1) Sexual reproduction is often misunderstood as the overwhelmingly positive aspect driving human evolution due to its ability to create genetic variation, but this is not a complete view. Although sexual reproduction has its advantages, its disadvantages are plentiful. The biological process of sexual reproduction ensure genetic variation at the risk of eliminating successful genes pairs. In sexual reproduction, haploid cells exist as broken versions of successful genes which then get randomly paired with a new gene. There is no guarantee that this new pairing can succeed. In fact, half of the genetic variants created in sexual reproduction fail. Asexual reproduction, in comparison, ensures that successful genes will be passed on.
Sexual reproduction is generally understood as positive due to the genetic diversity it creates. While this is a very simplified understanding of the biology of sexual reproduction, there is truth to the statement. If a massive cataclysmic event were to affect a population or even the entire world, but a few sexually reproduced organisms of the same species had a specific genotype allowing them to survive, sexual reproduction would be to thank for that species’ survival and evolution. While the genetic diversity can help a species, sexual reproduction is largely disadvantageous.
4) Female primates likely have the natural capacity for orgasms, but arguing that orgasms are detrimental to reproductive success relies on a sociobiological view of sex, largely projecting human social views of sex onto that of primates. In order to argue that female orgasms in primates is detrimental to reproduction, one must falsely equate primate sex and orgasms to human sex and orgasm, wherein sex is a continuous process. Primates, unlike humans, have quick mating behaviors – sexual activity is quick and rapidly repeated. While this repetitive act of sex may bring the female primates to orgasm, we cannot be certain. Studies showing female primates’ capacity for orgasms have only exists through human stimulation, not natural sexual encounters.
The next assumption is the projection of sex as a service. This assumption exists as a way to discourage the sexuality of females and focus instead on reproduction as the real motive of sex, not pleasure. However, primates do not have the conceptual knowledge of how reproduction works. Arguing against female primate orgasming on the basis of focusing on reproduction assumes a conscious effort to sexually reproduce, which is not possible in primates. A final false argument against female primate orgasming is the conservation of energy and choosiness of females. This argument states that females reaching orgasm will begin having sexual encounters for pleasure and will not mate with the best available mate. Because of the energy required to create eggs, female primates in this argument should be choosy – only the best should be able to impregnate her. This again assumes the knowledge of sexual reproduction, which is beyond the knowledge of primates, and is simply not evident in primates. Female primates do not have sexual intercourse with any mate simply for pleasure. There are aspects of bonding between male and female primates, affecting the decisions of females. Furthermore, male primates who are less dominant and therefore less desirable in a social view may have been injured by dominant males, including possible injuries to the testicles. In this instance, the male primate cannot have reproductive sex with the female, further disputing the argument that female primate orgasms are detrimental to sexual reproduction.
5) Scientists reconstructing our evolutionary ancestors often make the mistake of forcing evidence into the existing narrative rather than searching for the truth in the evidence. This is true for the common approach of explaining behavior of our ancestors as well as for determining who our ancestors even were. The constant hero myth serves as a great example of the desire to fit evidence into an existing story – an ape is born with an incredibly large brain and the increased capacity for knowledge allows him to be human. This oversimplification of human evolution is a constant frame for researchers to try to support. The desire to fit this narrative is greatly represented in the Piltdown Man hoax. A skull with a large brain and an ape-like jaw was found in England and said to be the link between humans and apes. This skull fit perfectly into the narrative – a smart ape became human due to increased brain capacity. Although the likelihood of the Piltdown Man being authentic was very low, it was widely accepted because it fit the narrative and because its location furthered an idea of white supremacy and English pride.
The Ramapithecus jaw also shows the desire to apply an existing narrative to new evidence. The jaw was found in India, a desirable location due to its Caucasian ancestry, and was reconstructed to mimic the parabolic shape of a human jaw rather than the correct square jaw. The Ramapithecus was accepted as a step in human evolution because it fit the narrative scientists wanted to prove – a Caucasian origin of humanity.
Behavioral reconstruction also exists as an extension of a narrative. The baboon model applies a patriarchal and capitalistic view to human ancestors. This model stresses a high level of dominance-based hierarchy, although male baboons are not dominant over female baboons. It also features the assumption that hunting and the use of tools is evidence of heightened intelligence of our ancestors, but evidence shows increased brain size before hunting began and females often used tools because they were smaller and not as strong. Finally, the baboon model assumes equilibration and impulse control. This assumption requires males to control females, which is not seen in baboons. The entire model exists as a projection of masculine and patriarchal human ideas rather than finding real evidence. By applying modern social standards and theories to our evolutionary ancestors, we limit our ability to understand the real behavioral models.
