What is Dinosaurs: Definition and 26 Discussions

Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago, although the exact origin and timing of the evolution of dinosaurs is the subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 million years ago; their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are modern feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage to survive the Cretaceous–Paleogene extinction event approximately 66 million years ago. Dinosaurs can therefore be divided into avian dinosaurs, or birds; and the extinct non-avian dinosaurs, which are all dinosaurs other than birds.
Dinosaurs are a varied group of animals from taxonomic, morphological and ecological standpoints. Birds, at over 10,700 living species, are among the most diverse group of vertebrates. Using fossil evidence, paleontologists have identified over 900 distinct genera and more than 1,000 different species of non-avian dinosaurs. Dinosaurs are represented on every continent by both extant species (birds) and fossil remains. Through the first half of the 20th century, before birds were recognized as dinosaurs, most of the scientific community believed dinosaurs to have been sluggish and cold-blooded. Most research conducted since the 1970s, however, has indicated that dinosaurs were active animals with elevated metabolisms and numerous adaptations for social interaction. Some were herbivorous, others carnivorous. Evidence suggests that all dinosaurs were egg-laying; and that nest-building was a trait shared by many dinosaurs, both avian and non-avian.
While dinosaurs were ancestrally bipedal, many extinct groups included quadrupedal species, and some were able to shift between these stances. Elaborate display structures such as horns or crests are common to all dinosaur groups, and some extinct groups developed skeletal modifications such as bony armor and spines. While the dinosaurs' modern-day surviving avian lineage (birds) are generally small due to the constraints of flight, many prehistoric dinosaurs (non-avian and avian) were large-bodied—the largest sauropod dinosaurs are estimated to have reached lengths of 39.7 meters (130 feet) and heights of 18 m (59 ft) and were the largest land animals of all time. The misconception that non-avian dinosaurs were uniformly gigantic is based in part on preservation bias, as large, sturdy bones are more likely to last until they are fossilized. Many dinosaurs were quite small, some measuring about 50 centimeters (20 inches) in length.
The first dinosaur fossils were recognized in the early 19th century, with the name "dinosaur" (meaning "terrible lizard") having been coined by Sir Richard Owen in 1841 to refer to these "great fossil lizards". Since then, mounted fossil dinosaur skeletons have been major attractions at museums worldwide, and dinosaurs have become an enduring part of popular culture. The large sizes of some dinosaurs, as well as their seemingly monstrous and fantastic nature, have ensured their regular appearance in best-selling books and films, such as Jurassic Park. Persistent public enthusiasm for the animals has resulted in significant funding for dinosaur science, and new discoveries are regularly covered by the media.

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  1. BillTre

    Which Dinosaurs Were Warm Blooded or Cold Blooded?

    In another well directed chemical analysis of fossils, a research group has indications that some but not all dinosaurs were warm blooded (endothermic), although some (Stegosauri and Triceratops) had apparently reverted to being cold blooded (ectothermic). In addition, it seems that the flying...
  2. Isopod

    What's your favourite dinosaur?

    ( https://www.nationalgeographic.com/magazine/article/dinosaur-nodosaur-fossil-discovery ) 1. Whats your favourite dinosaur? 2. Have you ever found a fossil (dinosaur or otherwise)? 3. Do you have any favourite non-dinosaur extinct creatures? 4. If you could travel back in time to see dinosaurs...
  3. E

    Is de-extinction of dinosaurs theoretically possible?

    Is de-extinction of dinosaurs theoretically possible? Has any research actually been done into this?
  4. J

    Are birds a subset of reptiles and dinosaurs, or are they th

    are birds a subset of reptiles and dinosaurs, or are they their own class? traditionally they are considered their own class, has that changed?
  5. caters

    Writing: Input Wanted T rex pack with a mysterious egg in their nest

    I have started writing a fiction book about dinosaurs. The first chapter is about a T rex pack with a mysterious egg in their nest. The pack itself has 1 adult female, 1 adult male, and 3 juveniles. The adult female was about to lay her eggs when she said "Oh my god, there is an egg in our...
  6. S

    Could we "catch" the light from prehistoric Earth and see dinosaurs?

    My first question on your forum. I just found you last week and have spent a whole lot of time reading. My question: Not actually a question, but a supposition seeking confirmation. Were it possible to travel faster than light, could we "catch" the light from prehistoric Earth and see...
  7. skepticwulf

    Do plants need direct sunlight?

    We all know the famous theory that an asteroid hits the Earth and kill the dinosaurs by starting a chain reaction where the dust is all over the atmosphere preventing sunlight to reach plants causing them eventually to die thus causing herbivorous to die thus causing carnivorous to die. But when...
  8. E

    C.200 mya - K-T 65 mya: emergence of mammals, coexistence w/ dinosaurs

    The following summary is derived from my 2003 biology textbook: Biology: concepts and applications, 5th edition, by Cecie Starr, published by Brooks/Cole, Thomson Learning. (I took biology 101 in fall 2004. This is not homework, but rather for my self-study and interest.) Chapter 24...
  9. Andre

    Dinosaurs died out due to fire 66 million years ago.

