Natural selection stripped down

I have a number of science literate friends who, while they are perfectly happy to accept that evolution is true, don’t know the real fundamental of what natural selection implies or how it was derived. This is not a criticism of them, as I have argued before, not all ‘argument from authority’ is invalid (in context) and indeed those arguing against something without understanding are not really helping the situation. However, it seemed like a fun challenge to try and explain the very fundamentals of evolution by natural selection and the evidence (or at least examples of it in action) in as few words as possible. Explanations of evolution tend to run to a line or two, or entire pages or even book chapters and there seemed to be a spot on the market for something in between. A couple of minutes reading that includes as much evidence, theory and explanation as possible but in a compact paragraph. It might well be of interest and of use to some, so here goes.

Evolution by natural selection is the process where, over numerous generations, organisms adapt to changing environments. The environment can mean climate, geography, competition from predators, prey, or others of the same species etc. Traits (like size, colour, stamina, resistance to diseases etc.) are inherited by offspring from their parents (you do after all, look like your parents, and they like their parents). However, changes also occur between generations, both from the mixing of genes through sex, or novel mutations (you don’t look exactly like your parents, or your siblings). Nature provides the selection of which genes are the most suited to keep the individual organisms alive and to prosper. If there is a heavy winter, those with more fat or thicker fur will be more likely to survive, if there is a drought, those best at retaining water will do best, if predators get faster, the fastest prey will most likely survive. Since traits are inherited, those animals which survive best or have the most young will be the ones to pass those traits onto their children. Over time then, certain traits (like thicker fur, or bigger bodies or longer legs) will become more common as the organism adapts to an ever changing world and the species as a whole evolves. This can be seen in the fossil record as organisms change over time (like the appearance of limbs and fingers in fish as they evolve into amphibians, or the change from five toes to three to one in fossil horses). This can be seen in the genes of organisms in the lab as they are forced through mutations and changes by scientists. This can be seen in the wild as pests evolve immunity to poisons or bight fish grow dull when new predators appear, or beaks change in finches to feed on different seeds during droughts. This all adds up to a convincing single picture as nature selects the best adapted individuals and they pass on their traits to their offspring and so over time the species adapts and evolves.

Well that’s a shade under 350 words. More than I had hoped, but less that I had feared and it does (I hope) combine the basics of the theory with easy to understand examples and real evidence, as well as avoiding jargon or complex terms. If I wanted to keep it really short, the latter 3/4 of the last sentence could be considered enough as it does give the very bare essentials. Still, I hope it does a decent job given the intended compaction of a hundred and fifty years of theory and research into a single long paragraph. I’d certainly welcome other efforts in the comments or on other blogs.

5 Responses to “Natural selection stripped down”

  1. 1 Lockwood 21/06/2010 at 1:44 am

    On the 150th anniversary of the publication of “The Origin of Species,” I tried to do much the same thing. My summary is in the seven bullets about the middle of the post… I’d appreciate feedback and/or corrections as well.

    • 2 David Hone 21/06/2010 at 9:42 am

      Looks good to me. THe only real difference is that yours seems to be directly related to Origin, whereas I was going for everything before and since. However, when you boil it down this much they are surprisingly similar (i.e. Darwin got all the basics right).

  2. 3 unique_stephen 22/06/2010 at 11:54 am

    Now – could you do the same with Batman’s Principal.

    The predictions of which, when considered closely with Game Theory are very useful…
    …. in the pub.

  3. 4 Casey Rentz 29/06/2010 at 1:06 am

    Good description with plenty of well-placed examples.

    I always wonder whether using the phrases ‘nature provides’ or ‘nature selects,’ as if nature is an active force or entity with some sort of goal ‘in mind’ is a good way to describe natural selection. Essentially, it’s just a way to use personification to make a point, but it can be confusing to the uneducated lay person.

    I mean, you could say nature (the collection of things and forces) has the goal of maximizing fitness, but most lay people think of nature as just what’s outside of cities. I’ve seen people draw the conclusion that ‘all the animals are ganging up on us’ or that there’s some kind of collective consciousness.


    • 5 David Hone 29/06/2010 at 7:44 am

      All good points really. But you have to draw the line *somewhere*, especially when trying to keep things simple. You simply can’t provide a definition of ‘nature’ and ‘selection’ (or even ‘organisms’ – do viruses and prions count or not?) etc. etc. while deliberately keeping it short. These are all issues that confuse people from time to time and with more time and space you could probably make it clearer (but longer). Personally I’d hope that someone who was even vaguely interested would take it upon themselves to go and look things up or ask questions to clear up any confusion. Experience tells me otherwise, sadly, but you can only lead horses to water….

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