rn to ground our understanding of early birds? 3
These observations necessitate a re-evaluation of widely accepted hypotheses of paravian phylogeny; such an exercise will have significant implications for our understanding of avialan origins and related issues such as the origin of flight. 4
The primary source is an article about the discovery of a fossil called Xiaotingia. Most of the article deals with a description of the fossil, including the number of teeth, the size and shape of its forelimbs, and various other skeletal elements. Based on all these measurements of Xiaotingia, they conclude that Archaeopteryx wasn’t a bird at all. Here is perhaps the most important paragraph summarizing the analysis.
When Xu et al. ran a phylogenetic analysis combining the attributes of Xiaotingia with those of Archaeopteryx, other basal avialans, deinonychosaurs, and oviraptorosaurs, not only did Xiaotingia and Anchiornis cluster with Archaeopteryx, but these archaeopterygids now were yanked out of Avialae and placed in Deinonychosauria. In other words, Archaeopteryx was no longer a bird. Surprised by this outcome, the authors re-ran the analysis with identical parameters, but this time omitting Xiaotingia. The result was that Archaeopteryx was restored to Avialae as the most basal bird. This experiment affirmed how crucial Xiaotingia is to understanding the evolution of advanced theropods. 5
Here’s what that means. They wrote a computer program that compares selected physical characteristics to decide how closely related various species are and assigns them to various groups. The comparisons that the computer makes are all based on what the programmer tells it to compare, and how heavily to weight each feature. The validity of the conclusion depends entirely upon the subjective decisions made by the programmer.
When they ran the program without including data about Xiaotingia, the computer program said that Archaeopteryx was a bird. When they added Xiaotingia, the computer changed its mind and said that Archaeopteryx wasn’t a bird.
Suppose someone wrote a program to determine how beautiful a woman is based on physical features of many women. The program tells you that a Julia Roberts is a pretty woman. But then, you add data about Marilyn Monroe, and it says that Julia Roberts is no longer pretty.
It isn’t the computer that decides if the woman is pretty or not—it’s the algorithm chosen by the programmer that determines the outcome. The fact that adding data about one individual changes the classification of another individual makes the algorithm questionable. Julia Roberts may not be as pretty (in someone’s opinion) as Marilyn Monroe was; but that does not make Julia Roberts ugly.
Witmer said, “This experiment affirmed how crucial Xiaotingia is to understanding the evolution of advanced theropods.” We would say, “This experiment affirmed how subjective the thinking about evolution is.”
Regardless of how similar Xiaotingia and Archaeopteryx are to modern birds or extinct dinosaurs, it doesn’t prove anything evolved from anything else. They could just as easily been created with similar characteristics.
Evolution isn’t science. It’s opinion. It’s speculation. It’s prejudice. This is evident from Witmer’s conclusion:
In truth, this chapter of the scientific story is just beginning. Just as Xiaotingia moved Archaeopteryx out of the birds, the next find could move it back in — or to somewhere else within this fuzzy tangled knot that makes up the origins of birds and bird-like dinosaurs. That said, during this sesquicentennial anniversary of Archaeopteryx, which is being honoured with exhibits and commemorative coins, the bitter irony may be that it may not have been the bird we've always thought it was. But Archaeopteryx will remain an icon of evolution, perhaps even more so now, providing compelling evidence that, as we should expect, evolutionary origins are rather messy affairs. 6
They are messy because they are wrong!
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New Scientist, 30 July 2011, “It’s been f