key concepts

The following concepts are key to teaching science and correlate to the national standards.

Psittacosaurus, a feathered dinosaur discovered int eh Liaoning Province
Psittacosaurus, a feathered dinosaur discovered in the Liaoning Province
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Scientific inquiry relies on evidence.
Scientists develop explanations using observations (evidence) and what they already know about the world (scientific knowledge). This exhibition presents several types of evidence for new theories about dinosaurs:

  • New fossils. Since the early 1990's, thousands of ancient plants and animals have been discovered in the Liaoning Province in China. One of these fossils is Dilong paradoxus, a primitive cousin of the Tyrannosaurus rex, which is covered in feathers. This find reinforces the idea that birds are living dinosaurs. Other fossils, like the juvenile Psittacosaurus found in the belly of a primitive mammal fossil, call into question accepted theories. (Scientists previously thought that mammals were much smaller and not in competition with dinosaurs.)

  • A 3-D mechanical T. rex sheds light on biomechanics
    A 3-D mechanical T. rex sheds light on biomechanics
    © AMNH
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  • New technology. Scientists today rely on computer-based technology to enhance the gathering and manipulation of data, particularly when dinosaur skeletons are incomplete, or too fragile (and heavy) to handle. The exhibition's 3-D mechanical Tyrannosaurus rex shows a scientist's rendering of how this giant actually moved, and an aluminum Apatosaurus model simulates this enormous creature's range of motion.

  • New ways of looking at old fossils. Scientists study modern animals for clues about the behavior of ancient dinosaurs. Because many dinosaurs have been extinct for 65 million years, understanding behavior and movement poses a real challenge. Scientists observe movement, tracks, and morphological features in living species, from chicken to crocodiles, in order to flesh out what we know about ancient animals.

Technological tools help scientists make better observations, measurements, and equipment for investigations.
For centuries paleontologists have relied on tools such as hammers, shovels, and compasses. But now scientists also study dinosaurs with everything from satellite technology to scanning electron microscopes. These technologies are helping paleontologists piece together more of the dinosaur puzzle than ever before. The accuracy and precision of the data, and therefore the quality of the exploration, depends on the technology used. These technologies help paleontologists:

  • Discover fossils faster. GPS systems help scientists navigate to dig sites (and relocate old ones).

  • Examine dinosaur locomotion: Computer-generated models replicate dinosaurs' speed, movement, and range of motion.

  • Simulate dinosaur behavior. Scientists are using computer models to simulate dinosaur herding behavior based on fossilized dinosaur tracks.

  • Peer inside fossils. Scientists can look inside fossils, like the fragile skull of the feathered Bambiraptor, without breaking them, thanks to advanced imaging technology like digital x-rays and CAT scans.

Scientific knowledge is subject to change as new evidence becomes available.
Scientific knowledge changes by evolving over time, building on earlier knowledge. Many theories about dinosaurs are undergoing major revision, such as:

  • Dinosaur extinction. For decades the leading theory about the extinction of dinosaurs was that a huge asteroid or comet slammed into Earth 65 million years ago, setting off global wildfires and blocking sunlight. In recent years, however, researchers have also been investigating whether other forces contributed to a drastic change in the environment, such massive volcanic eruptions and changes in sea level, which preceded the slow mass extinction of the dinosaurs.

  • Speed and range of movement. About a century ago, T. rex's discoverers wrote of its "destructive power and speed." Within decades, though, scientists had decided that all large dinosaurs, including T. rex, were sluggish giants. Later, opinions changed again, and T. rex regained its reputation as a fast, fierce carnivore. These days, T. rex may be slowing down once more. Recent biomechanical analysis suggests that while T. rex was a powerful—even "destructive"—animal, it wasn't very fast.

  • Frills and horns: Researchers have long wondered about the purpose of particular dinosaur features like the bony horns, crests, and plates sticking out of their backs. For years, paleontologists thought these features served to protect the animal in battle. More recently, scientists have come to another conclusion: Some of the features were used by dinosaurs in the competition for mates.

Science relies on human qualities of reasoning, insight, skepticism, and creativity.
Paleontologists do much more than dig for and assemble dinosaur bones-they develop innovative ways of solving problems, posing questions, and engaging the evidence. Scientists formulate and test their explanations of dinosaurs using:

  • Observation: It's more than just a keen eye. Paleontologists determine what to observe and how to apply those observations. For example, paleontologists observed male bighorn sheep engaged in head-to-head combat to determine whether horned Pachycephasaurs fought in the same way. Comparing the skulls of the two animals didn't provide enough information to determine their behavior.

  • Experiments: Birds are living dinosaurs, so studying the way large modern ground birds-ostrich, emu and rhea-walk and run can help scientists interpret extinct dinosaur footprints. Experimenters encouraged the birds to walk across a footprint-friendly surface, and then photographed and measured the results.

  • Theoretical models: After astronomers recorded a comet crashing into Jupiter in 1994, computer scientists have modeled the collision to show what might have happened when a meteor hit Earth. Models help scientists visualize and extrapolate from events that cannot be directly observed.