Retroactive Confessions of Ignorance and Overblown Claims of Evolution: Observing Evolutionist and Media Behavior after Discovering "Missing Links"

by Casey Luskin

First posted April 14, 2006. This page is adapted from posts which were originally made at Evolution News & Views as:

For Darwinian Evolution, It’s One Step Forward, Acknowledging Two Steps Back: Taking A Look at Tiktaalik
and

Media Overblows Claims of "Human Evolution": Examining the Newest "Missing Link"

Introduction:
Recent media and technical discussions of the finds of fossils of Tiktaalik and Australopithecus anamensis reveal the how only after discovering a new "missing link" will evolutionists acknowledge the previously paltry state of fossil evidence for evolution. These "retroactive confessions of ignorance" are fascinating, especially when one considers how the newly discovered fossil evidence provides paltry evidence for the evolutionary transitions in question.

This response contains thus two parts:

Part I: Response to claims of recently discovered evidence for "human evolution"

Part II: Response regarding the fossil find of Tiktaalik, an alleged "missing link" between fish and tetrapods

Part I: Overblown claims of "human evolution:"
Recent "retroactive confessions of ignorance" are witnessed in comments about the discovery of Australopithecus anamensis fossils in Ethiopia. The media has also exaggerated and overblown claims that this evidence supports "human evolution."

This latest "missing link" is actually comprised of a few tooth and bone fragments of Au. anamensis, an ape-like species that lived a little over 4 million years ago. Incredibly, claims of "intermediacy" are based upon 2-3 fragmented canines of "intermediate" size and shape. This has now led to grand claims in the media of finding a "missing link." Because some bone fragments from Ardipithecus ramidus and Australopithecus afarensis were also found in the area, MSNBC highlighted these finds on a front-page article calling this "the most complete chain of human evolution so far." Media coverage of this find thus follows an identical pattern to that of Tiktaalik: incredibly overblown claims of a "transitional fossil" follow stark admissions of how previously bleak the evidence was for evolution. Moreover, claims that this find enlightens "human evolution" are misleading, as these fossils come from ape-like species that long-predate the appearance of our genus Homo, and thought to be far removed from the origin of "humans."

Evolution was "obscure" then and it's obscure now:
As noted, evolutionists only admit how weak the evidence was for evolution after they have some new allegedly "transitional" fossil in their hands. Compare how identical diction was used in Nature to concede the previously "obscure" evidence for tetrapod, and then now australopithecine evolution after recent fossil discoveries were made:

Tiktaalik: "[T]he origin of major tetrapod features has remained obscure for lack of fossils that document the sequence of evolutionary changes" (Daeschler et al., “A Devonian tetrapod-like fish and the evolution of the tetrapod body plan,” Nature, Vol 440:757-763 (April 6, 2006); emphasis added)

Australopithecus: "Until recently, the origins of Australopithecus were obscured by a sparse fossil record." (White et al., "Asa Issie, Aramis and the origin of Australopithecus," Nature, Vol 440:883-889 (April 13, 2006); emphasis added) Apparently the MSNBC article even felt comfortable enough to admit that we never previously had a continuous sequence of fossils documenting "human evolution" in one place:

"Until now, what scientists had were snapshots of human evolution scattered around the world. Finding everything all in one general area makes those snapshots more of a mini home movie of evolution."
(Fossil discovery fills gap in human evolution, by Seth Borenstein, Associated Press, 4/12/06) Of course the lack of a "mini home movie" never bothered evolutionists before: critics have always been told not to request continuous fossil sequences exhibiting evolution because species can migrate, and often the evolution takes place in small, isolated populations that don't get preserved as fossils. As Niles Eldredge once said, evolution seems to always be "going on somewhere else." We wouldn't expect to find a continuous sequence of fossil species evolving all in on place; at least, that's what we were told before they found these fossil specimens.

If the origin of Australopithecus was previously "obscured by a sparse fossil record," then one would presume that now we have the answers. Turns out the evidence still remains very "obscure."

