Life on a Young Planet: The First Three Billion Years of Evolution on Earth (Hardcover)

What comes across loud and clear in the book is that a lot of progress is being made in evolution theory and paleontology using breakthroughs in the biological sciences along with modern research instrumentation. In other words a lot of exciting things are happening. This is not a quick read. It requires a clear mind and a determination to follow the author through a sophisticated but worthwhile scientific (and human) story. This is not a novel but it can be read and enjoyed.

This is a very well written book impressive in the detail, scope, and knowledge of the author. It is quite an impressive but short book for the general public on paleontology. This is a relatively short book of about 250 pages with 25 pages of notes and further readings, index, etc. The book contains a nice range of photos and charts, but it is mainly text. Short but intense.

It was painstakingly assembled to demonstrate a number of themes. One theme is the formation and development of ancient life; he explains that history. Another is to explain modern paleontology and how it actually function, i.e.: how can we go back in time. Another theme is - the interplay between the biodiversity and the environment. The latter describes the changes as the earth evolved through different climates and periods.

When Darwin wrote "Origin of the Species" he had only a partial view of the situation and it is generally agreed that he equivocates in his book about certain details. Since that time approximately 150 years has past and science has made many giant leaps forward. We have a much better understanding of the chemistry of plants, genetics, gene splicing, nuclear dating, and so on plus we have a broad array of new instruments and techniques to look at materials down to the sub-micron level and smaller.

Darwin's tree of life is in fact now composed of three branches being, i.e.: Bacteria, Eucarya (plants, animals, etc) and more recently Archaea being added. Furthermore this "tree" can be shown to be partially connected from genes. It is now clear that Prokaryotic (bacteria) metabolic processes form and sustain the fundamental ecology of life through the carbon, nitrogen, sulfur cycles on earth. Without the bacteria there would be no life as we know it - no us. And we of course know about our branch of the tree, but much less is known about this third branch Archaea.

The author goes into great detail to explain the study of ancient bacteria, the "Oxygen revolution", origins of Eukaryotic cells, animal fossils, and how they were discovered, where and what it all means. He discusses what is known and what are just guesses. He also discusses the search for life in meteorites. All in all it is short, intensive, but still very comprehensive and intensive.

Congratulations and thanks to the author for an excellent read. Five stars.

Jack in Toronto

Knoll asserts the benchmark for comprehending how life may have started was the Urey-Miller experiments of the 1950s. By assuming a particular composition of Earth's early atmosphere and bombarding that recipe with electricity to duplicate lightning, Urey and Miller produced amino acids. Knoll credits these experiments not with showing how life began, but by their stimulation of much further research. Since then, geologists have revealed increasingly older rocks. Instead of buried deep beneath the surface as might be expected, they are often found well exposed. Knoll's expeditions to chilly Siberian sites are offset by the roaring desert of outback Australia. Both locations have provided researchers with new information on composition, chemical and environmental processes, and, most significantly, Precambrian fossils.

The many research fields now involved in developing a picture of life's beginnings indicate how complex a task unveiling "simple" can be. Early life, of course, was microscopic. Sometimes it isn't fossils that are found, but spoor remains - tracks once left in mud, images of forms, and, most intriguing for many, chemical signatures. The chemical, is usually carbon, that fundamental element of life. But other elements, iron, sulfur and oxygen also carry messages about living processes.

Knoll manages a delicate arabesque as he presents us with the evidence obtained and the interpretations derived from it. He carefully delineates the fossil information given by the rocks, mixing it with geological and geochemical processes. Various researchers are given voice through his narrative. Where issues are contentious, and most ideas of early life fit that description, he explains the reasons behind the stance, then offers his own choice. While the conflict is rarely solved, none of his solutions are arbitrary or based on personality. You are still left to satisfy your own mind through his references. Knoll's prose presents this information and discussion with clarity and balance. At the end, with these lucid explanations as background, he considers that answers to many of our questions may be found on our nearest planetary neighbour - Mars.

Beyond the informative text provided, Knoll enhances the book with site photographs to convey the scale of the locations excavated. Ancient landscapes are today stark, and the photos do little to convey the nippy Kotuikan cliffs or the roasting Precambrian site of North Pole, Western Australia. A collection of plates offers stunning colour images of ancient fossils and some modern equivalents. He further diagrams phylogenetic trees showing the relationship of organisms and why they are considered related. Not all life, he reminds us, has followed the path to complexity. With a good, but not exhaustive, reading list to examine, the reader may continue the pursuit. The younger reader may even wish to further the knowledge we have. Knoll exhorts the next generation of early life researchers to examine the questions and go afield to provide more answers. There are few worthier causes. [stephen a. haines - Ottawa, Canada]