I can understand that at the start of life (or before), RNA/DNA came into being and started to replicate. And those molecules that replicated more effectively soon became more common than those less so, and so opened the door to change by evolution. I think I can imagine the same process happening within the genes in cells - selection just blindly choosing one over the other.

What I find difficult to imagine is how a living thing seems to have a desire to survive, compete and reproduce, and when and how this arose. Are there any ideas on this, or is it a bit like pondering the nature of consciousness?

Individuals that lack the drive to reproduce don't pass on the alleles that they possess. Those with the drive, do.

I was thinking more about how you go from inevitable chemical reactions, to animals with competitive thoughts and feelings. In effect, how can a chemical develop an emotion.

An emotional state is a chemical process. How can anything but an organized chemical structure develop emotion?

 

The "will to live" isn't magic. It's a set of behavioral drives and emotional states regulated by your bodies hormones and neural pathways. Those structures are all inherited. That makes the feelings and behaviors they produce heritable as well. Those individuals that inherit behaviors that make them avoid dying are less likely to die and therefore more likely to reproduce.

 

It's chemistry, not magic.