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    A desert tortoise emerging from its egg, surrounded by sand.

    What are the advantages of a water-tight egg?
    ::紧水蛋有什么好处?

    Obviously, water-tight eggs can be laid anywhere. They do not have to be kept constantly moist. There is no danger of the developing fetus dehydrating. Shown above is a tortoise hatching.
    ::显然,密水卵可以在任何地方产下。 它们不必一直保持湿润。 发育中的胎儿脱水没有危险。 上面显示的是一种乌龟孵化。

    Reptile Reproduction
    ::复制

    Most reproduce sexually and have internal fertilization . Males have one or two penises that pass from their cloaca to the cloaca of a female. occurs within the cloaca, and fertilized eggs leave the female’s body through the opening in the cloaca. In a minority of , the eggs are retained inside the female’s body until they hatch. Then the offspring leave the mother’s body through the cloaca opening.
    ::大部分的生殖是性生殖,并且有体内受精。 男性有一两个阴茎,从她们的阴茎到雌性的阴茎。 在阴茎里,受精的卵从雌性的身体里流出。 在阴茎里,受精的卵从雌性的身体里流出。 在少数的雌性体内,卵在孵化前保留在雌性体内。 然后,后代通过阴茎的开口离开母体。

    Amniotic Eggs
    ::羊蛋

    Unlike , reptiles produce amniotic eggs (see Figure ). The shell, membranes, and other structures of an amniotic egg protect and nourish the embryo . They keep the embryo moist and safe while it grows and develops. They also provide it with a rich, fatty food source (the yolk ).
    ::与爬行动物不同的是,爬行动物产出羊蛋(见图 ) 。 外壳、膜和其他的羊蛋结构保护和养殖胚胎。 它们保持胚胎的湿润和安全,同时胚胎在生长和发育。 它们也为胚胎提供了丰富、脂肪的食物来源(黄蛋 ) 。

    An amniotic egg, highlighting its protective structures and yolk.

    The amniotic egg is an important adaptation in fully terrestrial vertebrates. It first evolved in reptiles. The shells of reptile eggs are either hard or leathery.
    ::羊蛋是完全陆地脊椎动物的重要适应。 它首先在爬行动物中演变。 爬行动物蛋的壳状是硬的或皮质的。

    Reptile Young
    ::年轻人regtile Young

    Unlike amphibians, reptiles do not have a larval stage. Instead, newly hatched reptiles look like smaller versions of the adults. They are able to move about on their own, but they are vulnerable to predators . Even so, most reptile parents provide no care to their hatchlings . In fact, most reptiles don’t even take care of their eggs. For example, female sea lay their eggs on a sandy beach and then return to the ocean. The only exceptions are female crocodiles and alligators. They may defend their nest from predators and help the hatchlings reach the . If the young remain in the area, the mother may continue to protect them for up to a year.
    ::与两栖动物不同,爬行动物没有幼虫阶段。 相反,新孵化的爬行动物看起来像成人的较小版本。它们可以自己移动,但容易受到食肉动物的伤害。即使如此,大多数爬行动物的父母都不照顾幼崽。事实上,大多数爬行动物甚至不照顾它们的蛋。例如,雌性海藻在沙滩上产卵,然后返回海洋。唯一的例外是雌性鳄鱼和鳄鱼。它们可以保护自己的巢,免受食肉动物的侵扰,帮助孵化动物到达它们。如果年轻人留在这个区域,母亲可以继续保护它们长达一年。

    Summary
    ::摘要

    • Most reptiles reproduce sexually and have internal fertilization.
      ::大多数爬行动物性繁殖,并有内脏受精。
    • Reptile eggs are amniotic, so they can be laid on land instead of in water.
      ::爬虫蛋是羊水,所以可以放在陆地上而不是在水中。
    • Reptiles do not have a larval stage, and their hatchlings are relatively mature.
      ::爬虫没有幼虫阶段,它们的幼崽相对成熟。
    • Reptile parents provide little if any care to their young.
      ::爬虫父母对年幼者几乎没有任何照顾。

    Review
    ::回顾

    1. Outline the structure and function of an amniotic egg.
      ::概括出一个羊膜蛋的结构和功能。
    2. Describe young reptiles.
      ::描述年轻的爬行动物。