DeLong E F, Pace N R
Monterey Bay Aquarium Research Institute, 7700 Sandholdt Rd., Moss Landing, California 95039, USA.
Syst Biol. 2001 Aug;50(4):470-8.
The microbial way of life spans at least 3.8 billion years of evolution. Microbial organisms are pervasive, ubiquitous, and essential components of all ecosystems. The geochemical composition of Earth's biosphere has been molded largely by microbial activities. Yet, despite the predominance of microbes during the course of life's history, general principles and theory of microbial evolution and ecology are not well developed. Until recently, investigators had no idea how accurately cultivated microorganisms represented overall microbial diversity. The development of molecular phylogenetics has recently enabled characterization of naturally occurring microbial biota without cultivation. Free from the biases of culture-based studies, molecular phylogenetic surveys have revealed a vast array of new microbial groups. Many of these new microbes are widespread and abundant among contemporary microbiota and fall within novel divisions that branch deep within the tree of life. The breadth and extent of extant microbial diversity has become much clearer. A remaining challenge for microbial biologists is to better characterize the biological properties of these newly described microbial taxa. This more comprehensive picture will provide much better perspective on the natural history, ecology, and evolution of extant microbial life.
微生物的生活方式跨越了至少38亿年的进化历程。微生物是所有生态系统中普遍存在、无处不在且不可或缺的组成部分。地球生物圈的地球化学组成在很大程度上是由微生物活动塑造的。然而，尽管在生命历史进程中微生物占据主导地位，但微生物进化与生态学的一般原理和理论却并未得到充分发展。直到最近，研究人员都不清楚培养出的微生物能在多大程度上准确代表整体微生物多样性。分子系统发育学的发展最近使得无需培养就能对自然存在的微生物群落进行表征。分子系统发育调查摆脱了基于培养研究的偏差，揭示了大量新的微生物类群。这些新微生物中有许多在当代微生物群落中广泛存在且数量众多，属于生命之树中分支较深的新分类。现存微生物多样性的广度和范围已变得更加清晰。微生物生物学家面临的一个剩余挑战是更好地表征这些新描述的微生物分类单元的生物学特性。这一更全面的图景将为现存微生物生命的自然史、生态学和进化提供更好的视角。
