1.3 Quote Mining and the Case of Punctuated Equilibrium
Primary source case study, Old Earth Creationist Fazal Rana trips over his own sources.
That Punk-Eek is thus way less revolutionary than it sounds (and no threat to the notion of natural evolutionary common descent) is seen by going beyond Gouldian authority quotes to look at how the idea has been received (and more importantly used) by scientists since. The subject of speciation pacing will be surfacing many times in the chapters to come, but it has become clear that modern evolutionary thinking is incorporating the supposedly dreaded P-E without falling apart in the way the creationist sideline imagines.
Illustrations of the progression of P-E acceptance are not hard to find. While traditional morphology-grounded paleontologist Van Valen (1982b) warily included P-E among a range of competing concepts in working out biogeographical speciation dynamics, geneticist Parsons (1983) incorporated P-E into his framework without a bump. Later general evolution guides Gamlin & Vines (1986, 18-19) and Whitfield (1993, 178-181) matter-of-factly covered the principles regarding the remarkably detailed 4.5 million year showcase of fossil invertebrates at Lake Turkana in Kenya stemming from Williamson (1981). Move on into the 1990s and deeper theoretical issues arose in the technical back-and forth of Coyne et al. (1996) re Elena et al. (1996) on how beneficial mutations generate punctuated patterns at the bacterial level, and whether these findings can be applied to aspects of the vertebrate fossil record.
A later aside in Eldredge et al. (1997) reflected some of the turf wars at this early stage (in this case between paleontologists and geneticists trying to grapple with interacting processes operating in the past): Eldredge & Gould thought Coyne & Brian Charlesworth “perpetuate several incorrect perceptions of the original notion,” while Coyne & Charlesworth shot back that “Eldredge and Gould have proposed so many different versions of their theory that it is difficult to describe it with any accuracy.”
Young Earth Creationist Emerson McMullen (2002) subsequently deployed the Coyne/Charlesworth opinion (he may have been unaware that Eldredge and Gould had something to say here too) to glibly dismiss P-E as “not a scientific idea.” The problem for this logic is that Eldredge et al. (1997) is not the whole of the matter. One can track the actual trajectory of P-E’s usage all over the place. Just follow Levinton & Futuyma (1982), Simpson (1983, 171-176), Dawkins (1986, 223-252) and Berra (1990, 48-50) prior to the Prothero (1992) summary, and subsequently K. Miller (1999, 111-121), Jablonski (2000), Eldredge et al. (2005), Fortey (2009, 185-186), Milner (2009, 361-362), Tattersall (2009a, 151-156), and C. Zimmer (2009g, 217-220), with P-E inevitably filtering to educational venues far and wide, from McComas & Alters (1994) for student exercises to Saylo et al. (2011) explaining P-E thinking from a school in the Philippines.
The many technical papers and the fossil taxa discussed in them are as available to antievolutionists as they are to me, but antievolutionists pay no attention to them. And I mean this literally. No attention whatsoever. This is so even when they deliberately bring up the subject of Punctuated Equilibrium, which they do solely for its apologetic utility, as the obligatory talking point on how evolutionists are supposedly so reluctant to accept the evidence of their own study. And that is how an issue of allopatric vs. sympatric speciation and how that relates to the odds of getting preserved in the geologic column, gets transposed into an iconic “problem” for evolution at the macroevolutionary level.
Old Earth creationist (OEC) Hugh Ross (1998, 50-51, 201) represents one of those rare “exceptions that proves the rule” when he dipped down into a concrete example when asserted that the evolution of whales “changed far too rapidly for either Darwinism or punctuated equilibrium to explain.” According to Ross, P-E was ruled out here because it suggested, “that dramatic genetic changes occurred in sudden jumps propelled by severe environmental stress. The period from 48 to 52 million years ago, however, appears to have been remarkably tranquil, far less stressful than such a scenario demands.”
Ross neglected to document what genetic changes were involved (to assess their magnitude and relevance) or that punctuated equilibrium mandated such a climate change link (in the case of whales or any other) in the first place, or just how “remarkably tranquil” the period was. Oh really? That time frame actually fell smack in the peak of the Paleocene-Eocene Thermal Maximum (PETM) discussed in module 1.2 earlier. It certainly impacted ocean biotic chains, which is after all where the early whales would have been swimming—there is more on whale evolution and Intelligent Design proponents have dealt with it in Chapter 4 of Downard (2004).
The gossamer Ross scholarly style regarding punctuated equilibrium continues at his Reasons to Believe website, as evidenced by a sequence of 2008 posts by Fazale Rana trying to hijack P-E into a creation context.
