“A horse is a horse, of course, of course, and no one can talk to a horse, of course, unless, of course, the horse, of course, is the famous Mr. Ed!” From the introduction to the 1960s TV show “Mr Ed”
No one disputes that Mr. Ed really was a horse but what about the plains zebra, the quagga, or the donkey? Too bad they can’t tell us. Are these all horses (equines)? What about the other 15 extinct species, including the quagga, that are also called equines because they are assigned to the same genus? What about the other 20 or more fossil genera and many more fossil species that have been named that are similar to the modern genus Equus that include the horse, donkey and zebra. More to the point, when is a horse NOT a horse? These are questions that drive scientists to critically examine how we define species and how we understand species to have formed over time. I came across a story this past week about modern equine relationships based on complete mitochondrial genome sequences (for more on these genomes see: Of Kinds and Common Ancestors: Comparing Mitochondrial Genomes of Animals) that got me to thinking about what makes a horse a horse.
In the past decade, more and more creationists have turned to lumping huge numbers of species together and claim they are all members of one “kind” and therefore may have a single common ancestor. A donkey, a zebra and a horse may appear to be distinct species today but in the context of a creationist’ kind, also called a baramin, they are all just variants on one created thing that we could call generically a horse. But where does this horse kind end and another kind of thing begin? Does this horse kind include all of these other fossils, none of which are like any of today’s horses but neither are they radically different from them?
The “Horse Series” as a Favorite Creationist Punching Bag
The horse series shown in the figure to the right is similar to one that has been used as demonstration of how the fossil record can be interpreted as supporting the progressive evolution of the modern horse from a small dog-sized ancestor. The fossils are said to tell a story of a progression of tooth and foot bone changes over 40-50 million years that resulted in the variation that we see today. Creationists over the past 30 years have, not surprisingly, claimed that this fossil progression and evolution story was a lie. Rather, the fossils represent different kinds of animals that were caught up on a global flood and deposited in rocks sorted by size from smaller to larger in upper layers. Over and over again the horse fossil series has been held up as an example of an erroneous inference of evolution.
I’m probably going to sound like I’m beating a dead horse, but really I’m more interested in observing how the growing field of creationist’ baraminology (see here for more: More Thoughts on Baraminology) is impacting how creationists view the origin of species than I am in the relative merits of the horse series in evolution textbooks. I expect that for most lay Christians who believe the earth is young, when they hear the term species they think of animals like a zebra and horse or wolf and red fox and they equate these with species of animals God created on the 6th day of creation. I certainly remember images from Sunday school of the Garden of Eden with Adam naming animals that look just like the animals that we see around us today such as zebras, penguins, lions etc…. But, while the average fundamentalist Christian may still think that evolution can’t happen and that God created the species we see today, creation scientists have been progressively altering their views of just how much biological change has occurred since the creation.
While creationists don’t use the term evolution and roundly deny that evolutionary theory has any validity, they have changed and adapted the definitions of terms such as micro and macroevolution as they have sought to accommodate greater and greater amounts of genetic change to species. Over time they have replaced the definition of species as defined historically by taxonomists and evolutionists with the so-called Biblical concept of a kind or baramin. A baramin allows for much greater genetic breadth than does a species. In fact, so much genetic breadth is allowed that hundreds of biological species may be encompassed by a single baramin. The typical claim made is that this genetic breadth was the result of massive amounts of genetic variation built into the first created animals. The variation was then sorted into genetically distinct sets of organisms. However, I think a significant shift in the creationists’ landscape is happening right now as I see one creation scientist after another hinting that much of this genetic variation may actually come from new mutations even while claiming that “new” information/traits can’t evolve. In a future post I will provide quotes to back up my assertion that the landscape of creationists thinking has been changing and is becoming, dare I say, more evolutionary in its assumptions.
Getting back to the horse for a moment, in my next post I will look at an intramural debate among creationists about this horse series. That debate is about just how far can the evolutionary model be used to explain the great diversity in kinds of animals. In the image to the right of the diversity of “horses” in the fossil record and present, the question for young earth creationism is: Did all these horses evolve from a common ancestor and if so what did that ancestral pair on Noah’s Ark look like? Some creationists are now willing to consider that a small muti-toed horse stepped off the ark and “evolved” into the horse species we see today. In this case the “horse series” that is presented in biology textbooks is not such a lie after all. As you can imagine not all creationist are able to swallow such a radical view but even most of the critics are still inclined to think that all these fossils do represent past horses.
Until part II…