Horsing Around with Genetic Sorting: Horse Series Part IV

Noah's flood represents a tremendous bottleneck on genetic variation.  This isn't often recognized by creationists who claim that massive rapid diversification occurred after the flood.  For that to occur they require massive genetic variation upon which natural selection can draw. Creationists genetics models have no  source for this variation.

Noah’s flood represents a tremendous bottleneck on genetic variation. This isn’t often recognized by creationists who claim that massive rapid diversification occurred after the flood. For that to occur they require massive genetic variation upon which natural selection can draw. Creationists genetics models have no source for this variation.

Last time I looked at horses I noted there were differing opinions about the significance of the fossil record or horses and how it should be interpreted.   Among creationists, Wood and associates clearly see the horse fossil record differently than Sarfati and Molen.  So what are the later not seeing that Wood et al. see that has led them to suggest that all fossil horses came from a single common ancestor and followed the general path of speciation that has been proposed by evolutionists?

It’s all about the where the fossils are found!  I have pointed this out over and over:  young earth creationists have a Flood 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. Those divisions show up here in the considerations of 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 rightly recognizes that the fossil record of horses is all contained in rocks that virtually all YECs accept as having a post-flood origin. The logical conclusion that Wood comes to is that if all these fossils represent a collection of variation within a single horse kind then all those species of horses 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 are found on this side of the Flood it follows that they all then “evolved” from that pair.  It is becoming a common position in creationism to accept super-accelerated evolution after the flood (eg. all dogs species or all cats are from a single pair) and this is yet another example.

A recreation of fossil (extinct) "horses" showing the various sizes and shapes. All of these would be smaller than the common horse today. Image Credit: Wikipedia

A reminder of the variation found in fossil horses that some creationists say are all the same kind and thus must have sprung from a single pair of ancestors perserved on Noahs’ Ark. Image Credit: Wikipedia

Sarfati clearly believes in rapid diversification but apparently doesn’t’ want to accept the evidence from the fossils record of a progression of character evolution that leads to the modern horse.  Rather he wants to have all evolution be some sort of loss of information as if all the genetics and programming to make 100 different species of “horses” was present in the first created horse and all subsequent species that “evolved” from that horse are just the result of sorting variation and genetic switches that cause a loss of information.

But Sarfati has a serious problem and it is one that creationists very 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.

The genetic bottleneck effect. For young earth creationists the bottom of the figure could represent the variation in creation but then the Flood is the ultimate bottleneck of that varation. Following the flood there would be no variation to sort but rather variation has to develop again through the accumulation of mutations.  Most YECs abhor the idea of positive mutations but many are now being forced to consider that many of the variations we see today are the result of mutation rather than origin variation in the creation because of this bottleneck effect.

The genetic bottleneck effect. For young earth creationists the bottom of the figure could represent the variation in creation but then the Flood is the ultimate bottleneck of that variation. Following the flood there would be no variation to sort but rather variation has to develop again through the accumulation of mutations. Most YECs abhor the idea of positive mutations but many are now being forced to consider that many of the variations we see today are the result of mutation rather than origin variation in the creation because of this bottleneck effect.

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 100s of thousands of horses on day 6 of creation account and 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?  Just like today, it would have become sorted out and much of it eliminated from any individual horse 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.

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. I only had to look at an article published two days ago on creation.com (Creation Ministries International). In 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 behaviour, 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 had a lot of genetic variation much less the one individual 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

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Comments

  1. ashley haworth-roberts says:

    On a different topic, but relevant to human genetic bottlenecks, have you seen this?

    http://www.pnas.org/content/early/2013/04/24/1301474110.abstract

    http://www.bbc.co.uk/news/science-environment-22355515

  2. K. Hawrylak says:

    This is my first comment on your blog. I recently found out about your series of posts regarding horses and the fossil record via links from the GeoChristian blog (a personal favorite of mine). One issue that I didn’t see mentioned in this post series is why are there no “horse kind” fossils in what YECs consider to be the geologic layers formed from a global deluge?

    From a YEC perspective, there should’ve been many of the “horse kind” left outside of Noah’s ark just prior to said deluge. This category of air breathing animal would’ve drowned during the months long global flood and eventually buried somewhere within what the YECs claim to be the sedimentary rock layers formed during Noah’s flood. How do they explain the absence of any pre-flood “horse kind” remains (which one could safely assume numbered in the hundreds of thousands or even millions all over the earth at the time of Noah’s flood) within what they consider the flood rock layers?

    It would also be reasonable to assume that there would’ve been various combinations of young / old / small / large / fit / frail / awake / asleep of the “horse kind” on earth outside of Noah’s ark at the initiation of the global flood. These would’ve all eventually drowned over the course of the months that YECs propose that all of planet earth was covered with water. So, why is there no fossil record of what should’ve been the drowned and buried remains of this particular category of animal?

