Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrate
Class: Chondrichthyes
A Shark's Age
Sharks have been on the Earth for over four hundred MILLION years. (400,000,000 years) They have found evidence of sharks(Early forms at least) in the Ordovician period, Which is part of the Palaeozoic Era.
(The Paleozoic covers the time from the first appearance of abundant, soft-shelled fossils to the time when the continents were beginning to be dominated by large, relatively sophisticated reptiles and modern plants.)
A Shark's Body
+A shark's body has paired fins, paired nostrils, a cartilage skeleton, placid scales, and five to seven gills.
+When it comes to body shape most shark bodies are fusiform (bullet shaped), though some sharks like the Hammerhead have unique shapes depending on their habitat. on that note, sharks can be found in shallow waters, to the open ocean, to the deep-sea.
+The tail shape changes from different species of sharks. If the lobes are equal- (Like on a Great white shark) The shark will be faster. If the upper love is longer- (Like on a Nurse shark) It is used for downward movements.
For a look at the shapes- Please click Here.
A surprising fact about the shark's body that has attracted the eyes of scientists, is the shark's body is resistant to disease. Scientists have been using the shark in cancer prevention research (As well as horseshoe crabs)
The Shark's Senses
+Sharks can hear from 1.5 miles away
+Sharks can smell blood .5 miles away
+Sharks have a Lateral Line that can feel vibrations from 300ft away.
+Sharks eyes are very similar to human eyes, though when attacking, a membrane covers the eye to protect it.
+Sharks are actually very picky eaters. They don't hunt humans. Most shark bites are from humans swimming in murky water- (Its like us wondering around in thick fog) Surfers- (That look like seals- A shark's main diet) Or some misfortune humans that wonder into shark hunting grounds. (Places that fishers had dumped unwanted pieces of fish- chummed- etc) Regarding things like license plates being found in stomachs- The sharks will eat anything in their path of a fish.
+The sense we do not posses. The sixth sense. The ampulla de lorenzing is the sense that detects electrical impulses emitted from living prey. This is used in the final locomotion during an attack while the eyes are covered by the membrane. They are striking out blind at prey, relying on the sense.
Shark Feeding
+All sharks are carnivore, but not all sharks feed the same way on the same thing.
+Sharks such as Great whites, Tiger, and Mako sharks hunt prey. Prey being fish, seals, and other animals as such.
+Sharks such as Whale, Basking and Megamouth sharks use filter feeding. Filter feeding meaning feeding on plankton.
+Each shark species has their own way of feeding.
+Of course one of the most known facts of sharks is that they have rows of teeth that are replaced every few weeks-months.
Shark Respiration
Sharks are cartilage fish, Therefor they breath through gills. The water could travel in the mouth/throat or over the gills, and out the gill slits to pull in air.
+Some sharks can pump water in while sitting still, others need to move.
+Bottom dwellers and rays/skates have spiricales. Spiricales are openings on top of the head that waters flow into, and to the gills.
Shark Reproduction
+Sharks have internal fertilization, noting that most fish usually have external fertilization. As well as internal fertilization there is internal development.
-Males have two claspers located at the pelvic fins.
-Females are bigger with thicker skin.
