Ranking of sharks
Sharks are classified as a type of cartilaginous fish. It is specifically one of the two well-known cartilaginous fishes, as cartilaginous fishes are classified into two main groups, as follows:
- complete heads: (in English: Holocephali).
- cartilaginous gill lamellae
(in English: Elasmobranchii); Sharks belong to this group because there are 8 different orders of sharks within them, and each order denotes specific physical and biological characteristics and behaviors of the shark within it.
يُمكن تصنيف أسماك القرش علمياً بالتفصيل، فمثلاً سمك قرش ماكو قصير الزعانف يُمكن تصنيفه على النحو الآتي:
Lemmings, mackerel shark.
The internal parts of the shark are made of flexible cartilage instead of bone, as sharks have a cartilaginous skeleton, and they have 5-7 gill slits on each side of their head, as these gills are used for breathing and extracting air. water oxygen.
They also have mouths lined with several rows of teeth, which change and renew periodically, and the shape and size of their teeth vary, as some are serrated and pointed, and some are pointed like spears.
يوجد خط جانبي على كلّ جهة من جسم سمك القرش، ووظيفة هذه الخطوط هي اكتشاف حركة المياه المحيطة فيه لاستشعار حركة الفرائس والمساعدة في الحركة حول هذه الفرائس وخاصةً في الليل عندما تكون الرؤية تحت الماء ضعيفة.
These lines are sensor systems made up of a network of fluid-filled channels under the shark’s skin. These channels are affected by pressure changes in the water surrounding the shark and lead to vibration of the fluid in these channels. This vibration is transmitted to the nerve endings of the shark, then the signal is transmitted to the brain to be able to determine the appropriate direction of movement.
The sizes of sharks differ from each other, the largest of which is the whale shark, which can reach a length of 16.7 meters, and is considered the largest fish on earth in general, and the smallest of its types. is the dwarf lantern shark, which does not exceed a length of 20 cm, which means that it is the size of a hand armband, and there are other medium-sized types, such as the great white shark.
The habitats of sharks differ among types, and each type adapts to its surrounding environment, as sharks are considered to be well-adaptive fish to their surrounding environment, and the different types of sharks are distributed among shallow coastal areas, the deep ocean floor and in the open ocean.
تعيش بعض أنواع أسماك القرش في البحار الاستوائية معتدلة المناخ، ومنها ما يعيش في البحار الباردة والقطبية، وبعضها الآخر يعيش في المياه العذبة، وفيما يأتي بعض أنواع أسماك القرش وبيئتها التي تعيش فيها:
- sleeping sharks
It lives in arctic waters throughout the year.
- Big-eyed dog sharks
He lives at the bottom of the Red Sea at a depth of about 2195 meters.
- Bull sharks
It is often found in fresh water, such as: the waters of Lake Nicaragua, Lake Izabal in Guatemala, the Zambezi River in Africa, the Tigris River in Iraq, and 255 km up the Atchafalgia River in the state of Louisiana , and this type of shark has been known to travel an estimated 1000 miles (1,609 km) up the Mississippi River into Illinois until dams blocked their path.
Sharks depend on hunting for their food; Indeed, they are predatory and ferocious creatures that feed on a variety of marine animals, which gives them the freedom to move around the ocean frequently without fear of food sources being interrupted.
Sharks generally feed on fish and marine mammals1; Like dolphins, seals, and some smaller sharks, and there are types of sharks that prefer turtles, gulls, crustaceans, sea slugs, and aquaplankton as their meals.
Most sharks need to provide a permanent movement of water around their gills, which provide them with the necessary oxygen, and for this they must be in a continuous and permanent swimming movement even during periods of sleep, because they swim while sleeping in the water. , but their brain is less active.
But there are other types of sharks that don’t need to continuously swim through water because their bodies contain small ventilation holes located just behind their eyes, and these openings push water through their gills to complete the breathing process.
The reproductive process of sharks is similar to the reproductive process of mammals, where adult male and female sharks must physically meet for the male to transmit his male gametes to the female’s body and fertilize her eggs, and this process differs from the method of reproduction of other types of fish, where normal fish reproduce by releasing fish gametes to meet and fertilize eggs.
