"Why the male, female schism in a species?"
After watching the fantastic educational video called "Evolution" by PBS (of particular interest is "why Sex?"), which was followed by a small research via google, I was just too excited to not to write this blog post. It seems that Darwin's theory of evolution answers the question of 'dimorphism' in a species. To understand the question, and hence the answer, we need to know more about reproduction. Reproduction is merely a side-effect of the process of mating. Reproduction can be brought about in different manners. We are, of course, familiar with the sexual process. But the process that we are interested in is the bizzare and fascinating subject of 'Asexual reproduction' [link].
Asexual reproduction involves the genesis of a progeny from the cell of just one parent. Although this method of reproduction is more common among plants, it it not quite popular among animals. Less so among mammals. Its nature's way of cloning. Most plants can be propagated asexually by grafting or replanting a cutting of its stem or root. Asexual animals that I am familiar are mexican pond guppies and mexican whiptail lizards. These are bizzare creatures which propagate by Parthenogenesis, which is a method of cloning where the female produces an egg which matures without fertilization. This species lizards all look alike because, well, they are all clones.
So why then didn't humans and other animals follow this particular path to their ancestry's immortality? No males running behind the females and trying to impress them with lame antics. Girls reading this may already be wondering, why-oh-why didn't it turn out like that? There are some more reasons why females might want to wish-away males. Sexual process of reproduction can be more trouble than you might recognize:
- Engaging in mating rituals is tiring for the female. They have to choose a male who has worthy enough characteristics that would allow him (and hence the offspring) to survive and, of course, there is the actual act of mating.
- On the other hand, female Parthenogenesis (virgin birth) is very much possible. There even need not be those crazy and violent males running around, endangering your child's life.
Not only the females, come to think of it, but the males too have it hard :
- A male in search of female should grow ridiculously large appendages or bright plummages or learn to build beautiful nests or sing loudly. All these activities and/or growth increases the males' risk of getting spotted by predators.
- Competition among males competing for a small number of females can lead to embarassing defeats, debilitating wounds or, sometimes, fatal wounds.
Even as a species, they stand to gain more by following Parthenogenesis. A single parthenogenetic female can colonize a new area, whereas atleast one male and one female of the same species are required otherwise.
So, what is the big prize that awaits those species who like to endure all the pains of being a heterogenous one?
New possiblities. Adaptation to changes in environment, resistance to new strains of parasites, escape from newly introduced predators and the ability to exploit new varieties of food resources are the prize. The 'dimorphic' model of species assures the continuation of lineage with the help of "genetic recombination" or the shuffling of the genes, each with random mutations giving the "gene-holder" an aegis against a threat. This recombination might hold the previous gene "mistakes" and add another reshuffling "mistake". A mutation, which is survival's coveted secret behind its grand experiment of Evolution.
These are just a few of the observations that my computer science mind could comprehend. I might even have got some of these things wrong. But hopefully not.
Here's a fantastic link to a book extract that I 'tried' to read through: Male, Female: The Evolution of Human Sex Differences
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