0_Wizard
Sharks are elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins
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.
chosen_Shark_0
Shark
chosen_topic_0_Shark
Shark
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.
List of cartilaginous fish of Sri Lanka
Sri Lanka is a tropical island situated close to the southern tip of India. The diversity of fish fauna within the inland waterways and around the island is very high considering the small size of the island. Among the marine fishes, sharks and batoids (rays and skates) form a considerable diversity. A preliminary checklist of Sharks around Sri Lanka was compiled by marine biologist, ornithologist, astronomer and well known diver Rex I. De Silva in 1985. It is cited as the first most comprehensive catalogue to Sri Lankan cartilage fishes. On 2016 May, he published Illustrated guide of Sharks of Sri Lanka.
Fish anatomy
Fish anatomy is the study of the form or morphology of fishes. It can be contrasted with fish physiology, which is the study of how the component parts of fish function together in the living fish. In practice, fish anatomy and fish physiology complement each other, the former dealing with the structure of a fish, its organs or component parts and how they are put together, such as might be observed on the dissecting table or under the microscope, and the latter dealing with how those components function together in living fish. The anatomy of fish is often shaped by the physical characteristics of water, the medium in which fish live.
Fish fin
Fins are usually the most distinctive anatomical features of a fish. They are composed of bony spines or rays protruding from the body with skin covering them and joining them together, either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as seen in sharks. Apart from the tail or caudal fin, fish fins have no direct connection with the spine and are supported only by muscles. Their principal function is to help the fish swim. Fins located in different places on the fish serve different purposes such as moving forward, turning, keeping an upright position or stopping. Most fish use fins when swimming, flying fish use pectoral fins for gliding, and frogfish use them for crawling.
Fish physiology
Fish physiology is the scientific study of how the component parts of fish function together in the living fish. It can be contrasted with fish anatomy, which is the study of the form or morphology of fishes. In practice, fish anatomy and physiology complement each other, the former dealing with the structure of a fish, its organs or component parts and how they are put together, such as might be observed on the dissecting table or under the microscope, and the later dealing with how those components function together in the living fish. Most fish exchange gases using gills on either side of the pharynx (throat).
Manta ray
Manta rays are large rays belonging to the genus "Manta". The larger species, "M. birostris", reaches in width while the smaller, "M. alfredi", reaches . Both have triangular pectoral fins, horn-shaped cephalic fins and large, forward-facing mouths. They are classified among the Myliobatiformes (stingrays and relatives) and are placed in the family Myliobatidae (eagle rays). Mantas are found in warm temperate, subtropical and tropical waters. Both species are pelagic; "M. birostris" migrates across open oceans, singly or in groups, while "M. alfredi" tends to be resident and coastal. They are filter feeders and eat large quantities of zooplankton, which they swallow with their open mouths as they swim.
Broadnose sevengill shark
The broadnose sevengill shark ("Notorynchus cepedianus") is the only extant member of the genus "Notorynchus", in the family Hexanchidae. It is recognizable because of its seven gill slits, while most shark species have five gill slits, with the exception of the members of the order Hexanchiformes and the sixgill sawshark. This shark has a large, thick body, with a broad head and blunt snout. The top jaw has jagged, cusped teeth and the bottom jaw has comb-shaped teeth. Its single dorsal fin is set far back along the spine towards the caudal fin, and is behind the pelvic fins. In this shark the upper caudal fin is much longer than the lower, and is slightly notched near the tip.
1_Apprentice
Well okay then! I know there are lots of different species as well -- and that they definitely get a bad rap!
0_Wizard
Today's shark is classified as  clade Selachimorpha which is not too different from ray
Modern sharks are classified within the clade Selachimorpha (or Selachii) and are the sister group to the rays.
chosen_Shark_0
Shark
chosen_topic_0_Shark
Shark
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.
List of cartilaginous fish of Sri Lanka
Sri Lanka is a tropical island situated close to the southern tip of India. The diversity of fish fauna within the inland waterways and around the island is very high considering the small size of the island. Among the marine fishes, sharks and batoids (rays and skates) form a considerable diversity. A preliminary checklist of Sharks around Sri Lanka was compiled by marine biologist, ornithologist, astronomer and well known diver Rex I. De Silva in 1985. It is cited as the first most comprehensive catalogue to Sri Lankan cartilage fishes. On 2016 May, he published Illustrated guide of Sharks of Sri Lanka.
Megalodon
Megalodon ("Carcharocles megalodon"), meaning "big tooth," is an extinct species of shark that lived approximately 23 to 2.6 million years ago (mya), during the Early Miocene to the end of the Pliocene. There had been some debate regarding the taxonomy of megalodon: some researchers argued that it was of the family Lamnidae and closely related to the great white shark ("Carcharodon carcharias"), while others argued that it belonged to the extinct family Otodontidae; presently, there is near unanimous consensus that the latter view is correct. Its genus placement is still debated, authors placing it in either "Carcharocles", "Megaselachus", "Otodus", or "Procarcharodon".
List of Plasmodium species
The genus "Plasmodium" is a member of the order Haemosporidia. It is the largest genus within this order and currently consists of over 250 species. They cause malaria in many different vertebrates. The species in this genus are entirely parasitic with part of their life cycle spent in a vertebrate host and another in an invertebrate host - usually a mosquito. Vertebrates infected by members of this genus include mammals, birds and reptiles. Host range among the mammalian orders is non uniform. At least 29 species infect non human primates; rodents outside the tropical parts of Africa are rarely affected; a few species are known to infect bats, porcupines and squirrels; carnivores, insectivores and marsupials are not known to act as hosts.
Fish
Fish are the gill-bearing aquatic craniate animals that lack limbs with digits. They form a sister group to the tunicates, together forming the olfactores. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Tetrapods emerged within lobe-finned fishes, so cladistically they are fish as well. However, traditionally fish are rendered paraphyletic by excluding the tetrapods (i.e., the amphibians, reptiles, birds and mammals which all descended from within the same ancestry). Because in this manner the term "fish" is defined negatively as a paraphyletic group, it is not considered a formal taxonomic grouping in systematic biology.
Great white shark
The great white shark ("Carcharodon carcharias"), commonly known as the great white or the white shark, is a species of large mackerel shark which can be found in the coastal surface waters of all the major oceans. The great white shark is notable for its size, with larger female individuals growing to in length and in weight at maturity. However most are smaller, males measuring and females on average. According to a 2014 study the lifespan of great white sharks is estimated to be as long as 70 years or more, well above previous estimates, making it one of the longest lived cartilaginous fish currently known.
Zebra shark
The zebra shark ("Stegostoma fasciatum") is a species of carpet shark and the sole member of the family Stegostomatidae. It is found throughout the tropical Indo-Pacific, frequenting coral reefs and sandy flats to a depth of . Adult zebra sharks are distinctive in appearance, with five longitudinal ridges on a cylindrical body, a low caudal fin comprising nearly half the total length, and a pattern of dark spots on a pale background. Young zebra sharks under long have a completely different pattern, consisting of light vertical stripes on a brown background, and lack the ridges. This species attains a length of .