Evolution made Clearer

Those of you who follow my posts on here might not know that one of my hobby–passions is evolution. I find the science of evolution fascinating and so incredibly important. I also find that it is very often poorly taught, such that we end up with many people not even believing in it, and even those who do believe in it often do not really understand it.

So here are a few commonly used statements about evolution that are actually misleading.

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“Survival of the fittest” 

When we hear the word “fit”, we think of athletes, strong and fast. And while being strong and fast are great ways to survive, they are far from the only ways.

“Fittest” really means the best suited to the situation. Whichever organism is best suited to the environmental conditions will out-survive those that are not.

This is why tall trees survive better than short trees in environments populated with leaf eating animals and why leaf-eating animals with longer necks survive better than short-necked leaf-eating animals in environments with tall trees.

But this also leads us to the next misleading idea. We often hear that something evolved for a certain function; for example, a giraffe evolved its long neck to reach the tops of tall trees. Again, this gives the wrong idea of how evolution happens.

Giraffes didn’t need long necks and go about evolving them to fulfill their goal of eating leaves. It might seem like a small point, but it is important to recognise that giraffes did not evolve long necks *TO* eat long leaves, but rather giraffes evolved long necks *BECAUSE* giraffes with short necks could not reach the high leaves and so died out.

Indeed, many of the things that have evolved in various organisms are used very differently now than they were at the time of their initial origin. For example, one might think we evolved lungs TO breath, but in fact when lungs first evolved, they were used by our aquatic ancestors for buoyancy.

Furthermore, the heavy focus on the ideas above gives a sense that “survival of the fittest” is the whole picture, but it is only one part of a complex system. I find it more helpful to talk about the evolution as being driven by three forces:

Environmental Pressure

Random Mutation

Sexual Selection

Environmental Pressure corresponds to the ideas we have discussed about, re: survival of the fittest. Environmental Pressure, i.e. the organism’s living conditions, determine whether an organism will survive or not. If the environment is hot or cold, if there is an abundance or a scarcity of resources, whether there are predators or not. An organism can be more or less likely to survive depending on how well equipped it is to face its environment.

And if an environment suddenly changes—for example through climate change or external interference, such as human interference or the introductuon of non-native species—then organisms that were once well equipped to survive might suddenly find themselves in existential danger.

Random Mutation is the driving force behind change. Without random mutation, we would not be here at all. In fact, nothing beyond single-celled organisms would have ever arisen—maybe not even that! Random mutation is how the offspring of one organism (or a pair of organisms) can be different from its “parent”.

When an organism reproduces—which can happen through several different processes—it creates a copy of its genes. But these copies are not always perfect. At a random rate, some of these copies will not be exact, so that the copy contains different information from the original. Some of these differences will be insignificant, entirely unnoticeable; some of them will lead to illness, disease or deformity; and some of them might give a tiny survival advantage to the new offspring.

In the last case, the organism with the mutation will out-survive its “relatives” that do not have the mutation, and as it reproduces, this advantage is passed on to its offspring.

Which brings us to the third driving force of evolution, sexual selection. This is the process by which sexually reproducing organisms choose their mates. Organisms that are better equipped for survival are generally more attractive, so they are more likely to attract a mate and reproduce, meaning that they are more likely to have offspring than their less-well-equipped, less attractive peers.

Through this process, the genes of organisms better equipped for survival are more likely to be passed on, meaning that a population will become gradually better equipped for survival. Not to mention that an organism cannot reproduce if it is already dead, meaning that especially poorly-equipped organisms will simply not have the chance to pass on their poor genes to the next generation.

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While what most people learn about evolution (Survival of the Fittest) is true, it is not the most enlightening way of describing the process.

The way we talk about ideas is very important; it has a huge impact on the way people think about them. And over simplifying a process so complex as evolution not only means that people have a poor understanding of it, but it also makes it less believable: how could something so simple give rise to such complex systems?

Evolution is one of the most powerful ideas in the history of science, and it deserves to be explained clearly! I hope this article has helped…

I want to add the caveat here that I am not an evolutionary biologist; as I stated in the opening paragraph, this is more of a hobby than anything else. So if you are better educated in the field than I and notice inaccuracies in this post, please let me know! I want to clear up any misunderstandings I might have, and I also want to ensure the post is not misleading.