Unraveling an Evolutionary Puzzle: Why Evolution Can't Solve Every Problem?

This article will serve more as an introduction to the next one than a standalone one, I hope you find it interesting. The goal will be to understand some very basic concepts about biological evolution and why, being such a strong force of nature, it isn't capable of fixing everything.

Think about this question: How much sense does it make that a system as strong as evolution, which has engineered a process enabling us to go from microscopic microbes to conscious beings walking on the moon, is not capable of solving minuscule problems such as Cancer, Alzheimer's, or Cholesterol; insignificant annoyances compared to the masterpiece of life itself??Let that sink in...

To answer this question, we need to agree on some basic concepts about biological evolution, but once we have, we will be able to answer a second one (and the topic of the next article): What's stopping us from living 200 years, or even more, much, much more?

My passion for this question was ignited by two books that I strongly recommend if you share an interest in the subject:

"The Selfish Gene" by Richard Dawkins (the one that sparked my interest in biology).

In a nutshell, how does evolution work?

The fantastic feat of evolution spans on some very basic properties, laws, and concepts: randomness, statistics, and probability, among many others, of course.

DNA is the source code that carries the genetic instructions for growth, development, and functioning in all known living organisms. The information is encoded in sequences of nucleotides ordered in specific concatenations that make up genes, providing information for building and maintaining organisms. It's the blueprint of life.

Now, the interesting part is how it was (and still is) created: RANDOMNESS, well, of course, if you believe in evolution and in Sir Charles Darwin, et al.

Every time a new creature is made, a new unique version of DNA is created, most of the time by combining the originating DNA of two different ones. During this process, tiny mistakes are made; we call them "mutations." Imagine that you are copying a very long recipe (human DNA has 6 billion bases), and you accidentally change one ingredient.

Most of the time, these mistakes don't change anything, or the change might even be harmful. But once in a while, a mutation can be helpful, like some extra lemon that gives the cake a delicious "sweet and sour" kick, and now everyone wants an extra slice.

If the newborn gets a helpful mutation that increases the chances of survival and reproduction, those babies will inherit the "extra kick." Eventually, almost the whole town will have the recipe for that better-tasting cake!

That's, in a nutshell, how evolution works and how we have managed to own this resourceful DNA that we often take for granted. I know that if you are a stranger to this field of science, this could be very hard to believe; how can simple randomness, without any consciousness and planning, build something so functional?

I will not dare to explain that conundrum here; it is way too big for me. But let's recall that I mentioned two other concepts: STATISTICS and PROBABILITY.

Life is estimated to have begun on Earth around 3.5 to 4 billion years ago. Each offspring created is equivalent to one more copy of that cake recipe, subject to "mistakes." For simplicity, let's use human scale.

An average generation takes 20 years. Let's assume we come from a linear lineage, so one human gives birth to one human. If this were to occur for 3.5 billion years, that process would have happened 175 million times. Now let's spice things up.

Since we are way more than 1 human, that gig happens many times at each generation. Recent discoveries now suggest that Homo sapiens have existed for 200,000 years, yielding an estimated number of 117 billion members of our species who have ever been born on Earth.

Finally, remember that we come from much earlier, and our actual DNA started to be crafted with the very first living organism. Many of them have orders of magnitude larger numbers of living members at the same time and much, much shorter generations. So this trick of "imperfectly" copying the lemon cake recipe has happened 117 billion times to the power of an unknown number, but trust me, it's very large.

Can you imagine what a fantastic lemon cake you can develop if you were to make that recipe 1 billion times, making just one mistake at a time and starting with the best one for the next round? Well, that's how evolution works.

And now, we can answer the real question we are here for: How is it that the amazing trick of evolution has not been able to solve minuscule problems such as cancer, Alzheimer's, or cholesterol; insignificant annoyances compared to the masterpiece of life itself?

For "positive" mistakes to carry over, they need to fulfill one very simple rule: increase chances of reproduction, so the trait will increase its presence in the population. That's why we managed to stand on just two feet or grow teeth.

But what about curing cancer, for example? This one is very simple. When does cancer generally occur? If we look at the cancers with the highest death toll, we will find lung, colorectal, pancreatic, liver, and esophageal, with ages of diagnosis ranging from 60 in the case of esophageal to 70 in lung and pancreatic.

And what about reproduction? Unsurprisingly, that occurs much earlier, with the biggest portion of offspring being born when their parents range between 20 and 34 years. This is 30 years before most dangerous cancers appear. Even more, the average reproductive age ends on average between 40 and 50, also decades before most cancers show up.

What about Alzheimer's? 65. Death commonly caused by high cholesterol? 60.

Do you get it? The problem is not for evolution to cure these diseases; the problem is that the trick only works if the improvement happens before our reproductive age. If it happens after, the "positive mistake" simply fades away. So most likely, all this has been cracked by evolution already; we simply never found out, and never will.

Unless we can crack evolution, and that's what my next article will be about. So stay tuned.