Continuing the discussion from Fuz Rana Answers @Guy_Coe's Question about Genesis 1 and 2:
That conversation uncovered some real beauty that really must be shared. Of course, I have an affection here, because whales first arose in India. What follows is a technical discussion, but you might enjoy reading this book.
A recent article questioning whale evolution was published at the Discovery Institute: Adam and the Genome and Whale Fossils | Evolution News Whale evolution is a remarkable example where we have uncovered a smooth progression of forms from an terrestrial mamal to an obligate aquatic mammal. Here are just a few of the animals in this progression:
Looking at this progression we uncover an amazing fact. Surprisingly, whales have the same body plan as a terrestrial mammal~! It’s the same body plan, with several intermediate forms. Looking at several features (e.g. ears, bone density, teach), we can see this transition beautifully. Look how we can see the nostrils slowly move back to the top of the head:
Nonetheless, this DI article decleares:
even if we accept some of the fossils as “intermediates” between whale and land mammals, there is not enough time for the complex adaptations needed for whales’ fully aquatic lifestyle to evolve. Whatever the correct explanation is for the origin of whales, unguided evolutionary mechanisms are not the answer.
First of all, I should point out that I do not argue for “unguided” evolution (about which I am agnostic), but I do argue against bad arguments against unguided evolution. Instead, I affirm evolution as God’s providential governed way of creating us all. So the “unguided” point is really beside the point. If there is a very unlikely set of events required to evolve whales, I’m not sure how we could know, based on the evidence we see. That does not, however, negate God’s providential governance of all things.
Getting back to the claim that millions of years is “not enough time.” There is no genetic or mathematical analysis to back up this conjecture. What types of genetic changes are required for whale evolution? How unlikely or likely are they? This leads us to this phenomenal review of the genetic details of whale evolution:
This is a really beautiful review, bringing together a vast amount of excellent work to untangle the history of the beasts of the sea.
It is remarkable how many of the changes required for whale evolution are caused by loss of function mutations (which end causing “pseudogenes”), or small tweaks to proteins. This is one of the big surprises of mammalian evolution. Large changes can take place with tweaks to the genetic code. Eyes adapt to underwater vision by losing a rhodopsin gene. Hind Limbs are lost with the loss of a homeobox gene. Taste buds are lost when two genes are lost. Smell receptors are almost entirely lost in most species too. In all these cases, we see remnants of the broken genes, and in many cases the details of how these losses increase function are well understood.
Remarkably, it does not appear any new enzymes or de novo genes are required in whale evolution. It appears that small tweaks to existing proteins, or loss or alteration of the function of existing genes, account for the changes we see see at this point.
Also, there does not appear to be any reason that a large number of these changes must happen at the same time. They appear gradually in the tree, and its not clear at all why they would need to be “coordinated”. They do not appear to need to occur at the same place and time to be useful. So this does not make these transitions unlikely.
Also, we also see convergent mutations between whales, bats (echolocation), and beavers (diving adaptations to blood). These “homoplasies” are the rare exceptions to the nested clade pattern of common descent, and are exactly what we expect in evolutionary process, just like we see recurrent mutations in cancer, and convergent evolution in human HLA variation. Everyone agrees that human variation arises by natural processes, and that cancer arises by natural processes, yet we see homeoplasies here too; this is what we expect from common descent.
What are we left with? With all this evidence (DNA and fossil) for the common descent of whales, even some young earth creationists (yup, that’s right!) have come to accept this as a clear example of evolution. Some wonder if walking whales were on the Ark, and think 4,000 years was enough time for them all to evolve. Says Dr. Kurt Wise,
“…some of the animals which are aquatic or marine today may not have been aquatic at the time of the Flood. The marine and sea otters, for example, are members of the mustelid (weasel) family and their aquatic character is likely to have been revealed after the Flood. The whales might turn out to be another example… Vestigial legs and hips in modern whales confirm legged ancestors of the whales existed only a short time ago. It is possible that the purely marine cetaceans of the present were derived from semi-aquatic or even terrestrial ancestors on the ark.” Walking Whales On Board Noah’s Ark: The Inevitable End-point of Creationists’ Post-Flood Hyper-Speciation Belief? – Naturalis Historia
We have to commend Dr. Wise for following the evidence here. However, I think this process still needs a few million years to take place. 4,000 years is not enough.
To be clear, we have certainly not mapped out all the mutations required. There sill remain a lot to understand. However, there is no reason to think these patterns will change. For whatever reason, it really looks like whales, hippos, chimpanzees, and all of us share common ancestry. Whether or not its true, that is how our genomes look.