Sorry for the off topic but most non-biologists fail to precisely understand what Cambrian explosion means. It was a time when suddenly an huge variety of spec

Sorry for the off topic but most non-biologists fail to precisely understand what Cambrian explosion means. It was a time when suddenly an huge variety of species appeared and what was new among them all was the trait of a body plan or body structure with diferent cells forming organs for specific functions. The explanation most accepted by biologists is the appearance of HOX genes. These are genes that switch on/off the expression of other genes and that is what causes cells in the same organism with the same genetic code to be very different in morphology.