Rana (2008a) trotted out Greg Hunt (2007b), a technical paper confirming that P-E was real and that the theory was correct in suggesting that directional change in fossil life was fairly rare, occurring only about 5% of the time (with the remaining 95% of traits divided between “random walks” and outright stasis) though more prevalent in planktonic (upper oceanic) organisms than benthic (deep sea) ones. It was not specifically addressing the issue of species origination, but rather assessing which of the three modes were more in play regarding the microevolutionary shifts of traits within the studied lineages (shell size and width in assorted molluscs, for instance). Subsequent work by Hunt et al. (2015) suggest the dynamics of evolving life show even more variety than the three modes studied in the 2007 paper, though still no less natural and evolutionary.
Rana’s effort to co-opt Hunt for creationist apologetics was a study in his own befuddlement. Evidently with some perfectly created original in mind, Rana couldn’t see how the traits of size and shape being measured in the Hunt paper were indicative of animals not created optimally to begin with. In a design context this meant repeatedly jumping in to tweak the model to render it fitter—how is this any different from the unguided natural processes creationists are so keen to banish from nature?
In any case, the stasis examples in Hunt were not instances of an absence of change, but simply whether the observed variations showed selective trends or varied more randomly or remained within a static range, a difference Hunt had quite clearly explained. Starting with directional evolution, “When operating in directional mode, evolutionary divergence accrues steadily, and descendants are readily discriminated from ancestral populations of the same lineage.” He illustrated this specifically by the shell conicity seen in the foraminifera Contusotruncana that gradually increased over the last 3 million years of the Late Cretaceous. The original paper Kucera & Malmgren (1998) had noted that this change in shell shape shouldn’t be viewed in isolation: there was a marked decrease in the abundance of that lineage over the same period, suggesting selection pressures were at work (remember that a mass extinction was looming, and the Cretaceous oceans were being affected first).
“Unbiased random walks are intermediate in pattern,” explained Hunt, “they are not inherently directional, but phenotypic differences accumulate so that expected divergence increases with elapsed time.” Hunt’s illustration was shell width in a recent island snail Mandarina chichijimana, drawing on Chiba (1996). Over 40,000 years it had first undergone a rise to a higher stable state, then a more pronounced drop of around 15% until a few thousand years ago when it has undergone some upward blips again, though still well below its prior peak.
“At the opposite extreme, stasis allows for fluctuations between populations but predicts no net change within evolutionary sequences.” Hunt’s example here was drawn from Kelley (1983), concerning changes in shell convexity in the extinct Miocene bivalve Chesapecten nefrens over four million years. Starting about 14 Mya, C. nefrens exhibited jumps of around 10% above and below its starting mean (at the low end of the 10-20% fluctuation range for the molluscs observed by Kelley). The mollusc wasn’t changeless over that time, just “static” in the narrow sense Hunt used (ending up with roughly the same initial features showing up at the end). To mistake this for stasis in the way creationists use it is understandable: they don’t bother to investigate the specific examples or then progress to specifying what variation means in their own design framework.
Only because Rana never discussed any of the data in Hunt’s paper did he escape seeing how the two were not addressing the same subject (P-E microevolutionary issues for Hunt—the supposed absence of evolutionary change for Rana). This situation only got worse in the follow-up of Rana (2008c): “Even though punctuated equilibrium can explain the troubling features of the fossil record, one key question remains. Does the mechanism undergirding punctuated equilibrium actually work? Research results published in 2001 indicated, no.” For which claim Rana cited two more papers.
According to Rana, Higgins & Lynch (2001) “shows that the essential processes making up punctuated equilibrium’s mechanism lead to extinction, not evolution. These scientists demonstrated that risk of extinction significantly increases for a species when its population becomes disconnected. Moreover, environmental changes and habitat fragmentation exacerbate population’s susceptibility to extinction. Population and habitat fragmentation, along with an altered environment, stand at the center of punctuated equilibrium’s mechanism.” And for confirmation, Rana asserted A. Templeton et al. (2001) “showed that habitat fragmentation doesn’t drive speciation, rather it leads to extinction.”
It should have rung warning bells for Rana that neither of these two papers mentioned punctuated equilibrium at all, or even cited any papers relevant to it. The fact that neither claimed their work undermined any P-E mechanisms might have been a clue that they didn’t think they had done that.
Higgins & Lynch were working out the parameters of extinction threats in populations. It was clear that populations that fall below a certain threshold become exceptionally vulnerable to extinction, especially if their habitat is disrupted, as by human activity. Since population size is a primary variable, Rana could invoke their paper in this service only if he could show that the population sizes of candidate P-E groups fell within that fateful low level. This Rana certainly did not do.
