EVOLUTION: The Essential Basics
What everyone needs to know and should know about evolution by natural selection and random mutation first is that it is not ‘just’ a theory. Scientifically speaking it is a theory. But this is not the same as a theory in the parlance of everyday English usage.
Example of everyday usage:
My theory is that Patel is sick and that’s why he isn’t here today. (This theory is little more than an opinion pulled from whoever’s asshole.)
Example of scientific usage:
The theory of evolution by natural selection and random mutation is a series of tested and general propositions that are so well substantiated and grounded in their subject matter that they can actually explain and even predict certain phenomena. (See the difference there? One is underpinned by volumes of evidence that empirically substantiate claims while the other is just conjecture. This is the usage we use with evolution.)
The next major misapprehension that people seem to suffer chronically from is this notion that human beings are somehow descended from monkeys. No, we are not descended from monkeys. Monkeys, apes, and human beings all share a common ancestor that ramified into the lot of us. In fact, no species alive today evolved from another species alive today, we simply share common ancestors.
You may feel a little confused at this point if you are among the majority of people who seriously misunderstand this concept. Don’t worry, you’re not stupid, just misinformed. Or you might be stupid. I don’t know. But let’s examine my diagram below and maybe you’ll begin to get the big picture.
Let’s imagine we have one species called ‘A’. ‘A’ will represent a large population of early primates. Maybe something like lemurs. ‘A’ is going to diverge into three separate populations due to geography.
Species ‘A’ is isolated over time by mountain ranges and rivers.
Three isolated, but genetically indistinguishable populations exist apart.
A (Original population splits into the three below, all genetically the same at first)
- Aa (separated by and live in mountains)
- Ab (sought refuge in and remain in a jungle valley)
- Ac (migrated down a lengthy river)
Now, before these three populations of species ‘A’ separated, its members were able to mingle and breed, keeping the gene pool of the species pretty stable and uniform. But when the three populations separated there was no more mingling, too much space and too many obstacles kept them from exchanging genetic information via reproduction or migration.
Thousands of years pass and advantageous mutations have accumulated in all three populations. However, these mutations are unique to each population and specific to their new environments, creating a wedge that begins to isolate them genetically. You see, because the populations no longer mingle, the once uniform species ‘A’ is beginning to show unique traits and even behaviors among its disparate subpopulations; a, b, and c.
Where do these mutations come from? Simple, they’re just the mistakes left over from faulty DNA replication. Most of the time this ranges from innocuous to deleterious and those that suffer from genetic malfunctions die off and fail to reproduce. But sometimes innocuous mutations build up into something useful for survival. Maybe our mountain-going lemurs formed larger lungs for higher altitudes, while our valley lemurs developed longer, more dexterous digits and tails for climbing, and still our river lemurs managed to form some webbing between their toes for swimming and a love of water. Now let’s fast forward a million years.
Aa (This subpopulation evolves into two distinct species over time)
- Aaa -> B
- Aab -> Aac -> C
Ab (Also splits, one population remains the same while Aba evolves into a new species)
- Ab -> Ab (could still breed with original population ‘A’ if it still existed)
- Aba -> D
Ac simply evolves into E over time.
Ac -> Aca -> E
We see that subpopulation ‘Aa’ formed two distinct sub-groups. Maybe they took up different places over the mountain range and stopped mingling, leading to two distinct modern species, ‘B’ and ‘C’, over hundreds of thousands of years of separation. These two species are extant (are alive and well). ‘Aaa’ and ‘Aab’, as well as ‘Aac’, no longer exist. Their offspring were early predecessors of ‘B’ and ‘C’.
‘Ab’, the other subpopulation of parent species ‘A’ has remained largely unchanged from the initial population, and could in fact breed with it if it still existed. All this while the other subgroup ‘Abb’ has evolved into the distinct species ‘D’. But remember, the parent population ‘A’ is no more as it split into three groups which evolved separately.
‘Ac’ ultimately diversified into a subgroup apart from parent species ‘A’ and into a distinct species, ‘E’.
The change to ‘new and distinct’ species is not sudden or even detectable in some cases. It takes a very long, long time and transpires most slowly. It is not as though one day a baby is born and it is separate from its mother. Imagine it like a book of white pages that gradually turn more and more yellow as you turn them. Eventually you realize the color has changed but it is difficult to say where and when exactly.
Now there may still be come of you concerned with the vast differences between say a crocodile and a peacock. How can this be? How could this have come to be? Well, over a very lengthy period of time forces in nature, random genetic mutation, and sexual selection on the part of breeding pairs, all come together to craft a species that can survive and weather existence.
You may wish to remember that an English bulldog and a poodle could actually fuck and have children and yet, imagine how different they look. And mind you the genetic variation there is essentially negligible. Dog breeds can be sufficiently differentiated over mere decades of intentional breeding. Imagine what nature could do over several million years.
For those of you questioning the observable forces of evolution, feel free to do the most basic google search. Microevolution, which can easily be extrapolated, has indeed been observed and the fossil record provides an easily observable history of macroevolution.
But the last thing I want to add here is about the usual criticism of the fossil record regarding ‘gaps’. There are no such ‘gaps’ in the fossil record as many critics suppose. I say this because the ‘gaps’ they refer to are born of their stupidly ignorant imaginations, notions of hybrid animals that are perfect amalgams of their progenitor and what they are becoming.
You say birds come from reptiles? Well where are all the birdtiles? Where are the snakes with wings? Or the crocodiles with duck feet?
Basically these gap critics imagine a world of half-and-half animals running around and until we find those fossils we have no such proof of evolution. Except this is neither here nor there, because there is no ‘intermediate’ stage of any species, not really. Each species was its own species, get it? Homo-erectus, one of our ancestors, was a fully developed species. H. erectus was not a kind of ‘half-human’. Intermediates in evolutionary history only appear so because they are between an ancestor and descendant. Despite all this, however, there are in fact many transitional fossil forms to see.
There are, of course, numerous species we will never find or know existed. But this has nothing to do with evolution and the evidence for it. Genetics, the fossil record, and observable microevolution among populations of bacteria, cichlids, and fruit flies are all the evidence necessary to put this brilliant baby of a theory to rest. Case closed.