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What Killed the Dinosaurs? |
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Introduction | Asteroid Impact | Volcanism | Mammal Competition | Continental Drift | Conclusion |
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It is one of the greatest
puzzles in paleontology.
For more than 150 million years, dinosaurs dominated Earth. They were
so successful that other animal groups -- mammals included -- had little chance of
playing anything more than secondary roles.
Then, 65 million years ago, the dinosaurs vanished from the world
forever.
Did they meet a quick and catastrophic end, or did they fade away
gradually?
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What happened 65 million years ago?
In the search for answers to what killed the dinosaurs, scientists
have looked beyond fossils. Geological evidence also holds
clues and has contributed to many hypotheses, working
explanations of how dinosaurs may have become extinct.
The extinction mystery is far from a simple "whodunit." The same
piece of evidence is sometimes subject to multiple interpretations. And, as yet, there
is no obvious "smoking gun," no piece of evidence that strongly supports only one
hypothesis while disproving all others.
So what do we know about dinosaur extinction, and how do we know it?
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Evidence
Scientific evidence and observation are the building blocks of hypotheses. Initially,
the same evidence and observations may support different hypotheses. As more evidence
becomes available, some hypotheses are substantiated, others are disproved, and new
ones are formed.
Hypothesis
A dinosaur extinction hypothesis is a testable statement describing factors that may
have contributed to the dinosaurs' demise and how long the process may have taken.
Evidence, observation, and experimentation can serve to support or disprove a hypothesis.
Regardless of its ultimate acceptance or rejection, though, a valid hypothesis provides
direction for future scientific inquiry.
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-> Explore the mystery, one hypothesis at a time,
of what killed the dinosaurs.
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Introduction | Asteroid Impact | Volcanism | Mammal Competition | Continental Drift | Conclusion |
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