Skip to main content

The spirit of LIFE, sexual selection

OK, natural selection is the retroactive mechanism in evolution. But sexual selection is proactive, it's all the singing birds, and the stubborn determination of people to control their environment and to change the environment of other living beings. If it wasn't for sexual selection, an extra layer of life would be taken away from evolution. In fact, sexual selection changes the pool of properties of living things, be them genes or behavioural patterns, more than natural selection ever could. Natural selection is a rather rudimentary process by which the utmost unsuitable, on the fringe organisms and their genes get removed, those that have ceased to be complementary to their environment. That leaves all those others, and there are quite a lot in between. Essentially, contrary to what may appear like an obvious "designer", natural selection does not shape perfectly suited organisms to their environments. It removes the unsuited ones, but of those which remain, they present a gradient of survivability factor.

That is, they are all equally suited to survive and reproduce in their environments, but not all do. Unlike natural selection, sexual selection actively seeks the very best characteristics. The best characteristics to suit an environment, and in humans' case, the best characteristics to change the environment. The more we alter our environments, the more we diminish the role of natural selection, in favour of sexual selection. Essentially, otherwise naturally occurring selection pressures (such as disease or lack of resources) have been taken over by artificially occurring ones. Therefore, it is safe to assume that there is a negative correlation between the intensity of natural selection versus sexual selection. In a case where sexual selection hardly takes place, natural selection will appear more predominant, since it will take place relatively more often, and hence a species will be merely shaped by characteristics deemed suitable to cope with certain natural selection pressures. However, in a case where sexual selection is so active that it leads a species to progressively alter its natural environment, consequently natural selection will be less prominent in the species' evolution.


Comments

Popular posts from this blog

By-products of Evolution - why not everything has a purpose

Last time we looked at how certain major adaptations such as hair loss have enabled humans to survive over the millennia in different conditions, and when faced with competition from other species. Not everything about the human body has a specific purpose, though, in the sense that we expect it to. One example of such thing is the philtrum - that little channel leading from the base of your nose to the upper lip. Recent research suggests that this development dates back millions of years, and has been inherited from fish. Apparently, when human embryos develop their face in the womb, all parts of the forehead, mouth, etc come together and fuse where the philtrum is located.


Some adaptations, on the other hand, are no longer relevant not because of their nature, but because the environmental selection pressure for which they evolved has disappeared. For example, an East Asian's typical eyelid shape evolved as a result of higher light intensities in that area of the world, yet the …

The evolution of the human body

In order to be able to look at ourselves in the mirror and be able to answer the question "Why do I look like this?", we must look back to our ancestry and their lifestyle, over a very long period of time. For the purpose of this analysis, let's look at the human versus the neanderthal. Recently there have been found neanderthal genes within the human gene pool, but the two species are different enough to compare, yet not too different (human versus fly would be too different).

As you can see, the construction of the human pelvis and toes is different, and the human has less hair. This results in humans being able to run easily for long distances, in the detriment of short-distance running which we are worse at. We sweat better, so we can do more long-term effort. This feat is essential to better settlements, as we can discover a larger area with potentially better resources. It might seem counterproductive to not be able to run quickly for a short period, when it comes …

4 Reasons Google's Calico Won't "Solve Death"

The on-line world has been taken ablaze by Calico's bid to end ageing, and thus death itself, but is this what they will actually focus on, and will they achieve it?



The fact is ageing will be reversed, and death by "natural causes" will go with it. The questions are "When?" and "By whom?".

Until recently, not a lot was known about the approach Calico would take in this venture dubbed "moonshot thinking" - a term touted by Google as the source of all considerable human progress throughout history. This we don't doubt, but is this what Calico is all about?


CNN's Dan Primack has revealed details about Calico's plan, which hint at a less-than-moonshot thinking approach, and cast a serious question mark on its ability to deliver the punchy TIME headline. Here is why:

1. The man with the idea, Bill Maris, arrived at the conclusion that the root of all death-causing disease is simply ageing itself. Not only is this widely known in the ant…