Outline of sharks

Outline of sharks
A great white shark at Isla Guadalupe, Mexico

Sharks (superorder Selachimorpha) are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago, before the time of the dinosaurs.[1]

Since that time, sharks have diversified into more than 440 species, ranging 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, which reaches approximately 12 metres (39 ft 4 in) and which feeds only on plankton, squid, and small fish by filter feeding. Sharks are found in all seas and are common down to depths of 2,000 metres (6,600 ft). They generally do not live in freshwater, with a few exceptions such as the bull shark and the river shark which can live both in seawater and freshwater.[2] They breathe through five to seven gill slits and have a covering of dermal denticles that protect their skin from damage and parasites. Denticles also improve their fluid dynamics by maintaining turbulent flow over the animals body, this means that the shark can move faster. They have several sets of replaceable teeth.[3]

Some well-known species such as the great white shark, tiger shark, and the hammerhead are apex predators, at the top of the underwater food chain. Their skills as predators fascinate and frighten humans, even as their survival is under serious threat from fishing and other human activities.

The following outline is provided as an overview of and topical guide to sharks:

Contents

Fields

  • Ichthyology – branch of zoology devoted to fish (including sharks)
  • Meristics – branch of ichthyology that relates to counting features of fish, such as the number of fins or scales

Biological classification

Diagram showing shark "family tree"

Types

Subdivisions of the biological classification Selachimorpha include:

Behavior

Photo of front page of newspaper showing photo of large shark with open mouth
The Philadelphia Inquirer report of Jersey Shore shark attack.

Attacks

Range and habitats

Range

  • Bodies of water in which sharks can be found include:
  • Depths: from the surface down to depths of 2,000 metres (6,600 ft).
Photo of whale shark with silhouettes of human observers at bottom of picture
A whale shark in the Georgia Aquarium

Habitats

  • White Shark Cafe – remote mid-Pacific Ocean area noted as a winter and spring habitat of otherwise coastal great white sharks

In captivity

  • Shark tank
  • Shark tunnel – underwater tunnel that passes through an aquarium that keeps sharks

Anatomy

Anatomical shark drawing showing snout, nostril, eye, spiracle, dorsal fin spine, first and second dorsal fins, precaudal pit, caudal fin, caudal keel, anal fin, clasper, pelvic fin, pectoral fin, gill openings, labial furrow, and mouth

Protective equipment

Simplified diagram of shark net

Fishing

Conservation

Shark Trust logo
  • 1992 Cageless shark-diving expedition – 1st publicized cageless dive with great white sharks which contributed to changing public opinions about the supposed "killing machine"
  • Shark Alliance – coalition of non-governmental organizations dedicated to restoring and conserving shark populations by improving European fishing policy
  • Shark Conservation Act – Proposed US law to protect sharks
  • Shark sanctuary – Palau's first-ever attempt to prohibit taking sharks within its territorial waters
  • Shark tourism – form of ecotourism showcasing sharks
  • Shark Trust – A UK organisation for conservation of sharks

Notable sharks

Notable researchers and people

Photo of bearded man
Hans Hass, diving pioneer
  • Peter Benchley – author of the novel Jaws, later worked for shark conservation
  • Jacques-Yves CousteauFrench naval officer, explorer, ecologist, filmmaker, innovator, scientist, photographer, author and researcher who studied the sea and all forms of life in water including sharks
  • Eugenie Clark–American ichthyologist researching poisonous fish and the behavior of sharks; popularly known as The Shark Lady
  • Leonard Compagno–international authority on shark taxonomy, best known for 1984 catalog of shark species (FAO)
  • Ben CroppAustralian former shark hunter, who stopped in 1962 to produced some 150 wildlife documentaries
  • Richard Ellis – American marine biologist, author, and illustrator.
  • Rodney Fox – South Australian film maker, conservationist, survivor of great white shark attack and one of the world's foremost authorities on them
  • Andre HartmanSouth African diving guide best known for free-diving unprotected with great white sharks
  • Hans Hass – diving pioneer, known for shark documentaries
  • Mike Rutzen – great white shark expert and outspoken champion of shark conservation; known for free diving unprotected with great white sharks
  • Ron & Valerie Taylor – ex-spearfishing champions who switched from killing to filming underwater documentaries

References

  1. ^ Martin, R. Aidan. "Geologic Time". ReefQuest. http://www.elasmo-research.org/education/evolution/geologic_time.htm. Retrieved 2006-09-09. 
  2. ^ Allen, Thomas B. (1999). The Shark Almanac. New York: The Lyons Press. ISBN 1-55821-582-4. OCLC 39627633. 
  3. ^ Budker, Paul (1971). The Life of Sharks. London: Weidenfeld and Nicolson. SBN 297003070. 
  4. ^ Fernicola, Twelve Days of Terror
  5. ^ "Summer of the Shark". Time. July 30, 2001. http://www.time.com/time/2001/sharks/. Retrieved May 20, 2010. 

See also


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