Question

Are sharks ureotelic?

Answer 1

Sharks are a group of elasmobranch fish characterized by cartilaginous skeletons, five to seven-gill slits on the sides of the head, and pectoral fins not fused to the head. Modern sharks are classified within the Selachimorpha clade and are the sister group to the rays.

Complete answer:
The process of excreting nitrogenous waste in the form of ammonia is called ammonia. Phenomena are known as ammonotelism. Birds, amphibians, reptiles, most aquatic animals, including fish, some terrestrial invertebrates, larvae, and mammals, including humans, excrete urea acid as waste.

The ureotelic organism excretes excess nitrogen like urea. Urea is less toxic and needs less water than Ammonia. Uric acid or its salts are excreted by the uricotelic organism. In contrast to Ammonia and Urea, uric acid is the least toxic and the most water-soluble. It can be stored in cells and body tissues without toxic effects and therefore needs the least water and is a highly efficient mode of excretion in comparison to two other methods.Example: Ureotelic organisms include cartilaginous fish, bone fishes, adult amphibians, and mammals, including humans.

In particular, unlike other vertebrates, sharks have a skeletal cartilage structure rather than bone structure. Urea and trimethylamine in their blood and tissues help maintain their osmotic balance. They have no ordinary urinary tract, so they concentrate urea in their blood and excrete it through their skin.

Thus, sharks, along with most other cartilaginous fish are ureotelic.

Note: Species that excrete uric acid waste are referred to as uricotelic organisms. Uricate excreta is usually white paste and insoluble solids or semi-solids. Needs very little water to flush out the uric acid. Ex: Uricotelic organisms include earthly arthropods (including insects), lizards, snakes, and birds.