Saturday, 24 May 2014

The 3 most common misconceptions about evolution

Evolution, the great divider, the topic probably accounts for about 80% of all arguments on the internet. But why? Simply, it's a lack of understanding compounded by an unwillingness to look at evidence that might differ to your opinion. While I can't really do anything about the unwillingness, I can certainly help with the lack of understanding. 

First, a little introduction on what evolution actually is, as a lot of people don't really know. Evolution itself is just another word for change. The theory of evolution by natural selection is a very good explanation of how the species we see today came about; through the creation non-random survival advantages by random mutations in the genome. For example, an animal in an environment full of grazing animals that carried a mutation that gave it a slightly longer neck, enabling it to eat from places that others could not reach would put it at a selective advantage, meaning it is more likely to survive and reproduce than other members of its species thus increasing the amount of members of that species that had longer necks and increasing the survival of that species. 

While the theory is not yet fully complete (there isn't a record for every single species that ever existed) it is by far the best explanation of how the species we see today came to be. However this doesn't stop a lot of people from trying to disprove it. So just to be clear, let's just go through what the theory of evolution does not do...

 It does not explain how life originated, it only explains how the many different species we have today came to be once life had begun. It is also not proof that God does not exist, it is evidence that divine creation (as described by any religion) is wrong though. So let's get into some misconceptions that people have about evolution.

Evolution Doesn't Have to Create a New Species

Evolution quite often eventually leads to new species eventually, but that doesn't always happen. In order to create a new species, a population of a species has to be so genetically different to the rest of the population that they can no longer produce sterile offspring if they mated. This often due to things like physical isolation, where a population becomes isolated and evolves separately from the rest of the species. However, this doesn't mean that any change in DNA creates a new species, just take humans- there is so much variation within our species yet we can still all reproduce with one another, even if our ancestors have lived on opposite sides of the world for numerous generations. These variations give us advantages based on our environment that aid our survival, but they do not make us a different species.

There is no Goal in Evolution

Evolution does not have a goal, there is no species that is the best adapted to every environment. Many people often ask the question, why have apes not evolved into humans? The answer is simple, humans already exist. There were even other species of human-like apes that are now extinct, the other species of apes (while the closest to us now) have had a completely different evolutionary history since humans split away from the other apes, so they never would be able to evolve into us, as their genes have changed in different ways to ours. This is partly because of pictures like these...

what most people think of when you mention evolution

These timelines are correct in that humans evolved from apes, but they create a false impression that modern chimps would evolve into us. This is wrong, the ancestors of chimps and humans split into many other species before ending up with the species we have today. The real timeline looks more like this...

This branching diagram illustrates how humans and chimpanzees evolved from a common ancestor

The other reason is this, species do not have to evolve to become more adapted all the time. There are many species eg sharks, fungi, chimps etc that are adapted just fine to their environments which means there is little selective pressure and thus little evolutionary drive.

Evolution is not Perfect

Evolution does not always produce perfectly adapted species (as I just mentioned) it also doesn't always make a species more adapted. Because these random mutations are exactly that, random, it is entirely possible for an organism to become less adapted- of course this would mean it would be at a selective disadvantage and eventually die out if the disadvantage was too severe. 

There are countless other misconceptions and invalid arguments against evolutionary theory that I haven't covered here. I'll eventually get to the other frankly absurd ideas that some people have, including social darwinism and arguments against homosexuality. If you'd like to learn more then please take the time to do your own research, ask me (or anyone else with an understanding of evolution) about it or follow these links below. 

Sources and Reading university of berkely


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