    That sounds pretty obvious. But it wasn't because of the interpretation of evidence. The charcoal / soot required as evidence was not available. In a nutshell. Robertson et al 2013 explain that it was merely a misinterpretation. The charcoal is simply dilluted by the debris from the...
  10. B

    Dinosaurs may have experienced less gravitational pull as a result 21.9hour day

    There are a number of factors involved in weight experienced by a particular mass on the surface of the earth. There is of course the Mass of the Earth itself, the variable distribution of heavier elements in the Earth itself, the motion of the ocean mass due to tides etc, the motion of the...
  11. S

    Gravity has crushed dinosaurs

    How do we know that gravity did not change very much? We have the such facts? For example - can we measure the gravitational constant in space? Use double stars, in millions of light years, etc. --- Sorry my English is bad.
  12. P

    Fire Breathing Dinosaurs: Debunking a Myth

    Before I start, I want to make sure you all realize that I'm completely serious; this isn't a joke. So my mom is religious, and I'm not. Since I'm into science, she likes to try to provide all kinds of "scientific facts" to back up intelligent design, most of which is simply made up or draws...
  13. C

    National Geographic Special: Dinosaurs Decoded

    Something that might be of interest to those here. It's a National Geographic special entitled Decoding Dinosaurs that will present new theories on dinosaur development. Here is a summary of the show: Dinosaurs Decoded is airing 9pm EST October 11th as a prime-time National Geographic...
  14. G

    Uncovering the Science Behind Chicken Dinosaurs: Enzymes and Genome Manipulation

    There was a program on the discovery channel awhile ago about a scientist who made chicken embryos with teeth and a tail. But I can't find anything on how he did it. I think there was something about enzymes. Anybody got info? Can scientists do that kind of thing with the genome yet?
  15. P

    Exploring the Weight of Dinosaurs in our Universe

    When looking at dinosaurs and how they lived many millions of years ago it is clear that they must have done so under less gravitational pull from earth. But it is possible that Earth's gravity was the same when they roamed the planet but what allowed them to weigh less was that all mass in the...
  16. C

    The Earth's Electric Field and the size of Dinosaurs.

    Hello, I have heard a theory on how the Earth's electric field is presently stronger than it was at the time of the dinosaurs. The theory reasons that larger dinosaurs, like say a Brontasaurus (pardon spelling) were simply too massive in size and weight for their bodies to be held up by their...
  17. Cyrus

    Modern Dinosaurs: Unusual Animals Roaming Today

    Im still in the process of reading Dawkins book, "The God Delusion", in which he invokes the theory of natural selection many times. When people talk about dinosaurs, they often have mental images of something like this: http://www.kokorodinosaurs.com/tricera.jpg...
  18. W

    Reasons for dinosaurs being so big?

    I have always had this idea but not sure if it is real. I always thought they were so big because there was more o2 in the air, and eventually they reduced o2 levels leading evolution to favor creatures that didn't need so much of it. Is this true?
  19. L

    Why Did The Dinosaurs Die Out?

    Right, I don't know if I can put this here, but I will try. I know a asteroid, or something, wiped out the dinosaurs. But how exactly were they wiped out, did it just completely destroy the area they live in or what? Luke.
  20. G

    Did All Carnivorous Dinosaurs Have Speed and Agility?

    I just wanted to ask that are all or most carnivorous dinosaurs were fast and agile?
  21. G

    Could Have The Smartest Dinosaurs

    Evolved into a more intelligent dinosaur, obtaining human-like intelligence? And if us humans had suddenly got extinct, which evolutionary lineage do you think would have the best chance of taking our place, obtaining our kind of intelligence and dominating the planet.
  22. F

    Ceramic Dinosaurs Discovered in Acambaro: What Do You Think?

    What do you guys think of this? http://www.omniology.com/3-Ceramic-Dinos.html
  23. wasteofo2

    Mamal which ate dinosaurs discovered

    http://news.bbc.co.uk/2/hi/science/nature/4165973.stm Turns out that the stuff I learned as a kid about the only mamals during the time of the Dinosaurs being little mice who scurried away everytime a Dinosaur came along might not be totally true afterall. Just imagine how many...
  24. R

    Discovering new species of dinosaurs

    Most paleontologists, on discovering new species of dinosaurs, give them exceedingly convoluted scientific names. So, it came as a surprise to find an interestingly named dinosaur. The story goes that once, a new species of dinosaur was discovered by a group of paleontologists, but the first...
  25. P

    How long ago the dinosaurs died

    Would you please tell me when those animals completely got killed ? Can you please give me some links to sites that you think good to start with, where I can read a little about this ? I honestly don't know anything about this, or know if this thread would be right to be placed here...Since I...
  26. Ivan Seeking

    Volcanoes may have choked Earth, helped dinosaurs: CNN