Are birds technically dinosaurs?

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Mar 19, 2020
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If all life perishes, there would be nothing on the planet. In the case of the dinosaurs, it is likely that a few very lucky dinos survived the meteorite, and over time evolved into birds. The meteorite did not kill all living beings, otherwise the earth would most likely be a barren wasteland. Therefore, the birds of today all trace lineage to those very lucky dinos millions of years ago, making them an extension of the dinosaur family tree.
Birds lived alongside Cretaceous dinosaurs. Birds as a seprate group diverged in the very late Jurrassic. The way evolutionary descent works means that we are Reptiliomorpha, because our ancestors decended from permian therapsids like the ugly Gorgonapsid. So yes, they are an extension of the dinosaurs.
 
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Mar 19, 2020
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If dinosaurs were annilated, then birds ARE a separate species. Dino s are not relatives. That is absurd.
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Small, feathered therapods eventually diverged into birds and the groups we think of when we think 'velociraptor'. Are your grandparents still your ancestors even if they and your Aunt are dead?
 
Mar 19, 2020
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Birds are descended from dinosaurs, but it depends on whether you think that they have evolved away from dinosaurs enough to consider them different or not. Some taxonomists, called cladists, group animals by whether they all come from one common ancestor. Therefore,they would make reptiles and birds into one group.
Not all reptiles came from dinosaurs, but all birds came from dinosaurs. If you are wondering why modern lizards do not have the same stature dinosaurs do, is because the Crocodylomorpha surrvived the extinction. But you are right that modern taxonomy is not as based on physical characteristics as it is on the phylogeny. The previous groupings are now obsolete and kept around at certain levels hust because we want to.
 
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I live in the country in central North Carolina. We often see wildlife of various sorts in our yard. It never fails when I catch a wild turkey out of the corner of my eye, I am always startled by the fact that a tyrannosaurus rex is standing in my yard.
Well this is obviously sarcasm, but when you think about it, that is how it feels.
 
Oct 7, 2020
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Okay, Let’s start with a question. Dinosaurs are reptile while birds, well, birds. So if birds is evolution from Dinosaurs, why are they not categorized as reptile? So I think to have the answer, we need to understand bird`s position in nature.

In 1998, there were fossils of
two new species of dinosaurs have been discovered, and they have feathers. This is when the debate started! Birds and dinosaurs happen to be shared a close revolutionary heritage.Birds Dinosaurs.png
 
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So far from what I read, birds are technically evolved from a dinosaur but not from the pterosaurs.

This is because all the flying dinosaur like the pteranodon etc. was being mistaken as part of a dinosaur. They are coincidently living in the same era as the dinosaur. That's why.

Birds are eventually evolved from small, feathered, terrestrial dinosaurs.
 
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Gringoz

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Oct 3, 2020
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I am not sure if it is snobbery in favor of modern species, but it seems that the scientific community recognizes birds as having evolved from dinosaurs, but not actually BEING dinosaurs.

As there are a vast array of dinosaur species out there, flapping, swimming, crawling, running, jumping, lumping and otherwise dominating the landscape for many million years. Archeaopteryx were a dinosaur that could be called birds, even though they had teeth.

There are a great many articles about the creatures, which lean one way or another, but leaning toward being merely an "evolutionary link" rather than continuation:
Birds themselves have evolved to incredibly dimorphic forms, from flappy, tubby penguins to gangly flamingos to tiny hummingbirds. There are flightless birds, diving birds, soaring birds, as different from each other as the archeaopteryx is from other dinosaurs, but noone questions they are all birds.

So ARE birds dinosaurs? I'm interested in the opinions of my fellow mammals.
Griff
No birds have no teeth
 
Jan 27, 2020
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Since Jurassic Park aired, dinosaurs like Velociraptor have received something of a makeover. It began in the late 1990s when Chinese palaeontologists found a stunning series of dinosaur fossils with distinct traces of feathers around their bodies. Some were just covered in a downy fluff, while others like Microraptor had fully-formed wings and were probably capable of true flight.

