这个世界上为什么要有男人？最新科学研究给出答案(图)

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男人为什么存在？这是个哲学问题还是个科学问题？

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The existence of men has long puzzled scientists. Sexual reproduction is inefficient and costly, yet the majority of multicellular species opt for this method to keep their genes going. So why do men exist? Researchers from the University of East Anglia (UAE) believe they may have finally cracked it, suggesting that the evolutionary force known as ‘sexual selection’ plays a key role in improving population health and protecting us against extinction.

“男人为什么会存在”长期以来一直困扰着科学家们。性繁殖效率低、成本高，但大多 数多细胞物种选择这种方法来保持基因的持续。那么男人为什么存在呢？东英吉利大学 (阿联酋) 的研究人员认为，他们可能最终找到了答案，他们的发现表明被称为 "性选 择" 的进化驱动力，在改善人类群体的健康和保护我们免遭灭绝起着关键作用。

The study, published in the journal Nature, looked at Tribolium flour beetles to understand why most multicellular organisms rely on sex to reproduce. Under controlled laboratory conditions, researchers studied 50 generations of beetles over a ten year period and tested the impact of sexual selection. Famously theorized by Charles Darwin, sexual selection is a process whereby males compete for a chance to reproduce and females choose which male to reproduce with.

这项研究发表在《自然》杂志上，通过观察三棱粉甲虫来了解为什么大多数多细胞有机 体依赖性繁殖。在受控实验室条件下，研究人员在十年时间内研究了50代甲虫，并测试 了性选择的影响。被达尔文非常著名的推论说，性选择是，雄性为繁殖的机会而竞争、 雌性为选择和哪一个雄性繁殖的一个过程。

"Almost all multicellular species on earth reproduce using sex, but its existence isn't easy to explain because sex carries big burdens, the most obvious of which is that only half of your offspring—daughters—will actually produce offspring. Why should any species waste all that effort on sons?” lead researcher Professor Matt Gage, from UEA's School of Biological Sciences, said in a statement.

“地球上几乎所有多细胞物种都使用性繁殖，但因为性承担着巨大的负担，所以它的存 在并不容易解释， 最明显的是，只有一半的后代 — 女儿 — 实际上会生产后代。那 为什么任何物种要在儿子身上花费那么多的经历呢？ “来自东英吉利大学生物科学学 院的首席研究员，Matt Gage博士，在一份声明中说。

"We wanted to understand how Darwinian selection can allow this widespread and seemingly wasteful reproductive system to persist, when a system where all individuals produce offspring without sex—as in all-female asexual populations—would be a far more effective route to reproduce greater numbers of offspring," he added.

“我们想弄明白达尔文的物竞天择的规律怎么会允许这种广泛的且貌似浪费的生殖系 统持续存在。 相比之下，所有个体都能不通过性即能繁衍后代的系统 - 就像母性无性 繁殖人口那样 - 会是一个更有效的繁衍更多后代的方式。”他补充说。

The researchers found that when sexual selection was removed and beetles were paired up into monogamous couples, the population's health declined rapidly and the bugs were wiped out by the 10th generation. Conversely, beetles that had a strong influence on sexual selection, where intense competition saw 90 males trying to compete to reproduce with only 10 females , were more resilient to extinction.

研究人员发现，当性选择被排除的情况下，甲虫被配对成一夫一妻制的夫妇时，人口的 健康迅速下降，到了第十代，这批虫子就灭绝了。相反，在强烈性选择影响的甲虫 ， 90只雄性试图与仅有的10只雌性繁衍的激烈的竞争中，它们更有顽强的生命力。

"To be good at out-competing rivals and attracting partners in the struggle to reproduce, an individual has to be good at most things, so sexual selection provides an important and effective filter to maintain and improve population genetic health,” said Gage. "Our findings provide direct support for the idea that sex persists as a dominant mode of reproduction because it allows sexual selection to provide these important genetic benefits.”

“要善于在竞争中胜过对手，并吸引伴侣在争斗中进行繁殖，个人必须擅长绝大多数的 技能，因此性选择为此提供了一个重要而有效的筛选机制，来维持和改良人口遗传基因 ，” Gage说。“由于它允许性选择，所以才能作为繁殖的主导模式，我们的研究结果 对于这一理论直接提供了支持。”

The study suggests that sexual selection plays a crucial role in sifting out harmful genetic mutations, as competition means females are less likely to mate with genetically inferior individuals. Even after 20 generations of inbreeding, the study found that the populations that were strongly influenced by sexual selection had a higher fitness and were able to maintain population health and avoid extinction.

研究表明，性选择在筛选有害基因突变方面起着至关重要的作用，因为竞争意味着雌性 不太可能与基因低下的个体交配。该研究发现，即使在20代近亲繁殖后，受性选择强烈 影响的群体仍具有较强的体质，能够维持群体健康，避免灭绝。