Shark

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Introduction1

Dictionary

shark : any of numerous mostly marine cartilaginous fishes of medium to large size that have a fusiform body, lateral branchial clefts, and a tough usually dull gray skin roughened by minute tubercles and are typically active predators sometimes dangerous to humans — Webster

OneLook, Free Dictionary, Wiktionary

Encyclopedia

Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the rays. However, the term “shark” has also been used for extinct members of the subclass Elasmobranchii outside the Selachimorpha, such as Cladoselache and Xenacanthus, as well as other Chondrichthyes such as the holocephalid eugenedontidans. Under this broader definition, the earliest known sharks date back to more than 420 million years ago. Acanthodians are often referred to as “spiny sharks”; though they are not part of Chondrichthyes proper, they are a paraphyletic assemblage leading to cartilaginous fish as a whole.

Since then, sharks have diversified into over 500 species. They range in size from the small dwarf lanternshark (Etmopterus perryi), a deep sea species of only 17 centimetres (6.7 in) in length, to the whale shark (Rhincodon typus), the largest fish in the world, which reaches approximately 12 metres (40 ft) in length. Sharks are found in all seas and are common to depths of 2,000 metres (6,600 ft). They generally do not live in freshwater although there are a few known exceptions, such as the bull shark and the river shark, which can survive and be found in both seawater and freshwater. Sharks have a covering of dermal denticles that protects their skin from damage and parasites in addition to improving their fluid dynamics. They have numerous sets of replaceable teeth.

Well-known species such as the great white shark, tiger shark, blue shark, mako shark, thresher shark, and the hammerhead shark are apex predators—organisms at the top of their underwater food chain. Many shark populations are threatened by human activities. — Wikipedia

Encyclopædia Britannica

Outline

Outline of Sharks (Wikipedia)

Portal

Sharks Portal (Wikipedia)

Shark FAQs (Northeast Fisheries Science Center, NOAA Fisheries)
Sharks (Smithsonian Ocean)
Nature, Shark (PBS)

Search

WolframAlpha

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Inspiration

Note: These are 360° videos — press and hold to explore them!

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Preservation

Sharks Are Friends Not Food (Explore.org, YouTube Playlist)
Biodiversity Heritage Library

Florida Program for Shark Research (Florida Museum)

Racing Extinction (Official Site)
Racing Extinction (Wikipedia)
Ocean Preservation Society (Official Site)
Ocean Preservation Society (Wikipedia)

History

The Epic History of Sharks (BBC Documentary)

Museum

Sharks & Fish, Reptiles & Amphibians oh my! (YouTube Playlist)
Sharks (Chicago Field Museum)

Library

WorldCat, Library of Congress, UPenn Online Books, Open Library

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Participation

Education

Course

OER Commons: Open Educational Resources

Community

Organization

Shark Trust

News

Shark Trust News, Phys.org, NPR Archives

Book

ISBNdb

Government

Document

USA.gov

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Expression

Fun

Humor

Three People Allegedly Stole a Shark From Texas Aquarium By Disguising It as a Baby in a Stroller (Alexia Fernandez, People)

Adventure

10 Best Places to Swim With Sharks (Professional Association of Diving Instructors, Condé Nast Traveler)
25 Best Destinations for Sharks and Adventure (Travis Marshall, Scuba Diving)
Shark Diving Tips and Advice (Shart Trust)
10 Shark Diving Tips (Dive Magazine)

Poem

OEDILF: The Omnificent English Dictionary In Limerick Form

Music

Song Lyrics

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Related

Here are links to pages about closely related subjects.

Knowledge Realm

Terrestrial

Sphere Land, Ice, Water (Ocean), Air
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Life Cell, Gene, Tree of Life
Microorganism
Plant Flower, Tree
Animal
Invertebrate Cuttlefish, Octopus, Ant, Bee, Butterfly, Spider, Lobster
Vertebrate Fish, Seahorse, Ray, Shark, Frog, Turtle, Tortoise, Dinosaur
Bird, Ostrich, Owl, Crow, Parrot
Mammal Bat, Rabbit, Giraffe, Camel, Horse, Elephant, Mammoth
Whale, Dolphin, Walrus, Seal, Polar Bear, Bear, Cat, Tiger, Lion, Dog, Wolf
Monkey, Chimpanzee, Human

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Notes

1.   The resources on this page are are organized by a classification scheme developed exclusively for Cosma.