Evolution Vs. Adaptation

Isn't this basically this:

However one's physical traits may change won't affect the genetic make-up of that particular individual directly.

You're correct on this.
This is funny because I now realize it's the very concept of OOP. Store states inside and interact on the outside through functions.

Also, the idea of natural selection is clear; what I want to know is how it happens in the first place.

People with worse traits die off. People with better traits live and pass on their traits through the population.
I understand that it is central to modern biology and it is often misunderstood as "evolving to a better state", but that is not the case here and I think I've failed to establish that, so I'm explicitly stating that now.

In Africa, black-skin is more prominent because, well, I don't need to repeat it. It's easier to survive being black-skinned than white-skinned there.

Okay, so we have 2 factors after all these posts: background genetic variations through reproduction and environmental variations.
Let's put environmental variation out of the picture for a moment.
Now we have an Asian lineage. Chances are that an Asian couple, though having potentially 2^32 x 2^32 possible combination of gamete coupling, will give birth to a fairly Asian-looking boy. Granted, his genetic information will be far different from that of either of his parents, but the outward traits shouldn't be outrageously varying.
This is probably accountable for geniuses emerging from time to time, but it surely isn't going to explain how fish started to walk on land. Even if it is, I'm not going to either easily or readily understand how.

Fish walked on land because one magical day there was this one fish that had genes mutated to go onto land. It was gradual. It probably started out as reproducing in water, but living on land, and eventually, it became full-blown onto land.

With just this alone, I believe there will be no major "evolution" as time passes. After all, humans are humans, we aren't going to grow fins, scales and maybe another eye just because the ground gradually sinks into the sea.
And we will be wiped out, most likely.

Exactly. We will get wiped out...you do realize 99% of all species are wiped out. The 1 remaining % is still living because they evolved to those conditions over tens and tens of millions of years. Evolution is not gradual. Earth is 4 billion years old. There's plenty of time.

So that sort of puts me under the impression that major changes in history was driven by something else, something that breaks the cycle, something from OUTSIDE the cycle.

Bottleneck effect.

Though, environmental effects aren't exactly reflected in genetic levels, as suggested by the central dogma (again, muscular dads don't produce muscular boys), so they don't really contribute to the variety of alleles there are.

Evolution.

So it must be something else, that I concluded. What is that something else? I knew of radiation (often known to cause cancer, which is most likely an undesired mutation), mishaps in reproduction, viruses, etc... but none of that would explain even the skin color of different people in different continents.

Because black-skinned people are better suited to living there. Humans have been around for several million years. That's enough time for something minor as skin color to mutate.

Comments in bold.

Cracked article on the fastest evolving animals currently.