No, they aren't. Are you a zoologist?
are you?
Larry, I suspect this is a waste of time because you've shown in this thread not only a real ignorance of biology and science in general, but a refusal to really read any of the posts that attempt to unscramble your muddled questions and give you straightforward answers, but anyway -Dinosaurs looked very dissimilar to modern reptiles. Dinosaurs shared some diagnostic features of the bones in the skull that tells us that they were almost certainly reptiles (at least, no other modern or fossil group shares them except for other reptiles). Outside of that, though, dinosaurs were their own deal. The shape of their pelvic girdle tells us that they were all descended from a bipedal ancestor, and many of them retained this posture throughout their evolutionary history. However, anatomist would ever, ever, ever confuse a dinosaur skeleton with the skeleton of other types of reptiles, such as lepidosaurs (modern and fossil lizards and snakes), anapsids (modern and fossil turtles), or other archasaurs (which include dinosaurs, modern and fossil birds, and modern and fossil crocodilians). The skeletal features are completely different, although there are enough common features (as well as egg-laying) that lead us to put all these things in the same larger grouping of "reptiles". In other words, a dinosaur doesn't have a lot in common with a turtle or a lizard, but it has more in common with them than it does with a mammal or amphibian. Birds - Birds appeared on the scene long before dinosaurs went extinct 65 million years ago. We have fossil birds dating back 90 million years. There are several transitional forms that show a melange of dinosaur and bird features, which, along with several key similarities in morphology, make scientists fairly confident that the two groups are closely related and that birds descended from a group of small bipedal dinosaurs called theropods (although not always small! T Rex awas a theropod). While this confidence dates back to the late 19th century, two discoveries really drove home the lesson. The first was the discovery of Archeopteryx. Archeopteryx was a bird, since it had feathers and at the time of discovery anything with feathers was automatically called a bird. But Archeopteryx shared a number of features with dinosaurs that no modern bird possesses, included a dinosaur-like hip bone and a long bony tail. It also had teeth. The rock strata that Archeopteryx was found in dates back more than 80 million years, and if you don't like the dates, then at the very least they were a lot older than the most recent dinosaur-bearing rocks.More recently (in the last 20 years) paleontologists have found a host of fossils linking dinosaurs to birds that pretty much removes all doubt. First, several small dinosaurs have been discovered that actually had feathers! The shape in the rocks was charachteristic of a primitive unbranched feather, and in one case enough of the original feather material was left intact to chemically test it - and sure enough, it was a type of keratin (a class of protein also found in scales, hair, fingernails, claws, and other structures built by skin cells) that is unique to feathers. These dinosaurs were small, lightly built, and were skeletally similar enough that many paleontologists today refer to birds as "non-dinosaur theropods".The question of why dinosaurs went extinct but not birds and mammals is a good one. The likely answer is that a lot of birds and mammals did go extinct along with the dinosaurs, and that the birds and mammals you see around you today are the result of the subsequent proliferation of the relatively few survivors. It might have been some built in characteristic like a high metabolism and small size that helped get a few mammals and birds over the hump but left the dinos behind. Or it might have been plain dumb luck, as is often the case in natural history. We really don't know, but these are good questions to ask. The funny thing is, you could have answered all those questions yourself by reading a high school or freshman college biology textbook. Or by googling "dinosaur" and "bird". It's not secret information.