These species were primitive members of the dromaeosaurids, a group of small, agile predators that Velociraptor also belongs to. With feathered ancestors and evolutionary cousins, it was always extremely likely that Velociraptor also had a feathered coat but until now, that was always an educated guess.

The breakthrough came from Alan Turner and Mark Norell from the American Museum of Natural History and Peter Markovicky of the Field Museum of Chicago. They were studying the forearm of a Velociraptor unearthed in 1998, when they noticed six evenly spaced knobs of bone on the back edge.
The team recognised these as quill knobs, small lumps of bone that act as attachment points for feathers. These knobs are direct evidence that Velociraptor carried a row of feathers on its forearm, probably about 14 by Turner’s count (see Fig. 1, below).

quill knobs.jpg

The quill knobs also suggest that Velociraptor‘s feathers had a distinctly modern style. They probably looked much like those of today’s birds, rather than the hair-like fuzzy proto-feathers of its ancestors.

Not all dinosaurs have obvious similarities to birds, but for those that do, the similarities are not only frightening, but suggest that dinosaurs evolved into modern day birds.

Coelurosaurs are the theropod group that includes tyrannosaurs and dromaeosaurs.

The latter group includes such members as Bambiraptor and the Velociraptor, which share a more recent common ancestor with birds. Considering who came first, perhaps we should stop describing dinosaurs as having bird-like behaviour and start thinking of birds as behaving like dinosaurs.

The fossilised skeleton of Mei long, a non-avian coelurosaur from China, was preserved with its head ‘tucked’ under its forelimb. This posture resembles the ‘sleeping’ pose commonly used by modern birds. Such inferred behaviour strengthens the link between non-avian dinosaurs and birds.

Although it is widely accepted that a small group of theropod dinosaurs gave rise to birds, finding feathered dinosaurs in the fossil record that predate the earliest known bird Archaeopteryx* (150 myo) has proven elusive. That was until Anchiornis huxleyi was announced in 2009. This species, found in China, dates to between 161-151 million years old and has well-developed feathers on all four limbs. Quick on its heals was the announcement of another stunning new feathered dinosaur Haplocheirus sollers, also from China and about 160 million years old. Haplocheirus is a type of alvarezsauriod, a group of dinosaurs once thought to be flightless birds, but lacks the bird-like features found in later alvarezsauriods such as fused wrist bones and a backward-facing pubis.

archaeopteryx.jpg
Archaeopteryx

The legs and feet of bipedal dinosaurs closely resemble that of a bird, three toes forward, one toe back. Some fossilized dinosaur tracks resemble exactly, with the exception of size, the tracks of an Emu. Both dinosaurs and birds have legs with ankles that are about midway up the leg, and our equivalent of a knee, is even higher.

Although some dinosaurs walked on all fours, many stood on their two hind legs. With a small stretch of the imagination we can see a connection between any bipedal dinosaur and an ostrich or emu.

Recent evidence has indicated the the bones of some dinosaurs were hollow, much like those of a bird. These lightweight bones would lend themselves not only to flight, but in dinosaurs they were used for breathing purposes too. In order for dinosaurs to grow as big as they did, they needed to process more oxygen, this was done with the help of air sacks in their bones. Birds need to process more oxygen, too, but for the purposes of flying faster, higher, or diving deeper.

Birds and dinosaurs share a unique style of breathing, which is not quite the way humans and other animals breathe. Birds have lungs that do not expand and collapse as ours do. One cannot watch a bird breathe as you can watch a cat or dog, by seeing the chest expand and collapse. Instead birds used a system of air sacks to pump air through the lungs. These same features have been indicated on a newly discovered species of dinosaur called Aerosteon riocoloradensis.

