有性生殖

En la primera etapa de la reproducción sexual, 'meiosis', el número de cromosomas es reducido de un número diploide (2n) a uno haploide (n). Durante la 'fertilización', los gametos haploides se unen para formar un cigoto diploide y restablecer el número original de cromosomas (2n).

Australian emperor laying egg, guarded by the male

Flowers are the sexual organs of flowering plants.

有性生殖是生殖的一种类型，它导致了后代加强基因多样化。它可以用两个进程刻画。第一个是减数分裂，涉及将染色体个数减半。第二个是受精，它使得两个配偶子融合，并恢复原来的染色体个数。在减数分裂时，每对染色体通常交叉以达到基因重组。

性的演变是现代演化生物学的重大谜团。最早的有性繁殖的生物的化石证据是来自狭带纪的真核细胞，距今约12到10亿年。有性生殖是绝大多数可见生命体的繁殖形式，包括几乎所有的动物和植物。细菌接合（bacterial conjugation），也就是两个细菌之间的DNA转移，有时被错误地视为有性生殖，因为机理其实很相似。

Sexual reproduction 有性生殖

In the first stage of sexual reproduction,

Sexual reproduction is a form of reproduction where two morphologically distinct types of specialized reproductive cells called gametes fuse together, involving a female's large ovum (or egg) and a male's smaller sperm. Each gamete contains half the number of chromosomes of normal cells. They are created by a specialized type of cell division, which only occurs in eukaryotic cells, known as meiosis. The two gametes fuse during fertilization to produce DNA replication and the creation of a single-celled zygote which includes genetic material from both gametes. In a process called genetic recombination, genetic material (DNA) joins up so that homologous chromosome sequences are aligned with each other, and this is followed by exchange of genetic information. Two rounds of cell division then produce four daughter cells with half the number of chromosomes from each original parent cell, and the same number of chromosomes as both parents, though self-fertilization can occur. For instance, in human reproduction each human cell contains 46 chromosomes, 23 pairs, except gamete cells, which only contain 23 chromosomes, so the child will have 23 chromosomes from each parent genetically recombined into 23 pairs. Cell division initiates the development of a new individual organism in multicellular organisms, including animals and plants, for the vast majority of whom this is the primary method of reproduction. A species is defined as a taxonomic rank. A species is often defined as the largest group of organisms where two hybrids are capable of reproducing fertile offspring, typically using sexual reproduction, although the species problem encompasses a series of difficult related questions that often come up when biologists define the word species.

