Evolution of Sex — The dilemma The origin and subsequent maintenance of sex and recombination is a phenomena not easily explained by Darwinian evolution. Evolutionary mechanisms such as natural selection are not able to reveal why organisms should abandon asexual reproduction in favor of more costly and inefficient sexual reproduction. Perhaps no other natural phenomenon has aroused so much interest; certainly none has sowed as much confusion. The insights of Darwin and Mendel, which have illuminated so many mysteries, have so far failed to shed more than a dim and wavering light on the central mystery of sexuality, emphasizing its obscurity by its very isolation.
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Gender roles in childhood
Evolution: Sex: The Advantage of Sex
Home Feedback Links Books. The origin and maintenance of sex and recombination is not easily explained by natural selection. Evolutionary biology is unable to reveal why animals would abandon asexual reproduction in favor of more costly and inefficient sexual reproduction. Exactly how did we arrive at two separate genders-each with its own physiology? Is sex the product of a historical accident or the product of an intelligent Creator? The current article reviews some of the current theories for why sexual reproduction exists today.
Viruses: their extraordinary role in shaping human evolution
Gender roles in any society dictates specific standards by which each individual based on gender is expected to act. Proper decorum based on sex, is manifested in the way men and women verbally express themselves, reason, act, and participate with each other. These differences in social expectations have impacted the way in which humanity perceives family responsibilities, job allocation, entertainment and even tangible products based on masculinity or femininity.
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete such as a sperm or egg cell with a single set of chromosomes haploid combines with another to produce an organism composed of cells with two sets of chromosomes diploid. Sexual reproduction does not occur in prokaryotes organisms without cell nuclei , but they have processes with similar effects such as bacterial conjugation , transformation and transduction , which may have been precursors to sexual reproduction in early eukaryotes. In the production of sex cells in eukaryotes, diploid mother cells divide to produce haploid cells known as gametes in a process called meiosis that involves genetic recombination. The homologous chromosomes pair up so that their DNA sequences are aligned with each other, and this is followed by exchange of genetic information between them.