6) The evolution of bipedalism in human ancestry is directly related to the loss of obvious estrus in our species. Bipedalism completely changed methods of sex and behavioral assumptions. The first and most important connection between bipedalism and the loss of estrus is the shifting of the pelvis and vaginal opening to a more hidden location, limiting the ability of males to physically see when the females are ready to have sex. This shift also forced the pelvis to change its shape to keep organs from leaving the body. This change in shape makes childbirth more painful for modern females.
The shift to bipedalism also affected the way our ancestors approached sex. The change forced frontal sex, which stimulates a more direct contact between mates. The loss of body hair during evolution created more sensual sex. The most important note in the approachment of sex is the question of male choices. Without being able to see the genitalia of females, males had no way to know if potential mates were in estrus and open to sexual behavior. This created two options – never have sex or always be ready for sex. The males who did not see estrus and based sexual activity of that were not able to reproduce while the males who did not limit arousal to estrus were able to produce offspring. The loss of estrus also pushed females into a more continuous level of sexual reception. Due to the lack of obvious external signifiers telling the female that sex is an available option, she will likely have less aversion to sex that will not result in reproduction. While subtle clues may be perceived by other animals, humans and our ancestors cannot look at or smell a female and know their sexual reception like animals with obvious estrus can.
8) Sperm is much smaller than a female’s eggs and requires less energy to create. Because of this, it is easy for males to risk wasting sperm on sexual activity that will not result in reproduction. Female eggs are large and require much more energy to create. Because of this, females do not create large amounts of eggs at once and they cannot be wasted. The difference in energy required in egg and sperm creation leads to different strategies in reproduction. Males can afford to waste sperm because it is very cheap. Sperm does not use much energy, so males can use energy for hunting and dominant actions instead. Males can also risk having sex with a female that is not receptible to sex or is undesirable because the loss of sperm is not detrimental. Females, on the other hand, use large amounts of energy to create eggs and can only create a finite amount in their lifetimes. Because of this, it is risky to have sex with an undesirable mate. The egg would be wasted on a less attractive mate, and those genetics may be passed down to the offspring. It can be argued that the overproduction of sperm and the caution of females with their eggs may explain human social views of male and female sexuality.
Males are allowed to explore their sexuality from a much younger age than females are. Females are typically taught that sex is shameful and should be reserved for a suitable mate. Males do not have this pressure. Just as male animals can have sex with multiple females without wasting massive amounts of sperm and energy, male humans can have sex with multiple females without wasting sperm and energy. Females cannot afford to waste a potential pregnancy on an undesirable mate. These social pressures align with the sexual behaviors of animals, but these human behaviors are built on patriarchal prejudices while animal behaviors are built on distribution of energy. 9) Although monogamy is generally the pressured social structure of relationships among humans, there is no evidence in nature that humans are in any way meant or required to be monogamous. The human push for monogamy relates largely to the joint effort of raising a child. A male and a female who create offspring should be parents together to give the offspring the best possible chance at success. This is not a natural requirement.
The main example of natural monogamy exists in imprinting, which creates a forced monogamy. This does not exist in humans as far as we are aware. While there may be some room for arguments, human imprinting does not yet have any scientific support. Another example of natural monogamy is in gibbons. Gibbons typically stick to one mate, but will engage in sexual activities it their partner is gone. The existence of female breasts is further evidence of a non-monogamous ancestral past. Females could feed offspring with just nipples, but the enlarged breast shows a physical desire to be sexually competitive. Just as males in other species are often elaborate to attract mates, human females use breasts to attract mates. This implies a competition among females to impress and attract males, further proving human polygamy. The size of human male testicles and the shape of the penis is also evidence of human polygamy.
In other species, males may have very large or very small testicles depending on the level of competition. If a male gorilla is very dominant and has no competition, he has no need to create and store large amounts of sperm, so his testicles will be small. Chimps have a lot of competition, so whichever male successfully fertilizes the female will likely have a lot of sperm, indicating large testicles. Human testicles are an average size, indicating a certain degree of sperm competition, which implies a lack of inherent monogamy. The shape of the human male penis is a tool to help succeed in sperm competition, as well. The head of the penis works to scoop any other sperm out of the vagina to ensure a better chance at fertilization. This assumes a lack of monogamy as it assumes the female may have multiple partners. The concept of human monogamy exists because of cultural limitations and adjustments. Humans are sexually driven creatures, and social rules were established to prevent chaos. These social limitations, however, do not imply natural monogamy.