The presence of an amniotic buffer, of a water-impermeable skin, and of a robust, air-breathing, respiratory system, allow amniotes to live on land as true terrestrial animals. Amniotes have the ability to procreate without water bodies .

羊膜動物（学名： Amniota ）是脊椎動物的一个演化支，其特征是胚胎在发育过程中会形成胎膜，使其可以在远离水体的陆地环境进行繁殖。 羊膜动物与不具备胎膜的两栖动物一起组成了代表陆生脊椎动物的四足总纲。. 与半水生的两栖动物不同，羊膜动物在其生命周期中的任何一个阶段都 …

The 'invention' of the cleidoic egg, and its embryonic membranes, is the main reason why the eggs of an amniote do not need to be laid in water. Thus, as distinct from the amphibians, amniotes are truly terrestrial. Secondarily, many reptiles and mammals returned to water, and mammals bear the young live, as do some reptile groups.

2024年12月16日 · 羊膜动物（学名： Amniota ）是脊椎动物的一个演化支，其特征是胚胎在发育过程中会形成胎膜，使其可以在远离水体的陆地环境进行繁殖。 羊膜动物与不具备胎膜的两栖动物一起组成了代表陆生脊椎动物的四足总纲。. 与半水生的两栖动物不同，羊膜动物在其生命周期中的任何一个阶段都不用鳃进行 ...

The amniotic fluid allows the free movements of the fetus during the later stages of pregnancy, and also protects it by diminishing the risk of injury from without. It contains less than two percent solids, consisting of urea and other extractives, inorganic salts, a small amount of protein, and frequently a trace of sugar. That some of the ...

The amniotic sac, also called the bag of waters [1] [2] or the membranes, [3] is the sac in which the embryo and later fetus develops in amniotes. It is a thin but tough transparent pair of membranes that hold a developing embryo (and later fetus) until shortly before birth .

The name "anamniote" is a back-formation word created by adding the prefix an-to the word amniote, which in turn refers to the amnion, an extraembryonic membrane present during the amniotes' embryonic development which serves as a biochemical barrier that shields the embryo from environmental fluctuations by regulating the oxygen, carbon ...

The amniotic fluid is the protective liquid contained by the amniotic sac of a gravid amniote. This fluid serves as a cushion for the growing fetus, but also serves to facilitate the exchange of nutrients, water, and biochemical products between mother and fetus. For humans, the amniotic fluid is commonly called water or waters (Latin liquor ...

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Fully terrestrial life was achieved with the development of the amniote egg, where a number of membranous sacks protect the embryo and facilitate gas exchange between the egg and the atmosphere. The first to evolve was probably the allantois, a …