It is debatable if the chicken came first, or the egg, except to say that dinosaurs laid eggs long before chickens were in existance. Many dinosaurs have also been shown to make nests and rear their young. Most birds bring food and feed their young, although not all do. Chickens, for example, do not bring food to their young. It is likely that some dinosaurs fed their young and others did not.

The bone at the front of the chest that attaches to the flight muscles in birds is called a keeled sternum. Some dinosaurs have been shown to have a similar shaped sternum.

Some birds, such as the ostrich, emu, and turacos have primitive claws on their wings, these very much resemble the diminutive claws on the front limbs of some dinosaurs, particularly the meat eaters.

Look at the neck of a bird, preferably a larger bird, you will see from the side that the neck is typically “S” shaped. This is similar to that of a dinosaur. Some birds, like some dinosaurs, have longer necks, making this more pronounced than others.

The orbit is the hole in the skull for the eye socket, in both birds, and dinosaurs these holes are relatively large in proportion to the skull itself.

The shape of a pelvis is very telling, while not true of all dinosaurs, some had pelvises shaped like those of a bird. Those with a bird-liked shaped pelvis were of the order Ornithischia.

Undoubtedly many meat eating dinosaurs did not use their feeble forelegs for killing or fighting. Instead they relied on powerful hind legs. The same attribute of having powerful hind legs belongs to birds like ostriches and emus. Their hind limbs are so powerful that a well placed forward strike can disembowel a human.

We all know about the fancy headgear of some dinosaurs. Interestingly enough some birds sport just as much headgear. One such bird is the Cassowary, a strikingly primitive looking bird.

The Archaeopteryx has been preserved to clearly show it had feathers but more recently other dinosaurs have been found to have similar features too. These being “theropods”. These feathers were not initially for flight and probably served the purpose of keeping the animals warm, allowing them to be more effective hunters, since with added warmth they could hunt during the cool nights, when the newly developing mammals were active.

Certainly there are some dinosaurs which resemble birds more than others. Equally so there are some birds which resemble dinosaurs more than others. The similarities alone do not prove one descended from the other, but they certainly hint at it.

While it’s clear simply from looking at the skulls of dinosaurs and modern birds that the creatures are vastly different — dinosaurs have distinctively long snouts and mouths bristling with teeth, while birds have proportionally larger eyes and brains — it was the realization that skulls of modern birds and juvenile dinosaurs show a surprising degree of similarity.

“No one had told the big story of the evolution of the bird head before,” Bhart-Anjan Bhullar said. “There had been a number of smaller studies that focused on particular points of the anatomy, but no one had looked at the entire picture. What’s interesting is that when you do that, you see the origins of the features that make the bird head special lie deep in the history of the evolution of archosaurs, a group of animals that were the dominant meat-eating animals for millions of years.”

To tackle the problem, the researchers turned to an unusual methodology. Using CT scanners, they scanned dozens of skulls, ranging from modern birds to theropods — the dinosaurs most closely related to birds — to early dinosaur species. By marking various “landmarks” — such as the orbits and cranial cavity — on each scan, researchers were able to track how the skull changed shape over millions of years.

“We examined skulls from the entire lineage that gave rise to modern birds,” Arkhat Abzhanov revealed. “We looked back approximately 250 million years, to the archosaurs, the group which gave rise to crocodiles and alligators as well as modern birds. Our goal was to look at these skulls to see how they changed, and try to understand what actually happened during the evolution of the bird skull.”

What Arkhat Abzhanov, associate professor of organismic and evolutionary biology, and Bhart-Anjan Bhullar, a Ph.D. student in Abzhanov’s laboratory and the first author of the study and colleagues, found evidence that the evolution of birds is the result of a drastic developmental change. It was surprising — while early dinosaurs, even those closely related to modern birds, undergo vast morphological changes as they mature, the skulls of juvenile and adult birds remain remarkably similar.

