Book contents
- Frontmatter
- Contents
- Contributors
- THE MOLECULAR ORIGINS OF LIFE CAMBRIDGE
- Introduction
- Part I Setting the stage
- Part II Organic molecules on the early Earth
- Part III Possible starts for primitive life
- Part IV Clues from the bacterial world
- 15 Hyperthermophiles and their possible role as ancestors of modern life
- 16 Tracing the roots of the Universal Tree of Life
- Part V Clues from other planets
- Conclusion
- Index
16 - Tracing the roots of the Universal Tree of Life
Published online by Cambridge University Press: 06 January 2010
- Frontmatter
- Contents
- Contributors
- THE MOLECULAR ORIGINS OF LIFE CAMBRIDGE
- Introduction
- Part I Setting the stage
- Part II Organic molecules on the early Earth
- Part III Possible starts for primitive life
- Part IV Clues from the bacterial world
- 15 Hyperthermophiles and their possible role as ancestors of modern life
- 16 Tracing the roots of the Universal Tree of Life
- Part V Clues from other planets
- Conclusion
- Index
Summary
Tracing life's roots: progress and problems
Precambrian paleobiology: a new field of science
In 1859, when Charles Darwin unveiled his monumental monograph, The Origin of Species, major chapters in the history of life had already been deciphered. The familiar progressions from seaweeds to land plants, from marine invertebrates to higher mammals, provided Darwin a fossil-based foundation for his grand thesis. This evolutionary sequence from water to land is the history of Phanerozoic life, dating from 543 million years (Ma) ago and the appearance of calcareous algae and shelled invertebrates that marks the beginning of the Cambrian Period of geologic time. But what happened earlier? What were the forerunners of these early algae and primitive invertebrates? In short, how did evolution proceed during the Precambrian Eon, the pre- Phanerozoic seven-eighths of Earth history?
To these questions Darwin had no answers – indeed, until a scant three decades ago, Precambrian biologic history was terra incognita. But Darwin did know that if answers were not forthcoming, his theory was in jeopardy:
If the theory [of evolution] be true it is indisputable that before the lowest Cambrian stratum was deposited … the world swarmed with living creatures. [Yet] to the question why we do not find rich fossiliferous deposits belonging to these earliest periods … I can give no satisfactory answer. The case at present must remain inexplicable; and may be truly urged as a valid argument against the views here entertained. (Darwin 1859, Chapter X)
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- The Molecular Origins of LifeAssembling Pieces of the Puzzle, pp. 336 - 362Publisher: Cambridge University PressPrint publication year: 1998
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