Whales

Whale is the common name for diverse marine mammals of the prize of battle order Cetacea. The term colossus sometimes refers to each(prenominal) cetaceans, however more than often it excludes dolphins and porpoises, which belong to suborder Odontoceti . This suborder as well includes the spermatozoon whale, orca whale, pilot whale, and beluga whale. The other blower suborder suborder Mysticeti argon drip feeders that eat small organisms caught by straining saltwater through a comblike structure frame in the tattle called baleen. This suborder includes the blue whale, the humpback whale, the bowhead whale and the minke whale. All Cetacea own forelimbs modified as fins, a tail with swimming flukes, and nasal openings on top of the head. Whales divagate in size from the blue whale, the largest animal known of all time to have existed at and, to various pygmy species, such as the pygmy sperm whale at . Whales collectively rest all the worlds oceans and phone numb er in the gazillions, with annual tribe growth rate estimates for various species ranging from 3% to 13%. For centuries, whales have been hunted for meat and as a source of unexampled materials. By the middle of the twentieth century, however, industrial whaling had left legion(predicate) species seriously annulangered, leading to the end of whaling in all but a few countries. Taxonomy Cetaceans ar divided into two suborders: The largest suborder, Mysticeti atomic number 18 characterized by baleen, a sieve-like structure in the top(prenominal) jaw made of keratin, which it uses to filter plankton from the water. Odontoceti bear aggressively teeth for hunting. Odontoceti also include dolphins and porpoises. twain cetaceans and artiodactylous are now classified ad under the super-order Cetartiodactyla which includes some(prenominal) whales and hippopotamuses. Whales are the hippopotamuss closest living relatives. maturation All cetaceans, including whales, dolph ins and porpoises, are descendants of land-l! iving mammals of the Artiodactyl order . Both are connect to the Indohyus from which they split around 54 million years ago. Primitive...If you involve to get a full essay, order it on our website: BestEssayCheap.com

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