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Topics to be covred in sexual selection
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Sexual selection is choosing a mate based on a preference for certain characteristics. These preferences evolved to increase the probability of survival. Females are almost always the ones to make this choice while males compete for the opportunity to mate with females and pass on their genes. Over time, genes that indicate health have often become extravagant or excessive. The advantages of sexual reproduction rather than asexual reproduction are genetic diversity and the selection of the healthiest genes to pass on. Genetic diversity caused by meiosis in sexual reproduction makes a species more likely to survive because varied traits make them more fit to their environment and diverse immune systems make them less susceptible to disease.
16. Describe two evolutionary consequences if the process of crossing over in meiosis ceased to occur. If crossing over in meiosis ceased to occur there would be less genetic variations and no diversity among a species. This would essentially mean that a species would not be able to adapt to an issue that could arise in the future, meaning that its species could potentially become extinct due to climate change or other arising events.
Evolution is the process by which organisms develop unique derived traits. Evolved traits that decrease an organism’s survival rate are selected against in a population. Traits that increase an organism’s survival rate, on the other hand, are often selected for, meaning that those traits will appear more frequently in the genetic codes of members in a population. This process of selection can take several forms, one of them called sexual selection. Sexual selection occurs when one member of a particular species selects a mate with more favorable traits than other members of their species. An example of sexual selection would be the evolution of “hairlessness” in modern humans. Modern humans do not have a single coat of undiversified hair, unlike
There is a lot of controversy regarding the use of technologies that allow sex selection. Modern science allows parents to choose the sex of their future child. Although this could be an effective way to determine genetic disorders, I do not support screening to be used solely for sex selection as this can lead to social inequality and gender bias.
Reproduction in Homo sapiens, as in all animals, is a primary driving force and has been elaborated upon since the beginnings of society. Humans must take part in sexual reproduction to produce offspring, thus initiation behaviors can be studied. Commonly, the male makes advances and the female is the selector, or chooses the mate. For humans, this holds true and behavior is modified to maximize competitive receptability. This phenomenon carries across all cultural boundaries and is deeply rooted in the overall behavior patterns in the people of the culture. People try to refine their natural appearance to maximize mating opportunity. The males attempt to enhance features for success in initiation and females compete for receptability completeness.
Meiosis allows cell variation and genetic differences between each. cell, whereas mitosis is an exact replication of each cell. There are three main ways meiosis produces genetic variation, this through. independent assortment, cross-over and random fertilization. During
Darwin states that this struggle need not be competitive in nature and also entails a species’ efficiency at producing offspring. Natural selection works not as an active entity that seeks and exterminates species that are not suited for their environment; instead, it retains variations that heighten a species’ ability to dominate in the struggle for existence and discards those that are detrimental or useless to that species. Stephen J. Gould explains the case of r-selection in which a species’ chances of survival are most reliant on its ability to reproduce rapidly and not on its structure being ideally suited for its environment. Gould’s example shows the beneficial results of perceiving natural selection not as something that changes a species in accordance with its environment but as something that preserves characteristics beneficial in the s... ...
Natural and sexual selection are not random processes. If there is no difference between the individuals within the species there would be no selection. Sexual selection is related to mating, it acts on individual’s ability to obtain or successfully copulate with a partner. The idea of sexual selection was introduced by Charles Darwin in 1871; he revealed that there are organisms with traits which are not explained by the concept natural selection, for example the tail of a male peacock. His found two main ways in which sexual selection works, these are intra-sexual competition and inter-sexual selection. Intra sexual competition happens within species, usually between males. They compete against each other to be chosen as a mate by a member of opposite sex. Inter-sexual selection is choosing a mate among the members of opposite sex, usually done by females.
In order to understand the present lifestyles relating to different approaches and tactics applied by humans in mate choice preferences, there is the need to refer to Darwin (1859, 1871) evolutionary perspectives. Darwin (1871) sexual selection is the driving force for males and females reproductive quest for their genes survival. These driving forces have been classified into two categories as intra-sexual and intersexual mate selection.Intersexual selection is male sexual selection process whereby males compete with other males and the females choose the strongest as their ideal partner. Intra-sexual selection occurs when the male species fight among themselves and the strongest gain access to females for
Natural selection is driven by reproductive success. If a species can reproduce and its offspring survive than any traits in its genotype that assisted in its survival will be passed on from generation to generation and ensure that the species will live on. Around the time the Theory of Evolution was suggested, society was very religious and very pressed on the Theory of Creation, so the publication of Darwin’s The Origin of Species by Means of Natural Selection caused a lot of controversy. Darwin gave the world strong evidence that natural selection and evolution played a major role in the development of the species that we see today. Of course natural selection is not the only process driving evolution.
It is the easiest to resort to Nature. After all, all living species breed and most of them parent. We are, all taken into consideration, animals and, therefore, subject to the same instinctive behaviour patterns. There is no point in looking for a reason: survival itself (whether of the gene pool or, on a higher level, of the species) is at stake. Breeding is a transport mechanism: handing the precious cargo of genetics down generations of "organic containers".
Many scientists in the past, such as Aristotle and Plato, believed that there were no changes in populations; however, other scientists, such as Darwin and Wallace, arose and argued that species inherit heritable traits from common ancestors and environmental forces drives out certain heritable traits that makes the species better suited to survive or be more “fit” for that environment. Therefore, species do change over a period of time and they were able to support their theory by showing that evolution does occur. There were four basic mechanisms of evolution in their theory: mutation, migration, genetic drift, and natural selection. Natural selection is the gradual process by which heritable traits that makes it more likely for an organism to survive and successfully reproduce increases, whereas there is a decline in those who do have those beneficial heritable traits (Natural Selection). For example, there is a decrease in rain which causes a drought in the finches’ environment. The seeds in the finches’ environment would not be soft enough for the smaller and weaker beak finches to break; therefore, they cannot compete with the larger and stronger beak finches for food. The larger and stronger beak finches has a heritable trait that helps them survive and reproduce better than others for that particular environment which makes them categorized under natural selection (Freeman, 2002).
With an increasing knowledge and understanding of the natural world including ourselves we are now in a position to manage not only our environment but also our own biology including our reproduction. This does not only have consequences for individuals but also for society and even the world at large.
Survival of the fittest. This idea, also known as Darwinism, was theorized by scientist Charles Darwin to explain the evolution of animal species. In the late 1800s, however, the idea of Social Darwinism emerged and applied the same concepts of Darwinism but on humans not animals. As defined by the dictionary, Social Darwinism is a belief, popular in the late Victorian era throughout the world, which states that the strongest or toughest should survive and flourish in society, while the weak and unfit should be allowed to die (“Social” 1). Science fiction writer H.G. Wells lived when the ideas of Social Darwinism were at their peak. He was able to see firsthand what effects Social Darwinism had on the world, and he was by no means impressed. By examining the different critical lenses of The Time Machine, the reader can see how H.G. Wells warns how the adverse effects of Social Darwinism are endangering the future of humanity.
Who chooses the mate in the species Homo sapiens? Does the male chase and the female choose as Darwin observed in other species? Darwin saw that female choosiness leads to sexual selection, where the traits are not related to survival. Two categories of sexual selection persist of intra-male competition and female choice. The intra-male competition is when males evolve to be bigger and
Natural selection is based on the concept “survival of the fittest” where the most favourable individual best suited in the environment survive and pass on their genes for the next generation. Those individual who are less suited to the environment will die.