Reproduction

Once life had appeared it spread. If it had not spread it would quickly have been damaged and died out.

Genes were able to reproduce because of the way they were made.

First the two halves of the gene were unzipped by an enzyme.

Then new genes were built up on each half.

In this way two exact copies of the original gene were made

Because of the way the bases fitted together, they both carried exactly the same information as the original gene. So these two genes carried the information for exactly the same protein. Life could continue as before.

This is called reproduction. Life reproduced and spread.