I recently read The Selfish Gene by Richard Dawkins, which I found very interesting. In one of the last chapters, he gives multiple possible explanations to the question "Why did natural selection give rise to complicated lifeforms?".
Since complex (say: multi celled) life exists, that means natural selection at some point did increase complexity, as we went from the primal soup to multi celled organisms (with many steps in between). My question is whether this trend of increasing complexity is still going on? Is natural selection a never-ending arms race, tending towards increasingly complicated genomes? Or did natural selection reach some plateau, local optimum, of biological complexity, after which the only evolution taking place is "on the same level".
I have thought a bit about a metric for complexity, but since I have no background in biology I am not at all certain. At first thought, the length of the genome sounds like a promising candidate, but the phenomenon of freeloading, not-functioning DNA (conveniently described in The Selfish Gene too) undermines this. I hope it is clear what I mean by "complexity".
Thanks for answers in advance, it has been fun speculating.