• Question: how did life on earth arise?

    Asked by 12swanb to Lyn, Katy, Paul, PB, Ruth on 20 Jun 2013. This question was also asked by russewil.
    • Photo: Peter Balfe

      Peter Balfe answered on 20 Jun 2013:

      You’ll know all about “primordial soup” I’m sure (if not, go wiki!). But the key leap probably was the first soup to develop a membrane. Once you have an inside and an outside, you are on your way!

    • Photo: Paul Waines

      Paul Waines answered on 20 Jun 2013:

      12swanb-
      As Peter says, scientists believe that life began through chemical changes happening in a ‘primordial soup’. Some scientists today are trying to recreate this in the lab, and also by studying chemical reactions in areas of high volcanic activity- these areas are probably the closest thing we have on earth today to conditions found in those early days.
      Once these chemical changes resulted in simple chemicals which could reproduce themselves, then life was up and running (well, not quite running, more like floating…)

    • Photo: Katy Brown

      Katy Brown answered on 20 Jun 2013:

      Further to this, it seems like there were simple organisms with one cell around 3.6 billion years ago, and the first organisms with more than one cell lived 1 billion years ago. The earliest known animal looked like a very small slug and lived underwater 585 million years ago.

    • Photo: Ruth Mitchell

      Ruth Mitchell answered on 23 Jun 2013:

      The other scientist have given the scientific answer. I believe that God created life on earth.

    • Photo: Ee Lyn Lim

      Ee Lyn Lim answered on 24 Jun 2013:

      I like Paul’s answer! I think the most basic thing about ‘life’ is probably that it can reproduce itself – like mothers give birth to babies, and plants growing seeds which grow into new plants. Cells and bacteria can also split to form two smaller cells or bacteria. But at the root of all this, there is DNA replication – you can’t make another copy a cell until you make a copy of the cell’s DNA!

      So how is DNA copied? It’s like having a lock and a key – if you have a key, you can make a lock to fit it, and if you have a lock you can make a key to fit it. So if you have a lock and key that fit each other, and you separate them, you can very soon make TWO locks and TWO keys that are identical to each other! That’s how DNA replication works – two parts that each tell you how to make the other part. I think the first step to life on earth was probably the appearance of a molecule that could fit this special criterion. As to how this molecule was created, we don’t really know – but it was probably a random product of the extremely hot, high-pressure, electrically charged atmosphere of early earth!

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