison to the moths with a lighter color, they breaded and drastically increased in number. For the white-bodied peppered moth, they were easily picked up by birds because they were more conspicuous. The increase in the dark-colored moth in comparison to the light-colored is an observation that can be explained by natural selection, just as it is espoused by Charles Darwin. Charles Darwin asserts that due to environmental dynamics, only the fittest organisms fair well and hence, those who cannot adapt to environmental changes become extinct. Besides this, genetics can also explain the observation related to dark-colored moths being dominant. It is postulated that there was a mutation in the light-colored moth. The genetic mutation ensured color change from light to dark. This made them to camouflage, hence, they increased because they were not prayed on as much.
Homology is the presence of similarity of some traits in the development of species by virtue of the organisms in question possessing a common evolutionary ancestor. Similar traits can be observed in organisms' structure or physiology. Convergent evolution is the change in traits of organisms in a way that tends to be similar. One of the significant differences between homology and the latter is that organisms in questions do not have a similar ancestral origin in homology. Convergent evolution can be contextualized by the development of sharks and dolphins. Although they do not have any ancestral relations, they have evolved in a way that make them similarly fit for their environment. Some of the features they have in common are dorsal fins, streamlined fins, and flippers. These features make them to easily pursue their prey. On the other hand, homology can be best explained by the features standard in some animals such as frogs, birds, rabbits, and lizards. These animals have forelimbs that best suit them to the ecosystem they live in. However, in all these animals, the forelimbs have the same set of bones. The ulna, humerus, and radius are the bones that make the forelimbs of such animals. This similarity point to the fact that they have a common ancestry, even though they are very different.
