Where Did Whales Come From?

Yesterday's post highlighted the complexity of the elephant's trunk and how difficult it would be for such structure and function to emerge from random genetic mutations and fortuitous selection unguided by any intelligence.

Today's post offers up a video of another of the largest mammals on the planet - the humpback whale. The humpback whale poses the same sort of problems for a naturalistic account of origins as does the elephant's trunk, but the problems are far more numerous.

Until recently the consensus opinion among biologists was that whales evolved from land animals, but recent finds have made this view increasingly untenable. Not only is the window of available time for all the requisite changes to adapt a terrestrial creature to a marine environment very narrow, but the sheer number and scope of the changes strains credulity.

Here are a few of the changes that would need to have occurred within the span of about 3-5 million years for whales to make the transition from land to sea:

• 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 control

This excellent nine minute video from the talented filmmakers at The John 10:10 Project illustrates some of the difficulties in evolving a completely aquatic mammal from terrestrial ancestors:

This animated video explains how a sperm whale uses its sense of echolocation, another evolutionary enigma, as it hunts giant squid:

It may have happened that whales evolved from land animals and that, indeed, all forms of life on earth descended from a single ancestral form, but it seems that the more we learn about the difficulties such a process entails, the less reason we have for thinking that they did.