Biologist today still finds “The evolution of sex” to be the biggest questions up for debate. Despite the obvious benefits, sexual reproduction poses more costly and inefficient means of reproduction. Asexual reproduction does not pose any costly means when reproducing nor does it have to combine its genetic material with another male or female. Asexual organisms have the ability to grow at twice the rate of sexual reproducing organisms. A sexually reproducing population must, in fact, produce both sexes, which leads to only 50% of them able to give birth on their own. Contrasting this with asexual reproducing populations, 100% of their offspring potentially can give birth. This analogy is called the two-fold cost. So the question remains, given the advantages of asexual reproduction, why do most organisms prefer reproducing sexually? The question presented had been called the paradox of sex. There are multiple mechanisms required to try to explain the emergence and maintenance of sexual reproduction. “Of the many explanations for the prevalence of recombination and sex that have been posed, a number of them are considered to be most likely”. (Kondrashov 1993). Muller’s Ratchet, adaptation to fluctuating environments and, an increase rate in adaptation might just be the answer to how sex evolved. Can these theories be good enough to outweigh the cost of sex? Or will it take a combination of all theories to solve the biggest mystery of all, sex?
Over the course of several years, evolutionists have tried to explain the actuality of sexual reproduction to promote genetic variability. However, this explanation is not only faulty but poses a few disadvantages as well. Sexual reproduction happens by the formation of g...
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...roach by combing all three of these mechanisms might be required to fully balance the two-fold cost of sex. (West, Lively, Read) The mutation accumulation theory requires mutation rates to be high, (Kondrashov, 1993 Deleterious mutations and the evolution of sexual reproduction), each deleterious mutation will lead to a decrease in log fitness then the previous one, and population sizes have to be large for it to work properly. Even though some models may not be able to fully explain the two-fold cost of sex, it just might play an important role. A pluralistic approach helps “shift the emphasis of empirical work away from the search for discriminating prediction to parameter estimation”. This approach also “emphasizes environmental and mutational mechanisms interact synergistically in a number of ways and outweighs each other’s weaknesses”. (West, Livley, Read)
"Persistent female choice for a particular male trait values should erode genitive variance in male traits and thereby remove the benefits of choice, yet choice persists” (Miller, Christine and Allen Moore). This phenomenon is know as the Lek Paradox and has puzzled scientists for many years. Throughout all species there has been abundant evidence showing continuous female choice of male traits, yet there is still no definite answer as to what allows for genetic variance to be maintained, and why a specific trait never becomes fixed. Many hypotheses have been theorized and researched, all providing some explanation as to how this variance in species is maintained, from traits signaling resistance to parasites, according to Hamilton and Zuk, to the hypothesis of mutational and environmental affects. Condition-dependence can also provide information as to how the lek paradox is able to exist; this hypothesis will be looked at in this paper.
Some individuals have developed different traits to help them in the process of intra-sexual competition. The organisms with more distinctive traits have greater reproductive success. More genes of those traits are then ‘selected’ and are passed onto the offspring of the organisms. Throughout time variability in these traits becomes
Darwin's theory of sexual selection is an intriguing one because it offers an explanation of human striving and cultural value systems. The theory is that humans who are more sexually desirable will have more offspring and thus their traits will be passed on to future generations to a greater extent than those of less sexually desirable humans. As opposed to Darwin's other theory, natural selection, those who are the best adapted to their environment will be more likely to pass on their genes, or, "survival of the fittest", you might call sexual selection "survival of the sexiest." The theory is intended to in part explain why, when humans diverged from other primates, the human brain tripled in size in just two million years. At first glance, this theory also seems to explain much of the motivation behind human culture and achievement. Upon closer inspection, there are some fairly conspicuous problems with it, especially when it is extended to describe not only human evolution in the distant past but it the present, but it may still be the most plausible explanation available to explain why humans mental capacities have expanded so far beyond those of our primate relatives.
In The Decent of Man (1872/1958) Darwin adopted hunter’s distinction between primary and secondary sexual traits with one important difference. Instead of
Three of which can be a counterfactual account, a manipulability account, and a controlled experiment account (Millstein, 2006), but only the first two will be reviewed. For each of the three cases heritable differences in physical characteristics and differences in reproductive success can be seen (Millstein, 2006). With the counterfactual account, the heritable difference can be explained by saying that the differences in reproductive success do not occur (Millstein, 2006). Natural selection favors the counterfactuals because, if there were no heritable differences in characteristics among organisms in the population, then there would be no differences in reproductive success (Millstein, 2006). This would mean that natural selection had nothing to do with all organisms having the same genotype (Millstein, 2006).
