What Killed the Dinosaurs?
picturesAdvanced Photoshop Pictures Contest – 16 image entries What Really Killed the Dinosaurs Contest Directions: Until recently, the most accepted theory of dinosaur extinction suggested that dinosaurs were wiped from the face of the planet because of the climatic changes caused by a gigantic asteroid hitting the Earth some 75 million years ago. However, the most recent research suggests that the dinosaurs were killed by disease carrying mosquitoes. The size of dinosaurs made them the biggest predators on Earth, but even the dinosaurs the size of a double decker could be infected and killed with a single mosquito bite. Today you are to suggest your own theory of what really killed the dinosaurs. Try to be creative and don’t be afraid to use even the most ridiculous scenarios of why the dinosaurs became extinct – smoking, drugs, Colonel Sanders, etc. Feel welcome to photoshop your theory as a book or magazine cover.
Sixty-five million years ago the last of the non-avian dinosaurs went extinct. So too did the giant mosasaurs and plesiosaurs in the seas and the pterosaurs in the skies. Plankton, the base of the ocean food chain, took a hard hit. Many families of brachiopods and sea sponges disappeared. The remaining hard-shelled ammonites vanished. Shark diversity shriveled. Most vegetation withered. In all, more than half of the world’s species were obliterated. What caused this mass extinction that marks the end of the Cretaceous and the beginning of the Paleogene? Scientists have yet to find an answer. The one that does must explain why these animals died while most mammals, turtles, crocodiles, salamanders, and frogs survived. Birds escaped. So did snails, bivalves, sea stars (starfish), and sea urchins. Even hardy plants able to weather climate extremes fared OK. Scientists tend to huddle around one of two hypotheses that may explain the Cretaceous extinction: an extraterrestrial impact, such a
One hundred million years ago the monstrous dinosaur was the king of beasts. Then the dinosaurs suddenly died off, leaving dominance of the earth to smaller, warm-blooded mammals. One theory is that the great die-off was caused by a sudden change of climate. Another is that the slow-witted, blundering dinosaurs could not cope with mammals that destroyed their eggs. Biochemist Albert Schatz of National Agricultural College, Doylestown, Pa. has a third theory: that the evolution of modern plants was the death of the dinosaurs.
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?
