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Early tetrapods probably had a three-chambered heart, as do modern amphibians and lepidosaurian and chelonian reptiles, in which oxygenated blood from the lungs and de-oxygenated blood from the respiring tissues enters by separate atria, and is directed via a spiral valve to the appropriate vessel — aorta for oxygenated blood and pulmonary ...
By the Upper Devonian period, the fin-limb transition as well as other skeletal changes such as gill arch reduction, opercular series loss, mid-line fin loss, and scale reduction were already completed in many aquatic organisms. [ 3] As aquatic tetrapods began their transition to land, several skeletal changes are thought to have occurred to ...
Family Uropeltidae (shieldtail snakes) Family Viperidae (vipers, rattlesnakes, and more) Family Xenodermatidae. Family Xenopeltidae (sunbeam snakes) Family Anomalepidae (dawn blind snakes) Family Gerrhopilidae (Indo-Malayan blind snakes) Family Leptotyphlopidae (slender blind snakes) Family Typhlopidae ("true" blind snakes) Family Xenotyphlopidae.
The evolution of tetrapods began about 400 million years ago in the Devonian Period with the earliest tetrapods evolved from lobe-finned fishes. [1] Tetrapods (under the apomorphy-based definition used on this page) are categorized as animals in the biological superclass Tetrapoda, which includes all living and extinct amphibians, reptiles, birds, and mammals.
Pangalloanserae (fowl) Neoaves. Synonyms. Neornithes Gadow, 1883. Birds are a group of warm-blooded vertebrates constituting the class Aves (/ ˈeɪviːz /), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton.
Avesuchia Benton, 1999. Archosauria (lit. 'ruling reptiles') or archosaurs (/ ˈɑːrkəˌsɔːr / [3]) is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only extant representatives. Although broadly classified as reptiles, which traditionally exclude birds, the cladistic sense of the term includes all living and ...
Fish physiology is the scientific study of how the component parts of fish function together in the living fish. [2] 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 ...
Gnathostomata is traditionally a infraphylum, broken into three top-level groupings: Chondrichthyes, or the cartilaginous fish; Placodermi, an extinct grade of armored fish; and Teleostomi, which includes the familiar classes of bony fish, birds, mammals, reptiles, and amphibians. Some classification systems have used the term Amphirhina.