The first article, Dinosaur family tree gives fresh insight into rapid rise of birds, provides a overall review of how the diversity of dinosaur species allowed for rapid morphological adaptations and also discusses the relatively quick evolution of flight. They authors focus on related changes in bone shape and structure and other traits seen in modern birds which first appeared in their dinosaur forbearers.
The study mentions that the familiar anatomical features of birds – such as feathers, wings, hollowed long bones and wishbones – “all first evolving piecemeal” in their dinosaur ancestors over tens of millions of years. The article postulates that once a fully functioning bird body shape evolved, “an evolutionary explosion began”, causing a rapid increase in the rate at which birds adapted around the globe.
“Based on (their) findings from fossil records, researchers say the emergence of birds some 150 million years ago was a gradual process, as some dinosaurs became more bird-like over time. This makes it very difficult to draw a dividing line on the family tree between dinosaurs and birds.”
The second of the two articles, How dinosaur arms turned into bird wings, describes in excellent detail how adaptations of wrist bones would allow select ancient species of dinosaur to adapt to flight. The morphological changes appear in dinosaurs, had become recessive and then at some point reappear in birds, leading to flight. Here is the explanation given by the scientists who authored the article:
“…new data obtained by the Vargas lab has revealed the first developmental evidence that the bird semilunate was formed by the fusion of the two dinosaur bones. They go on to show that another bone -- the pisiform -- was lost in bird-like dinosaurs, but then re-acquired in the early evolution of birds, probably as an adaptation for flight, where it allows transmission of force on the downstroke while restricting flexibility on the upstroke. Combined, the fossil and developmental data provide a compelling scenario for a rare case of evolutionary reversal.”
I have always had a great respect for our feathered friends. Even watching common pigeons will stop me in my tracks as I begin watch their behavior and think about their ancient lineage. I do tend to daydream back 65 million years before mammals would radiate and speciate around the globe and onto every continent.
In each case these two articles should be respected for offering evidenced-based details which creationists will have a harder and more difficult time refuting. Evolution, whether it is dinosaur-bird; or fish; or plant; or viruses and bacterial; or mammalian and primate, is real and true.
As the evidence continues to expand and mount on all fronts, be it fossil or genetic in nature, after almost 160 years sine the publication of the Origin of Species, science has more than enough data to prove Darwin’s theory…no…make that Law of Evolution is correct.