Friday, November 4, 2011

Top 10 misconceptions about Dinosaurs

Link: Top 10 misconceptions about Dinosaurs


1. Dinosaurs represent failure and extinction.


Rather, dinosaurs are the best examples of success and adaptation. They ruled the Earth longer than any other land animals (over 150 million years), and gave rise to birds.


2. Dinosaurs and “humans” coexisted.


The death of the last dinosaur and the appearance of the first “human” (genus Homo) were separated by about 62 million years.


3. Dinosaurs were either all hot-blooded or all cold-blooded.


Mesozoic dinosaurs were not “warm-blooded” like modern mammals, nor were they “cold-blooded” like modern lizards. Most specialists believe that dinosaurs were “dinosaur-blooded”, a condition that combines certain aspects of “warm-bloodedness” with a changing metabolism over the animal’s lifetime.


4. The word dinosaur means “terrible-lizard”


Actually it was originally defined to mean “fearfully-great lizard”, by Richard Owen in 1842. The greek word “deinos”, when used as a superlative, means “fearfully-great” (as used by Homer in The Iliad). It became simplified over time, as a simple adjective, to mean “terrible”. Dinosaurs are neither terrible nor are they lizards!


5. Whatever you read in the latest “dinosaur book” or see on TV or in the movies must be true.


Popular books, movies, and TV specials need not be 100% accurate. They often contain errors and outdated information, and may reflect the personal bias of the writer. (Most dinosaur books and TV scripts are not reviewed by professional dinosaur paleontologists).


6. Dinosaurs all lived and died at the same time.


The distance in time between Tyrannosaurus and Apatosaurus (formerly called Brontosaurus) is more than the time between Tyrannosaurus and your parents, about 65 million years. Of the (approximately) 900 named species of Mesozoic dinosaurs, only two or three dozen species faced the final extinction in North America.


7. Mammals arose after the dinosaurs, and helped drive the dinosaurs into extinction by eating dinosaurs eggs.


Mammals and dinosaurs both appeared in the Late Triassic Period. There is no evidence that dinosaurs went extinct because of predation on their eggs.


8. An asteroid (or comet) killed the dinosaurs


The controversy over the cause of the dinosaur extinction continues among paleontologists. However, evidence from a deep sea core drilled off the coast of Florida proves that an asteroid hit the Earth at the end of the Cretaceous which caused the dinosaur extinction. Most dinosaur specialists are willing to accept that an asteroid hit the Earth, but some do not think that it was the sole cause of the Mesozoic extinctions. Instead, they claim that dinosaurian diversity was already in decline by the end of the Cretaceous. The asteroid impact may have been “the straw that broke the camel’s back.” 


9. All big reptiles from the prehistoric past (“monsters”) are dinosaurs.


Dinosaurs represented less than 10% of the 40 groups of reptiles from the Mesozoic Era (Pterodactyls, sea-serpents, giant lizards, pelycosaurs, and other big prehistoric beasts are not dinosaurs). “Monsters” and Dragons are the products of fiction and mythology.


10. Archeologist dig up dinosaurs.


Archaeology and paleoanthropology (subdivisions of Anthropology) only deal with humans and cover the last 3-4 million years. Paleontology (a combination of Geology and Biology) deals with all fossils and covers the last 3.5 billion years! 


(via Smithsonian)


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