Earth Sciences 1089F/G Lecture Notes - Lecture 17: Theropoda, Ischium, Bipedalism
7 Oct 2016
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Possible that dragon myths were spawned from dinosaurs. Dragons are described as large reptiles with wings, that spit fire. Most primitive reptile group is termed the stem reptiles small, lizard-like forms that evolved from amphibians. By the permian period, three groups branched off from stem-reptiles : mammal-like reptiles evolved into mammals, marine reptiles, all other reptiles two subgroups, squamates (lizards/snakes, archosaurs (crocodiles, dinosaurs, birds. Success of the dinosaur can be attributed to the development of an upright posture. Stem reptiles & lizards have a sprawling posture that limits mobility and breathing. Thecodonts attained a semi-upright posture that allowed for better mobility. Later forms developed a nearly full upright posture. Dinosaurs attained full upright posture with legs positioned directly beneath the body allowing for maximum mobility. Oldest known are about 228 million years old, from mid-triassic rocks in. Appears the earliest dinosaurs were meat-eating saurichians, plant-eating saurichians appeared by the late triassic and ornithischians appeared by.
