What Evolution Is
I’ve summarized in Parts 1-4 (here, here, here, and here) the way that science sees the world and does it’s business. Now I invite you to stand at the kitchen sink and look out the window with wonder. Let’s see what the world has to tell us. But first let me take a minute to outline a few things that evolution is not. The word is banged around so much in so many contexts that it can be hard to remember that it is an easy concept that evolution is the:
Descent with modification with natural selection resulting in a change in allele frequency in a population.
That’s it. Don’t make it too difficult.
What Evolution Is Not
1. Evolution is not abiogenesis
Abiogenesis is the idea that life began from non-life and specifically refers to how life started on earth. By definition it is not a component of evolution which is properly the question of how life diversified. ‘Life’ had to be functioning here for it to diversity. This is an admittedly difficult subject and a snag that you will be drawn into if you engage at all with creationists. Here’s an example from Biologos with my comments italicized:
“Of course, it is fair to distinguish between the two claims (Nice guys. Of course, it is fair. It is proper.) However, in referring to abiogenesis as ‘evolution’, creationists are generally not confusing the proposition that life had a naturalistic origin with the proposition that all life is related by common descent (To lump all ‘creationists’ together is a numbers game. Creationists think a multitude of things). Rather, the point is that concepts like abiogenesis, universal common ancestry, and even the alleged development of stars, galaxies and planets from simpler structures are all connected to each other like intersecting threads in a much larger web of controversy.” (There is no ‘web of controversy among the great bulk of working scientists.)
Creationist literature will also chide the evolutionists for believing in ‘spontaneous generation,’ the idea finally put to bed by Pasteur. That they conflate abiogenesis with spontaneous generation is telling. Note that the ‘beginning of life’ was anything other than spontaneous. Molecular evolution has recently been snagged by the some in the Intelligent Design creationist fold as a fine example of creation: surely it takes a mind to invent life from non-life. This might very well be true and there is a branch of creationism that argues as such, called ‘theistic evolution.’ These folks believe that god began the evolutionary ball rolling and then stepped back to let nature take it’s course. This describes most of the religious. Unfortunately, propositions about god cannot be shown with hold-in-your-hand evidence. It might be true and it might not be true: we have no way of knowing.
This is far and away the most mis-queued topic in evolution. Evolution explains the diversity of life based on descent with modification and selection. It does not explain, nor seeks to explain, the origin of life. Biologists don’t even have a standard definition of life. It’s a fascinating and difficult topic, and I’m frankly unsure that we will ever come to a hard consensus on it. Abiogenesis differs from evolution in that there is just so little evidence left behind. Forget fossil bones – how about looking for ‘fossil molecules’? But we have glimpses based on climatology and geology and chemistry from which we can make predictive models. Maybe these will sort out one day to paint a more clear picture for us?
When banged over the head by someone demanding that you to prove how life started, there are a couple of things to consider. First is to avoid what I call the ‘0-100 miles per hour’ question. You will invariably be asked how you can believe that a couple of unrelated molecules roiled in a pond until a man walked out. Yes, it’s silly and ignores a few billion years but expect it. What we know is that it is possible that certain molecules could combine with others to transform in such a way as to have new reproductive and self-organizing properties. Once this domino-type chain begins, could it be possible to continue replication until organics appear? Evidence says, yes.
Forget the question of how randomness drive this. There is little in nature that is entirely random. Everything in nature – including molecules – act according to the physical laws of their materials. They must or the universe falls apart. Molecules and proteins fold, attract, and repel according to natural law. There is nothing different about ancient or modern molecules. And when you are asked to explain what existed before the Big Bang – the question will be more of a demand – just be honest. Shrug your shoulders and say that you haven’t a clue. It puts you head and shoulders above anyone else who thinks they do.
Read about abiogenesis here at Talk.Origins. I will look at this later in the series but, if you can’t wait, go here for articles about lipid layer construction and molecular self organization. Fascinating stuff.
2. Evolution is not a formula
Another misconception about evolution is that is is a simple formula and, like the quadratic equation, if any term is wrong then the whole thing fails. This is partly tied to a misunderstanding of what a theory is. Equating evolution to an equation misses that a theory is an overarching description of processes we see repeated in nature. This error rolls in like a flood if research shows that we have been wrong about something or if anything in biology needs tweaking. “See! Dawkins said this and now we know that he is wrong! So evolution can’t be true!” The real truth is that when research or observation shows that our predictions or hypotheses are wrong then we edge closer to a better description of nature. Knowing what a thing is not is just as important as knowing what it is.
Does this make evolution tautologous? No. No more than chemistry or quantum mechanics or acoustics is. Is evolution falsifiable? Yes. Fossils could be found out of place. Dating discoveries could upend our time-line of geology and biological development. Genetic relationships could show that we are wrong about the concept of species and relatedness. For now, though, all that we learn builds a better case for Darwin’s dictum of descent with modification and natural selection.
3. Evolution isn’t about individuals
You do not evolve. Populations evolve. Individuals evolve only in the way that Brad Pitt has evolved to be a better actor. Individuals are selected for by their environment and those who are most fit to reproduce create more offspring. With each generation, natural selection changes the genotype of the of the population.
So far, epigenetics doesn’t appear to change this model. Epigenetics is the term used for non-sexual genomic changes that begin from outside or external factors. So while it can appear that they participate in evolution, the genome isn’t changed in the offspring. The same compliment of genes and epigenetic factors can be passed to offspring that may or may not exhibit the same characteristics of the parents. For now the jury is out. Epigentics is an exciting and profitable study but the contribution to evolution is still not understood.
4. Evolution does not explain everything
Not every characteristic of every organism has a direct evolutionary correlation to reproductive fitness. Where to draw the line is one of the constantly moving questions in biology. Quora is full of questions similar to “How does a man’s nostril hair relate to evolution.” Yes. I’m making this question up.
Go here to read Stephen Jay Gould’s and Richard Lewontin’s famous paper The Spandrels of San Marco.
5. Evolution is not anti-religious
Science doesn’t care one whit about religion but only about repeatable, measurable, predictable, and tangible evidence. Because religions tend to argue from outside the realm of the material world, the scientific method doesn’t usually apply to religious claims.
That being said, it will not go unnoticed by the most casual observer that there is a small, loud, and primarily American subset of thirteen people from a particular division of a specific religion that rejects evolution on the grounds that it evidentially argues that human beings are not a special creation of recent origin but instead share a common lineage with all organisms spanning the last billion years of life on earth. Bully for them. Evolutionary theory requires no belief in anything other than the reality and repeatability of nature.
Go to Amazon to see the book Faith vs. Fact. Nails shut the case that religion can meaningfully speak to science.
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