Question: How do you think life began?

Sam Briggs answered on 21 Jun 2016:

Hi HiI’mSophie,

Good question. So there a bunch of different theories in science about the order in which things happened but people generally agree that a few things had to exist in order for darwinian biological evolution to take over from chemical randomness and chance. These are:

Compartmentalisation
Metabolism
Replication
Homeostasis

These are all fancy words for describing a set of chemicals that have come together in an organised way such that they can continue to stay that way, they can produce other systems organised in the same way and can use things around them to maintain their configuration.

Now scientists argue about the types of environment required for any or all of these things to have come into existence, but you can imagine most scenarios involve large volumes of water with lots of basic elements and materials just floating around, sometimes very hot, sometimes very cold and sometimes in between. So the science we have to do to determine the route that life took to come into existence on our planet is gather lots of data about those conditions and then make experiments using materials that would have been abundant at the time and try to use our knowledge of chemistry as a map to how all those pieces of the puzzle fit into place.

I recommend reading a famous paper by Miller and Urey on early amino acid synthesis, they suggest that all the basic building blocks for DNA could have been synthesised using simple gases in water in the presence of strong UV from an early sun or from lightning!

Hope that helps?