请输入您要查询的英文单词:

 

单词 viviparity
释义

viviparity


vi·vip·a·rous

V0131700 (vī-vĭp′ər-əs, vĭ-)adj.1. Zoology Giving birth to living offspring that develop within the mother's body. Most mammals and some other animals are viviparous.2. Botany a. Germinating or producing seeds that germinate before becoming detached from the parent plant, as in the mangrove.b. Producing bulbils or new plants rather than seed, as in the tiger lily.
[From Latin vīviparus : vīvus, alive; see gwei- in Indo-European roots + -parus, -parous.]
vi′vi·par′i·ty (vī′və-păr′ĭ-tē, vĭv′ə-) n.vi·vip′a·rous·ly adv.
Translations

Viviparity


Viviparity

 

a means of reproducing offspring in which the embryo develops in the mother’s body, is nourished directly by the mother through a placenta, and is born more or less developed and free of any egg covering.

Viviparity is counterposed to oviparity, in which the development of the embryo and its release from the egg covering occur outside the mother’s body (after the eggs are laid). The historical connection between viviparity and oviparity is indicated by rare cases of ovoviviparity, in which the embryo develops from an egg in the mother’s body and is nourished chiefly on substances stored in the egg itself, but also is secreted by the mother’s body and is freed of the egg covering, usually after the egg is laid.

Among invertebrates, viviparity is characteristic of some coelenterates, arthropods, mollusks, worms, and echinoderms. Among chordates, it is characteristic of salpas, many sharks and rays, some cyprinodonts, frogs, Caeciliidae, salamanders, tortoises, lizards, and snakes, and of the majority of mammals (except Echidna, Proechidna, and the platypus), including man. Development of the embryo in viviparity may occur in the ovary, the oviducts or dilations of them converted into a uterus, or in the vagina. In many viviparous animals embryonic membranes are formed around the embryo.

viviparity


viv·i·par·i·ty

(viv'i-pār'i-tē), The quality or state of being viviparous, that is, producing offspring that are living at the time of birth. Synonym(s): zoogony

viviparity

(vĭv″ĭ-păr′ĭ-tē) The ability to produce living young rather than producing young by laying an egg that hatches.
ThesaurusSeeviviparous
随便看

 

英语词典包含2567994条英英释义在线翻译词条,基本涵盖了全部常用单词的英英翻译及用法,是英语学习的有利工具。

 

Copyright © 2004-2022 Newdu.com All Rights Reserved
更新时间:2024/11/11 18:43:00