WebIn an era where the genomes of many vertebrate species are becoming available, studies are now exploring the molecular basis of this transition from oviparity to viviparity, and in … WebMarine amphibians: A) do not exist at all B) are gill-breathers C) are fish-like D) include only tropical species E) are oviparous. A) do not exist at all. All tetrapods are: A) endotherms B) inhabitants of land C) air-breathers D) live-bearers E) vertebrates except groups such as sea squirts. C) air-breathers.

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The amniotic egg formed through a series of evolutionary steps. After internal fertilization and the habit of laying eggs in terrestrial environments became a reproduction strategy amongst the amniote ancestors, the next major breakthrough appears to have involved a gradual replacement of the gelatinous … See more Amniotes are a clade of tetrapod vertebrates that comprises sauropsids (including all reptiles and birds, and extinct parareptiles and non-avian dinosaurs) and synapsids (including pelycosaurs and therapsids such as See more Zoologists characterize amniotes in part by embryonic development that includes the formation of several extensive membranes, the amnion, chorion, and allantois. Amniotes develop directly into a (typically) terrestrial form with limbs and a thick stratified See more The term amniote comes from the amnion, which derives from Greek ἀμνίον (amnion), meaning "membrane surrounding the fetus". The term originally meant "bowl in which the blood of sacrificed animals was caught", which derived from ἀμνός (amnos), meaning … See more Amniota was first formally described by the embryologist Ernst Haeckel in 1866 on the presence of the amnion, hence the name. A problem with this definition is that the trait (apomorphy) in question does not fossilize, and the status of fossil forms has to be inferred from … See more WebMammals move about in a great variety of ways: burrowing, bipedal or tetrapedal running, flying, or swimming. Reproduction in mammals is usually viviparous, the young developing in the uterus, where nutritive materials are made available through an allantoic placenta or, in a few cases, a yolk sac. The fertilized egg develops directly into the ... orchid trees for sale

Evolution of viviparous reproduction in Paleozoic and Mesozoic

WebLori C. Albergotti, Louis J. Guillette Jr., in Hormones and Reproduction of Vertebrates: Reptiles, 2011 10 Conclusions. In squamates, the transition from oviparity to viviparity involves changes in the timing of egg retention, thickness of the eggshell, and the development of a placenta. These physiological and morphological requirements of … WebMay 25, 2024 · Description. Vertebrate Life distills the necessary information from vertebrate anatomy, physiology, ecology, and behavioral studies and then helps students see important connections across levels of biological scale. The result is students come to understand how organisms function effectively in their environments and how lineages of … WebViviparity occurs in every vertebrate class, except birds. In invertebrates it has only rarely been described. Evidence from reptiles lends support to the view of saltational mode of appearance of viviparity, matrotrophy, and placentation ( Blackburn, 1992 ). ir remote creator