m asked in Science & MathematicsZoology · 2 months ago

Are ALL birds descended from dinosaurs?

I have heard that birds are descended from dinosaurs, but does this mean all birds, from the budgie to the ostrich, or just certain birds?

Also, which other animals today descend from dinosaurs?

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  • Yes, all birds that exist today are descended from dinosaurs.

    No other animals existing today are descended from dinosaurs. That is quite clear from the current evidence. All of the non-avian dinosaurs died out as a result of the impact of a massive asteroid on the earth 66 million years ago. In fact, not only did the non-avian dinosaurs all die out as a result of the impact, but it also caused the extinction of some 75 percent of ALL species on the planet at that time.

    The appearances of the evolutionary sequences of species through the fossil record make that quite clear. The thin iridium (which is rare on earth but common in meteors and asteroids) layer that is found all over the world between the last stratum in which dinosaur fossils are found and the upper fossil layers that show the subsequent expansion of the surviving species show that quite well. The animals that survived included some of the early mammals that existed during the age of the dinosaurs and which evolved and expanded over millions of years into the present-day species.

    First, contrary to what some people think, not all dinosaurs were huge. The fossil record shows that several species of dinosaurs were small.

    Second, it is now clear of their bone structure from the fossil evidence that at least some branches of the dinosaurs were warm blooded and much more active than their reptilian ancestors. Numerous examples from the fossil record--and contrary to the claims of  those who say otherwise--also show that many of these dinosaurs had evolved feathers, which would have originally been used for insulation. From that initial use other uses would have arisen, such as for camouflage or elongated for sexual display. Some of the smaller tree-climbing feathered theropod (again, contrary to what some people say) dinosaurs began using their elongated feathers on their arms for gliding. Eventually, they evolved into powered flyers.

    The earliest example of such feathered, winged dinosaurs was that of Archaeopteryx, which was first found in the 1800s. See the image below for one of those fossils. It also shows its skeleton in relation to modern type birds. It is clear that the skeleton is still more theropod dinosaur like than being bird like, including having teeth, a long boned tail and separate forelimb digits with claws instead of the fused digits of modern type birds.

    As I said before, fossil of numerous other small, feathered, dinosaurs, including winged, have been found in the past thirty years, enough to make it clear that birds descended from a theropod dinosaur, though it is not clear.yet as to which one it was.

    See the video below for a couple of other examples of that type of dinosaur.

    https://www.youtube.com/watch?v=-fyxUxGdrns

    Youtube thumbnail

    One other thing. Contrary to what some say, Longisqauma insignis was not at all birdlike, and its "feathers" were likely elongated scales. Look it up on Wikipedia.

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  • Gabe
    Lv 6
    2 months ago

    YES, ALL BIRDS!!!!

  • Anonymous
    2 months ago

    The short answer is that zero bird descended from a dinosaur. The most likely ancestor of all birds is Longisqauma insignis, which is a small Triassic reptile that glided and had feathers.  

    All living birds are ornithurine birds, also called modern birds. They share a common ancestor. During the age of dinosaurs, there were also enantiornithine birds, also known as opposite birds, because their leg bones fuse in the opposite direction as ornithurine birds. When the dinosaurs were wiped out 65 million years ago by a giant meteor that struck the earth, all enantiorithine birds were also completely wiped out, along with all pterosaurs or flying reptiles. Only a small number of ornithurine birds survived because they were able to survive the heat by being shorebirds and living near the water. All living birds, from the tiniest hummingbirds to the ostrich, evolved from the small number of ornithurine birds that survived the mass extinction.

    Going back farther in time, we find that the earliest known bird was Archaeopteryx, which lived in Germany 150 million years ago. Recently some birds like Scansoriopteryx and Anchiornis have also been found that were even older than Archaeopteryx, by about 10 million years.  Scientists have determined that all birds, including the ornithurine and enantiornithine birds, evolved from a single common ancestor that lived no later than 160 million years ago. There are some scientists in the early 20th century who suggested that ostriches, because they look a lot like dinosaurs, may have evolved directly from a dinosaur instead of from the earliest known birds. Scientists since then has pooh poohed the idea, and indeed ostriches descended from a flying bird that survived the extinction 65 million years ago according to the latest DNA evidence. 

    The theory that birds evolve from a dinosaur has become religious dogma for a group of "scientists" who are known as cladists. They will NOT accept any evidence that birds did not evolve from a dinosaur because it does not fit their religious belief. According to biophysicists, it is implausible (extremely unlikely) that birds evolved from a dinosaur, because dinosaurs are large and heavy and evolving flight from the ground up is implausible. Flight most likely evolved from the tree down. That means the common ancestor of all birds is extremely unlikely to be a dinosaur but instead it was most likely a small animal that lived in the trees. In fact a likely ancestor of all birds has been known since the 1970s. A Soviet era scientist discovered a small fossil that has feather-like scales. These scales were given a more detailed examination in 1999 when it was transported to the USA for exhibition. Scientists who examined it published a paper in 2000 and they concluded that this fossil has feathers that share anatomical and developmental details with avian feathers. Since feathers is highly complex, it is unlikely to have evolved twice. That means this fossil, named Longisquama insignis, is probably the closest known relative of birds. In fact it may well be the direct ancestor of all birds that ever lived. 

