Shark - Wikipedia
网页The earliest confirmed modern sharks (selachimorphs) are known from the Early Jurassic around 200 million years ago, with the oldest known member being Agaleus, though records of true sharks may extend back as far as the Permian. [3]
Shark evolution: a 450 million year timeline - Natural History …
网页1137. Sharks have been around for hundreds of millions of years, appearing in the fossil record before trees even existed. But what did they evolve from, are they 'living fossils', and how did they survive five mass extinctions?
Shark | Attacks, Types, & Facts | Britannica
网页2024年9月11日 · shark, any of numerous species of cartilaginous fishes of predatory habit that constitute the order Selachii (class Chondrichthyes). Sharks, together with rays and skates, make up the subclass Elasmobranchii of the Chondrichthyes. Sharks differ from other elasmobranchs, however, and resemble ordinary fishes, in …
A Timeline Of Shark Evolution - Shark Sider
网页During the Cretaceous Era, 145 to 65 million years ago, many of the sharks still alive today developed. Deep sea sharks like the Goblin Shark or the Frilled Shark, originated during the Cretaceous Era. Filter feeders like the Whale Shark, the Basking Shark, and the megamouth shark first appeared.
Sharks, explained - National Geographic
网页Based on fossilized teeth and scales, scientists believe that sharks have been around for more than 400 million years—long before the dinosaurs. The ocean’s top predators have evolved...
Sharks | Smithsonian Ocean
网页Sharks and their relatives were the first vertebrate predators, and their prowess, honed over millions of years of evolution, allows them to hunt as top predators and keep ecosystems in balance. But sharks are in trouble around the world.
All About Sharks: Species, Conservation, & Fun Facts
网页Although their ancestors can be traced back to at least the “Age of Fishes,” that is, the Devonian Period (419.2 million to 358.9 million years ago), sharks didn’t dominate the oceans until the Carboniferous Period (358.9 million to 298.9 million years ago). Modern sharks would not appear until more than 97 million years later.
The Secret History of Sharks: The Rise of the Ocean's Most …
网页2024年7月2日 · John Long, who for decades has been on the cutting edge of shark research, weaves a thrilling story of sharks’ unparalleled reign. The Secret History of Sharks showcases the global search to discover sharks’ largely unknown evolution, led by Long and dozens of other extraordinary scientists.
Megalodon - Wikipedia
网页Otodus megalodon (/ ˈmɛɡələdɒn / MEG-əl-ə-don; meaning "big tooth"), commonly known as megalodon, is an extinct species of giant mackerel shark that lived approximately 23 to 3.6 million years ago (Mya), from the Early Miocene to the Pliocene epochs.
The Sinking of the USS Indianapolis Triggered the Worst Shark …
网页18 小时之前 · The Sinking of the USS Indianapolis Triggered the Worst Shark Attack in History. In the final weeks of World War II, a Japanese torpedo sank an American heavy cruiser. Only 316 of the 900...