The role of human intervention in species extinction was specifically the subject of the Templeton paper, which contrasted the unnatural conditions of the lizard they were studying (human logging in its range had significantly altered the habitat) with the natural evolutionary system of organisms moving into a vibrant and expanding ecological niche (which they note can induce macroevolution of groups via the founder effect—Ernst Mayr’s concepts being applied, by the way—where an animal entering a new environment can have novel variations favored in a way different than back home). Again, in order for Rana to invoke the Templeton paper for his apologetic purpose he would have to show that the ecological conditions of the candidate P-E cases were fragmented in the way Templeton characterized for his lizard sample. Otherwise founder effects could play a role and P-E move ahead unhindered. And once more, Rana completely failed to make that essential link.
Both papers were discussing a different field than the one Rana wanted to drag them onto. So while they did not “create a serious problem for the evolutionary paradigm” they did expose a “serious problem” in the way Rana approached technical literature, which he only compounded by going on to offer a prior post of his to further support the claim that “strict Darwinian evolution lacks the necessary corroboration from the fossil record and cannot be declared a fact.”
This turned out to be Rana (2008b) trying to undermine the idea that humans descended from the australopithecines in Africa millions of years so. But the paper Rana cited, Lockwood et al. (2007), wasn’t addressing which lineage we stemmed from, let alone offering problems for it, but rather the characteristics of one species outside that group, Paranthropus robustus. As Gibbons (2007b) explained in her commentary, the paper identified a sexual dimorphism (males much larger than females) that was consistent with that species having a harem-style mating strategy comparable to silverback gorillas today. Fine and dandy, but how does this have any bearing on what is happening with other completely separate species, or even genera, pertaining to our track through the hominid landscape?
What Rana was doing here was as though he were trying to prove that the Titanic didn’t sink by an iceberg in 1912 solely because the Andrea Doria sank in 1956 by ship collision. As the two aren’t related to begin with, the comparisons are irrelevant.
In the very rare “exception to prove the rule” department, an even fuzzier example involves Ray Bohlin of Probe Ministries, a YEC-friendly apologist who helped get the ID movement started (much more on that in section 1.7 later). While Herr & Bohlin (2005) were content with invoking the Gould “extreme rarity” quotation as tactical ammunition in an assault on the Quammen (2004) article on evolution in National Geographic, in “The Natural Limits to Biological Change” Bohlin (1994b) had decided that for Eldredge and Gould, “where there is lots of speciation, there should be lots of morphological differences. Where there is little speciation, there will be few morphological differences,” and that consequently P-E required that “groups of organisms that contain large numbers of species should also display large morphological differences within the group.”
Bohlin then went on to give animal examples contradicting this proposition—unfortunately, what Bohlin failed to do was document exactly where Gould and Eldredge supposedly made these connections in the first place, so readers could evaluate whether Bohlin’s ammunition was relevant or not. Bohlin plowed on, though, to pronounce P-E
is of little use to evolutionary biologists because they cannot imagine a way to make it work with real organisms. Gould and Eldredge admitted as much in their review of punctuated equilibrium’s progress in the journal, Nature, in 1993 when they lamented that: “But continuing unhappiness, justified this time, focuses upon claims that speciation causes significant morphological change, for no validation of such a position has emerged.”
Incidentally, that particular quote has percolated through the creationist/ID subculture, the Expelled Exposed (2008) website noting a metastasized misquoted version (“There is no validation of the position that speciation causes significant morphological change”) was trotted out along with a bevy of creationist canards in slide lectures by “intelligent design” promoter Caroline Crocker—one of those purportedly persecuted Darwin critics extolled in Ben Stein’s boldly selective 2008 documentary Expelled (more on which in due course). Crocker (2011) pressed for “Integrity in Science,” and she has taken her “bunk science” claims about evolution and climate change into the Kulturkampf antievolutionist subculture, lecturing the Creation Science Fellowship in September 2012, Creation Science Fellowship (2014), and including ID-themed postings at the American Institute for Technology and Science Education website, such as AITSE (2011) and Crocker (2013).
Alas, for Bohlin (or the painfully secondary Crocker), Gould and Eldredge had by that point in their 1993 review moved on to another topic, but Bohlin hadn’t noticed. For Bohlin the acknowledgment that there was a legitimate debate about the degree to which speciation was the primary generator of major change (by which animals would be changing because they were speciating, as opposed to elements of change occurring less frequently along a path of many incremental speciation events) got conflated with the original P-E issue of how the quite observable allopatric speciation mechanism (without or without morphological change) could be reflected in a fossil record whose geological processes were typically far too slow to trap them.
That there was still an observable correlation between speciation and morphology (that visible changes in animals understandably reflected their having diverged so far that they now represented distinct species or genera compared to their predecessors) should have been clear enough to Bohlin, though, given how Gould & Eldredge (1993, 226) had concluded the very paragraph he had mined for his quote: “the association of morphological change with speciation remains as a major pattern in the fossil record.”