Why sex? The secret of survival is sex. Sex propels evolution and evolution propels sex.
Why does life need sex? 700 millions of years ago, simple single- cell organisms reproduced in an asexual way, forming identical copies of themselves, and transmitting all their genes. Many studies show that there are lots of species in nature that can reproduce without the participation of two genders, in particular without the male. Ex. Lizard in Texas
There has to be some fundamental biological evolutionary reason for sexual reproduction.The case of the fishes in the desert of Sonora, in Mexico. The Red Queen Theory: ‘Evolution is a race’.If all the genes were shared, so would all the weaknesses.
The origin of sex: a casual meeting which resulted successful.The two strategies: Quantity versus quality. Speed versus nutrients.The war between sexes. Fewer egg means less chance to pass your genes and therefore, females do better being choosy. It explains a lot about how species evolve, and why they look and act the way they do.
Natural selection versus Sexual SelectionIf Natural Selection is operating on all organisms the same, why is it that, in nature, you can see differences between males and females? There must be a reason.Some scientists support another idea advanced by Darwin: the Sexual Selection Theory.
Big eyes, beautiful singing, bright colors, big horns, long necks, etc., they are all examples of the most useful things to attract females, but in some cases of natural selection, they provoked the extinction of species because the females’ tastes conditioned the daily life of males.An example is the extinction of the Irish elk.
The following question is… Then, have females controlled the evolution through their choices?According to the Sexual selection Theory, males usually compete for the best opportunity to mate, and females choose the best genes for their progeny.However, sometimes it’s important to pay as much attention to behavior features as to physical ones.
Evolution has favored many species in which male and female share de role of parenting.The result is monogamy: a social solution to a biological dilemma.Nevertheless, … females sometimes cheat. (In some migratory birds, 40 % of all chicks are not descendents of the males that feed them).
And, what about humans?Sexuality in primates is more than fertilization, it became a way of communication and socialization in a community.That behavior prepared the basis for the human reproduction. In our case, all began some few million of years ago, when we went down the trees and we became bipeds.
Some anatomical changes in the pelvis and sexual organs were required, but the most important step in terms of sexuality was the growth of the brain. According to some scientists, the human brain grew so much that humans had to do a shorter pregnancy, and, as babies were less mature at the moment of birth, the relationships had to be stronger and durable.
This change supposed the birth of love.We needed a long- lasting union with our partner, and it affected our anatomy, developing an area of the brain totally devoted to love.
Some studies carried out by evolutionary psychologists show more things about human reproduction.For example, we are able to recognize the amount of genes that results more different from ours and, therefore, they are better in order to introduce variability in our offspring, and it’s amazing because we do it just by smelling.
Moreover, females choose more masculine characteristics for a short term relationship (trait of high testosterone levels), whereas we choose softer faces for a long term relationship, and more than that, we change our choice at different moments of our menstrual cycle.
It’s clear that our choices have conditioned our evolution and they remain doing it. More than that, we don’t do these choices only for beauty but for the brain too. Ex. Cyrano de Bergerac.Evolutionary psychologists say that our cultural expressions are part of a reproductive strategy. This is a controversial theory.
Finally, we must think about another question…Humans changed sex forever by including love, and now we are taking a farther step, taking our own evolution in our hands, and isolating this one from sex.Sex became futurist when humans could create other living beings in a Petri dish.What about the future of sex and human evolution then?
Some scientists tell us that, in the future, human evolution will be conscious, and it will be irresponsible to leave the extremely important process of conceiving a child to chance .Is it possible that humans forget millions of years of natural evolution in order to control the future of the species?
Bibliographyhttp://en.wikipedia.org/wiki/Evolution_of_sexual_re productionThe evolution of sex https://www.youtube.com/watch?v=wxysZmNsyDkEvolution Why sex? https://www.youtube.com/watch?v=89rQDlx5MXAEl sexo en la evolución https://www.youtube.com/watch?v=EAver-bRjEg