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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

5 Bizarre Dinosaurs You Didn't Know Existed Admit it, everything you know about dinosaurs you learned from watching Jurassic Park. Or, possibly, you learned it while paying attention in school. That's never really been our scene, but to each their own. But no matter what route you took, there's a good chance your education was less than adequate. #5. Homestead.com Look, we're all adults here. Oh, you thought we were going to mention the shiny red shaft and matching set of testicles that's taken up permanent residence on this absurd dinosaur's stupid head? To be fair, the dinosaur in this picture is actually a toy. See? #4. Dinossaurosecia You know how people like to make fun of the T. rex because it has those stupid little arms that would be completely useless in a fistfight? What the hell are those things? #3. Critters.Pixel-Shack Similar to Edward Dildohands above, the Ouranosaurus seems perfectly designed or evolved for a life of suffering. No, seriously, we're asking. #2. Wikipedia #1. Dinopedia

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.

Velociraptor - Predatory Behavior Smaller than other dromaeosaurids like Deinonychus and Achillobator, Velociraptor nevertheless shared many of the same anatomical features. It was a bipedal, feathered carnivore with a long tail and an enlarged sickle-shaped claw on each hindfoot, which is thought to have been used to tackle prey. Velociraptor can be distinguished from other dromaeosaurids by its long and low skull, with an upturned snout. Description V. mongoliensis compared in size to a human Velociraptor was a mid-sized dromaeosaurid, with adults measuring up to 2.07 m (6.8 ft) long, 0.5 m (1.6 ft) high at the hip, and weighing up to 15 kg (33 lb).[4] The skull, which grew up to 25 cm (9.8 in) long, was uniquely up-curved, concave on the upper surface and convex on the lower. Skeletal restoration As in other dromaeosaurs, Velociraptor tails had long bony projections (prezygapophyses) on the upper surfaces of the vertebrae, as well as ossified tendons underneath. Feathers History of discovery Provenance Paleoecology

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.

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