Much Ado about Ida: The Missing Link that Wasn’t

Posted: November 1, 2009 in Science
Tags: , , , , , , , , , ,

Do you remember the introduction to the world of “Ida” this past May? The media frenzy and hype around this small, 47 million-year-old primate went far beyond the usual, even when it comes to the intriguing & controversial issue of human evolution. In addition to publication of the scientific paper itself in PLoS ONE, within a week’s time there was the public “unveiling” at the American Museum of Natural History by NYC Mayor Bloomberg, coverage by People magazine, debut of an official Ida web-site, a book (The Link: Uncovering Our Earliest Ancestor), and a TV special narrated by Sir David Attenborough.

Here’s what the fuss was about….

Many primatologists & paleoanthropologists postulate that, roughly 50-60 million years ago, the original Primate gave “birth” to two Suborders — the Haplorhini (or, “Dry Noses”) and the Strepsirrhini (or, “Wet Noses”). (There’s at least one alternative “school” that breaks them out a little differently, but we’ll stick with this one, for now.) The haplorhines, in turn, gave rise to various branches that produced tarsiers, monkeys, apes, hominids, and eventually modern Man. Meanwhile, the strepsirrhines didn’t change much, leading to today’s lemurs, lorises, & bush babies.

What got people excited was the fact that, while she does have many lemur-like qualities, Ida does not have certain other physical characteristics that would normally place her among the strepsirrhines. Therefore, they concluded, she must be a primitive haplorhine — perhaps even the first! This would make her an evolutionary ancestor to humans, or, at least, a distant cousin.

So, the 95%-complete skeleton became the latest find touted to be a “missing link” in the evolutionary development of Man and “clear proof of Darwin’s theory of evolution”. As Attenborough put it, Ida is “a link between the apes, monkeys and us with the rest of the mammals and ultimately the whole animal kingdom. I think Darwin would have been thrilled.” Lead researcher Jorn Hurum (who named the fossil after his daughter) said, “This fossil rewrites our understanding of the evolution of primates.” At least one paper even called her the “eighth wonder of the world.”

Ida

Ida fossil & her x-ray

But, other experts were either surprisingly mum or expressed concern over the hyperbole. Professor John Fleagle of Stony Brook University in New York challenged the claims, cautioning that the paper’s full significance would not be known until other scientists had a chance to properly examine the findings and engage in extensive debate.

The August 2009 issue of the august (pun intended) journal Science featured a review of the Ida book called “Much Hype and Many Errors” by paleoanthropologist Richard F. Kay of Duke University. Noting the sensationalistic writing style in several chapters, Kay laments, “Ida is a reprise of the seamier side of paleontology: the exploitation, with the complicity of major museums, of our natural heritage for profit.” He goes on to point out many inaccuracies and misleading statements, hinting the many errors were largely the result of a fame-seeking carelessness in rushing the book to press in time for the media blitz. Kay then questions the paleontological classification of the fossil by Philip Gingerich, University of Michigan – Ann Arbor, concluding “So [Ida] cannot be both an adapoid and a monkey ancestor. [. . .] So, Link‘s premise, that Ida is our ancestor, is fallacious. Ida is a lemur.”

And so the controversy went….

Now, it seems, the final nail may have been put in the coffin of the Ida-as-missing-link theory. Stony Brook University’s Erik Seiffert recently led a team of primatologists and paleoanthropologists that analyzed and compared 360 specific anatomical features of 117 primate species (living & extinct), including another recent (though less complete) specimen, Afradapis longicristatus, from Egypt. The goal of the study was to construct a decisive “family tree” for the Primate Order. Actually, most of the work was done a few months ago, but they put off publication until they had a chance to examine & compare Ida, too. The just-out issue of the journal Nature contains their findings.

As reported by the Associated Press, “The scientists who formally announced the finding said they weren’t claiming [Ida] was a direct ancestor of monkeys, apes and humans. But they did argue that it belongs in the same major evolutionary grouping, and that it showed what an actual ancestor of that era might have looked like. The new analysis says [Ida] does not belong in the same primate category as monkeys, apes and humans. Instead, the analysis concluded, it falls into the other major grouping, which includes lemurs.” (Sound familiar?)

More precisely, while all agree that Ida represents a new genus & species of early primate (Darwinius massillae), it now seems that she does indeed belong in the haplorhine lineage, though as part of a small side-branch that quickly went extinct. Of course, this means she cannot be a “missing link” to humans. Another very important point is that those characteristics Ida shares with the higher primates must have appeared separately from the anthropoids. This is yet another case of “convergent evolution” — something that appears to have happened quite a bit over the eons but is not supposed to be possible within the neo-Darwinian paradigm. How embarrassing!

