Ostracoderms definition
Webostracoderm [ ŏs ′trə-kŏ-dûrm′ ] Any of various extinct primitive jawless fishes of the Ordovician through the Devonian Period. Most ostracoderms had their heads or entire … Webnoun Any of various extinct primitive jawless fishes of the Ordovician through the Devonian periods, having bodies encased in an armor of bony plates. American Heritage Similar …
Ostracoderms definition
Did you know?
WebDefinition the evolutionary development of a group; establishes relationships among organisms based upon derived characteristics and describes patterns of evolutionary change Term taxonomy Definition the study of the classification of organisms, including the theoretical basis for the classification Term systematics Definition WebOstracoderms like Cephalaspis and Boreaspis lived in an environment with turbulent waters like today’s estuaries or deltas, which supplied them a steady flow of fresh …
WebThe Osteostraci (bony armored jawless fish) are generally considered the sister taxon of Gnathostomata. [2] [8] [9] Jaw development in vertebrates is likely a product of the supporting gill arches. This development would help push water into the mouth by the movement of the jaw, so that it would pass over the gills for gas exchange. WebVerified answer. physics. Find the tension in the Achilles tendon and the force that the tibia exerts on the ankle joint when a person who weighs 750 N supports himself on …
Web3. External Features of Lamprey: The body comprises a cylindrical head and trunk and laterally flattened tail. The paired fins are absent, but the tail bears a median fin, which is expanded in front as a dorsal fin. In female the anal fin is present while in male copulatory papilla is found. Webostracoderms. Definition in the dictionary English. ostracoderms. Definitions. noun. plural of [i]ostracoderm[/i] Examples Stem. It was long thought that the first true vertebrates …
Webostracoderm. Definition in the dictionary English. ostracoderm. Definitions. noun (zoology) grammar. Any of the armored jawless fishes of the Paleozoic. noun. extinct fish …
WebOstracoderms were small fishes, often less than 1 foot (30 cm) long and were probably slow, bottom-dwelling animals. Their fins were small, and they lacked lateral fins, but did have medial fins. They had permanently open mouths. Another innovation of ostracoderms was the use of gills not for feeding, but exclusively for respiration. In all ... 57 電気番号WebStudy with Quizlet and memorize flashcards containing terms like 1. All chordates have a. a single, dorsal, tubular, nerve cord. b. a ventral heart. c. pharyngeal slits. d. a postanal tail as some stage. e. all of the choices are chordate features., 2. Although several invertebrate groups have been proposed as chordate ancestors, most zoologists now believe the … 57 河合奈保子Webos•tra•co•derm (ˈɒs trə koʊˌdɜrm) n. any of several extinct jawless fishes of the Ordovician to Devonian periods that had the body enclosed in an armor of bony … 57 虎牙WebEvolution fish Definition. The evolution of fish begins around 530 million years before the detonation of Cambria. Agnatha or jawless fish is the primary ancestor fish. Although it is not clear if the benefit of a hinged mandible is greater than the very cool strength, increased respiration, or a combination of factors, it might be that a jawed ... 57 英寸WebPlacodermi is a class of armoured prehistoric fish, known from fossils, which lived from the Silurian to the end of the Devonian period. Their head and thorax were covered by articulated armoured plates and the rest of the body was scaled or naked, depending on the species.Placoderms were among the first jawed fish; their jaws likely evolved from the … 57 電気記号WebDefinition of Ostracoderms 1. ostracoderm [n] - See also: ostracoderm Lexicographical Neighbors of Ostracoderms ostracisms ostracite ostracites ostracizable ostracization … 57 金鐘Webindex fossil, any animal or plant preserved in the rock record of the Earth that is characteristic of a particular span of geologic time or environment. A useful index fossil must be distinctive or easily recognizable, abundant, and have a wide geographic distribution and a short range through time. 5702厂招聘