Whale evolution is supposed to be one of the best documented cases of gradualism in the fossil record.  No doubt, when you stack the fossils up next to each other, you can see what appears to be a morphological transition from a terrestrial mammal to an aquatic whale (see the graphic below).  

Since evolution occurs at the biochemical level, however, to determine whether or not this series of fossils represent an actual evolution of mammals into whales, or if they are morphologically similar but distinct species, we must determine whether the 10 million years that separates the first whale from its mammalian ancestor is enough time to re-engineer a mammal into a whale. Consider the extent of the required changes:

  1. “Whales require an intra-abdominal counter current heat exchange system (the testis are inside the body right next to the muscles that generate heat during swimming)
  2. They need to possess a ball vertebra because the tail has to move up and down instead of side-to-side
  3. They require a re-organization of kidney tissue to facilitate the intake of salt water
  4. They require a re-orientation of the fetus for giving birth under water
  5. They require a modification of the mammary glands for the nursing of young under water
  6. The forelimbs have to be transformed into flippers
  7. The hindlimbs need to be substantially reduced
  8. They require a special lung surfactant (the lung has to re-expand very rapidly upon coming up to the surface), etc.”[1]

The task of turning a mammal into a sea creature is comparable to the engineering task required to turn a car into a submarine.  These are not minor changes, but a perfectly coordinated overhaul of virtually every aspect of mammalian features.  To demonstrate that this series of fossils represents an actual evolution of the whale from non-whale ancestors requires more than pointing out the morphological similarities.  Biologists must be able to identify the biochemical pathways required to produce such changes, and demonstrate that such pathways could reasonably be traversed given the amount of time available.

Keep in mind that when it comes to evolvability, time is the least important factor to consider.  The rate of evolution is determined primarily by population size, reproduction rates, and mutation rates.  The larger the population, the smaller the generation times, and the faster the mutation rates, the faster the rate of evolution.  Conversely, the smaller the population, the larger the generation times, and the slower the mutation rates, the slower the rate of evolution.  If you have a small population, long generation times, and an average mutation rate, it will take a long time for mutations to create enough raw materials on which natural selection can act.  To see how this works, contrast whales and mice.  Because of the small population size and long generation times of whales, it takes whales 200 million years to accumulate the same number of mutations mice can accumulate in 1500 years.  If mice haven’t changed in 1500 years, then why should we expect mammals to have evolved into whales over a period of 200 million years, yet alone the 10 million years in which it is claimed the process took place in?

Given a population size of 100,000 whales per generation, and generation times of five years, Richard Sternberg has calculated that it would take 43.3 million years for just two specific coordinated mutations to become fixed in the species.  If it would take 43 million years for two specific coordinated mutations to become fixed in the species, and the re-engineering of mammals into whales would require thousands of such changes, then it is not feasible to believe that mammals could evolve into whales in 3 billion years, yet alone 10 million years.  While the morphological similarities between Pakicetids, Ambulocetids, Rodhocetus, and Basilosaurids are very interesting and might suggest an evolutionary relationship at first glance, the biochemical data demonstrates that it is not reasonable to believe they share an evolutionary relationship.  They cannot be causally connected to each other because there simply was not enough time for such an evolution to occur.

The whale evolution story has been further complicated by the recent discovery in Antarctica of a jawbone of the oldest, fully aquatic whale (announced October 2011).  It dates to 49 million years ago.  This is nine million years older than Basilosaurids—an organism previously thought to be the oldest fully aquatic whale—and only 3 million years younger than what is purported to be the ancestor to whales, Pakicetus: a fully terrestrial creature.  In fact, this new find dates to the same age as what used to be thought of as the first proto-whale, Ambulocetus: a semi-aquatic creature that lived in the waters of South Asia.  It’s difficult to maintain that these fossils represent an evolution of the whale when the first fully aquatic whale appears on the scene at the same time as its supposed oldest semi-aquatic ancestor.  That’s like saying you were born at the same time as your great great great great grandfather.

Casey Luskin illustrates the evolutionary story of whale evolution both before and after this new discovery:

Before

After
Pakicetids (fully terrestrial): ~50 mya Pakicetids (fully terrestrial): ~50 mya
Ambulocetids (semi-aquatic): 49 mya New fossil discovery (fully aquatic): 49 mya
Remingtonocetids (semi-aquatic): 49 mya Ambulocetids (semi-aquatic): 49 mya
Rodhocetus (a Protocetid, semi-aquatic): 47 mya Remingtonocetids (semi-aquatic): 49 mya
Basilosaurids (fully aquatic): 40 mya Rodhocetus (a Protocetid, semi-aquatic): 47 mya
Basilosaurids (fully aquatic): 40 mya

Now, rather than having to explain how a terrestrial animal could become a fully aquatic animal in a mere 10 million years, Darwinists must explain how this could happen in less than three million years.[2]  If it is unreasonable to believe a mammal could be biochemically re-engineered via a process of natural selection acting on random mutations in a period of 10 million years, it is all the more unreasonable to believe it could be done in 3 million years.

[1]Jonathan M, “A Whale of a Problem for Evolution: Ancient Whale Jawbone Found in Antarctica”; available from http://www.uncommondescent.com/intelligent-design/a-whale-of-a-problem-for-evolution-ancient-whale-jawbone-found-in-antartica/?mid=501; Internet; accessed 17 October 2011.
[2]Casey Luskin, “Discovery of ‘Oldest Fully Aquatic Whale’ Fossil Throws a Major Bone into Whale Evolution Story”; available from http://www.evolutionnews.org/2011/10/discovery_of_oldest_fully_aqua052021.html; Internet; accessed 19 October 2011.