• Question: what happens during evolution?

    Asked by marieharris to Ed, Katie, Sam, Steve, Vera on 19 Jun 2011.
    • Photo: Vera Weisbecker

      Vera Weisbecker answered on 17 Jun 2011:

      I could write several volumes on this, but here is Darwin’s very simple but very precise explanation.

      1) There are only limited resources (e.g. space, food, shelter) for members of a species
      2) Within a species, there is variation – that means that not all members of a species look identical (like, there are big and small ones)
      3) This variation is heritable, meaning that if the parents have a successful feature then the babies will also have it.

      From these three observation, Darwin worked out what happens – from the many different members of a species, only those that are particularly well suited to the environment (let’s say, because they are bigger) survive to have babies. Because suitability to the environment is passed on to the babies, more and more individuals of the “successful kind” – in this example, bigger ones – are being born. Over many generations, there will be more and more big individuals , until the whole species is has turned bigger. This is Evolution – nature selects what type of animal makes it to the next round, a process not unreasonably called “natural selection”.

    • Photo: Sam Tazzyman

      Sam Tazzyman answered on 17 Jun 2011:

      Vera’s answer is great. To add to this (which Darwin didn’t know) the main way in which the heritable variation is passed on from parents to offspring is via their genes. So the “successful” individuals in a species (in line with Vera, let’s say the bigger ones) who survive and reproduce have “successful” genes (in our case, genes for being big). The genes are then passed on. But sometimes there’s a mistake in passing the genes on and they get slightly changed. This is called “mutation”, appears to be random, and is what provides the variation of Vera’s point 2.

    • Photo: Steven Daly

      Steven Daly answered on 18 Jun 2011:

      Another thing to add is that not everything we can inherit is genetically based. Certain behaviours in humans, such as our communication are not genetically coded but are still passed from one generation to the next. although this is not natural selection in a typical sense, things like this are important for human survival.

    • Photo: Katie Marriott

      Katie Marriott answered on 19 Jun 2011:

      Very good answer from Vera there!

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