What did they really find?
What has really been found has been said to be nothing "new," just an interesting new "location": "The species anamensis is not new, but its location is what helps explain the shift from one early phase of human-like development to the next, scientists say." (MSNBC article, emphasis added) According to the National Geographic news article, the find consisted "mainly of jawbone fragments, upper and lower teeth, and a thigh bone"--not an impressive array of bones. The Nature article notes that the teeth they found are nothing new because they "definitively place the Asa Issie sample within expected ranges of Au. anamensis variation." (Nature 440:883-889.) So in other words, they found a few tooth and bone fragments representative of a pre-existing species--nothing truly new!

Missing Link or Missing Teeth?
Incredibly, the entire claim that this species represents a "transitional form" is due to a couple teeth which have intermediate size: "'This appears to be the link between Australopithecus and Ardipithecus as two different species,' White said. The major noticeable difference between the phases of man can be seen in Australopithecus’ bigger chewing teeth to eat harder food, he said." (MSNBC article) If this incredible new evidence isn't about to make you a convert, then consider how impressive the media has stated this evidence is: "The latest fossil unearthed from a human ancestral hot spot in Africa allows scientists to link together the most complete chain of human evolution so far." (MSNBC article) But here's where the evolutionists make their public relations error: if this is "the most complete chain," then their best "chain" has a lot of missing "links." These bone fragments purportedly tell us how the ape-like genus Australopithecus evolved from the ape-like genus Ardipithecus. Let's look at 3 graphics to asses just how impressive this evidence actually is:

1. Photo of the bone and tooth fragments from which came this "missing link":


(from MSNBC article)

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2. Figure 3 from White et al.: Figures 3a and 3b show the glued-together teeth and/or fragments of teeth which form the entire basis for calling this find "intermediate." This is the whole basis for the authors' and the media's claims that this is a "missing link." In 3b there are 2 canines, which form the basis for the "intermediate" claims. In Figures 3d - 3g, the new "intermediate" data is represented in the ASI 2&5 column, which consists of a meager 2 - 3 tooth specimens (seen in the 2 - 3 small square data-points in that column).


(Adapted by permission from Macmillan Publishers Ltd: Nature, T. D. White et. al. "Asa Issie, Aramis and the origin of Australopithecus," 440:886 (2006).)

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3. Figure 4 from White at al.: Figure 4a shows precisely what was transitional in this Au. anamensis species: its "Masticatory robusticity" (in other words, its ability to chew harder stuff). Seriously, I am not kidding: this forms the basis for the authors' and the media's claims that this is a "missing link." The evidence for evolution is so abundant [note: sarcasm] that when comparing evolutionary models in Figures 4b and 4c, they explain that "Neither hypothesis can be falsified with available sample densities" because the fossil record is so poor. That's fine: but this should help us to understand the state of the evidence if this is "the most complete chain of human evolution so far."
(Adapted by permission from Macmillan Publishers Ltd: Nature, T. D. White et. al., "Asa Issie, Aramis and the origin of Australopithecus," 440:886 (2006).) As a Neo-Darwinism skeptic, all I ask is please don't throw me in that briar patch of "intermediate-sized/shaped" (and sometimes glued-together) tooth fragments of previously known hominid species! Putting the Evidence Into Perspective
Australopithecus was an ape-like genus that is said to have lived from about 1-4 million years ago, and some of its members are said to have evolved into our genus, Homo, around 2 Ma. But this locale doesn't implicate fossils of Homo, nor does it show anything but very early Australopithecus fragments and some Ardipithecus fragments. This find doesn't document anything about the evolution of our actual genus Homo. So why do these media articles misleadingly state this evidence documents "human evolution?"