“This phenomenon, where a change in the developmental timing of a creature produces morphological changes, is called heterochrony, and paedomorphosis is one example of it,” Abzhanov explained. “In the case of birds, we can see that the adults of a species look increasingly like the juveniles of their ancestors.”
In the case of modern birds, he said, the change is the result of a process known as progenesis, which speeds up an animal’s sexual development. Unlike their dinosaurian ancestors, modern birds take dramatically less time — just 12 weeks in some species — to reach maturity, allowing birds to retain the characteristics of their juvenile ancestors into adulthood.

Ultimately, Abzhanov said, the way the bird skull evolved — through changes in the developmental timeline — highlights the diversity of evolutionary strategies that have been used over millions of years.

“That you can have such dramatic success simply by changing the relative timing of events in a creature’s development is remarkable,” Professor Abzhanov said. “We now understand the relationship between birds and dinosaurs that much better, and we can say that, when we look at mature birds, we are actually looking at juvenile dinosaurs.”

See: https://scitechdaily.com/evidence-shows-that-birds-are-essentially-living-dinosaurs/

See: https://australian.museum/learn/dinosaurs/bird-like-dinosaurs/

See: http://www.actforlibraries.org/what-are-the-similarities-between-dinosaurs-and-birds/

Dr. Daniel Field from Cambridge’s Department of Earth Sciences, who led the research. “This is one of the best-preserved fossil bird skulls of any age, from anywhere in the world. We almost had to pinch ourselves when we saw it, knowing that it was from such an important time in Earth’s history.

“The ability to CT scan fossils, like we can at the Cambridge Biotomography Centre, has completely transformed how we study paleontology in the 21st century.”

“Finding the skull blew my mind,” said co-author Juan Benito, also from Cambridge, who was CT scanning the fossils with Field when the skull was discovered. “Without these cutting-edge scans, we never would have known that we were holding the oldest modern bird skull in the world.”

The skull, despite its age, is clearly recognizable as a modern bird. It combines many features common to the group that includes living chickens and ducks — a group called Galloanserae. Field describes the skull as a kind of ‘mash-up’ of a chicken and a duck.

The researchers have given it the slightly more elegant name of Asteriornis, in reference to Asteria, the Greek Titan goddess of falling stars.

“We thought it was an appropriate name for a creature that lived just before the end-Cretaceous asteroid impact,” said co-author Dr. Daniel Ksepka from the Bruce Museum in Greenwich, Connecticut. “In Greek mythology, Asteria transforms herself into a quail, and we believe Asteriornis was close to the common ancestor that today includes quails, as well as chickens and ducks.”

The fact that Asteriornis was found in Europe is another thing which makes it so extraordinary. “The late Cretaceous fossil record of birds from Europe is extremely sparse,” said co-author Dr. John Jagt from the Natuurhistorische Museum Maastricht in the Netherlands. “The discovery of Asteriornis provides some of the first evidence that Europe was a key area in the early evolutionary history of modern birds.”

“This fossil tells us that early on, at least some modern birds were fairly small-bodied, ground-dwelling birds that lived near the seashore,” said Field. “Asteriornis now gives us a search image for future fossil discoveries — hopefully it ushers in a new era of fossil finds that help clarify how, when and where modern birds first evolved.”

Wonderchicken-Ecosystem-.jpg

Reference: “Late Cretaceous neornithine from Europe illuminates the origins of crown birds” by Daniel J. Field, Juan Benito, Albert Chen, John W. M. Jagt and Daniel T. Ksepka, 18 March 2020, Nature.
DOI: 10.1038/s41586-020-2096-0

Imagine, modern birds and juvenile dinosaurs are a lot alike. Science is forever advancing and making comparisons where none had been made before for our greater understanding. Abzhanov's and Bhullar's paper will appear in the May 27, 2021, edition of Nature, stay tuned. Dinosaurs, whose major types are known by almost every child, will have their offspring compared to birds. And now grasp the idea that perhaps the first modern bird was obliterated by the asteroid which created the Chicxulub Crater and ended the Cretaceous Era. How sad.
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