One prediction of evolution: Birds will never be born with mammary glands or three earbones, or differentiated dentition. Another prediction of evolution: Frogs will never develop feathers.
This all has to do with Vade's query to gore3000 on whether he can explain why paleontologists are sure T. Rex did not have boobs. It all has to do with the framework provided by evolutionary theory -- this framework allows us to categorically predict that some things will never happen, and other things will.
Those aren't predictions. Those are observations. Birds don't have mammaries. Frogs don't have feathers.
The framework predicts that animals with mammary glands are live bearing. The framework has been proven wrong by living species - the platypus and the echidna. The framework is that evolution is chasing its tail and making excuses for not being able to prove its assertions.