• Question: How do you think the first life on Earth may have been evolved?

    Asked by dltjdgy to Katie, Ed, Sam, Steve, Vera on 15 Jun 2011. This question was also asked by charj008, tsungai.
    • Photo: Katie Marriott

      Katie Marriott answered on 14 Jun 2011:


      Things always have to start off with something simple that can be get more complicated. So:

      Firstly, there would have been simple chemicals like that in the air, so Oxygen, Nitrogen and other chemicals that are more reactive (for example, formaldehyde and compounds that contain nitrogen and oxygen – do you understand what I mean by a compound?).

      These simple chemicals would have reacted together to make larger compounds – for example, formaldehyde can react with more formaldehyde to make a sugar like glucose.

      It is possible that these larger compounds could start interacting with one another but not necessarily reacting. In our bodies lots of chemicals interact with one another like enzymes breaking down a substrate but they do not necessarily form bonds so they are not reacting.

      From here all you need to add is a cell membrane to keep all the interacting chemicals together, and this would for a simple organism, like a bacteria.

      It all sounds very simple really, but it’s actually very complicated! This process would have taken millions of years. it is still very unclear how the simple molecules formed the complicated molecules that we find in our biology today. The fact that nature had billions of years makes this research very difficult as well as scientists do not have this time span! The reactions I do are on for days to weeks to even months, which is a very long time in chemistry!

    • Photo: Sam Tazzyman

      Sam Tazzyman answered on 15 Jun 2011:


      Great answer, Katie – fascinating stuff!

    • Photo: Steven Daly

      Steven Daly answered on 15 Jun 2011:


      It is also possible that some of the molecules needed to start life came from space! There have been a lot of molecules found in space, and also in comets.

      I think Katie’s answer here is very good!

    • Photo: Vera Weisbecker

      Vera Weisbecker answered on 15 Jun 2011:


      Great explanation Katie! I had no idea so I also learned something today!

    • Photo: Ed Morrison

      Ed Morrison answered on 15 Jun 2011:


      Katie is a real expert isn’t she?

      An interesting question is what exactly is life. It’s not as simple as it sounds. Viruses are an example – they are very small (much smaller than bacteria) and they are basically just molecular machines than can replicate themselves. They don’t eat, or have membranes like bacteria. Are they alive? It’s hard to say.

      Whatever the first lifeforms were like, they would had the ability to replicate themselves. And once things start replicating, evolution can happen to make them more and more complex.

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