I find evolution a fascinating subject and I tend to discuss it with people. When discussing it I have seen this type of question often. Unfortunately it often stems from a bit of a misunderstanding about how evolution works, so I will try to clear up some terms here before I try to answer the question.

Evolution is not magic

This is the first thing that we should make sure that we understand. Evolution isn’t some sentient force that constantly pushes living beings into becoming “better and better.”

Even people who really know this sometimes forgets it, because that’s how evolution may look from our perspective. But it is important to remember that evolution doesn’t have a plan or purpose, and no direction.

Unfortunately, movies and TV often depict evolution as if it was a magic force to make things better. In the realm of entertainment there can for instance often be machines to “evolve” and “de-evolve” a member of a species. Those machines will make the individual smarter and “better” by evolving it, and dumber and “worse” by de-evolving it.

But that isn’t how evolution works. Evolution isn’t a ladder on which species starts on a low rung and steadily climbs upwards, and you certainly can’t have a machine that moves an individual up and down that ladder. There simply isn’t such a thing as “more evolved” or “less evolved.”

So, is evolution random then?

Many people will think that if evolution has no purpose or direction, it is an entirely random process, but that isn’t true either.

There is a random element in evolution, random mutations in genes, but the whole process of evolution is by no means random.

Natural selection

The most important topics when it comes to evolution are natural selection, selection pressure and adaptation. These are the processes that make evolution work and what makes it not random, but still not “directed” in any usual sense of the word.

Natural selection is something that can be compared with artificial selection, which is the process we use when we breed dogs, horses, plants or whatever it might be, to produce new breeds and variants of them.

Throughout recorded history, humans have had great success with this. We have combined the best (by some definition of “best”) individuals of a species to produce bigger and stronger working animals, better crops, cuter pets and so on. A similar thing happens in nature, without being guided by human hands.

In nature, we can see populations of various animals and plant life. Within these populations some will survive long enough to reproduce, some will not. Some will find a mate to reproduce with, some will not. The ones who do propagate will bring their particular traits into the next generation, those who don’t propagate will obviously not.

The essence of natural selection is that some traits will make it more or less likely that an individual will be able to reproduce. These traits are said to be favored.

The favored traits are more likely to show up in a higher frequency in the next generation of the population and might eventually become more and more prominent if they continue to be advantageous for the population. When this happens the species is adapting to its environment by having traits that are good for its survival.

Selection pressure 

Selection pressure is what “decides” which traits are the most favorable. If there is a shortage of food, the individuals who have an easier time getting food (for instance a longer neck or narrower beak or better sight) will have a greater chance of surviving to reproduce. If the population is hunted by predators, the individuals who have a greater chance of escaping will be more likely to reproduce. If there is a shortage of water, individuals who are less prone to getting dehydrated will survive longer, and so on.

This is often called survival of the fittest, which turns out to be a wholly bad choice of words. It is entirely true, but conjures up a very negative mental image in many people. There are many who believe that survival of the fittest tells us that we should be competitive in a nasty way, stealing food and resources from each other, to survive.

But this isn’t necessarily true. “Fittest”, in this context, just means the ones who are the most fit to survive in the particular environment that they live in. It puts no value, positive or negative, on being fit.

The process of evolution doesn’t just “reward” things like strong muscles, fast legs and sharp teeth. In some populations the individuals who have a tendency to cooperate will be far more likely to survive than those who don’t, and then that trait will be favored. And of course it’s always favorable to take care of your young so that they grow up to reproduce and continue passing on your traits. So “fittest” doesn’t have to be taken in a negative way; natural selection can reward many different types of traits.

The term survival of the fittest can also be confusing because people equate the word fittest with the word best, thinking that the best individuals survive. This isn’t necessarily true in the way that most people think. For instance, a bigger and stronger body or a larger and more advanced brain might be advantageous to some and might be considered “good” qualities by us. But it can also cost a lot of energy to maintain, and if food is scarce it might be the smaller individuals who survive.

So, in essence evolution will lead a species on a path, but this path will not necessarily lead in a direction that is considered good by human standards.

First of all we have to recognize that in general there isn’t any selection pressure for us. Humans will generally survive long enough to reproduce without having to compete for resources in the traditional sense.

Modern healthcare and vaccines mean that even some of the “weaker members of the herd” will survive. Our buildings, cities and advanced tools protects us from the weather, predators and many natural disasters, meaning that anyone has a chance to survive them. Optometry gives even the ones with very bad eyesight a chance to see, and our society makes sure that even those with no eyesight at all can survive. A good supply of food (in parts of the world; more on that later) means that even those who would have been worthless hunters or gatherers can eat.

So, since there is generally no selection pressure, there are no favored traits. Each successive generation is pretty much the same as the previous, with no traits being in significantly higher frequency. This would in essence mean that humans aren’t evolving at all.

What about poor areas of the world?

Many readers will no doubt wonder how I can possibly claim that people have food, shelter and medicine, when that isn’t true for much of the world.

And yes, of course that is a valid thing to bring up. What I said in the previous section is true for those of us who are fortunate enough to live in a relatively rich country. Much of the world’s population isn’t so lucky, unfortunately.

In for instance some of the poorest countries of Africa there is still significant selection pressure. There is a massive shortage of food, certain diseases run rampant, and so on, meaning that not everyone survive long enough to reproduce.

In the long run this can mean that certain traits will become more prominent. Those who are more resistant to diseases like tuberculosis, people who can survive on less food, and so on, might very well survive in greater numbers. This could for instance lead to future humans who have better immune systems and more efficient bodies.

But we must remember that evolution works on very large timescales. It takes many generations for a population to change significantly, and I am an optimist hoping that the sad state of affairs in much of the world won’t continue for all that long. If we can have a bit more fair distribution of resources in the world, we might not have any areas with such relatively strong selection pressure.

Idiocracy

There is one other kind of “selection” at play today that I thought that I would mention before closing this up. This is something mentioned in a movie called Idiocracy.

I don’t really enjoy silly comedies, and Idiocracy is certainly as silly as they come at times. But the beginning part of it is extremely entertaining, and somewhat scary. The movie starts with a description of why the future will be inhabited by very unintelligent people.

This has simply to do with who has the most children. In general, people who are very well-educated will focus much on their careers and have very few children. People who are not well-educated will often focus more on their family (and sex) earlier in their lives and have many more children.

If the people who are more educated are smarter than the ones who are less educated, this could mean that every subsequent generation are having more and more children born of less intelligent parents and less children born of more intelligent parents, which could mean that the overall intelligence of the species could sink rapidly.

Fortunately this doesn’t have to be true though. It is true that people with more education generally have fewer children, but it is not necessarily true that people with less education are less intelligent. So I don’t think that this will have any great effect on the future of humanity.

But in conclusion I would still like to say that it might be the most probable thing for us. Evolution might bring the human race slightly better immune systems and things like that, but there isn’t any real reason to believe that we would develop any “extraordinary abilities” like we see in X-Men and similar works of fiction. The most probable thing is that we will get slightly dumber.