Evolution – Facts and fallacies

One of the many attractions and innovations of the theory of evolution is its simplicity. The theory, in a basic form, can be described with a few simple points, yet its applicability and reach is pervasive throughout the world of biology and further afield. One potential drawback of this ease with which evolution can be described may be that some of the finer points of the theory get lost, and irrationalities and errors arise as a consequence. So, in this post, we’re going to look at some of the common misconceptions surrounding the theory of evolution, and eventually lead into our next post which will address one of the tougher questions evolution has had to answer.

To start, it may be best to outline what the theory of evolution states so as to be best able to see where misconceptions could arise. Briefly, evolution is the process of change in an organism over a series of generations, wherein the organism becomes better suited to its environment. This change occurs at a genetic level – small mutations lead to changes in behaviour, function, or some other facet, which in turn make the organism better (or less) able to survive in its environment. Those organisms that possess mutations which make them better suited to their environment are more likely to survive to reproductive age (be selected through natural selection), and therefore have offspring that also posses the same mutation that made the original organism better able to survive. Over many generations, those organisms better suited to their environment are more likely to have offspring (which share their DNA), whilst those organisms which are less suited to their environment die out, and so do not pass on their DNA. Over long periods of time, this leads to significant changes in any given organism, sometimes leading to speciation (where an organism becomes so significantly different to its predecessors that it becomes its own species).

So there we have it, a very short (and simplistic) description of the theory of evolution. Now let’s have a look at some of the popular misconceptions surrounding the theory.

  1. Humans evolved from apes

 Arguably the most widely held and frequently cited is the misconceptions that humans evolved from apes (or chimpanzees). Where this error originally arose from, I am unsure, but its presence it easy to see. For example, I’m sure you’ve seen the graphic showing the ‘stages’ of evolution where the ape slowly becomes more and more upright and human-like as you move from left to right, supposedly showing the trajectory of evolution from apes, to humanoids, to humans (I believe it’s called the March of Progress). The graphic is incorrect, but it does well to highlight the common misconception we’re addressing.

In reality, humans and apes share a common ancestor. At some point in evolutionary history, organisms from the same species were separated and began living in separate conditions. Over time, those organisms became better adapted to their respective environment to the point where they became two separate species. Eventually, these two species became apes (technically they became chimpanzees, bonobos, etc. because ‘ape’ isn’t really a species) and humans (homo sapiens).

One result of this misconception that humans evolved from apes, is that some believe that there is a hierarchy of evolution – that some organisms are more highly evolved that others – which is the next fallacy we’re going to address.

 

  1. Some organisms are more highly evolved than others

I can imagine that the basis of this fallacy arises as a result of phrases like “highly-evolved mammals”, as well as a consequence of our consciousness, or more specifically, the fact that we appear to be the only animals capable of conscious thought. Whether this is true or not is irrelevant, but nonetheless, our belief that we possess unique abilities lends itself to the belief that, because these abilities are the most complex, we must be the most highly evolved animals. For example, if we compare our nervous system to that of a fruit fly, the disparity in complexity seems to suggest that we are somehow more highly evolved. This point is described rather funnily in the Ricky Gervais Show podcasts, wherein Karl Pilkington believes that all animals are aiming to be human, and that humans are the pinnacle of evolution. To quote the conversation exactly, Gervais says to Karl “A slug is as evolved as we are”, to which Karl responds, “It’s not, it’s nowhere near what we’re like”.

In reality, any organism that is still reproducing and not dying out (due to natural causes, not human intervention), is as evolved as any other organism! While we may think that consciousness is the best attribute to have, the animals without consciousness are not on an evolutionary trajectory toward it – in reality, they don’t have consciousness because their environment doesn’t demand it.

Why exactly humans required consciousness and abstract thought in our evolutionary history is unbeknownst to me, but regardless, these abilities are not the high point of evolution. And consequently, any animal that doesn’t have an attribute that we do, does not mean that animal is any less evolved.

To wrap up, consider the discord in humans’ and dogs’ sense of smell. While the dog’s sense of smell may be considerably better, that doesn’t mean that dogs have a more evolved sense of smell. Instead, they have a sense of smell that is appropriate to their environment, and so do we. In fact, if we had the olfactory ability of a dog, we would likely struggle due to sensory overload (despite what superhero/vampire/werewolf films and media may portray).

  1. Evolution is always in progress – an organism is never not evolving OR Humans are no longer evolving

This is (I would imagine) one of the lesser held misconceptions about evolution, but one that I believe is important. For a multitude of reasons, we as humans tend to believe that we have lifted ourselves out of the animal kingdom, and therefore aren’t affected by the same influences as the rest of the animal world. In reality, we’re just as animal as any other animal. Whilst we do have technological advances that have downplayed or decreased the speed of evolution in our species, as long as the environment we live in is changing (which it is), we are still evolving. For example, suppose that the appendix is a completely vestigial organ, with no function (it isn’t at all, but for argument’s sake we will imagine that it is). If it serves no function, it provides no evolutionary benefit to an individual. But, appendixes can burst, and this eventuality can be fatal without medical care. With modern medicine, fatality levels from appendicitis is fairly low, but does still occur. Over many, many thousands of generations, having an appendix puts an individual at a slight disadvantage. Therefore, if an individual mutated to have a smaller appendix (with a subsequent smaller chance of lethal appendicitis) or without an appendix at all, then he or she would be at an evolutionary advantage. Given enough time, these individuals would be more likely to survive and the appendix would disappear. I understand that this is extremely unlikely to happen as the appendix does appear to serve an important immune function, this hypothetical acts to demonstrate how we are not impervious to the process of evolution.

On the other hand, that is not to say that an organism must be evolving at any one time. If that organism is adapted to its surroundings, as long as those surroundings don’t change, then evolution won’t occur. Organisms with mutations will still be born, but if the organism is already perfectly adapted, then no mutation can be beneficial and so the mutated organism will be at a disadvantage. Take the cockroach for example. The cockroach has remained (largely) unchanged for millions and millions of years. While cockroaches with mutations are still born, no mutation can make the cockroach better suited to its surroundings, and so the mutated individual is not selected and the species remains unchanged. Importantly then, if an organism’s surroundings are changing, or the organism is not perfectly adapted, then evolution will occur. If the organism is already perfectly adapted, and the organism’s evolutionary environment remains constant, then no evolution need take place.

The final misconception I’m going to address, I am going to do so in a separate blog post due to its complexity, but we’ll briefly touch on it now. I came across this fallacy whilst in the dark reaches of YouTube, watching videos on mad conspiracy theories and supposed refutations of the theory of evolution. One particular video that caught my attention posited that evolution cannot be true because complex organs require hundreds if not thousands of genes. Mutations that are selected for (or against) are seldom more than mutations in one or two genes, but an organ has no function unless it is complete. Therefore, a mutation to produce a functioning organ (an eye for example) would require thousands of mutations, which is essentially impossible. Whilst this particular individual used this logic as proof that evolution is incorrect and intelligent design must instead be the cause of the natural world (which I certainly wouldn’t agree with), the video itself did act to highlight an important point for the theory of evolution. How do complex organs evolve?

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