While our natural sex is selected for us soon after our conception, however, our gender identity is not. Our psychological characteristics, the role we decided to take in society, and even our behaviors shape our gender identity. Whether your true gender identity is learned from those closest to you as a child, or if you decide to change you physical sex to match your gender identity at a point in your life, the expectations of society still play a huge role in shaping how parts of your life are lived.
In addition to the sexes male and female, Fausto-Sterling proposes we add three more categories including herm, (a true hermaphrodite) which has both testes and ovaries, merm (a male pseudo-hermaphrodite), which has testes and no ovaries, although some aspects of female genitalia, and fem, (a female pseudo-hermaphrodite) which has ovaries and some aspects of male genitalia but no testes. The reason for the addition of these sexes is to be more accurate and inclusive for all persons. Fausto-Sterling’s arguments for having at least five sex categories are valid because only having two categories is biologically inaccurate, and exclusive to people who do not fit into either category perfectly, both contributing to societal
The construction of human sexuality has been and remains an enigma in today’s society. The prominent and well fought debate can be compacted into one simple title: Nature vs. Nurture. There is no clear answer to how our human sexuality is formed.
Reproduction is one of the most powerful sources known on this earth. Reproduction allows animal, plants, and other organisms to thrive for generations. All organisms have to reproduce, otherwise their species will simply die out. Out of all of the organisms that reproduce, some of the most interesting include social insects of the Hymenoptera order. Social insects exhibit various interesting traits and strategies that they use for reproduction, such as the formation of a queen, worker reproduction, queen signaling or control, and sexual selection. Many of these traits and strategies can be seen in social wasp populations.
Gender has been around throughout history; however, within recent years, gender has separated itself from the traditional view of sex, e.i., male or female, and has become centered on ones masculinity or femininity. Of course gender is more than just ones masculinity or femininity, gender has become a way for one to describe, he or she, in a way in which they are different from everyone else. Gender has turned into a sense of identity, a way for one to feel different and fulfilled among all of those around them. Of course gender’s sense of freedom would seem outside of structure and only affected by one’s own agency, however, structure is a key component in establishing gender. We can look into both ethnic Mexican’s culture practices regarding sexuality, children songs and games, and see that cultural traditions still heavily influence gender, creating what is masculine and what is feminine and what is the role of each gender, as well as challenging the notions that gender is solely based on agency.
Homosexuality and Heterosexuality are two entirely different sex patterns. Globalization has drastically changed the traditional social pattern of sex and relationship pattern. It has introduced some new concepts in sexual characteristics of genders. The issue of heterosexual and homosexual is said to be a philosophical rather psychological concept of human sexuality which place sexual course on a permanent range from heterosexuality to homosexuality. Before presenting thorough comparison of both types it is important to first define them.
It comes as no surprise that our bodies are made to reproduce and that the urge to procreate is a fundamental part of life. Reproduction is what allows us to create generation after generation. It is incredible to think we all start as one single vulnerable cell and then we all blossom into one hundred trillion cells with no person being completely identical to another. It seems nearly impossible to have that many variations. With that
Gender and sexuality can be comprehended through social science. Social science is “the study of human society and of individual relationships in and to society” (free dictionary, 2009). The study of social science deals with different aspects of society such as politics, economics, and the social aspects of society. Gender identity is closely interlinked with social science as it is based on an identity of an individual in the society. Sexuality is “the condition of being characterized and distinguished by sex” (free dictionary, 2009). There are different gender identities such as male, female, gay, lesbian, transgender, and bisexual that exists all around the world. There is inequality in gender identities and dominance of a male regardless of which sexuality they fall under. The males are superior over the females and gays superior over the lesbians, however it different depending on the place and circumstances. This paper will look at the gender roles and stereotypes, social policy, and homosexuality from a modern and a traditional society perspective. The three different areas will be compared by the two different societies to understand how much changes has occurred and whether or not anything has really changed. In general a traditional society is more conservative where as a modern society is fundamentally liberal. This is to say that a traditional society lists certain roles depending on the gender and there are stereotypes that are connected with the genders. One must obey the one that is dominant and make decisions. On the other hand, a modern society is lenient, It accepts the individual’s identity and sexuality. There is no inequality and everyone in the society is to be seen as individuals not a part of a family unit...
Asexuality is a subject that has received very little academic attention. A few early studies on sexuality in general noted its existence, however, it wasn’t until a national probability sample in 2004 that any research began to actually focus on asexuality itself. The asexual community isn’t much older. Of course asexuals have existed throughout history, but prior to the public availability of internet, few identified as such, or were aware that others like them existed. Many small groups of asexuals formed online, but it wasn’t until 2001, with the launch of AVEN (the Asexuality Visibility and Education Network), that they drew the attention of people who did not identify as asexual.