Anthropology professor Eric Sargis of Yale is “not surprised” at the results of the Seiffert team’s analysis. The University of Toronto’s paleoanthropologist David Begun says this “confirms what most scientists think.” For his part, Hurum seems unfazed, saying “we are happy to start the scientific discussion” about where Ida & her kin fit in the primate “family tree”.

Why do I bring up all of this controversy over Ida, anyway? Well, it is NOT to cast aspersions upon scientists in general or evolutionists, or to accuse anyone of duplicity. But there are a few lessons to be had from all this, reminders of things we should always keep in mind.

1) Scientists are human, too. (Heh!) OK, what I mean is that, despite the objective nature of the scientific process, the people doing the science still have biases to deal with. It may be a particular philosophy of and approach to science; or, favoring a particular (personal?) model/theory; or, pressure to publish a paper or make sufficient progress to keep their grant; etc. These can lead to hopeful, yet hasty, conclusions, however rational they may seem at the time.

2) A certain amount of “talking up” one’s research is to be expected and is generally accepted within the scientific community. In order to justify funding, obtain desirable positions and other opportunities, etc., one must show progress, publish papers, and get people excited about what they are doing. Sometimes doing this amongst fellow researchers and academics is sufficient; but, sometimes they need a little boost, so they take it to the public via the media. (NASA and others in space exploration do this all the time.) Unfortunately, this can be taken too far, as with the case of Ida. Which leads to our third lesson….

3) As exemplified by Professors Fleagle and Kay’s comments above, the flap within the scientific community centers on two separate-but-related things. First, the lack of detailed documentation to support the initial researchers’ interpretation of the data presented in the paper, book, and documentary. As pointed out by freelance science writer & blogger Brian Switek: “Even though the authors of the paper constructed a very simple cladogram, they did not undertake a full, rigorous cladistic analysis to support their claims. I am baffled as to how they could stress the significance of this fossil without undertaking the requisite research to support their hypothesis.” From what I have read, Hurum’s supporting analysis/documentation is still a work in progress.

The other half of this is, of course, the necessity for peer review. It isn’t perfect, but the peer review process allows for more objective analysis by other scientists. Most welcome this (at least to some degree), because such critiques lead to identification of weaknesses in their theories and interpretations, which then shows them what areas to concentrate on in order to strengthen those theories. Everyone — scientists, media, politicians, and the rest of us — must recognize the need for rigorous research standards, healthy exchange of ideas, and vigorous debate.

(Ironically, though the media blitz was not nearly as great, Charles Darwin bypassed peer review when he published his book On the Origin of Species.)

The second issue is that of the questionable motives — ostensibly, profit and fame — that drove Hurum and others to sensationalize the find and push it out to the general public so quickly. As Kay said, this belies the “seamier side” of science. Some may think such a “purist” opinion is too stiff or behind-the-times or just unrealistic. Regardless, the concern that money & headlines can compromise the accuracy and objectivity of scientific research is a valid one.

4) The whole business of properly classifying the fossil record, especially hominids and humans, is all very complicated and depends on relatively few bones and a lot of inference & conjecture, with no definitive links. (I’ve probably rankled quite a few with that statement, but I’ll address the broader issue of “missing links” some other time.) Indeed, there are many different positions within the scientific community on the details of how the various species are connected. Those who try to figure it out solely through morphology (i.e., the shapes of anatomical structures), such as Seiffert’s team, often conclude one set of connections, while those who look at the genetics come up with a different “family tree”. Remember this the next time you hear or read somebody speaking as if everything is very well-known and fits together all neat & tidy.

Here’s the bottom line….

Ida is indeed a fantastic find — an amazingly preserved, near-complete skeleton of a new genus & species — that is proving to be very interesting. Her existence may even throw (yet another) monkey wrench into the reigning understanding of primate evolution. But, it is becoming clearer & clearer that she is not the much-trumpeted “missing link” that Hurum et al. would like us to think she is. At least, that’s my take on it.

I conclude with a quote from David Tyler of the Access Research Network (ARN.org): “The best outcome of all this is for scientists to demonstrate more humility in handling data. So many seem to grasp at some data and brandish ‘evidence’ as though it provides a definitive answer to controversy. But this is not how data should be handled in research. Data needs to be interpreted and history shows that there is always more than one way of interpreting it. If we can all adopt a ‘multiple working hypotheses’ approach when using the scientific method, it will be progress indeed.”

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Comments
  1. […] you may recall (go here, then come back), there was a lot of hype last year when Ida was revealed to the world with her […]

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