About Arctica Expertise I can answer a broad range of questions about the history of life on Earth, from the origins of single-celled organisms to the evolutionary history of plants, invertebrates and, particularly, vertebrates. I am also experienced in debating creationists and can provide rebuttals of many common creationist arguments. I cannot, however, answer questions about archaeology, and I generally cannot answer technical questions about rocks, bone structures or fossils - I am a reader, not a digger.
Experience Many years of research into the history of life on Earth. I have no formal qualifications, but what I lack in technical expertise I make up for in range. I have spent many months debating creationists on the BBC''s science forum, and have consequently thoroughly researched a great deal of creationist and anti-creationist material.
Question Being a creationist, I find your profile very interesting. I do not know much about the view of the supposed evolution of dinosaurs to birds (and I suppose that even there I'm rashly assuming that you hold that view), so I would just like to ask some fair and curious questions. If dinosaurs did evolve into birds, into what kind of birds did all the sauropods such as diplodocus evolve? Or T-Rex? Wouldn't it have made survival easier for the creatures anyway if they had stayed dinosaurs instead of evolving into birds? What kind of global conditions would have arisen that would have cause dinosaurs to have lived out "the survival of the fittest" by turning into birds?
Thank you very much for your time!
LM
Answer Hello there! Thank you very much for your interesting question - I am SO sorry that it has taken me so long to respond. I have been busy lately and haven't checked my email in about a week - not a very good excuse I know. Anyway on to your question.
Evolution does not work the way you seem to think. Any group of related animals has a single common ancestral species. Birds evolved from dinosaurs (and yes I hold that view - the evidence is overwhelming), but ultimately from only one species of dinosaur. By rigorous analysis of the skeletal features of the earliest birds (such as Archaeopteryx) we can pin down pretty closely the group of dinosaurs from which birds evolved. That group was part of the larger group known as theropods (think T-rex, Velociraptor etc. - the two-legged predators). Sauropods did NOT evolve into birds. And neither did most theropods - they either went extinct or gave rise to other theropods which went extinct or gave rise to other species ... and so on and so on, right up until 65 million years ago, at which point there were a) lots of ornithischian dinosaurs, b) lots of sauropods, c) lots of theropods that weren't birds (scientists call these non-avian theropods), and d) lots of theropods that WERE birds (having all been descended from the first bird, which was itself simply a feathered theropod that could fly). A lot of the non-avian theropods had feathers, as some very fine fossils from China have shown recently. It is possible that T-rex had feathers too.
Then came that great extinction event, which killed all of the ornithischians, all of the sauropods, all of the non-avian theropods, and MOST of the birds. It may have been pure luck that the only dinosaurs to make it through happened to have been birds, but I think it more likely that the flying habit of birds saved them. Perhaps the survivors were seabirds, which were still able to catch fish while the land-bound dinosaurs starved in the terrible conditions that followed the meteorite impact (or volcanic activity, or both, depending on which extinction hypothesis you subscribe to).
Feathers evolved for some purpose other than flight - possibly for insulation. Flight was a beneficial side-effect, and selective pressure for more efficient flight then steered feather evolution in a more flight-oriented direction. The earliest birds were not great fliers by modern standards - they lacked the keeled sternum which provides anchorage for the flight muscles in today's birds, they had long bony tails (like other theropods) and instead of beaks they had bony jaws with teeth (also like other theropods). In fact one skeleton of Archaeopteryx was mis-labeled for years as a non-avian theropod called Compsognathus for many years - the two animals were THAT similar (skeletally).
Evolution has no forward-thinking purpose, no 'goal', no conscious direction - it is not 'aware'. It is simply the process by which species adapt to suit their current conditions. If their conditions change over time, species will slowly change until they are different enough from their ancestors that we can say that they have evolved into new species. The change from dinosaurs to birds may seem huge now, but it was made up of lots of very small changes that took tens of millions of years to occur. During that time, each animal in that chain of descent was very nicely suited to its habitat - it would have to have been, otherwise it would have gone extinct.
So dinosaurs had absolutely no choice in whether they 'stayed' dinosaurs. By current scientific definitions, birds are in fact still dinosaurs, and will forever remain so no matter how different they become. Just as we remain primates and mammals.
I hope I have answered your question to your satisfaction, but I am more than happy to elaborate on anything you're still unclear about. Thanks again for your question!
