There hasn't been a single argument made in this thread that refutes NotSoBlindFaith's basic point, that in the span of 4,500 years explosive speciation produced the diversity of rodentia that we see today from an original founder stock.
Additionally, the arguments that are made seem to reveal a strong lack of understanding of the predictions of the theory of evolution. I am also particularly disappointed to see that all of the evo arguments are restatements of fallacious creo arguments.
The claim has been made that evos don't call each other to task when such errors are made; while I do so my intent is not to offend, but rather to correct glaring errors and inform along the way:
Error 1: Speciation is regular and exponential:
Discreat_Label writes:
Well to be truthful a linear equation describing speciation in my opinion would be intelletually dishonest, mostly because populations don't follow linear rates of growth. But understandable to using a linear module because it is the easiest model to describe.
Yaro's commentary writes:
If the flood happened 3000 years ago, we are expecting a rate of 1 new rodent a year. But, as Discreat_Label pointed out, speciation in a population is non-linear so in truth an actual calculation would be exponential. This means you are expecting on the order of 467 new species a year!... We should litteraly be able to see rodents morphing before our very eyes.
(Since we don't directly observe evolution
(morphing, ack!), it hasn't happened in a certain way. A standard creationist argument.)
Discreat_Label makes an
enormous error here by horribly
confusing the growth (via reproduction) of populations with the evolution (speciation) of populations. Growth of populations does, indeed, proceed exponentially until limited by resources essential for individual growth and reproduction (think bacteria in a nutrient-rich broth).
Evolution of new species follows a completely different path. Potential for speciation relies largely upon changes in the environment, it is in no way an automatic event given a set amount of time, which is what is truly suggested by the evo arguments here.
If anything, Discreat_Label got things backwards, that is, it is expected that speciation would occur much more rapidly immediately post-Flood as a massive array of open niches were made available, and
slow down exponentially as those niches were filled and the species within them optimized.
Once this optimization occurs, the species are under "stabilizing", "normalizing" or "neutralizing selection"(
1,
2), meaning that since they are optimized for their niche, selection will maintain the current optimal state until the environment changes and new selective pressures are encountered.
Extremely rapid speciation into suddenly-available niches has been called "explosive speciation", but a more general term that doesn't include the rate qualification is "adaptive radiation". The most famous example of an adaptive radiation is the
Galapagos finches, which were founded by a single pair of finches
(according to genetic analysis by the Grants) whose offspring eventually speciated as they specialized and colonized every available niche on the archipelago. Additionally, the Grants have shown that the finches continue to rapidly evolve (
1,
2), even in
seasonal timespans.
Another good example of explosive speciation into newly opened niches is the colonization of the Great Rift Lakes of East Africa, where
over a thousand speciation events occurred in the past million years as a few river species adapted to the enormous number of niches in the newly formed lakes.
Error 2: Failure to breed beavers from mice refutes rapid speciation:
Yaro writes:
If NSBF's proposition is true, scientists should be able to breed rats, capybaras, or beavers out of a mouse or perhaps a squirrel.
Simply not true, and essentially a restatement of many off-base creationist arguments
(as in: if evolution is correct, we should be able to produce humans through selective chimp breeding).
If my understanding is correct, NSBF never claimed that a beaver could evolve from a squirrel, but rather that they both rapidly evolved from a single common ancestor. I'm assuming that the pro-evolution side here would agree with the common ancestry.
When species (or breeds or lines) form under selection, the genetic information segregates into each species based on differences in selection. Once this happens, there is no way for one species to "recapture" the genetic information that ended up in another species, even though the two species shared a common ancestor and thus a single founding gene pool.
A comparable claim to your rodent claim above: in order to demonstrate that the dog breeds have recently diverged, we should be able to produce Saint Bernards from a chihuahua line through selective breeding. There is no reason to believe this would be possible, since many "Saint Bernard genes" were long ago selected out of the chihuahua gene pool line, as "chihuahua genes" were selectively fixed.