And what about those "links" farther down the "chain" showing how Australopithecus evolved into Homo? Consider what some authors wrote in a study that wasn't highlighted on the front page of MSNBC: "The anatomy of the earliest H. sapiens [here meaning Homo erectus & Homo ergaster] sample indicates significant modifications of the ancestral genome and is not simply an extension of evolutionary trends in an earlier australopithecine lineage throughout the Pliocene. In fact, its combination of features never appears earlier..."
(Hawks, J., Hunley, K., Sang-Hee, L., Wolpoff, M., "Population Bottlenecks and Pleistocene Evolution," Journal of Molecular Biology and Evolution, 17(1):2-22 (January, 2000)) MSNBC never highlighted this article on their front page because these authors said the origin of Homo required "a genetic revolution" where "no australopithecine species is obviously transitional." (Sorry, but Au. habilis doesn't cut it.) One commentator even called the state of evidence as showing a "big bang theory" of human evolution (see "New study suggests big bang theory of human evolution"). Perhaps this is because "[t]he first members of early Homo sapiens are really quite distinct from their australopithecine predecessors and contemporaries":


(Left: early member of the genus Homo. Right: one of our alleged australopithecine ancestors. Here the missingness of the link becomes stark. Quote and graphic from New study suggests big bang theory of human evolution)

But the evidence presently on MSNBC doesn't even deal with how Homo evolved from Australopithecus. If this is the most complete "chain," then indeed, we're dealing with very fragmentary evidence for "human evolution." More poignantly, this article is wrong to imply this evidence says anything about how ape-like australopithecines evolved into our genus, Homo. Even lead author of the Nature article, Timothy D. White, misleadingly stated in the MSNBC article that this evidence documents "phases of man." That's not true: if anything, these bone fragments provide miniscule suggestions of early phases of very ape-like hominids that predate Homo by 2 m.y. and "man" (Homo sapiens sapiens) by over 3 m.y. This evidence may help plug a miniscule gap in australopithecine evolution (recall, no new species was found, and all they found that was interesting were a couple canines of intermediate size), but contrary to what the MSNBC article says, nothing documents "human evolution" or "phases of man."

The More Things Evolve, The More Things Undergo Stasis
Recent news articles are engaging in emotionalism to blow up these finds of Au. anamensis fossils into something they aren't: a "missing link" that documents "human evolution." It seems that little has changed since 1981 when Constance Holden wrote in Science: "The field of paleoanthropology naturally excites interest because of our own interest in origins. And, because conclusions of emotional significance to many must be drawn from extremely paltry evidence, it is often difficult to separate the personal from the scientific disputes raging in the field." ("The Politics of Paleoanthropology," Science, p.737 (August 14, 1981).) If the present evidence for australopithecine evolution before this find was "obscure," perhaps it's safe to say they're still very much in the dark, and that very little has changed in the past 25 years.

