Horsing Around with Genetic Sorting: Horse Series Part IV

Are modern horse species descendants of a small dog-sized common ancestor or do all fossil horse-like species represent unique creations? For many, this dichotomous choice may sound like a setup to test if a person is an atheist evolutionist or a bible believing Christian.  However, we previously noted that this is a question that literal six-day creations have been asking themselves in recent years.   They have debated among themselves about how they should interpret the fossil record or horses and many have found themselves increasingly embracing an evolutionary model of horse origins–albeit through some radical adjustments to the conventional model.

For example, among creationists, we observed that Dr. Wood and associates clearly see the horse fossil record differently than Drs. Sarfati and Molen.  So why do these young-earth creationists come to very different conclusions about the origin of horses?

It’s all about understanding where the fossils are found!  I have pointed this out over and over:  young earth creationists have a fossil problem.* There are some deep divisions within young earth creationism (YEC) over what fossils were formed during a global Flood and which were formed after the Flood.  Another way of putting this is that they can’t agree which rocks were formed during the global deluge year and which formed in post-flood local catastrophes and the timing of those events.

These disputes manifest themselves when YECs authors consider horse fossils.   Molen and Sarfati talk circles around the fossil record of horses, not appearing to want to commit to all the fossils being post-flood in origin.  Wood and other colleagues rightly recognizes that the fossil record of horses wholly contained in rocks that most YECs accept as post-Floodin origin. The logical conclusion that Wood comes to is that if all these fossils represent species variation within a single horse kind then the entirety of that “horse kind” variation must have been derived from a single pair that was on Noah’s ark.

Wood is committed to an interpretation of earth’s history wherein all life with breath was eliminated except a single pair of each kind (of unclean animals at least).  So because all fossil species of horses (equines more generally) are found in post-Flood deposits follows that they all then have “evolved” from that original pair.   This pair has been called the “ark kind” or as I call them the common ark ancestors.  YECs have been rapidly embracing a form of super-accelerated evolution after the flood (eg. all dogs species or all cats are from a single pair) and this is yet another dramatic example of just how creationism has changed over time.

Sarfati also believes in rapid diversification following the departure from the Ark but does seem to believe that sequences that the fossils are found in can be interpreted as a progression of character evolution leading to the living equine species.  Rather he wants to have all the changes from the ark common ancestor 4500 years ago to present be the result of losses of information.  He implies that all the genetic programming to make 100 different species of horses was present in the first created horse and preserved from creation through the Flood.  After the flood hundreds of species “diversified” as a result of sorting and reshuffling of the original variation, genetic switches and mutations that cause losses of characteristics.

But Sarfati has a serious problem and it is one that creationists rarely acknowledge or attempt to accommodate.  We can see the problem more clearly if we lay out the assumptions that most creationists seem to share:

Premise 1:  Assuming special creation, God created the original horse kind with tremendous variation such that all the species of horses could have come from that ancestral kind
Premise 2:  All the fossils of horse species are found in deposits that creationists say occurred after the Flood
Premise 3:  No matter the number of species present prior to the Flood, only a single pair representing the horse “kind” was on the ark.
Unspoken premise 3B:  In a single pair of “horses” the amount of variation is much less than that found in the original created kind
Conclusion:  All of today’s “horses” and the fossils that look similar to horses are the result of species formed from the two horses on the ark.

I’ve included a premise 3B here that I believe is very important and is the one not often recognized.   You can go to nearly any young earth creationist article that mentions biological diversity and find something about how God created all the animals and even plants with great genetic diversity so they would be able to adapt to the sinful world in which we live.   But this diversity was created in the original version of each kind.  Even if it could be argued that God created hundreds of thousands of horses on day six of creation collectively these horses has massive amounts of variation, as horses reproduced from that starting point of creation to the Flood what would we expect to happen to that genetic variation?  Much of it would be eliminated from any individual horses even if much was maintained in the total population leaving any two horses selected to go on the ark with only a small subset of the original variation. As a result, after the Flood the gene pool (all the genetic variants) with which each “kind” had to work with to produce hundreds of new species would have been extremely limited (see figure to the right).  This is called the bottleneck effect in population genetics and in this case we have the most extreme form of genetic bottleneck possible: reduction of a species, or even more dramatically a kind, to just two individuals.  (See my post: The Great Genetic Bottleneck that Contradicts Ken Ham’s Radical Accelerated Diversification for more details)

