Nature, the scientific journal, is reporting a new discovery in the evolution of birds from dinosaurs. It seemed worth commenting on what evidence we have for that series.
Unfortunately, this is just evolution news, not a full report on the evidence for the evolution of birds from dinosaurs. That full report will have to wait until I have time to make such a page.
A New Scientist article does an excellent job of explaining the significance of the Nature article, but you do have to get a free membership to read it. So here's my explanation.
Scientists began to suspect a real link between a branch of dinosaurs called theropods and and the evolution of birds when they saw the striking similarities between some theropods and the incredible intermediary between dinosaurs and birds, archaeopteryx. It wasn't until the 1990's, however, that we discovered there is another remarkable similarity: feathers.
Those feathered dinosaurs were discovered in China where, despite the famous mistake in which National Geographic jumped the gun and reported a fabricated feathered dinosaur, many real feathered dinosaurs have been found. Now another has been found, named Anchiornis, which is earlier than any of the others.
This is important because there was a timing issue. Yes, feathered dinosaurs had been discovered, but they were more recent than archaeopteryx. Having a lineage that includes archaeopteryx with no feathers, which is already part bird, followed by full-fledged dinosaurs with feathers is not very satisfying.
The "extensive feathering" of Anchiornis, a theropod, provides one more piece of evidence for the evolution of birds from dinosaurs. Further, it enhances our wonder, for every time we look at birds, we are almost certainly looking at dinosaurs!
How confident can we be of the evolution of birds from dinosaurs? Well, as the evidence mounts higher and higher, we can have great confidence in the fact that all life, as we know it, evolved from a common ancestor.
Some of the specifics, however, are harder to pin down.
Thank God that with the discovery of Anchiornis, we know a little bit more, but I have to point out the overconfidence in the New Scientist article.
The writer of the article starts the article with a first paragraph in italics that says:
Really? Beyond reasonable doubt?
The very last sentence of the article reads:
Hmm. Those few must be the unreasonable scientists, since he says that we can say beyond "reasonable" doubt that birds are dinosaurs.
It's good to stay humble. Science in general can be pretty good at that. Individually, we all have difficulty with it.