Among animals, viviparity is development of the embryo inside the body of the mother. This is opposed to oviparity which is a reproductive mode in which females lay developing eggs that complete their development and hatch externally from the mother. The term 'viviparity' and its adjective form 'viviparous' derive from the Latin viv… 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

5 Vertebrate Groups Britannica

WebMar 24, 2010 · Reptile Vocabulary Amniotic egg – adaptation to terrestrial life that results in a water-proof egg with extra-embryonic membranes that aid in the vital functions of a living organism Extinct – all members of a species have died; ex) pterosaurs Extant – members of a species are still alive Bask – behavioral adaptation ... WebNov 22, 2024 · Answer: amniotic eggs. Amniotic eggs are eggs where the young (embryo) is covered by multiple life-supporting membranes, which in turn are covered by a hard shell. Tetrapods that give birth... great headstones

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 … WebAbstract. In the vertebrate tree of life, viviparity or live birth has independently evolved many times, resulting in a rich diversity of reproductive strategies. Viviparity is believed to be a mode of reproduction that evolved from the ancestral condition of oviparity or egg laying, where most of the fetal development occurs outside the body. WebApr 1, 1992 · Quantitative analyses based upon the superimposition of phylogenetic and reproductive data have revealed that viviparity has originated on at least 132 independent occasions among vertebrates, with 98 of these origins having occurred among reptiles. Quantitative analyses based upon the superimposition of phylogenetic and reproductive … great head throat relaxer