This isn't true for all species, it's (in a way) different depending on species. Your statement assumes that evolution is a constant, time-dependent process; i

This isn't true for all species, it's (in a way) different depending on species. Your statement assumes that evolution is a constant, time-dependent process; it isn't. For an example, I point to the horseshoe crab. We're separated by x million years of evolution from the horseshoe crab, because at some point there's a common ancestor. Its ancestor evolved to the horseshoe crab, millions of years ago, and then stopped. Meanwhile, our ancestor continued to evolve into us. The horseshoe crab is a prehistoric animal, a "living fossil". It hasn't evolved significantly in millions of years. This is quite different from mice. Another example is the coelacanth fish; it was thought to be long-extinct as we have prehistoric fossils of it dating to the dinosaur days. Turns out it's still alive. Another less-extreme example is the shark: it's a little different than its prehistoric ancestors, but not much. I'm sure a biologist could point to a bunch of other species that haven't changed significantly since the days of the dinosaurs. Mammals like mice have indeed been evolving just as long as we have, but many non-mammalian species have not.