• Question: Does the size of something affect how quickly evolution happens

    Asked by jake321 to Ed, Katie, Sam, Steve, Vera on 14 Jun 2011.
    • Photo: Katie Marriott

      Katie Marriott answered on 14 Jun 2011:

      I am not sure about this one so maybe someone else can help out!

      I know the evolution of something depends on the length of their DNA and the lifespan. So do small things such as bacteria instantly have a shorter lifespan? i am not sure!

    • Photo: Sam Tazzyman

      Sam Tazzyman answered on 14 Jun 2011:

      Lots of things affect how quickly evolution happens, such as the number of organisms in a population, the details of the genetics of the population, whether the species reproduces by sexual or asexual reproduction (asexual reproduction is cloning, like happens in bacteria for example), the strength of the force that is making the population evolve, and the length of the average lifespan of an individual organism. Now I am not sure it is a hard and fast rule, but in general larger lifeforms such as elephants have longer lifespans than smaller lifeforms like mice. Also there tend to be fewer large lifeforms in each population – there are usually more mice in a place where mice live than there are elephants in a herd. So indirectly, because of these reasons I would expect that the size of something could affect how quickly it evolves. But there are likely to be other factors too.

    • Photo: Steven Daly

      Steven Daly answered on 14 Jun 2011:

      I don’t think I can put this any better than Sam here. I would say in general the size does affect how as Sam says. It is also more likely that large animals will go extinct, for the same reasons given. They find it harder to adapt to changes.

    • Photo: Vera Weisbecker

      Vera Weisbecker answered on 14 Jun 2011:

      I think Sam is right there. Also, large mammals (at least) take a lot longer to have a baby than small ones. Hamsters only take about 2 weeks or a bit more, while elephants take 2ish years! And then it takes elephants extra-long to turn into an adult that can also have babies – Hamsters are ready in a few days, elephants take 15 or so years (depending on their sex). As every time you have a baby the genetic “cards” are re-shuffled and mutations can pop up, this means that evolution can work much faster in hamsters than in elephants – hence you’d expect hamsters to evolve faster.

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