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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 extinct relatives of ...
Fish, in contrast, have two chambers, an atrium and a ventricle, while most reptiles have three chambers. [5] In a healthy heart, blood flows one way through the heart due to heart valves, which prevent backflow. [3] The heart is enclosed in a protective sac, the pericardium, which also contains a small amount of fluid.
Sauropsida (includes reptiles) A tetrapod (/ ˈtɛtrəˌpɒd /; [5] from Ancient Greek τετρα- (tetra-) 'four' and πούς (poús) 'foot') is any four- limbed vertebrate animal of the superclass Tetrapoda (/ tɛˈtræpədə /). [6] Tetrapods include all extant and extinct amphibians and amniotes, with the latter in turn evolving into two ...
Crocodilia (or Crocodylia, both / krɒkəˈdɪliə /) is an order of semiaquatic, predatory reptiles known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorph pseudosuchian, a subset of archosaurs that appeared about 235 million years ago and ...
The circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. [1][2] It includes the cardiovascular system, or vascular system, that consists of the heart and blood vessels (from Greek kardia meaning heart, and from Latin vascula ...
Tuatara are of interest for studying the evolution of reptiles. Tuatara are greenish brown and grey, and measure up to 80 cm (31 in) from head to tail-tip and weigh up to 1.3 kg (2.9 lb) [12] with a spiny crest along the back, especially pronounced in males. They have two rows of teeth in the upper jaw overlapping one row on the lower jaw ...
Physiology of dinosaurs. The physiology of dinosaurs has historically been a controversial subject, particularly their thermoregulation. Recently, many new lines of evidence have been brought to bear on dinosaur physiology generally, including not only metabolic systems and thermoregulation, but on respiratory and cardiovascular systems as well.
3.3 Reptile anatomy. 3.4 Bird anatomy. 3.5 ... The heart has two chambers and pumps the blood through the respiratory surfaces of the gills and on round the body ...