School of Biology, School of Chemistry, and Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, Georgia, USA.
Cold Spring Harb Perspect Biol. 2010 Jan;2(1):a002238. doi: 10.1101/cshperspect.a002238.
The Darwinian concept of biological evolution assumes that life on Earth shares a common ancestor. The diversification of this common ancestor through speciation events and vertical transmission of genetic material implies that the classification of life can be illustrated in a tree-like manner, commonly referred to as the Tree of Life. This article describes features of the Tree of Life, such as how the tree has been both pruned and become bushier throughout the past century as our knowledge of biology has expanded. We present current views that the classification of life may be best illustrated as a ring or even a coral with tree-like characteristics. This article also discusses how the organization of the Tree of Life offers clues about ancient life on Earth. In particular, we focus on the environmental conditions and temperature history of Precambrian life and show how chemical, biological, and geological data can converge to better understand this history."You know, a tree is a tree. How many more do you need to look at?"--Ronald Reagan (Governor of California), quoted in the Sacramento Bee, opposing expansion of Redwood National Park, March 3, 1966.
达尔文的生物进化观点假设地球上的生命拥有共同的祖先。通过物种形成事件和遗传物质的垂直传递，这个共同祖先的多样化意味着生命的分类可以用树状图的方式来表示，通常被称为生命之树。本文描述了生命之树的一些特征，例如，随着生物学知识的不断扩展，在过去的一个世纪中，生命之树的分支是如何被修剪和变得更加繁茂的。我们提出了目前的观点，即生命的分类可能最好用环形或甚至珊瑚状的方式来表示，具有树状特征。本文还讨论了生命之树的组织如何为了解地球上的古代生命提供线索。特别是，我们关注前寒武纪生命的环境条件和温度历史，并展示了如何通过化学、生物和地质数据的融合来更好地理解这段历史。“你知道，树就是树。你还需要看多少棵？”——罗纳德·里根（加利福尼亚州州长），引自《萨克拉门托蜜蜂报》，反对扩建红杉国家公园，1966 年 3 月 3 日。
