The unabashed confidence that moves "Celebrated JW scholars" to challenge any expert in any field has led them to produce two major rebuttals of evolutionary theory over the years. Did Man Get Here By Evolution Or By Creation? appeared in 1967 and Life – How Did It Get Here? By Evolution Or By Creation? was released in 1985.
This week's JW science quote again touches on the subject of evolution. I hope everyone understands that the intent of these topics is not to start a debate on the subject. There are certainly scientifically literate critics of evolutionary theory out there and I highly recommend reading what they have to say. The purpose of this post is to illustrate the need of truly understanding a subject before you challenge experts in that field.
In the chapter, "Fundamental Law Of All Living Things" the book Did Man Get Here By Evolution Or By Creation? presents three basic "rules" governing reproduction in Genesis "kinds." These were illustrated with examples on page 53:
Although the first and third examples are valid observations, there are number of problems with the middle example.
First: Strictly speaking, it is not correct, to say, "A horse and a donkey can produce the hybrid mule…"
A horse and a donkey do not produce a mule but they can produce a hinny. If you want a mule, you need to breed a donkey with a horse. (Note the order in which the two parents are listed.) As with many mammalian hybrids, the sex of the two parent species makes a big difference and this is not just a matter of semantics because the hinny and mule are two entirely different animals.
Here’s another way to look at it:
Jack + Mare = Mule or Molly
Stallion + Jennet = Hinny
The sire is always listed first, especially when you are using gender neutral animal names. That convention is also reflected in their scientific names:
Mule = Equus asinus x Equus caballus
Hinny = Equus caballus x Equus asinus
This is not what you would call a grave error, but again, if you’re going to pick a fight with evolutionary biologists, you should know at least as much about common barnyard animals and the terminology which describes them as the average farm boy does
Second: Claiming that the mule was the limit of the horse "kind" is an oversimplification of hybridization in family Equidae.
Let’s consider just zebra hybrids: A cross between a horse and zebra will produce a hebra. A cross between a zebra and a horse will produce a zorse. A cross between a donkey and a zebra will produce a zebret .A cross between a zebra and a donkey will produce a zebronkey. A cross between a zebra and a pony will produce a zony. A cross between a zebra and a Shetland Pony will produce a zetland. These are interesting animals if you’ve never seen one before:
Zorse
Zebronkey
Another example of the considerable degree of variation within the horse family is the extremes of size between the smallest of miniature ponies and large draft horses:
This is also not what you would call a grave error.
A more serious problem with this example is an apparent misunderstanding of hybrid sterility. While it’s true that the mule is sometimes presented as the classic "sterile hybrid" in cursory treatments of genetics, there are actually some fairly specific reasons for this sterility.
The Horse has 64 chromosomes while donkeys have 62. Mules and mollies have 31-paired chromosomes as well as an extra chromosome from the mare that is not paired, giving them a total of 63 (2n+1) But this in and of itself is not why mules are always sterile and mollies almost always are. A similar situation exists with hybrids between Przewalski’s horse (E. przewalskii) and the domestic horse. (E. caballus) The former has 66 chromosomes, so when it is crossed with the domestic horse, the offspring are trisomic just like mules, mollies and hinnies are. (i.e. They have one extra unpaired chromosome) But despite this, they are not sterile
Mules and hinny stallions are sterile because testicular meiosis is arrested at the primary spermatocyte stage (Meiosis I) by incompatibility of synaptal pairing between paternal and maternal chromosomes. Spermatozoa usually cannot even be found in the testicles of a mule. Horses and donkeys share most of the same genetic information and/or genetic loci on their respective sets of chromosomes, but the order of that information is scrambled. This is an organizational incompatibility, not an informational incompatibility and is simply a peculiarity of crossing these two species.
Therefore the sterility of the mule cannot legitimately be extrapolated into a "rule" governing all hybrids. This "rule" does not hold true for all animal hybrids, and it is not even true for all horse hybrids. It is most certainly not true with plants. Hybridization between plant species is recognized as a rapid means of speciation.
The last problem with this example is not quite as obvious as the other three. For the JW brand of creation, bringing up the issue of hybrid sterility between species that are considered to be the same "kind" is problematic. Species that can breed and actually produce viable offspring are obviously related and that is very good evidence of common ancestry. Sterility of the offspring is one of the first signs of genetic incompatibility and for two species with a common ancestry, this is pretty good evidence of divergence. In other words, they were probably more closely related in the past.
This is not a problem for scientifically literate varieties of creation that define "kinds" by taxonomic hierarchy, but it is a contradiction for the JW flavor of creation which defines "kinds" along purely reproductive lines. I’ve pointed this out before and some have disagreed, but it’s perfectly true. Take a look at the third and final example of "Reproduction according to its kind" on page 53 above. This "rule" holds that variations within a kind are fertile together.
Humans make a convenient example for this "rule" because they are one of the most homogenous species on the planet, but the situation becomes much more complicated with "kinds" composed of multiple species. The chromosomal rearrangement that causes almost complete sterility in the offspring of the donkey and horse can also make interspecific hybridization completely impossible by preventing conception entirely. So what the author(s) of this book were holding up as a stabilizing mechanism which limits variation is actually a process that drives a wedge between different members of what is ostensibly the same "kind."
That the author(s) of this book were unknowingly marching into this logical cul-de-sac is apparent on the preceding page where members of the dog "kind" are enumerated to include species that are not fertile together. By their own "rules" one and three, this would make those respective species different "kinds" and by agreeing that they sprang from a common ancestor, the author(s) are in effect, assenting to the idea that different "kinds" diverge from the same "kind."
That level of contradiction was embarrassing in a book intended to defend the JW brand of creation and it could have been avoided if the author(s) had simply understood what they were talking about. But that is a recurrent theme in the writings of "Celebrated JW scholars."