Question: How does life form?

Jake Langham answered on 15 Nov 2017:

This is one of scientists biggest open mysteries. We just don’t know for sure.

One thing we do have a lot of evidence for is that all life evolved from just one original lifeform. It would have been a tiny creature with just one cell with some DNA inside that contained the ‘genetic code’ that allowed it to replicate, like bacteria do. (If you want to know more about this ask Senga & Pete who are the bacteria experts.) Eventually life evolved to create organisms with more than one cell (called ‘eukaryotes’) but this took ages – a few billion years.

Biology isn’t my best subject, but I do find it very interesting so I tried to find out what it would have been like before the first lifeform and it’s tricky! There are very many chemical reactions that take place to sustain the life of even simple organisms with only one cell. On top of that you need to work out where DNA comes from because it is a very complex molecule with a specific function (reproduction of living things). There seem to be various theories about how this all happened. Roughly speaking, before there was evolution of life, there must have been a kind of ‘evolution of molecules’. What does that mean? It means that the conditions and environment must have been just right so that chemical reactions (which happen on their own) could get more and more complex, producing more and more complex molecules. Eventually this would have led to the the different chemical reactions the DNA that gave rise to the first organism: our great-great-great…(x a big number) ancestor!