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Showing 1 to 9 of 9 for “"viviparity"”.
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Constraints on the Evolution of Viviparity in the Lizard Genus Sceloporus
… possible constraints on the evolution of viviparity in the lizard genus Sceloporus by experimentally extending the length of egg retention past the normal time of oviposition for a number of oviparous species. Observations also included a representative of the genus Urosaurus, the sister …
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Physiological and Ecological Constraints on the Evolution of Viviparity in Sceloporine Lizards
… and ecological constraints on the evolution of viviparity in sceloporine lizards. In Chapters one and two, I investigated the role of in utero oxygen availability as a constraint on the capacity to support embryonic development during extended egg retention. I incubated eggs of sceloporine …
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Seasonal Changes in the Morphology of the Uterus of the Oviparous Lizard <em>Saproscincus mustelinus</em> and the Reproductively Bimodal Lizard <em>Saiphos equalis</em>.
… are supported by yolk, is the ancestral state to viviparity, the reproductive mode in which embryos are fully developed at birth. Viviparity in reptiles is found only in the squamates. Among the more than 100 origins of viviparity in squamates, many have occurred fairly recently and as a result …
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Life history evolution of the lizard Sceloporus scalaris: comparisons of lowland and montane populations
… others are viviparous, suggesting the origin of viviparity is relatively recent. This interpopulation comparison focused on Sceloporus scalaris in Arizona because low elevation (1500 m) and high elevation (2500-2900 m) populations exhibit short and long periods of egg retention, respectively, and …
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Constraints on the adaptive potential of ectotherms to climate change
… hypothesis” regarding the evolution of lizard viviparity. This model mechanistically demonstrates that fine-scale thermal environments, interacting with life-history trade-offs, drive the evolution of gestation length to navigate the impossibility of maximizing fitness across all life stages …
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Old World Serpents and New World Dragons: The Evolutionary Dynamics of Pythons and Liolaemid Lizards
… niche and reproductive mode (oviparity versus viviparity), I find that viviparity was the key factor in enabling liolamids to adapt to the high mountains of the Andes. Importantly, when lineages dispersed back into the lowlands, my results for Liolaemus, the most diverse genus in the family, …
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Old World Serpents and New World Dragons: The Evolutionary Dynamics of Pythons and Liolaemid Lizards
… niche and reproductive mode (oviparity versus viviparity), I find that viviparity was the key factor in enabling liolamids to adapt to the high mountains of the Andes. Importantly, when lineages dispersed back into the lowlands, my results for Liolaemus, the most diverse genus in the family, …
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Phenotypic Consequences of Gestation Temperature in the Northern Watersnake, Nerodia Sipedon
Temperature during embryonic development can strongly influence the developmental trajectory of reptiles. In snakes, offspring morphology, locomotor speed, anti-predator behavior, and growth are known to be affected by developmental temperature and are likely to have important fitness consequences. …
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Pattern and Mechanism of Calcium Mobilization During Embryonic Development in a Viviparous Snake, <em>Virginia striatula</em>.
<p>Yolk supplies the majority of embryonic calcium in snakes. Oviparous and viviparous snakes also receive calcium late in development from the eggshell and placenta, respectively. The pattern and mechanism of calcium transport are partly understood for oviparous snakes. I studied a viviparous …