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Theropod Dinosaur evolution into Birds

Theropod Dinosaur evolution into Birds
Related:  EvolutionBird Evolution

The 6 Weirdest Ways Wild Animals Are Having to Adapt to Us Humanity's track record with animals has never been stellar. After centuries of ocean dumping, worldwide deforestation, domestication and overhunting, it's safe to say we've got a greasy, opposable thumb in every one of Mother Nature's pies. That's not to say that humanity's only effect on the animal kingdom is pure destruction; in fact, sometimes our ecological footprint looks more like a clown shoe. #6. Probably the only thing you know about parrots and cockatoos is that they can talk. After all, the pets that are raised among humans and learn (or learn to imitate) dozens of words sometimes either escape or are released into the wild. That's why people around Sydney, Melbourne and other big cities in Australia have found wild cockatoos using English phrases. Now imagine how crazy you'd think you were going if one day you were walking through the woods and you suddenly heard a disembodied bird voice tell you to eat a dick. Photos.com"Y'all bitches ain't shit AWWWK! #5. Photos.comProzac.

Cretaceous Birds Survived Mass Extinction By Eating Seeds Variations in teeth shape – what’s called dental disparity – is a proxy for ecological stability. Decreases in variation would indicate ecosystem decline, but if differences between teeth were maintained over time, that would suggest a rich, stable ecosystem. To understand what bird-like dinosaurs were up to at the end-Cretaceous boundary, a team led by Derek Larson from the University of Toronto analyzed 3,104 maniraptoran teeth unearthed throughout western North America. These fossils represent four maniraptoran groups spanning 18 million years of the Cretaceous. Representative teeth from the four groups of bird-like dinosaurs, with enlarged images of tooth serrations. Tooth shape disparity showed no major decline leading up to the mass extinction event within any of the groups studied, but this prolonged period of ecological stability was followed by the sudden extinction of many bird-like dinosaurs. Photo Gallery

Cetacean Palaeobiology The archaeocetes are a paraphyletic group of primitive cetaceans that include the earliest, terrestrial 'whales'. The group consists of six families: Pakicetidae, Ambulocetidae, Remingtonocetidae, Protocetidae, Basilosauridae and Dorudontidae, although some scientists include the latter two in one single family Basilosauridae. The graph below shows, how these families are related to each other. Cetacean Evolution In order to understand the biology of the archaeocetes, it is important to first consider what sort of terrestrial animals cetaceans originally evolved from. The relations of early whales (archaeocetes) to artiodactyls and the two extant groups, odontoceti and mysticeti. But in 1994, Dan Graur and Desmond Higgins, two scientists working on cetacean gene sequences dropped a bombshell. Astragali of the Eocene protocetids Rodhocetus balochistanensis (left) and Artiocetus clavis (right), as compared to that of the pronghorn Antilocapra americana (centre). Protocetidae (Stromer 1908)

When Did Dino's Sprout Wings? Dinosaurs still walk—and fly—among us: We call them birds. Most paleontologists think birds descended from a group of winged dinosaurs, and thus dinos never went completely extinct. But where did the wings come from? New discoveries from Canada suggest that both wings and feathers arose earlier in dinosaur evolution than previously thought, possibly to attract members of the opposite sex or to protect hatching baby dinos. Although many details of the origins of birds and winged flight are fiercely debated, researchers generally agree that birds belong to a group of dinosaurs called maniraptorans, some of which had feathers and wings and could probably fly.Microraptor, discovered in China, is a leading example of such a dino flyer. But the restriction of these discoveries to such a limited geographical area has left a gap in the fossil record, leaving paleontologists to wonder whether wings and feathers might have evolved in dinosaur groups older than the maniraptorans.

CRACKED: 7 Animals That Are Evolving Right Before Our Eyes People who doubt evolution tend to have one main argument: "If evolution is true, why do we still see monkeys running around today, all chimp-like? Where are all the monkey-men I was promised?" Well, if you or someone you know refuses to believe that organisms change over time without proof on a monkey-man level, here are a buttload of animals in the middle of getting their evolve on. Elephants are Evolving to Lose Their Tusks (and Avoid Poachers) Here's a joke: What did the elephant say to the poacher? Getty"Stop! Sorry about that. GettyAnd ever since animal rights got involved, unemployment has shot up 300 percent. So elephants have decided to take matters into their own hands ... or trunks or weirdly rounded three-toed feet or whatever. By 2005, it was estimated that the tuskless population had risen to between 5 and 10 percent. GettyJust like your debilitating lisp after reading that out loud Which is incredible, because it's not like tusks are the elephant version of wisdom teeth.

How Dinosaurs Shrank and Became Birds From Quanta Magazine (find original story here). Modern birds descended from a group of two-legged dinosaurs known as theropods, whose members include the towering Tyrannosaurus rex and the smaller velociraptors. The theropods most closely related to avians generally weighed between 100 and 500 pounds — giants compared to most modern birds — and they had large snouts, big teeth, and not much between the ears. For decades, paleontologists’ only fossil link between birds and dinosaurs was archaeopteryx, a hybrid creature with feathered wings but with the teeth and long bony tail of a dinosaur. To explain this miraculous metamorphosis, scientists evoked a theory often referred to as “hopeful monsters.” But it has become increasingly clear that the story of how dinosaurs begat birds is much more subtle. A Phantom Leap In the 1990s, an influx of new dinosaur fossils from China revealed a feathery surprise. Yet once those avian features were in place, birds took off.

10 Animals You Won't Believe Are Closely Related Thanks to the know-it-all from second grade, we're all aware that dolphins and whales are mammals, not fish. But it's probably been a while since you've pondered just how incredibly, mind-blowingly weird it is that you and whales were the same animal more recently than whales and sharks. Or to put it in chart form, you and whales split up somewhere in the big tangle of bio diversity up top labeled "Age of Mammals" while whales and fish haven't been the same animals since way the hell down ... ... here where you see the word Selacchi. Courtesy of Getty Images." Turns out it's the same reason birds and bats both ended up flying around on wings: convergent evolution, the smarmy term for when completely unrelated species develop similar traits. Image By Glen Fergus What it looks like: You don't need your wife standing next to you screaming, "MOUSE! What it actually is: A tiny little mutant koala Image By Quartl Image By Cody PopeThe worst part? Image By Jagvar Via Wikipedia

"Dawn" bird oldest found bird A prehistoric beast the size of a pheasant has become a contender for the title of oldest bird to stalk the Earth. The small, feathered "Dawn" bird lived around 160m years ago, about 10m years before Archaeopteryx, which holds the official title of the earliest bird known to science. The new species, which scientists have named Aurornis xui, had claws and a long tail, with front and hind legs similar to those of Archaeopteryx, but some features of its bones were more primitive. It measured 50cm from its beak to the tip of its tail. Encased in sedimentary rock, the fossil preserved traces of downy feathers along the animal's tail, neck and chest, but the absence of larger feathers suggests it was not able to fly. When scientists reconstructed the evolutionary tree of similar beasts using measurements from their skeletons, A xui appeared on the bird lineage, but closer to the base of the tree than Archaeopteryx. Archaeopteryx holds a prized position in evolutionary history.

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