Introduction
Life on Earth is all about sex. But sex is far more attributable to our animalistic instincts than many humans even realize. Animals and human beings, alike, go through unimaginable things to ensure their genes are passed on for another generation. The one goal in most species’ lives is to reproduce so that some parts of their DNA or genes get handed down. Clearly without reproduction and sex, which are distinctly different terms, the species would become extinct. Because of this inescapable fact, the evolution of sex is a very important topic. One may say that sex drives evolution and evolution drives nature, which in turn makes sex the center of existence.
When examining the evolution of sex there are many different topics and facts to be looked at closely. This paper will give a brief description of the history of sexual reproduction and how it has evolved over the past 600 million years. Next, a discussion on Darwin’s theories of natural selection and sexual selection and their role in evolutionary theory will be presented. In addition, this paper will include a thorough examination of the different forms of reproduction; the history, current state, and future of human sexual reproduction; and various other interesting topics relating to the evolution of sex.
Reproduction
Wilson (1975) notes that an individual organism is part of an elaborate device that ensures the survival and replication of genes with the least possible biochemical alteration. Being that reproduction is thought to be one of the primary reasons for existence for many species, it is important to investigate its role in the evolution of sex. Webster defines reproduction as the act or process by which plants and animals give rise to offsp...
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In Making Sex by Thomas Laqueur, the author analysis sexual differences throughout the 18th century reviewing physicians, scientist, biologist and how society understood the anatomy and physiology of the human body. Laqueur brig us two sex models; the one-sex model and the two-sex model. He explains who we transition from the one-sex model to the two-sex model. How this two models had impacted our society and created an impact in history had it to do with the fact that a lot of evidence was drawn from science. Laqueur also explains how society constructed sex. He takes this investigation in very detail as he explains and investigates sexual differences.
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Sexuality over the years has been defined and reshaped in many ways by different researchers and experts. In the CNN article, “Being Gay is not a Choice,” James Hormel defines sexuality as something that you are born with and cannot hide or ignore your true identity. In the article, Hormel recalls the times in his life where he felt alone and when he hid the truth. Hormel goes on to state how he “spent the first 35 years of my life trying real hard not to be gay”(Hormel, pg. 1). However, despite Hormel 's views I disagree with this article in many ways as it shows little evidence on how someone could in fact be born gay. An individual decides his identity and sexuality, which in most cases is tied together with how one is raised and the environment in which one is raised in. John Hormel’s article on sexuality can be countered by an article written John D’Emilio. His article, “Capitalism
Darwin's General Summary and Conclusions of the Descent of Man and Selection in Relation to Sex In the "General Summary and Conclusions" of The Descent of Man, and
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.
Work Cited Colby, Chris. A. Web. " An Introduction to Evolutionary Biology." 28 August 2015.
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
Introduction The topic of gender differences must understandably be approached with caution in our modern world. Emotionally charged and fraught with ideas about political correctness, gender can be a difficult subject to address, particularly when discussed in correlation to behavior and social behavior. Throughout history, many people have strove to understand what makes men and women different. Until the modern era, this topic was generally left up to religious leaders and philosophers to discuss. However, with the acquisition of more specialized medical knowledge of human physiology and the advent of anthropology, we now know a great deal more about gender differences than at any other point in history.
In The Decent of Man (1872/1958) Darwin adopted hunter’s distinction between primary and secondary sexual traits with one important difference. Instead of
Unlike sex, the history of sexuality is dependant upon society and limited by its language in order to be defined and understood.
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
When these alterations are helpful, they grow to be fixed in a population and can result in the evolution of new phyla. Evo-devo seeks to figure out how new groups happen by understanding how the method of development has evolved in different lineages. In other word, evo-devo explains the interaction between phenotype and genotype (Hall, 2007). Explanation of morphological novelty of evolutionary origins is one of the middle challenges in current evolutionary biology, and is intertwined with energetic discussion regarding how to connect developmental biology to standard perspectives from the theory of evolution (Laubichler, 2010). A large amount of theoretical and experiential effort is being devoted to novelties that have challenged biologists for more than one hundred years, for instance, the basis of fins in fish, the fin-to-limb change and the evolution of feathers.
Martin, Emily. "The Egg and the Sperm: How Science Has Constructed a Romance Based on Stereotypical Male-Female Roles." Gender, Sex, and Sexuality. New York: Oxford University, 2009. 248-53. Print.
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.