To be honest, I have no idea how you would even measure the “complexity” of an organism. Corn has more genes than we do, but most people would say that humans are more complex than corn, perhaps objectively on the grounds that we have a wider variety of tissue types. Do we use our genes more efficiently (multiple versions through alternate splicing etc) or is this just another self-centred fallacy?

If you measure in actual time, we’re all equally “evolved”, bacteria, fish and people alike. And humans probably exhibit a lot more derived traits than bacteria. Question is if we exhibit more derived traits than fish? Although a derived trait obviously doesn’t have to be a more complex trait, the appendix is a derived trait after all and it’s less complex than its more functional cousins.

Here’s a thought: since a bacterial generation time is much less than a human’s (as low as 20 minutes in the extreme cases) bacteria are actually far more evolved than we are.