A'isha
Miss Schoolteacher
The past half a billion years is probably, very vaguely, in some sort of equilibrium in regards to "complexity".
Indeed.
For instance, it's generally accepted that the avian lineage descended from the dinosaur lineage, with the evolutionary divergence taking place over a period of several hundred million years.
What do you think that says about the relative complexity (genomic or morphologic) of a chicken vis a vis, say, a velociraptor, randman?