• Question: How did life begin?

    Asked by anon-243392 to Pan-ngum, Natalia, Mick, Manjit, Filipe, Bruce on 16 Mar 2020.
    • Photo: Natalia Brodaczewska

      Natalia Brodaczewska answered on 16 Mar 2020:

      This is a very good question though also a hard one to answer. We can’t really say anything for sure but scientists have some theories about that. First of all, it can be hard to define what is life – where does life actually start? After all, everything that goes on in our bodies is just a series of chemical reactions. When Earth was first formed, the Earth crust and the atmosphere surrounding it consisted of certain types of atoms and with time these atoms started to combine into bigger and more complex molecules as more and more chemical reactions were taking place. This was all dependent on the surrounding conditions such as temperature, pressure, presence of ultraviolet light – things that can help some reactions to happen. Eventually, more and more complex molecules would develop and start forming larger structures that can make copies of themselves. Some scientists have been trying to simulate the conditions that would be present billions of years ago to try and recreate this process in the lab. We also found some places deep in the ocean which are believed to be very similar to what the first oceans looked like. So we have some ideas on how the first cells could have come into being based on what we know about the chemical conditions on Earth back then but a lot of that is still a mystery.

    • Photo: Michael Schubert

      Michael Schubert answered on 16 Mar 2020:

      There are a lot of different ideas on how life began. Some scientists even think that it may have originated more than once! Most scientists these days agree on the “RNA world” hypothesis – that is, they think RNA was the first molecule of life, before DNA. Some of those scientists think that the first RNA arose spontaneously (the chemicals that make up RNA came together on their own) in one place. Others think it arose in many places at once, died out in some, and kept on living in others. There are also some scientists who think it’s very unlikely that this happened on its own; those scientists think that life might have come from somewhere else. For instance, there might have been life on an asteroid in space that hit the Earth, and that life kept on living on our planet, growing and changing.

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