Remarkably, there is an enormous amount of phenotypic variability that can be selective bred from fairly homogeneous mouse stocks - for example, starting with one mouse stock, one group produced multiple lines with
five-fold differences in body size and fat content. Drastic physiological differences have been selectively bred as well - it is this sort of physiologically selective breeding that many in the research community utilize to uncover the genetic basis of the function heart/kidney/liver/etc.
In any case, your squirrels-to-beavers claim would have no bearing on NSBF's argument, which involves the
rate of speciation from a
common ancestor.
Error 3: Sterile hybrids between closely-related species refute rapid evolution:
Coragyps writes:
Mus musculus domesticus, the house mouse, and Mus spretus, the Algerian mouse, make sterile hybrids if they're bred. But, as far as their genes indicate, they are more closely related than humans and chimps are. Does that raise any problems for the ante-Flood hyperspeciation? If these two aren't interfertile, how do we get beavers from mice in a couple thousand generations?
This was particularly painful to read. It is essentially a direct restatement of the Carico-speak that haunted by nightmares a couple of weeks ago:
"apes breed apes, humans breed humans, if they can't interbreed, then how do we get humans from apes?"
Separate of this reoccurring fallacy that species with recent common ancestry should somehow be able to bred
into one another, there is another issue here. The sterile hybrid example seems to be providing evidence more
for NSBF's hypothesis then against it:
An example is given of two closely related rodent species that produce sterile hybrids, thus the two species maintain separate gene pools - they are reproductively isolated, they are separate species. Since they are closely related, this speciation has happened relatively recently.
In other words, to counter the contention that rodents have recently speciated, a reference was given describing recently speciated rodents.
In fact,
mice appear exceptional in their rapid speciation - they are likely the fastest among the mammals. There has been a good deal of study on
Robertsonian translocations leading to speciation in Alpine and other mice - in this form of speciation,
based on sudden karyotype changes, speciation occurs in a few generations or doesn't occur at all. Such rapid, karyotype-driven speciation likely occurs in other rodents as well though it hasn't been discovered yet (mice are the most genetically analyzed mammal, so it is no surprise that the mechanism was elucidated in species of mice).
Error 4: Evolutionary stasis in one species in an adaptive radiation is predictive of trends in the radiation as a whole:
Nuggin writes:
Why haven't the rats changed in 700 years? Did they some how stabalize after the Flood?
Are these the same rats that the Chinese have in their calendar (ie the year of the rat)? That dates to 2500+ years ago. That means that Noah's son or grandson had to start the Chinese calendar
Kind of brings to mind the fallacious creationist argument, "the coelacanth hasn't changed in several million years, therefore evolution doesn't occur in a certain way".
The (implied) statement again suggests that speciation/evolution is a constant, regular event for each species - which is simply not the case. Evolution in all species "stabilizes" once optimization to the niche is reached (see comments on normalizing selection above).
Importantly, simply from evolutionary stasis in rats we can make no comment on the concurrent rate of evolution/speciation in any other rodent species. Furthermore, if the diversity of rodents is the result of the sort of explosive adaptive radiation that NSBF suggests, then we would expect the bulk of evolution to occur early in the time frame, not later - we should expect stasis of the kind pointed out.
By the way, it is likely that the Chinese rat was a different species/subspecies (maybe
R. tanezumi) than that involved in the European Black Plague (probably
R. norvegicus and/or
R. rattus). Also, given the Flood timeline, these would have had 2000 years on the front end of the adaptive radiation to speciate prior to your date for the Chinese calendar.
Interestingly,
rattus and
tanezumi are morphologically indistinguishable, and up until recently were considered one species. Karyotype differences distinguish the species - karyotype differences that can be a hallmark of a sudden/rapid speciation event.
Overall Error: A bunch of strawman arguments and arguments from incredulity:
Yaro writes:
These things simply could not have arisen from a squirrel-like ancestor some 3000 years ago... If we can't do it in the lab, why should we expect that to be happening in the wild? ...
It seems both sides of the argument agree that rodentia did evolve from a common ancestor, it's just the speed of the evolution which is in dispute. The only rate-of-evolution arguments that have been made are based on disbelief, with no evidence or substantiation.
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