A look at Why we are Attracted to the Things we are Attracted to...

As we have evolved, like other population, we evolve by natural selection. A big part of that selection is sexual. Since genes are what are passed onto the offspring they are what truly determine the characteristics that are displayed in the phenotype of the majority of the population. Our distant ancestors looked much different than we do today because they were still evolving and adapting to their environment and the sexual preferences of the opposite sex. Why we are attracted to the things we are attracted to is discussed in an article entitled “Theory of Sexual Selection - The Human Mind and the Peacock’s Tail” by Caspar Hewett.

In this article Hewett compares the development of the human mind to the development of the tail of the male peacock. The reason that the tail of the peacock is so gaudy and brightly colored is because the female peacock prefers the brighter male peacock to the more drab colored males when choosing a mate. The fact that the peacock’s tail was brighter meant that the peacock was in more danger from predators. But then again it does not matter how long you survive if you don’t reproduce because if you don’t reproduce then you don’t pass on your genetic material and your fitness is zero. So although the dully colored male peacocks potentially survive longer than the brightly colored ones will not be shown in future generations to come if they never mate.

The next question was why do female peacocks prefer the brighter colored males? What is the advantage to the male having a brighter tail? Different speculations were made but the most convincing one was that the bright color of the males actually represented a more important character trait. That being that the males with the more brightly colored tails were stronger and healthier than the dully colored ones. This would mean that the offspring produced would inherit stronger and healthier genes. The evolution of the coloration of the male peacock seems to be pointless if not deleterious to the male peacock, but with further investigation it is shown that the female’s preference for the brighter males was not a superfluous partiality.

As male peacocks used to have dully colored tails human both male and female had smaller brains. One of our older ancestors only had a brain the size of 400cc. The size of the brain of men and women today is 1400cc. This is a gigantic brain in proportion to the size of the human body, and almost seems unnecessary. Just like there are advantages for a peacock to have a more brightly colored tail there is an advantage for humans to have large brains.

One reason given in this article for the brain being larger is the preference for more juvenile looking beings. This is the idea of neotony where the adult form of a organism retains many if not all of the characteristics of the infant. The larger brain would make the development period longer and we would retain the more juvenile or infant like characteristics. The Machiavellian hypothesis is also brought up as a reason for the larger brain in humans. This hypothesis is the idea that the brain is larger because it evolved that way through human competition. Through this competition different abilities were developed. Some examples of these abilities are being able to be deceitful and the fact that we have a subconscious. Another reason given why the brain in humans is bigger is because we are more attracted to intelligence.

In this article it is suggested that the preference for intelligence was a random occurrence and that is why we don’t see this evolutionary path in other apes that we are closely related to. We also have a very different mating style than apes do. Humans, for the most part, practice monogamy and the two parents raise their child/children throughout their lives. This different mating practices and inclinations lead us to have many different affinities than apes. So our brains have adapted via natural selection to the way we live our lives.

Darwin’s Take on Sexual Selection

In Charles Darwin’s novel The Descent of Man he discusses sexual selection. Further on in the reading he talks about the secondary sexual characters of man. I would like to briefly discuss some of Darwin’s description of the secondary sexual characters of man.

MEN

Darwin describes the sexual characters of man as the man being taller than the woman on average, as well as heavier, and stronger. The male has much more body hair than the female, as well as much more defined muscles than the female. Darwin also observed that men and women differ in skin tone. This variation differs from race to race. Sometimes the man is on average darker and sometimes the opposite is true.

WOMEN

The woman is described as having rounder features than man. She is also described as having a wider pelvis than man, but Darwin states that this is much more a primary characteristic than secondary because of its function for birthing children. Women have much less body hair the men do. This varies from race to race as well, on the actual amount of body hair, but on average the women has less body hair. Women also mature earlier than men. He says that men do not develop their most distinct sexual characteristics until they are fully mature. For example the beard for most men does not appear until he is closer to full maturity.

CHILDREN

Darwin describes male and female children as almost identical in appearance. He says that a young boy more closely resembles an adult woman than an adult man. When you look at the skulls of male and female children he states that the difference is undetectable. If the male child is emasculated then there is a chance that some of his more masculine sexual features will never fully mature.

INTELLIGENCE

Darwin also says much about the size of the male and female skull in relation to intelligence. He says that the size of the female skull in intermediate between that of a child and that of an adult male. He says that man has a more “intuitive genius” than woman does and is more “courageous, pugnacious, and energetic” than women are. Darwin states that in other species the higher intelligence of the male in comparison to the female is visible as it is in humans as well.

COMPARISONS BETWEEN PRIMATES AND HUMANS

In the Descent of Man Darwin compares the secondary sexual characteristics of the primates with those of humans. He states that different characteristics such as rate of maturity and beard growth are similar in both species, as well as the differences in strength and muscular definition among other characters.

VARIATIONS BETWEEN RACES

Darwin states that these secondary sexual characteristics can vary in each race and vary even more between different races. Darwin found that overall men vary in their secondary sexual characteristics more than women do. One example is the amount of body hair from race to race. In Europe and Asia Darwin said that beards can be found until you go past India. As well as the more north you go the more hair you find and the more south you go the less body hair you find in the indigenous people that inhabit that environment.

DIFFERENT MENTAL POWERS

The mental power of men and women is discussed in the Descent of man as well. The women have more materialistic behaviors than man does. Women are more sensitive, and less selfish than men are, while men enjoy competition and are seen as more selfish.

MELODY

Music and singing are described as a type of courtship. Women are thought to have used their voices for this purpose first because they possess sweeter and much gentler voices than men. The secondary sexual characteristic is compared between humans and other species in its method and usefulness.

ADORNMENTS

People in all different part of the world have in the past and continue to, change their appearances with piercing, tattoos, and other adornments for the sake of beauty. Some different groups were said to flatten the heads of their children with boards because it made them more beautiful. Others knock out the front teeth because they are seen as hideous. And as seen on the right some insert disks in their lower lips. Whatever the case may be these sometimes painful procedures are all done for the sake of the opposite sex.

All of these qualities and even more specific practices are what make up the secondary sexual characteristics of man from Darwin’s Point of view.

This information was acquired from The Descent of Man by Charles Darwin
On Google books this information can be found starting at pages 568 Throughout the section entitled "Sexual Selection in Relation to Man".

Why Sexual Reproduction is Better than Asexual Reproduction

I feel like a good place to start is with an investigation to understand why sexual reproduction is better than asexual reproduction. On the surface asexual reproduction seems to have a lot more positive attributes than sexual reproduction. Organisms that reproduce asexually pass on a duplicate of their genetic material, and don't have to worry about the random outcome of allele frequencies from crossing over. Asexual reproduction occurs more quickly because the organism doesn't have to find a mate to reproduce. So asexual organisms don't have to worry about impressing anybody. All of these qualities that asexual reproducers possess are great if the environment they live in is unchanging. But what happens if the environment decides to change like it inevitably does. Well if the asexual reproducers aren't fit for the environment they die and so will the rest of their offspring because they inherited the exact same disabilities that the parent organism had.

This is one of the instances that sexual reproduction really comes in handy. If the parent of seven offspring dies because they was not adapt for the changes that occurred in the environment then the offspring still have a chance for survival if they inherited a trait from the other parent that would help them survive in the changing environment. Another reason why sexual reproduction is so beneficial is that it is better at combating disease. If a parent has a disease like Huntington's disease and that person reproduces with someone who doesn't have the disease there is a chance that when they reproduce the child will not have the disease. If a person reproduced asexually then if they had Huntington's disease then they would continually pass that on from generation to generation.





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