Most types of sharks are unable to sleep for long periods of time and compensate for this by taking periods of rest to renew their activity, sleeping very few minutes at a time, and the reason for the sharks inability to sleep is that they need to swim constantly in order to be able to breathe, as oxygenated water circulates through their gills when they move.
However, some types of sharks can sleep through their gills which are able to push oxygen-rich water into them without having to swim and move water through them, and an example of them is the shark. nurse.
There are many types of sharks, numbering around 400 species. Here are the best known of them:
It is the largest species of fish in the world, with a length of about 20 m and a weight of about 34,019 kg. This type of shark is distinguished by its dark colored skin.Gray, blue or brown, which is covered with regular light-colored spots, and the whale shark is abundant in the Pacific, Atlantic and Indian oceans.
- basking shark
It is the second largest species of fish in the world, as it reaches a length of about 12 m and weighs up to 7000 kg. Swims slowly forward while filtering water entering its mouth from its prey.
It is the fastest type of shark, and is characterized by short fins, and the length of the mako shark can reach about 4 m, and its weight reaches 553 kg, and its belly appears in a lighter color than its back blue, and this species is abundant in temperate and tropical waters of the Atlantic and Pacific, Indian and Mediterranean oceans.
It is distinguished by its large eyes, its small mouth and a long tail that looks like a whip to pick up its prey and stun it. There are 3 types of this shark: the common thresher, the salient thresher and the marine shark.
It is considered one of the most aggressive types of sharks to humans, as it prefers to be in warm, shallow, shady waters close to shore, and is characterized by a pointed nose and a gray back that becomes more clear in the lower part, and the length of this type of shark reaches about 3.5 m, While it weighs 226 kg.
- Great White shark
The length of the great white shark is about 6m, and it weighs about 1814kg, and it is one of the ferocious scary sharks that can bite humans but not devour them, and that is the strange nature of the white shark that it examines its prey before devouring it.
It is called by this name because of the color of its body, as it is dominated by dark blue on its back, and its sides are light blue, while the lower part of it is white in color, and the length of the blue shark reaches about 3.6 m. It is characterized by large eyes, a small mouth, a slender body, and a tendency to live in temperate and tropical oceans.
- Hammerhead shark
The hammerhead shark is an oceanic fish that has an oddly shaped head, giving it a wider field of vision. It also lives in tropical and temperate oceans. The hammerhead shark includes several types: winghead, hammerhead, scalloped hammerhead, muscovid, broad hammerhead, and head sharks.
Relationship of sharks with humans
Widespread misinformation that sharks are human-eating fish has led to increased attempts to cull and catch them, but the truth is there are only 10 types of sharks that pose a real danger to humans. humans.
As for the rest of the species, they present no danger to humans unless they are threatened, so treat sharks fairly, without aggression, and avoid provoking or threatening them to avoid their reaction.
- ↑ Jeffrey Carrier (5-11-2020), “Shark”, www.britannica.com, retrieved 2021-02-18. Edited.
- ^ a B J w “DISCOVER SOME OF THE MORE THAN 400 SPECIES OF SHARKS.”, www.requins.org, retrieved 2021-02-19. Edited.
- ^ a B J “The Sharks”, www.nationalgeographic.com, retrieved 2021-02-18. Edited.
- ^ a B J w vs h X Doctor Jennifer Kennedy (12/13/2019), “Shark Facts: Habitat, Behavior, Diet”, www.thinkco.com, retrieved 2021-02-19. Edited.
- ^ a B “Habitat”, seaworld.org, retrieved 2021-02-18. Edited.
- ^ a B J “Shark Habitat: Lessons for Kids”, study.com, retrieved 2021-02-18. Edited.
- ↑ Nick Whitney (2-8-2018), “How do sharks mate?” www.andersoncabotcenterforoceanlife.org, retrieved 2021-02-19. Edited.
- ^ a B “SharksFAQ”, Florida Museum, retrieved 2021-10-17. Edited.
- ^ a B Jennifer Kennedy (July 17, 2019), “Shark Species”, CO thought, retrieved 2021-10-17. Edited.
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