That would require knowing what they are evolving into to say, and that would require psychic powers.
We can speculate a bit. Certainly someone seeing some of the ancestors of the whales might speculate that the whales would eventually entirely lose their legs. Likewise we can speculate that penguins at some point might evolve into some whale-like ovoviviparous species.
Does evolution have intelligence? Do not the physical laws say that every thing is breaking down on evolving?