• Question: how do things evolve?

    Asked by mewett123 to Aled, Ellie, Fiona, Kev, Willem on 11 Mar 2014.
    • Photo: Kevin Arbuckle

      Kevin Arbuckle answered on 11 Mar 2014:

      That is a very big question indeed.
      In short (feel free to ask anything more specific), evolution happens because individuals of a species are not equally likely to die. It requires three things: heritability (traits can pass from parents to offspring), variation (which we can see in almost all traits – e.g. people are different heights), and selection (such that some forms of a trait cause the individual to have more children, survive better, etc.). These three conditions are almost always met in nature.

      Think of a camouflaged moth and one that is a bit easier to see. Camouflage is likely to be caused by genes (so is heritable) and we have variation (the two different kinds of moth). We also have selection because predators can see one type of moth better than the other. In this case, predators will eat more of the non-camouflaged moths, which means that more of the camouflaged ones will survive and have children. Over time this means that there will be more camouflaged moths, and this is what we call evolution.

      I hope this answers your question, if not, let me know.

    • Photo: Willem Heijltjes

      Willem Heijltjes answered on 11 Mar 2014:

      By two principles: “mutation” and “selection”. If you have these, you can make anything evolve! They work as follows. For example, take some fish, and (try to) evolve them to make them walk:

      1) “mutation” gives you one or several new fish, that are mostly similar, but slightly different than the one before

      2) “selection” means you take only those of the new fish that are the best at walking (even if it doesn’t look like walking at all, yet).

      If you repeat 1) and 2) often enough, each time with the new fish that are slightly better at walking, in the end you may get walking fish!

      While this is a good picture to understand the principle, two things are important. In nature, there is no “goal”: evolution just happens, and it doesn’t know where it’s going. That’s no problem, because “selection” in nature happens by “surviving” (or better: creating offspring) – so the result will be organisms that are “good at life” 😉

      Another thing is that you can’t get everything you want using evolution – it’s not magic! Even if you have “selection” and “mutation”, evolution only works if it is possible to find a solution in small steps… So pokemon is out 😉

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