Humpbacks, dolphins and Darwin

The speculation about genetics and diet could be looked at another way. Let me add your quoteso others may follow the discussion.

Evolution doesn't really differentiate in choices between long lived animals or short lived insects, in the short term. If you are looking at the long term, perhaps it would be better to design humans to be more like cockroaches, who have outlived dinosaurs, for instance. Just kidding.
>It is possible for evolutionary mistakes to be made, as far as the lifespan of the individual is concerned. If the evolutionary ancestor to both humpback and dolphins had filled the niche to the max, this would force the evolution of the dolphins to adapt to a more abundant food source, even though it meant that the dolphin would not live as long as it's now evolutionary cousin.