I often read – and get comments here – of the kind, “how can you possibly believe that life came about purely by chance?”. Well, the answer is simple, I don’t. This is a ‘popular’ misconception of evolution and natural selection that even a brief study (which, unfortunately the majority of evolution debunkers refuse to do) of the science would reveal.
Many years ago I was studying electronic theory and I was fascinated by feedback. Feedback is used in many systems, notably audio amplifiers, to regulate output and prevent runaway (or loss of control) of the amplifying process. The definition, in electronic context is: “The return of a portion of the output of a process or system to the input, especially when used to maintain performance or to control a system or process.”
In biology or evolutionary theory the definition is similar: “The process by which a system, often biological or ecological, is modulated, controlled, or changed by the product, output, or response it produces.”
Natural selection is a feedback process. It requires two “forces”, as it were, one acting to faithfully (but not quite perfectly) replicate the structure of the organism (reproduction and ontogeny) and the other sorting the interactive characteristics of organisms with the environment (the phenotype or set of traits) into those more or less efficient at survival and therefore at reproduction opportunities.
A better term for it, therefore, is “environmental sorting of heredity”, since it is the way in which certain traits equip organisms that increases or decreases their chances at being passed on, relative to other traits in that population of organisms.
In simpler language – natural selection leads to evolutionary change when individuals with certain characteristics have a greater survival or reproductive rate than other individuals in a population and pass on these inheritable genetic characteristics to their offspring.
If you look at Darwin’s brilliant, but simple idea, it soon becomes obvious that evolution by natural selection is the way that life works. Here’s the steps:
- There is variation in traits - for example, some moths in the same species are lighter coloured, some are darker coloured.
- There is differential reproduction – since the environment can’t support unlimited population growth, not all individuals get to reproduce to their full potential. So, for example, darker coloured moths stand out on lighter coloured barks and lichens and tend to get eaten by birds and survive to reproduce less often than the lighter coloured moths do.
- There is heredity – the surviving lighter coloured moths have lighter coloured baby moths because this trait has a genetic basis.
- End result – the more advantageous trait, the lighter colouration, which allows the moth to have more offspring, becomes more common in the population. If this process continues, eventually, the majority of individuals in the population evolve to be lighter coloured.
If you have variation, differential reproduction, and heredity, you will have evolution by natural selection as an outcome. It is so simple, yet so powerful isn’t it?
Natural selection was and is observable in modern times – and results of millions of years of evolution can be altered within a few generations by external environmental changes. The more widely read would have noticed why I chose the moth example above. From Wikipedia: Quote: “The evolution of the peppered moth over the last two hundred years has been studied in detail. Originally, the vast majority of peppered moths had light colouration, which effectively camouflaged them against the light-coloured trees and lichens which they rested upon. However, because of widespread pollution during the Industrial Revolution in England, many of the lichens died out, and the trees that peppered moths rested on became blackened by soot, causing most of the light-coloured moths, or typica, to die off from predation. At the same time, the dark-coloured, or melanic, moths, carbonaria, flourished because of their ability to hide on the darkened trees. Since then, with improved environmental standards, light-coloured peppered moths have again become common.”.
I find it incredible that this simple, observable fact is just ignored by the believers in magical creation. But then again, this is the strategy they use. Unless it fits with my fervently-held beliefs, I’ll just ignore it and maybe it will go away.
Now, before the debunkers start – yes, I know that this is ‘microevolution’ not ‘macroevolution’. I will cover the arguments for that in another posting…