There are species alive today that we are quite confident have undergone a severe bottleneck in the past such as cheetahs.  Geneticists have proposed that the cheetah population was once only a few hundred individuals or possibly less. As a result they exhibit extraordinarily low amounts of genetic variation today even though their populations are much greater today than they were in the past.   A cheetah could hardly be expected to evolve into all the other kinds of cats with virtually no genetic variation upon which natural selection can draw.   Without supernatural infusion of genetic variation into each of the two animals on the ark and their offspring, all of the animals stepping off the ark would have had very little genetic variation with which to work.   Creationists expect and predict that there was ultra-fast speciation after the flood which in itself would require amazing genetic mechanisms unknown to us today but on top of this they would be starting with material that could not have the variation present that we see in animals today.

Claims of Genetic Sorting of Ancestral Variation

One does not have to look too far to find statement in the creationist literature about rapid diversification from a pair of diverse progenitors.  For example, on creation.com (Creation Ministries International) there is an article by Russell Grigg entitled “Galapagos with David Attenborough: Evolution”  we find the following statement:

To set the record straight: no one knows how many tortoises reached the different Galápagos islands from South America in the four-and-a-half millennia since the Genesis Flood… But just suppose there was ‘a single founder’ (which would have had to have been a pregnant female), this one would have had all the genetic information for all the tortoises seen today. That is, the “11 types of giant tortoises left in the Galápagos, down from 15 when Darwin arrived.

And then later:

Rather, they all involve sorting and/or loss of existing gene information. Hence they do not support Darwinian (i.e. microbes-to-marine-iguana) evolution.

And then concluding with the following:

Changes of behavior, as a species learns to adapt to a new habitat, also is not Darwinian evolution. If such adaptation means an animal can no longer breed with its previous fellows, i.e. if speciation occurs, this too is not Darwinian evolution, because this involves a sorting of existing information, not the acquisition of new genetic information. In fact, such adaptation and speciation among the original created kinds is an integral part of the biblical Creation-Fall-Flood-migration worldview.

All of these quote show an emphasis of species creation by sorting of a pre-existing gene pool.   But this overly simplified view of evolution fails to consider the reality of genomes, observed genetic variation, and all that is known about population genetics.

Has the author considered that the individual founding tortoise of all the species (notice the authors avoids calling them species but used the term “types” instead) would have itself been the product of generations of genetic sorting after the original pair left the ark.  As we pointed out before with horses, without supernatural intervention, the tortoise pair on the ark would not have all of the genetic variation that presumably was in them when they were created much less the one  or two individuals that made it to the Galapagos Islands.  Rather than sorting and loss of genetic information in species formation there would have to have been an increase in genetic information on which selection could act to form species and this could only come from new mutations.  The genetics of these animals suggest exactly the opposite of what the author is proposing.

References:

The Non-evolution of the Horse.  by Jonathan Sarfation on the CME website.

 Baraminology: Creationists re-examine the horse series. by Tony Breeden on his blog “Defending Genesis”

Cavanaugh, D.P., Wood, T. and Wise, K.P., Fossil equidae: a monobaraminic, stratomorphic series; in: Walsh, R.E. (Ed.), Proceedings of the Fifth International Conference on Creationism, Creation Science Fellowship, Pittsburgh, PA, p. 143–149, 2003

The Evolution of the Horse by Mats Molen.  Journal of Creation 23(2):59–63  August 2009

*The other aspect of the fossil problem for YECs is that there are no equine fossils in Flood rocks.  If what most YECs believe about where the Flood and Post-Flood boundary is, no equine fossil has ever been found in rocks that YECs say were laid down during the Flood. If any equines lived before the Flood, and presumably they did because they had to have been created in the creation week, then how come none of these were preserved as fossils in the Flood?  And yet, thousands of sites on multiple continents contain equine fossils that were somehow preserved in post-flood rocks despite the fact that YECs often claim that it is the global flood that created ideal conditions for fossil preservation.

Cover Photo: “Wild” horses on Outer Banks of North Carolina. Photo by Joel Duff