The evolution or appearance of whales as been extraordinarily explosive (non-gradual). On the traditional evolutionary model, a coyote-like creature (Pakicetus)1 was transformed into a fully-aquatic whale within 4 million years, (perhaps significantly less) despite the requirements:
• Counter-current heat exchanger for intra-abdominal testes
• Ball vertebra
• Tail flukes and musculature
• Blubber for temperature insulation
• Ability to drink sea water (reorganization of kidney tissues)
• Fetus in breech position (for labor underwater)
• Nurse young underwater (modified mammae)
• Forelimbs transformed into flippers
• Reduction of hindlimbs
• Reduction/loss of pelvis and sacral vertebrae
• Reorganization of the musculature for the reproductive organs
• Hydrodynamic properties of the skin
• Special lung surfactants
• Novel muscle systems for the blowhole
• Modification of the teeth
• Modification of the eye for underwater vision
• Emergence and expansion of the mandibular fat pad with complex lipid distribution
• Reorganization of skull bones and musculature
• Modification of the ear bones
• Decoupling of esophagus and trachea
• Synthesis and metabolism of isovaleric acid (toxic to terrestrial mammals)
• Emergence of blowhole musculature and their neurological control2
New life-forms appear suddenly in the fossil record.1 This is relevant because, unless life were appearing suddenly in life-history, the fossil record would not be this way.
But so what if the fossil record only shows new life-forms arriving suddenly. Couldn't it be that the relevant rocks have been eroded or remain undiscovered (i.e. the appearance is an “artifact” of an incomplete sampling).