The third great domain of life, the archaea, look, under a microscope, like bacteria.

第三大“域”是古菌域，在显微镜下察看时，古菌看起来像细菌。

youdao

Or are there other biological domains hiding in the shadows—missed, like the archaea were for so long, because biologists have been using the wrong tools to look?

或者是否还有其他的生物“域”隐藏在某个神秘角落？ ——不为人所知，就好像古菌一样，因为生物学家误用观察工具所致，默默无闻多时。

youdao

As to importance, when originally identified as distinct, the archaea, too, were regarded as marginal-yet their methane-generating properties are now a factor in climate-change calculations.

至于其重要性，古菌群在最开始被认定为自成一类时，也被视为无关紧要——但是它们释放甲烷的特性现在已被纳入气候变化的考察因素。

youdao

That means leaving out the bacteria, which are ubiquitous but for whom the concept of 'species' is rather problematic, and the archaea, the third great class of Earthly life.

这意味着细菌（虽普遍存在但能否称为“物种”则备受争议）以及地球生命排在第三等级的古细菌都被排除在外。

youdao

But this doesn't mean there are no viruses that affect the Archaea.

但是这也并不意味着没有病毒可以影响到古生菌。

youdao

But while bacteria reproduce rapidly, the Archaea population doubles over the course of hundreds, even thousands, of years thanks to a slower metabolism and distinct genetic structure.

尽管细菌繁殖很快，但是由于古生菌新陈代谢较慢，细胞结构截然不同，其数量需要历经几百年甚至几千年的时间才能翻倍。

youdao

But while bacteria reproduce rapidly, the Archaea population doubles over the course of hundreds, even thousands, of years thanks to a slower metabolism and distinct genetic structure.

尽管细菌繁殖很快，但是由于古生菌新陈代谢较慢，细胞结构截然不同，其数量需要历经几百年甚至几千年的时间才能翻倍。

youdao