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The Q? Blog

Dinosaurs were just the Tip of the Iceberg

by Devin Reese -- Sep 10, 2014
Devin Reese, smiling

Devin is the lead digital science writer for the Q?rius website. She writes and gathers media for the Smithsonian Science How? webcast series,...

Late Cretaceous scene. Depiction by Mary Parrish, Smithsonian.
Late Cretaceous scene. Depiction by Mary Parrish, Smithsonian.

We’ve all fantasized about living in a world where dinosaurs roam the Earth, a place like Jurassic Park, rife with the perils and excitement of living amongst these odd creatures. While it’s safer for us now, what a shame that birds are the only living descendants of the dinosaurs that walked on two legs and included the infamous T. rex. About 66 million years ago, T. rex and other large dinosaurs disappeared from Earth suddenly. Their demise occurred over a period of several months or at most years, a very brief period of time in geologic terms.

While the disappearance of large dinosaurs is the most talked-about change, it was only the tip of the iceberg. Most of the other animal species on land went extinct as well-- including many insects, mammals, reptiles, amphibians, and snails. About half the life in the seas went extinct-- ranging from huge plesiosaurs to tiny animals called foraminifera. The fossil record is testimony to the dramatic, devastating change in life on Earth 66 million years ago that ended the period known as the Cretaceous. Plant fossils provide the starkest testimony of all, with more than 80 percent of plant species going extinct. All the dominant species of the time disappeared, making for an overhaul of ecosystems.

Find out more about what happened and how it happened. Watch a "Smithsonian Science How" webcast titled Solving the Dinosaur Mystery on the Q?rius website. Dr. Kirk Johnson, a paleobotanist and Director of the National Museum of Natural History, discusses and answers questions about the end-Cretaceous extinction.

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