    Have you (Natural Historian) heard or read of any explanation that you found to be reasonable from YECs explaining the lack of “horse kind” fossils in the rock layers they claim were laid down by Noah’s flood? Even if large / fit examples of the “horse kind” could manage to find higher ground to initially escape a global deluge, surely others of the “horse kind” that were smaller (or sick / asleep) during the initial phase of a global deluge would’ve wound up drowned and buried (and by extension, fossilized) somewhere within the proposed flood sediment layers.

    Since this is my first comment, I should give a little background on myself. I’m an Evangelical Christian who has both an undergraduate and a graduate (M.Sc.) degree related to the biologic sciences (my degrees were done a while back… during the 1980s). My initial (default) perspective on origins back then was YEC but over the last two decades I slowly shifted over to an old earth perspective (that shift happened primarily as I learned more about the fields of astronomy and geology).

    Lastly, I’ve enjoyed reading the perspective you present in your blog. Keep up the good work.

    • Thanks for your encouragement and for your excellent comments. Your question about the horse fossil record in pre-flood deposited by YEC thinking is an excellent one and I think you comment about it are right on the money. Here is my best shot of what I think the YEC comeback would be: No horse fossils have been found in the pre-flood rocks because God only created a single species of horses in the original creation and those horses did not ever become common or diversity before the flood. Therefore it is not surprising that we have yet to find any remains of the very few horses that existed during that time.

      Obviously this is an ad-hoc explanation. It is not impossible but the YEC problem is that it begins to stretch credibility as soon as you realize the same explanation would have to be used to explain the perplexing absence of nearly every single group of mammals alive today. You probably realize that the same problem of missing fossils in pre-flood rocks would apply to elephants, canines, felines, primates, rhinos, bears, seals, etc… It makes one wonder what the YEC think the world looked like when Adam was formed and placed in the garden. The fossil record would seem to be telling them that it was a world devoid of any mammal that we would recognize today but one where millions of dinosaurs, reptile and amphibians lived and were trapped by the global flood.

  3. This was a great read. As usual, your insights are very helpful. I wonder how the young earth perspective might interpret the horses which have become extinct, as well. They could not have been wiped out by the flood (some of them were on the Ark). So which end of the Flood did they die on (before the flood or after)? If it was before, then how does one explain the fossils in the sediment? If after, then posts like this present a different challenge.

    • You have identified an important question that I didn’t stress in my posts. It is a bit complicated because YEC are not in agreement about what constitutes pre-Flood, Flood, and post-Flood deposits and so two YEC might give different answers about whether any particular lineage of organisms is found only post-Flood or was killed by the Flood. This is the case with horses as Sarfati suggests that some of the “horses” represent pre-flood horse diversity killed by the Flood. However, Sarfati is inconsistent with his own stated believe about what rocks represent Flood rocks. Most YECs (but not all) put the end of the Flood in rocks that conventional geologists date to at least 40 million years old up to 65 million years old (K/T boundary where the dinos disappeared). This would mean that ALL horse fossils are found in deposits that are post-flood. This is why Todd Wood is arguing that horses are evolved from a common ancestral pair on the Ark because he recognizes that all the fossils are from post-flood deposits. So, really NO horse fossil has ever been found in Flood deposits. I think this should be disconcerting to YECS but that would only be the tip of the iceberg. YECs have a huge problem with mammals. Almost all mammals that you and I would recognize are found in rocks less than 65MYA and thus could all be post-flood. Certainly most YECs cutoff for Flood deposits would mean that there are NO elephants, bears, dogs, cats, primates, rodents, rhinos, etc.. that are found in Flood deposits. If you look just at flood deposits then and ask what did the world look like before the flood, it appears to have been covered with dinosaurs, reptiles (but different than today’s) and amphibians but almost NO mammals with maybe bats and a few “proto” rodent type mammals in the fossil record. Why no mammals killed in the Flood? This is one of those things that YECs just don’t talk about or, as likely, the just haven’t thought about enough to realize they have a huge problem. Of course, Genesis mentions domestic sheep/goats so we know there were mammals around before the Flood. The only thing that I think they YECs can say is that God make representatives of all the mammal “kinds” in creation but they were very very unsuccessful prior to the Flood (low population numbers and no speciation into different species) but that each kind was saved on the ark and then they went bananas after the Flood evolving into 1000s of species.

Trackbacks

  1. […] HORSE HYPEREVOLUTION – Naturalis Historia continues its series on YECs and the fossil record and evolution of horses. The problem this time is genetic bottlenecks. See Horsing Around with Genetic Sorting: Horse Series Part IV. […]

  2. […] Horsing Around with Genetic Sorting- How does the use of “kind” within YEC work in their own paradigm? Over at the Natural Historian, some young earth claims regarding genetic sorting are investigated. […]

  3. […] an old earth and for the overarching scenario of evolutionary biology. Such fascinating topics as Horsing Around With Genetic Sorting, Lake Sugitsu and the 60000 Year Varve Chronology, and The Frequently Overlooked Geological Context […]

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