[AndrewC]

And then there's all those evolving predator-prey relationships, bird/insect plant symbiotic relationships, foliage changes, the arising of grasslands and the spread of deciduous trees, and that's only the tip of an enormous iceberg of other environmental changes.

Makes you wonder why ants still look like ants and cyanobacteria still don't have legs.

[balrog666]

Makes you wonder why ants still look like ants ...

Well, they have lost some of their wasp characteristics, like permanent wings.