...dinosaurs, that is. CTV is reporting the discovering of collagen (a protein chemical substance that is the main support of skin, tendon, bone, cartilage and connective tissue) from a female T-Rex specimen found in Montana. While not DNA, this discovery has allowed scientists to obtain genetic information from the specimen and relate it to living species. Their conclusion:
"We have a protein sequence that we can compare to the protein sequence of other organisms that have had their genome. It looks like chicken may be its closest relative," [John Asara, a Harvard Medical School] told CTV.ca.
Now, what's interesting about this discovery beyond its intrinsic significance to paleontological studies, is how it can illuminate our current debate about global warming. For the bird dinosaur-connection, which this discovery supports, is in fact a matter of scientific consensus, the very concept of which has has come under attack by global warming deniers like Michael Crichton. For example, Crichton has argued that:
There is no such thing as consensus science. If it's consensus, it isn't science. If it's science, it isn't consensus. Period [...]Consensus is the business of politics.
However, that's clearly false in this case. From the wiki article:
There is an almost universal consensus among paleontologists that birds are the descendants of theropod dinosaurs. Using the strict cladistical definition that all descendants of a single common ancestor are related, modern birds are dinosaurs and dinosaurs are, therefore, not extinct.
Now, consensus means that:
A consensus implies that debate has taken place, the solution is generally accepted rather than a grudging compromise, and that agreement is deep-rooted enough that it can stand for some time without need to revisit the issue.
However, a consensus does not imply unanimity. For example, meet Alan Feduccia. We might call him a dinosaur-bird connection denier, believing in:
...of a basal archosaurian origin for Aves, that is a common descent of birds and theropods as opposed to a direct descent from advanced theropods, the currently popular theory.
Now the important points to note are:
1) Feduccia is a real scientist. No matter what his views on bird origins, he has done solid work in many other areas. He is kind of analogous to Richard Lindzen in the global warming debate.
2) He is one of a dwindling band. Most of his fellow travellers, who argued, for example, that Longisquama might have been the avian ancestor, seem to have jumped ship and embraced some version of the consensus. Larry Martin, for example, seems to have recently seen the light in this regard (although his position is nuanced and I may be mistaken).
3) He has become marginalized. If you were to work back through the archives of the Dinosaur Mailing List, and follow the popular press as they covered the "bird-dinosaur connection" controversy over lets say the past fifteen years, you would see that, while newspapers once gave Feduccia et al equal space in the debate, he is now represented, if at all, by a few lines towards the end of the article. In fact, the CTV piece that triggered this post mentions him not at all. This process has been gradual, as the evidence for the connection has accumulated. However, a tipping point probably came in the late 1990s when the first of the unambiguously feathered dinosaurs was pulled from the Yixian Formation in China.
This should all remind you of something: specifically, the course of the Global Warming debate. Because, I would argue that the history of the Global warming debate is pretty typical of the history of scientific debates in general. A new theory is proposed (the bird-dinosaur connection, anthropogenic global warming), and scientists take up sides. Sometimes the issue takes a long time to settle, and sometimes it never does, but often evidence dictates that one of the factions in it "win" and the others "lose". This "losing" does not take the form of being logically refuted (as idealistic, Popperian visions of Science would have it), and the "losers" do not necessarily stop being scientists after the consensus has gone against them. But, typically, when the dissenters finally die off they leave fewer and fewer intellectual descendants. This is what has occured in the bird-dinosaur connection debate, but because, lets face it, the interests of vast oil companies were not involved, it happened mostly beyond the gaze of the public. In the case of Global Warming, Exxon (for example) is essentially propping up the losing side to protect its market share, and so impeding the natural course of Science.
Don't Feed The Dinosaur!