This 'survival of the fittest' is a phrase so often used out of ignorance. This misunderstanding is not much more than a semantic argument, but it has huge consequences when it comes to the understanding of how life works.
So I'm gonna discuss here what is actually going on and how. I'm gonna keep it as simple as I can, straight from my brain, so even the most adamant denialists can understand.
Evolution
People often think 'survival of the fittest' implies strong, muscular men and the smart, beautiful women are the ones that are going to survive, and the stupid - the monkeys and chimps - die off.
Well of course these are thoughts only evolutionarily inferior humans would think. 'Survival of the fittest' should really be 'Survival of anything that is barely good enough to get through the day and plop out a baby'.
Think about it, If it was about incrementally getting smarter and more powerful over millions of years, you'd think we'd have dominated the galaxy by now. You'd think ants would have developed an exoskeleton so strong that you couldn't kill it with a battle axe.
Why isn't this true?
The problem is that people tend to think of evolution as some conscious force, some decision that was made at some point to progress life in a ceaseless, forward direction. But evolution is just a description of a phenomenon that happens partially randomly.
Partially?
Well, this is another misconception in itself, the idea that evolution is random. But the reality is evolution is somewhat opposite to that premise.
Let's look into that. It's another direction than I intended but whatever, I can post about whatever I want:
Random Mutation of DNA
DNA consists of four 'chemical letters', A C T and G, which stand for Adenine, Cytosine, Thymine and Guanine. These chemical bases are basically the instructions for the genes to do whatever they do. A genetic code, if you will. And yes, all DNA consists of these four and no more, but variation comes from having a really long list of these letters.
The human genome bookcase. A massive list of ACT and G...
... and they ain't wasting space!
DNA mutation is indeed random, but this is only part of the story. There are several types of mutations that occur in DNA:
Substitution - Quite simply, this is where one of those letters gets swapped out with another, so one strand might say ACCTTGGTA, and a mutation will change it to ACATTGGTA.
Insertion - Again, pretty self-explanatory, extra bases are added into a sequence. ACATTGGTA might become ACATCATGGTA.
Deletion - Yep, some bases get removed. ACATCATGGTA may become ACATGGTA
Duplication - I'll let you figure out what this one does.
Missense - This is where an incorrect amino acid is substituted for another within a protein.
Nonsense - The same thing as Missense, but the act of substitution stops the sequence short.
There are more ways to mutate of course, which you can Read more about here.
Causes of DNA mutation
These mutations don't occur because God said so, of course. There are some inevitable underlying causes, but it basically boils down to the fact that God doesn't exist. Therefore we are imperfect beings. Our DNA is also imperfect, as is our body's ability to repair broken DNA.
That being said, our bodies do a damn good job at it. Even if our body repairs DNA with a 99.99999% accuracy, that still allows 0.000001% (or whatever, I lost count) to mutate. After billions and trillions of replications, that little 0.000000001% isn't so small.
DNA can be damaged in a whole host of ways, from simply a naturally occurring mistake; an honest error in the system, to poisoning and radiation. Even the daily background radiation in your garden can do this, and the process of healing that damage happens to be 0.0000001% wrong in its replication when a mutation occurs.
That's all it takes
So because the act of nature and external influences can confidently be called random this is where the word random can correctly be used in the context of evolution, but that's pretty much where it ends.
The nonrandom part is where the misconception comes in:
Natural selection
Now my question to you is, why are there blind animals? Why are there flightless birds? Why are there ginger people?
They all exist because they have what it takes to survive in their environment. Nothing more, nothing less. In the situation where environments change, the animals that remain are the ones that have the ability to adapt in a way that is enough and fast enough to survive and breed.
Let me be clear; they do not need to be stronger than the biggest tigers, or more beautiful than their friends.
In a similar fashion, a bird does not need its wings to escape its enemy if it lives on a predator-free island.
But why get rid of wings, they're cool!
ENERGY SAVING! Wings are incredibly high-maintenance and require a lot of energy to use. Imagine if your arms were replaced with a 7-metre wingspan, and then try flapping hard enough so your whole body is lifted into the air. Not easy is it?
If you can, instead, just fold them in and sit around on a tree stump all day eating moss, I bet you would. But this doesn't mean the wings are useless. More often than not, body parts are given different roles, Generally if there is no role for them to take, they disappear entirely, like the blind animals in my Troglobite post.
No, a penguin uses its wings to swim, and Ostriches use them for balance while running fast, and mating decoration.
So although you might see some animals with exaggerated mating rituals showing that it is the most beautiful and healthy of them all, that is not a requirement. This nonrandom selection could favour the fattest, the smelliest, the funniest, or the one with the biggest... yeah. It really depends on what the environment demands from its inhabitants.
What else have I got wrong about evolution?
Well, this still implies that we strive for greatness. But one thing to consider is that there is not always a reason behind a particular trait in any given life form. Consider the human, with its male nipples. They serve no purpose to us, other than perhaps aesthetically, but if they are not of any consequence being there, a man born without nipples is no more likely to survive than one with them.
In fact I could argue they would more likely not pass their nipple-less genes because of how freaky they'd look. I dunno, just sayin'.
The giraffe is another classic example. Famous for their long necks, what most people don't know is that the giraffe's neck has a dark secret. Let's look at the laryngeal nerve in a human, a nerve that connected the brain directly to the larynx:
But hang on, what's going on in this picture? It looks like the laryngeal nerve got stuck under an artery and looped it way round. Nice going, God.
Well, imagine that set up, only evolution drives your neck to get longer and longer. Welcome to the giraffe neck
How on earth did this screw up happen?
Well, again, over such a slow period of time, the cost of having such a waste of a nerve wasn't enough to make much of a difference, if any at all, so 'screw up' is a relative term. It would have been a bigger screw up to look back at His design and go 'hang on that ain't right, let's go back a few million years and start again with a massive overhaul'.
So for the giraffe, why the hell not have a pointlessly long nerve? Why not have optical nerves that switch over to opposite eyes? Why not have ginger hair and overly sensitive skin? If I can survive, who cares?
And that brings us round to the silly monkey argument. Monkeys didn't die out because they are perfectly adapted to their environment. They're not the smartest in human terms; humans are. But they don't need to be smart. They have better swinging tails than us, furrier fur, louder squeals, bigger teeth.
We both evolved from a common ancestor and branched off in our own directions, but that's a post for another day.
Sometimes, there simply is no 'why', and that's just something we should be comfortable with.
Image Sources
Human genome book
Human Laryngeal Nerve
Giraffe Laryngeal Nerve
*Note: Though I am using the #suesascience tag, as part of the steemSTEM management, I am not actually taking part in this competition, but I wanted to do some misconception posts in the future anyway so, hell why not? Good luck to everybody participating!