Natural selection can be summed up with a single sentence: “Those individuals who are better suited to their environment are more likely to survive and pass those well suited traits on to the next generation.” It’s a long sentence, but it’s accurate. What it means is that only the very well adapted individuals will stave off death for long enough to reproduce. An adaptation is a slight change altering an individual’s functions.
Natural selection reigns true when discussing anything that experiences competition, from organisms to businesses to athletes. The poorly adapted individuals will die, or leave the competition in the case of athletes.
If an individual is much better adapted than the rest of the competition, within a few generations, the entire population will posses that advantageous trait. This happens much quicker when talking about humans because our ability to learn and correct means we don’t have to wait for the next generation to copy someone who is on to something big. If an individual comes along with a wildly advantageous trait that blows the competition out of the water, then it might completely conquer a niche. The competitors will either die or diversify.
Some quick examples to solidify that idea since I just used a lot of ambiguous words. Let’s start with the organism: a brown bear gives birth to a mutant, cub lacking melanin in it’s hair cells making it white. This cub might look vastly different from the rest of the population but things change when a massive snowstorm hits. The white cub is much better suited to sneaking up on its prey since it can camouflage with the surrounding snow. It will thrive in the snowy environment and pass on its trait to the next generation, eventually creating a population of white bears.
Next, a business: a grocery store opens up a self check-out line to speed up the purchasing process. It speeds things up causing more people to start shopping there. Competitors must now diversify to come up with some other way to attract customers or copy the first store’s lead. Eventually most grocery stores have a self check-out line.
Even athletes experience natural selection. Only the best basketball players can reach college basketball and the best of them are the only ones to make it to the NBA. The style of play has changed over the years and only players with the right skills survive in the league. The rest of the players without the necessary skills are forced out of the league leaving only the best players. Natural selection is everywhere.
The term “natural selection” is actually a misnomer because there is no selecting going on. When we hear the word “selecting” we automatically think that some conscious entity is picking and choosing which individuals will survive and which will die. This is not the case at all. Nature has no ability to decide because it does not think. Nature is random and plays by very specific rules. We can learn those rules and eventually make predictions, but that’s beside the point here.
The individuals that exist today are the ones that were able to explore unoccupied niches or the ones who conquered occupied niches because they were better adapted. Every other individual that is not ideally suited to its environment will eventually be replaced by an individual that is. “Natural elimination” is a more accurate phrase. “Survival of the fittest,” by the way, is a phrase Darwin never used when developing his theory.
Evolution seems to make a lot of people upset when they are told they are descendants of apes and fish because they think it makes them lesser. That’s not what natural selection is saying at all. Rather, it means you are the cream of the crop! You are alive today because your ancestors were the best at doing whatever was necessary to survive. They were the best at occupying their niches for long enough to finally make you. You are the culmination of success after success after success, despite all of the ridiculous challenges that life has faced over the last 3.5 billion years.