Let me explain evolution to you clowns.
Evolution is plain old Mathematics. It's simple number theory.
I used the words "combinatorial explosion". Do you know what that means?
Here's what it means. You've heard of Pascal's triangle, yes? Well, Pascal's triangle has three very important realizations. One is, the number of ways to choose subsets of size k from a set of size n. (Mathematicians call this "n choose k"). It turns out, that these numbers are identical to the coefficients of binomial expansion. So for instance if you have (a+b) squared, that's a squared plus 2ab plus b squared, the coefficients are 1,2,1 which is the second row of Pascal's triangle because we're raising to the power 2.
The third and arguably most important meaning in the real world is the probability of equally likely outcomes. It turns out that if you add up all the numbers in a row of Pascal's triangle, you get 2^n, which is the number of possible outcomes by flipping a coin n times. The likelihood of each outcome is given by the coefficients in the row. So if you flip a coin twice, there's only one way to get two heads and one way to get two tails, but there are two ways to get one head and one tail. Again, 1,2,1 - the same set of coefficients.
To understand combinatorial explosion, you merely have to look at the coefficients in Pascal's triangle. Look at the largest number in each row. (Which is in the middle of the row). Now look at the numbers around it. What do you see?
If you flip a coin 10,000 times (which corresponds to the 10,000th row of Pascal's triangle), the largest number in the row has an exponent of +28 !!!
That means, even though you're only doing 10^4 flips, there are 10^28 possible outcomes.
THAT is combinatorial explosion.
It means if you have 10,000 molecules to start with, there are 10^28 ways they can come together to form new molecules. If you have a DNA sequence of length 10,000, there are 10^28 permutations, and since the outcome of each coin flip is equally likely, the Law of Large Numbers says YOU WILL EVENTUALLY GET THEM ALL.
How long will that take? (What does "eventually" mean?) Well, it depends how fast you can flip a coin. The kinetics of chemical bonding are usually in the nanosecond to microsecond range. That means you can do 10,000 coin flips in a few milliseconds. Meaning, in MILLISECONDS you have 10^28 permutations when you only started out with 10,000.
Now - in evolution, they quaintly call this process "mutation", and we can measure the kinetics of mutation, both in water and in thin air, and it turns out there are CATALYSTS that increase the speed of coin flipping by millions of times. For example, copper and zinc are peptide bond and nucleotide bond catalysts. Copper is one of the most abundant ions on earth, it's everywhere - in the ocean and in every square inch of dirt on the planet. Whenever two amino acids get next to a copper ion, they'll make a protein. It happens 150 billion times EVERY SECOND in planet earth. That's what combinatorial explosion is about.
And, it's what drives the variety and richness of life. The universe tries every possible combination, and keeps the ones that work. It is part and parcel of the fabric of space and time. There is no avoiding it. There is no denying it. Everything you see, came into being this way. Every atom in the universe was created this way.
If you're religious, you could say "this is the way God works", and that description would be perfectly fine with me. But to deny its existence, is entirely nonsensical. Or to be perfectly rude about it, butt stupid.
Biological evolution is nothing more than combinatorial explosion, and keeping the combinations that work. Selection has many meanings, it could occur on the basis of stability, or on the basis of compatibility, or on the basis of a scientist (or God) making decisions based on a set of criteria. We have yet to discover all the possible ways someone could manipulate 10^28 outcomes.
And actually, the number of molecules on earth is greater than the number of stars and galaxies in the cosmos. It's some astronomically huge number like 10^156. It's a much bigger number than anyone can conceive of. The number of combinations available from that is vast.
Note: this is Mathematics. I never made reference to biology, life forms, or fitness. It's plain simple math. It can't be denied. It happens whenever and wherever you can count numbers.