• Question: How did the first living organism appear on Earth?

    Asked by Sonia045 to Carrie, Cedric, Ellen, Ines, Rupert on 8 Mar 2017.
    • Photo: Carrie Ijichi

      Carrie Ijichi answered on 8 Mar 2017:

      I’m not the best person to ask about this because behaviour doesn’t focus on the earliest life-forms – guess because we can’t watch them behaviour any more!

    • Photo: Ellen Williams

      Ellen Williams answered on 9 Mar 2017:

      Great question but I am really sorry I have absolutely no idea! I guess it depends on which theory of how we all came to be here you believe in? I am not even sure I am convinced which theory is correct! Hoping one of the other guys has more of an idea, sorry!

    • Photo: Rupert Marshall

      Rupert Marshall answered on 10 Mar 2017:

      A very good question. And scientists still aren’t completely sure. We know the earliest life came from the oceans: microbes, nearly 4 billion years ago. That’s a long time. They may have come from somewhere in space, arriving on an asteroid. Or they may have just arisen here on earth. We won’t know for sure until we can compare rocks from space with rocks of the same age here on earth – if ours have signs of life and those from space don’t then it suggests life might have arisen here first.
      We know that lightning can cause non-living chemicals turn into amino acids – the basis of life. But we aren’t sure yet if this is how life started on earth.

    • Photo: Ines Goncalves

      Ines Goncalves answered on 11 Mar 2017:

      Through some sort of physical and chemical reaction under very specific conditions. This sounds really vague and I’m sorry for this, but I think that is as much as we know right now. As Rupert answered, we know more or less when it happened and we have some idea of what earth looked like back in those days but we really don’t know what “sparkle” causes something that was not alive to become alive and start replicating itself. What I know is that some researchers are looking at other molecules (not DNA and not RNA) and trying to get these molecule to start replicating themselves. It won’t tell us exactly what happened 4 billion or so years ago, but it will help us understand the mechanisms and how such things can happen. Very sic-fi if you tell me!

    • Photo: Cedric Tan

      Cedric Tan answered on 15 Mar 2017:

      Great question! And a difficult one as there are several answers and yet noone really know which is true. The following answer is probably the most convincing one:

      The first living thing on Earth is either single-celled micro-organisms or microbes known as prokaryotes. It probably appeared on Earth almost four billion years ago.

      Imagine a world with non-living chemicals in a primordial soup. Some of these molecules/chemicals evolved into self-reproducing molecules, also known as ribonucleic acid (RNA). And because they can self-replicate, they do better than the non-living chemicals. Subsequently membranes enclosed these molecules and the RNA are able to gain protection against the external environment, this might have formed the first prokaryote.

Comments