为了正常的体验网站,请在浏览器设置里面开启Javascript功能!

女性更年期归因于 男人

2017-11-10 6页 doc 23KB 20阅读

用户头像

is_594905

暂无简介

举报
女性更年期归因于 男人女性更年期归因于 男人 海量资料下载 免费学习英语 www.englishvip.com/xinlw.htm (申请网址) After decades of laboring under other theories that never seemed to add up, a team led by biologist Rama Singh has concluded that what causes menopause(更年期) in women is men. Singh, an evolutionary gen...
女性更年期归因于 男人
女性更年期归因于 男人 海量资料下载 免费学习英语 www.englishvip.com/xinlw.htm (申请网址) After decades of laboring under other theories that never seemed to add up, a team led by biologist Rama Singh has concluded that what causes menopause(更年期) in women is men. Singh, an evolutionary geneticist, backed by computer models developed by colleagues Jonathan Stone and Richard Morton, has determined that menopause is actually an unintended outcome of natural selection -- the result of its effects having become relaxed in older women. Over time, human males have shown a preference for younger women in selecting mates, stacking the Darwinian deck against continued fertility in older women, the researchers have found. "In a sense it is like aging, but it is different because it is an all-or-nothing process that has been accelerated because of preferential(优先的) mating," says Singh, a professor in McMaster's Department of Biology whose research specialties include the evolution of human diversity. Stone is an associate professor in the Department of Biology and associate director of McMaster's Origins Institute, whose themes include the origins of humanity, while Morton is a professor emeritus in Biology. While conventional thinking has held that menopause prevents older women from continuing to reproduce, in fact, the researchers' new theory says it is the lack of reproduction that has given rise to menopause. Their work appears in the online, open-access journal PLOS Computational Biology. Menopause is believed to be unique to humans, but no one had yet been able to offer a satisfactory explanation for why it occurs, Singh says. The prevailing "grandmother theory" holds that women have evolved to become infertile after a certain age to allow them to assist with rearing grandchildren, thus improving the survival of kin. Singh says that does not add up from an evolutionary perspective. "How do you evolve infertility? It is contrary to the whole notion of natural selection. Natural selection selects for fertility, for reproduction -- not for stopping it," he says. The new theory holds that, over time, competition among men of all ages for younger mates has left older females with much less chance of reproducing. The forces of natural selection, Singh says, are concerned only with the survival of the species through individual fitness, so they protect fertility in women while they are most likely to reproduce. 洛基国际英语 竭诚为您服务 海量资料下载 免费学习英语 www.englishvip.com/xinlw.htm (申请网址) After that period, natural selection ceases to quell the genetic mutations that ultimately bring on menopause, leaving women not only infertile, but also vulnerable to a host of health problems. "This theory says that natural selection doesn't have to do anything," Singh says. "If women were reproducing all along, and there were no preference against older women, women would be reproducing like men are for their whole lives." The development of menopause, then, was not a change that improved the survival of the species, but one that merely recognized that fertility did not serve any ongoing purpose beyond a certain age. For the vast majority of other animals, fertility continues until death, Singh explains, but women continue to live past their fertility because men remain fertile throughout their lives, and longevity is not inherited by gender. Singh points out that if women had historically been the ones to select younger mates, the situation would have been reversed, with men losing fertility. The consequence of menopause, however, is not only lost fertility for women, but an increased risk of illness and death that arises with hormonal changes that occur with menopause. Singh says a benefit of the new research could be to suggest that if menopause developed over time, that ultimately it could also be reversed. 经过几十年的劳动在其他理论,似乎从来没有加起来,由生物学家拉玛?辛格领导的研究小组得出的结论 是什么原因导致女性更年期(更年期)是男人。进化遗传学家,支持下开发的计算机模型的同事乔纳森?斯 通和理查?莫顿,辛格已经确定,更年期是自然选择实际上是一个意外的结果-其影响已成为中老年妇女 放松的结果。 随着时间的推移,人类的男性都表现出了偏爱年轻的女性在选择伴侣,中老年妇女的生育率将继续反对 达尔文的甲板堆放,研究人员已经发现。 “从某种意义上说,它是像老化,但因为它的所有,或全无的过程中,已经被加快,因为优先(优先的) 交配,它是不同的,“说,辛格,一个教授在McMaster的生物系的研究特色包括人类多样性的演变。 石是副教授在McMaster的起源研究所,其主包括人类的起源,而莫顿生物学名誉教授生物学和副主 任部。 尽管传统思维认为,更年期防止老年妇女继续重现,事实上,研究人员的新理论说,这是缺乏再生产, 已经引起更年期。 他们的工作出现在网上,开放获取期刊PLoS计算生物学。 更年期被认为是人类独有的,但没有人尚未能提供一个令人满意的解释为什么会发生,辛格说。 洛基国际英语 竭诚为您服务 海量资料下载 免费学习英语 www.englishvip.com/xinlw.htm (申请网址) 现行的“祖母理论”认为女性已经发展到了一定年龄后变得贫瘠,让他们协助抚养孙子,从而提高了生存的近亲。辛格说,加起来不从进化的角度来看。 “你怎么演变不孕,这是违背自然选择的整个概念。自然选择选择生育,再现 - 而不是停止,”他说。 新的理论认为,随着时间的推移,男人各年龄段的年轻队友之间的竞争已经离开老年女性再现的机会要少得多。自然选择的力量,辛格说,只关心通过个人健身物种的生存,所以他们保护女性的生育能力,而他们是最有可能重现。 期限届满后,自然选择不再平息了基因突变,最终带来更年期,使妇女不但不育,但也容易受到健康问题的主机。 说:“这个理论,自然选择没有做任何事情,”辛格说。“如果妇女音响一直以来,有没有偏好对老年妇女,妇女将再现像男人一样为他们的整个生活。” 更年期的发展,那么,是不是发生变化,提高物种的生存,但仅仅认识到,生育超过了一定的年龄没有任何正在进行的目的服务。 对于绝大多数的其他动物,生育率继续,直至死亡,辛格解释,但过去他们的生育妇女继续生活保持肥沃,因为男人终其一生,性别不会继承和长寿。 辛格指出,如果女性历来的选择更年轻的队友,情况会得到扭转,与男子失去生育能力。 更年期的后果,然而,不仅是失去了生育能力的妇女,但发生更年期荷尔蒙的变化而产生的疾病和死亡的风险增加。辛格说,新的研究的好处可以是建议,如果更年期的发展随着时间的推移,最终它也可以被逆转。 “成千上万人疯狂下载。。。。。。 更多价值连城的绝密英语学习资料, 洛基内部秘密英语,技巧,策略 请在 网上 申请报名” 洛基国际英语 竭诚为您服务
/
本文档为【女性更年期归因于 男人】,请使用软件OFFICE或WPS软件打开。作品中的文字与图均可以修改和编辑, 图片更改请在作品中右键图片并更换,文字修改请直接点击文字进行修改,也可以新增和删除文档中的内容。
[版权声明] 本站所有资料为用户分享产生,若发现您的权利被侵害,请联系客服邮件isharekefu@iask.cn,我们尽快处理。 本作品所展示的图片、画像、字体、音乐的版权可能需版权方额外授权,请谨慎使用。 网站提供的党政主题相关内容(国旗、国徽、党徽..)目的在于配合国家政策宣传,仅限个人学习分享使用,禁止用于任何广告和商用目的。

历史搜索

    清空历史搜索