Part II: Retroactive Confessions of Ignorance Regarding Tetrapod Evolution and Tiktaalik
I love it when new "missing links" are discovered, because it's then--and only then--that Darwinists admit how precious little evidence had previously existed for the evolutionary transition in question. When reports came out this week of an alleged example of a fossil representative of the stock that might have led from fish to tetrapods -- Tiktaalik roseae -- evolutionists finally came clean about the previous lack of fossil evidence for such a transition: “The relationship of limbed vertebrates (tetrapods) to lobe-finned fish (sarcopterygians) is well established, but the origin of major tetrapod features has remained obscure for lack of fossils that document the sequence of evolutionary changes.”
(Edward B. Daeschler, Neil H. Shubin, and Farish A. Jenkins, “A Devonian tetrapod-like fish and the evolution of the tetrapod body plan,” Nature Vol 440: 757-763 (April 6, 2006)) Authority Jennifer Clack even admits that before finding Tiktaalik, the large morphological gap between fish and true tetrapods was "frustratingly wide": "It has long been clear that limbed vertebrates (tetrapods) evolved from osteolepiform lobefinned fishes3, but until recently the morphological gap between the two groups remained frustratingly wide. The gap was bounded at the top by primitive Devonian tetrapods such as Ichthyostega and Acanthostega from Greenland, and at the bottom by Panderichthys, a tetrapod-like predatory fish from the latest Middle Devonian of Latvia (Fig. 1)."
(Jennifer A. Clack & Per Erik Ahlberg, "A firm step from water to land," Nature 440:747-749 (April 6, 2006); emphasis added) Again Daeschler et al. reiterate the lack of evidence previous fossils provide for a transition, focusing on deficiencies in what was previously considered to be the closest fish to tetrapods (see the diagram below as well): "Panderichthys possesses relatively few tetrapod synapomorphies, and provides only partial insight into the origin of major features of the skull, limbs and axial skeleton of early tetrapods. In view of the morphological gap between elpistostegalian fish and tetrapods, the phylogenetic framework for the immediate sister group of tetrapods has been incomplete and our understanding of major anatomical transformations at the fish-tetrapod transition has remained limited."
(Edward B. Daeschler, Neil H. Shubin, and Farish A. Jenkins, “A Devonian tetrapod-like fish and the evolution of the tetrapod body plan,” Nature Vol 440: 757-763 (April 6, 2006)) Walk Off The Stage, Acanthostega
The previous darling of the "fish-to-tetrapod" transition-representatives was Acanthostega gunnari--a true tetrapod. Acanthostega has extremely tetrapod-like limbs, feet (with a few extra fingers), and a pelvic girdle. This little guy was a star of the PBS Evolution's episode II: "Great Transformations," where Jenny Clack called it a "fish with fingers" (The only problem is that Acanthostega wasn't a fish--as Daeschler et al. correctly categorize it as a non-fish tetrapod, contrasting "Skull roofs of elpistostegalian fish and the early tetrapod Acanthostega" [Nature 440:759]. Even Clack, quoted above, calls it a "tetrapod" and distinguishes it from fishes, making one wonder what was going on when PBS Evolution showed her calling it a "fish with fingers".) But only now that we have Tiktaalik will we hear evolutionists boast about the size of the previously large "gap" in this transition, and how Tiktaalik solves all these previously unanswered questions. I'm super skeptical that this new fossil is good evidence that a transition took place: Acanthostega was truly a tetrapod, but Tiktaalik is a fish. As Clack and Ahlberg write, there's still a large gap (and any usefulness a fin had for walking was the result of a lucky pre-adaptation): "There remains a large morphological gap between them and digits as seen in, for example, Acanthostega: if the digits evolved from these distal bones, the process must have involved considerable developmental repatterning. The implication is that function changed in advance of morphology." (Clack & Ahlberg, Nature 440:748; emphasis added). I think that Figure 4 from, "The pectoral fin of Tiktaalik roseae and the origin of the tetrapod limb" (by Neil H. Shubin, Edward B. Daeschler, & Farish A. Jenkins Jr, Nature, Vol 440:764-771 (April 6, 2006)) says it all:


(Adapted by permission from Macmillan Publishers Ltd: Neil H. Shubin, Edward B. Daeschler, & Farish A. Jenkins Jr, Nature, Vol 440:764-771 (April 6, 2006); figure resized to fit the page except for the text; click for the full figure)

This figure, which Nature graciously has granted permission to reprint, reveals the massive difference in the ray-finned fish-fin of Tiktaalik and the true tetrapod limbs of Acanthostega and Tulerpeton. Is evidence of a transition missing? This new fish fossil doesn’t seem to add much--if anything--to bridge the gap between fish fins and tetrapod limbs. In fact, if anything, the fin of Panderichthys appears closer to a true tetrapod limb than does the fin of Tiktaalik. I would assume that documenting how fins turned into feet would be one of the more important aspects of the fish-to-tetrapod evolutionary story.

In conclusion, this is a fascinating fossil which I'm sure will stir up much debate. But the next time we dig up some fossil of a fin-bound fish (possibly with a few tetrapod-ish characteristics), we'll hear again all about the previously existing big gaps and how Tiktaalik didn't really teach us much after all--but how the new fossil solves all the problems. That's how it usually works, and that makes me wonder where we're really left today. Anyone who thinks that we've found the "missing link" or clear evidence of an evolutionary transition has either forgotten history, or isn't looking very carefully at the evidence.