• Question: how do you think life began and when?

    Asked by 07quiambaoj to Alastair, Emma, Hywel, Keith, Vicki on 17 Jun 2010 in Categories: .
    • Photo: Vicki Stevenson

      Vicki Stevenson answered on 17 Jun 2010:

      I agree with Darwin’s theory of evolution, so I think that life began millions of years ago as very small creatures (microbes) which evolved into bigger more complicated lifeforms like the ones around us now.

    • Photo: Keith Brain

      Keith Brain answered on 17 Jun 2010:

      The most likely start was in the sea, where complex organic chemistry could slowly have developed from simple molecules. The key first step would have been for a self-replicating (self-copying) molecule to develop. No one has as yet found such a molecule; but perhaps it didn’t start with one molecule, but with a small set of simple molecules that found themselves in the same place. One way of generating likely life-starting molecules is to take the chemicals that would have been present in the early earth, like water, carbon dioxide, and ammonium, and then zap these chemical with electricity (just like a lightning bolt). Several groups of scientists have found that by doing so, a rich mixture of amino acids (basic building blocks of life) can be produced … maybe from out of such a mix self-replicating molecules, or molecule families, were produced. Other groups this that freezing conditions are better for forming such molecules!

      As to when? Probably about 4 billion years ago.

    • Photo: Alastair Sloan

      Alastair Sloan answered on 17 Jun 2010:

      Good question. Nobody is really sure, but recently some researchers in Manchester proposed that it would have been possible to make the genetic material RNA from the simple chemicals that were around on the developing planet Earth. Most people believe that RNA is the original molecule of life as it is a self replicating molecule. Although DNA is the genetic blueprint for life, RNA actually makes the proteins coded by DNA and is easier to make which is why people think if is the original molecule of life. As to when life started it was when the planet started cooling so around 3 or 4 billion years ago.

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