Evolution: Education and Outreach is usually a disappointment. The journal could do with more philosophically savvy writers and more critical reviewers. The various contributions provide very little evidence that they understand Kuhn’s thesis about the way science develops. Most of the authors are working in a silo and fail to understand anyone who operates outside their tightly defined paradigm. A notable exception was Daniel R. Brooks (2011) who wrote on “The Extended Synthesis: Something Old, Something New” (blogged here). Another is the theme of this blog: a review of Alan Feduccia’s “Riddle of the Feathered Dragons” by Egbert Giles Leigh Jr. What caught my eye was the acknowledgement that Feduccia provides a “powerful criticism of prevailing views of bird evolution”. Leigh explains that he is relatively new to this theme, and he appears shocked to find out what an intense battlefield he was entering.
“I was blissfully unaware of the raging dispute over just what group of reptiles gave rise to birds. The introduction, which opens with bitter comments on uncritical media hype about dinosaur ‘discoveries’, and the first chapter, subtitled ‘Blame to Go Around’, cured me rather brutally of that ignorance.” (p.1)
Leigh summarises the arguments of John Ostrom, who championed the thesis that birds evolved from theropod dinosaurs. He knew that dinosaurs like Deinonychus had many similarities with Archaeopteryx, and he promoted the idea that flight evolved ground up. The ancestors of birds were considered to be runners, flapping their forelimbs to catch insects, thereby evolving the functionality for flapping flight. Leigh reports Feduccia’s objections to Ostrom, obviously impressed by his arguments, and noting that “More recently, the tide of evidence has turned strongly against Ostrom’s case.” Part of this evidence relates to protofeathers, and Leigh is positive about the case for them being collagen fibres. (For further on this, go here and here.)
“The discovery that the ‘protofeathers’ of the bipedal, cursorial theropod Sinosauropteryx were collagen fibers representing various stages of skin decay (Lingham-Soliar et al. 2007) undermined the argument that feathers evolved for purposes other than flight. If Anchiornis and Archaeopteryx were ancestral birds, it would appear that that feathers, which Feduccia shows to be complex, intricate structures well adapted for flight, evolved for that purpose. Feathered wings did not first evolve to be clapped together to catch insects, as Ostrom (1974, 1979) had proposed.” (p.2)
The reason why this is important relates to the major point being made by Leigh: “The argument between Feduccia and Ostrom was later engulfed by a methodological one.” This methodological issue concerns cladism. Rarely does one read words like this:
“This method seemed to lend an objective rigor to inferring phylogenies from phenotypic data. Many practitioners of this method proclaim that birds derive from theropod dinosaurs.” (p.2)
What follows is one of the best concise critiques of cladism that I have read. It deserves to be quoted in full, but this seems unwise – especially as the review is Open Access. The issue of protofeathers is located at the beginning of the critique. If they are interpreted as primitive feathers, they constrain the cladistic analysis towards the theropod-bird evolutionary pathway. If however they represent collagen fibres released during skin decay, the outcome is quite different. Leigh sees this as an example of scientists craving for an objectivity that brings authority, latching on to a method that seems to offer this, and losing sight of other data that disturbs their conclusions.
“More generally, the search for the one objective scientific method, where subjective judgments play no role, is a recipe for ignoring what is crucial. So it was for the psychologists who saw stimulus-response analyses as the way to make animal behavior an objective science by avoiding the subjective world of consciousness. As Changeux (1985, p. 97) remarked, ‘Concerned with eliminating subjectivity from scientific observation, behaviorism restricted itself to considering the relationship between variations in the environment (the stimulus) and the motor response that was provoked’. This approach does not let us see that animals have intentions and project their hypotheses onto the external world (Changeux and Ricoeur 2000, p. 42). Is this also true of those cladists who see a particular algorithm for inferring phylogenies from phenotypic data as the one way to practice objective taxonomy? Such methods demand that their practitioners ignore those kinds of data that their methods cannot handle. Indeed, as in the case of scientific Marxism, supposed recipes for objectivity can become dogmas defended with religious zeal (Polanyi 1962, pp. 227-228). Feduccia (p. 2) cites instances of this process among some cladists. This process can discourage interesting science, as did the Roman inquisition of the 17th century (Changeux and Ricoeur 2000, p. 35). Feyerabend’s (1975) Against Method is a salutary warning against seeking one scientific method, apt for solving all problems.” (p.3)
In his concluding words, Leigh points to the BAD advocates (Birds Are Dinosaurs) as “intellectual prisoners of their cladistic methodology”. Although he represents the minority BAND (Birds Are Not Dinosaurs), and although the controversy is draining, Feduccia is presented as the champion of authentic science.
“[H]is book is eloquent testimony to the role of connoisseurship in effective science. For all its bitterness, Feduccia’s is a liberating voice, a reminder that methodology should be our servant, not our unquestioned master.” (p.3)
It’s a great review and it deserves to be widely read. This is not just a controversy over dino-fuzz – it has the potential to stimulate thinking about the way science is practised.
Alan Feduccia’s Riddle of the Feathered Dragons: what reptiles gave rise to birds?
Egbert Giles Leigh Jr
Evolution: Education and Outreach, March 2014, 7:9, (3 pages)
This book’s author is at home in the paleontology, anatomy, physiology, and behavior of birds. Who could be more qualified to write on their origin and evolution? This book is unusually, indeed wonderfully, well and clearly illustrated: its producers cannot be praised too highly. It is well worth the while of anyone interested in bird evolution to read it. [snip]