    Therefore not only did some birds not evolve from a dinosaur, apparently zero bird evolved from any dinosaur.  The cladists have denied that Longisquama insignis is the ancestor of birds, and they even claim that it does not have feathers, not because of lack of evidence but because it contradicts their religious dogma. So, even though the likely ancestor of birds have been known for 2 decades, many cladists still continue to insist that birds can ONLY evolve from a dinosaur and nothing else, even if they do not have a fossil dinosaur that they can point to as the closest living relative of birds that is older than the oldest known  birds. Longisquama lived some 65-75 million years before the oldest known bird, giving its descendants ample time to evolve into the earliest known birds. OTOH, the dinosaurs that resemble birds lived some 50-90 million years AFTER the earliest known birds. It takes unshakable faith and a willingness to ignore scientific evidence to believe that birds evolved from a dinosaur. OTOH it only takes an open mind and the willingness to examine the available evidence to conclude that birds most likely evolved from Longisquama or one of its closest relatives. 

    The so-called feathered dinosaurs found in museums is the biggest hoax in the history of science They are the work of cladists who work for these museums. Their feathers are most likely collagen fibers. When asked if these dinosaur "feathers" share any homology (shared similarities inherited from a common ancestor) with avian feathers, the cladists laid an egg. Dinosaurs feathers is just as real as the emperor's new clothes. People who deny that Longisquama is the more likely ancestor of birds than dinosaurs have a similar mindset as global warming deniers. Their minds cannot be changed. They will go to their graves insisting that birds evolved from a dinosaur, regardless of what the evidence says. Their minds cannot be changed by new evidence either. 

    Cladists have said that the debate of the origin of birds is over or closed. In fact, there is no scientific theory that is not subject to falsification so they are never closed. The only thing that is closed are the minds of the religious dogmatists, aka cladists. Many cladists climbed the professional or academic ladder by claiming that birds evolved from a dinosaur according to their inane cladograms. If they admit they have been wrong since the 1980s about birds evolving from a dinosaur, they will fall flat on their face figuratively, and their careers or reputation would become a grease spot on the ground, just as a dinosaur would have become a grease spot on the ground if it tried to fly. History nevertheless will prove that cladists are wrong, whether they admit it or not. They know they are wrong too, but they don't care about the truth. They just want to stay in power. 

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  • ?
    Lv 7
    2 months ago

    Theropod dinosaurs, widely accepted as the ancestors of birds, do not show a step-by-step gradational change to Archaeopteryx, the first known bird.  The vast majority of traits reverse themselves at least once in the cladistic sequence.  Those traits that do change in a unidirectional manner often show large jumps in the sequence.  Ironically, the most bird-like of theropods (including the much touted feathered ‘theropod,’ Caudipteryx), are now apparently confirmed (under evolutionary presuppositions) to be nothing more than ‘secondarily’ flightless descendants of Archaeopteryx!  Theropods fail as stratomorphic intermediates, occurring much too late in the stratigraphic record to serve as the ancestors of birds.  The course of volant (flying) bird evolution itself is also full of discontinuities and trait reversals.  Late Mesozoic birds fail to display a smooth connection either backwards to Archaeopteryx or forward to modern birds.

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  • 2 months ago

    That is the commonest misconception but I doubt it. Dinosaurs are a polyphyletic group and not one that is useful to people studying the. They are too specialized to have given rise to any animals in other classes. Birds probably branched off from one of the groups that also gave rise to one of the groups called dinosaurs before any of the dinosaurs did..

  • Jim
    Lv 7
    2 months ago

    Birds evolved from a group of meat-eating dinosaurs called theropods. That's the same group that Tyrannosaurus rex belonged to, although birds evolved from small theropods

  • 2 months ago

    All birds share a common ancestor, which came from the dinosaurs.  Lizards are similar.

    wikipedia:

    Birds are a group of feathered theropod dinosaurs, and constitute the only living dinosaurs. Likewise, birds are considered reptiles in the modern cladistic sense of the term, and their closest living relatives are the crocodilians. Birds are descendants of the primitive avialans (whose members include Archaeopteryx) which first appeared about 160 million years ago (mya) in China. According to DNA evidence, modern birds (Neornithes) evolved in the Middle to Late Cretaceous, and diversified dramatically around the time of the Cretaceous–Paleogene extinction event 66 mya, which killed off the pterosaurs and all non-avian dinosaurs.

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