单词	Sexual reproduction
释义	Sexual reproduction 英语例句库 The class Deuteromycetes or Fungi Imperfecti includes a variety of fungi that lack modes of sexual reproduction. 半知菌纲，包括大量无性繁殖的真菌。原声例句 BBC 听力 2014年7月合集 The experiment into the effect of weightlessness on reptiles' sexual reproduction is still continuing. 研究失重状态对壁虎性繁殖能力影响的实验仍在继续。 Scientific American 2013年3月合集 Researchers found that the male sparrows that adopted the newer songs had higher rates of sexual reproduction. 研究人员发现，雄性麻雀中声音比较新潮的麻雀有性繁殖的几率更高。 VOA慢速英语_科技 It is the only known species of jellyfish able to repeatedly change back into a larval stage after sexual reproduction. 灯塔水母是已知唯一一种在有性繁殖后能够反复回到幼虫阶段的水母。微观旅途 But sexual reproduction in the microcosmos is not like sexual reproduction for the rest of us. 但微观宇宙中的有性生殖不同于我们其他人的有性生殖。 Life Noggin So, how does this have to do with sexual reproduction? 那么，这与有性生殖有什么关系呢？ TED-Ed（视频版） IVF works by mimicking the brilliant design of sexual reproduction. IVF 的工作原理是模仿有性生殖的绝妙设计。 SciShow 合集 Researchers have called this solo style of sexual reproduction " selfing" . 研究人员称这种有性繁殖的独奏方式为“自交”。科学60秒听力 2016年9月合集 " And of course it is absolutely amazing and difficult for a human mind to understand that sexual reproduction begins so late in life." “当然对人类来说这绝对是相当惊人的，人类思维很难理解有性繁殖开始的这么晚。” Life Noggin Now, evolution is a slow process, but sexual reproduction can help speed it up. 进化是一个缓慢的过程，但有性繁殖可以帮助加快它的速度。微观旅途 In sexual reproduction, genes can flow much more easily through populations, which has a huge evolutionary advantage. 在有性繁殖中，基因可以更容易地在种群中流动，这具有巨大的进化优势。物种起源 With all organic beings, excepting perhaps some of the very lowest, sexual reproduction seems to be essentially similar. 对于所有有机生物，除了一些最低等的生物，有性繁殖似乎在本质上是相似的。 Osmosis-内分泌 Secondary sex characteristics refers to any sex-specific physical characteristic that is not directly involved or necessary in sexual reproduction, like pubic hair and breasts, in females. 第二性征是指其他所有性别特异的、而不直接与生育相关或在生育中不是必需的体征，例如阴毛和女性的乳房。双语版 TED-Ed 演讲精选 Like the rest of us, sexual reproduction is how Pando came into the world in the first place all those tens or hundreds of thousands of years ago. 与我们一样，有性繁殖是潘多在几十万或者几百万年前最初来到世上的方式。开启地球探索之旅 A coral consists of clonal colonies of the same organism, although sexual reproduction also occurs between corals through the release of spores. 珊瑚由同一生物的克隆群落组成，尽管珊瑚之间也会通过释放孢子进行有性生殖。自然奇观探索 Also, if environmental conditions are poor, asexual reproduction involves less effort than sexual reproduction because the female doesn't need to waste resources finding a mate. 此外，如果环境条件较差，无性生殖所需的努力比有性生殖要少，因为雌性不需要浪费资源寻找配偶。社会学 Crash Course Since sexual reproduction is necessary for the reproduction of society, this view says that sex has to be organized in some way, in order for society to function. 由于有性生殖对于社会的再生产是必要的，这种观点认为性必须以某种方式组织起来，以便社会运作。微观旅途 And while humans, with our experience of plants and animals, are of course most familiar with sexual reproduction, that is absolutely not the only way it can be done. 虽然人类凭借我们对植物和动物的经验，当然最熟悉有性繁殖，但这绝对不是唯一可以做到的方式。物种起源 It may be worth notice that when Wagner's remarkable discovery was first announced, I was asked how was it possible to account for the larvae of this fly having acquired the power of a sexual reproduction. 值得注意的是，当瓦格纳的非凡发现首次被宣布时，有人问我如何解释这种苍蝇的幼虫获得了有性生殖的能力。中文百科有性生殖有性生殖是生殖的一种类型，它导致了后代加强基因多样化。它可以用两个进程刻画。第一个是减数分裂，涉及将染色体个数减半。第二个是受精，它使得两个配偶子融合，并恢复原来的染色体个数。在减数分裂时，每对染色体通常交叉以达到基因重组。性的演变是现代演化生物学的重大谜团。最早的有性繁殖的生物的化石证据是来自狭带纪的真核细胞，距今约12到10亿年。有性生殖是绝大多数可见生命体的繁殖形式，包括几乎所有的动物和植物。细菌接合（bacterial conjugation），也就是两个细菌之间的DNA转移，有时被错误地视为有性生殖，因为机理其实很相似。英语百科 Sexual reproduction 有性生殖 Sexual reproduction is a form of reproduction where two morphologically distinct types of specialized reproductive cells called gametes fuse together, involving a female's large ovum (or egg) and a male's smaller sperm. Each gamete contains half the number of chromosomes of normal cells. They are created by a specialized type of cell division, which only occurs in eukaryotic cells, known as meiosis. The two gametes fuse during fertilization to produce DNA replication and the creation of a single-celled zygote which includes genetic material from both gametes. In a process called genetic recombination, genetic material (DNA) joins up so that homologous chromosome sequences are aligned with each other, and this is followed by exchange of genetic information. Two rounds of cell division then produce four daughter cells with half the number of chromosomes from each original parent cell, and the same number of chromosomes as both parents, though self-fertilization can occur. For instance, in human reproduction each human cell contains 46 chromosomes, 23 pairs, except gamete cells, which only contain 23 chromosomes, so the child will have 23 chromosomes from each parent genetically recombined into 23 pairs. Cell division initiates the development of a new individual organism in multicellular organisms, including animals and plants, for the vast majority of whom this is the primary method of reproduction. A species is defined as a taxonomic rank. A species is often defined as the largest group of organisms where two hybrids are capable of reproducing fertile offspring, typically using sexual reproduction, although the species problem encompasses a series of difficult related questions that often come up when biologists define the word species.
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