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46 of 46 people found the following review helpful:
5.0 out of 5 stars
The best non-fiction book I've read this year., September 7, 1999
If you're one of those who has felt worried that the earth might not survive what we're doing to it, then worry no longer! We, as a species which has brought 'wholesale ecological carnage' to the planet may not survive, but the earth surely will! What soon emerges from this insightful book is that humankind is a relatively young species, still 'vulnerable, error-prone.' Humans are not seen as the dominant species - the pinnacle of evolution - but as one of the still immature species. The real players are the species that have been here the longest, the bacteria. 'Even nuclear war would not be total apocalypse, since the hardy bacteria underlying life on the planetary scale would doubtless survive it.' Margulis and Sagan relegate Darwin to a secondary place within the order of things: the most powerful and important changes in evolution happen not through mutation - as Darwin would have it - but through symbiosis, '...the merging of organisms into new collectives, proves to be a major power of change on Earth.' In particular oxygen-breathing bacteria merged with other organisms to enable oxygen-based life on the once alien surface of this hydrogen filled planet. 'The symbiotic process goes on unceasingly.' 'Fully ten percent of our own dry body weight consists of bacteria - some of which.... we cannot live without.' That's an estimation of ten thousand billion bacteria each! Imagine a droplet of water with a membrane holding the water in place and allowing certain nutrients in. This is a simplified description of how it is imagined the first becteria came into being. The book offers a fascinating history of the evolution of life on our planet. This is a wonderful story full of fantastic developments spanning thousands of millions of years. Every now and then we are reminded by the authors that none of it could have taken place or could be happening now were it not for the metabolic abilities of bacteria. It gives a really eye-opening account of bacterial sex with the insight that all bacteria, all over the planet, are really part of one organism because they are all able to exchange genetic information. For instance it's thought that bacteria obtained their now well-known resistence to penicillen from their bacterial cousins in the soil. But also, you begin to get the impression that perhaps it's the bacteria which have used every means possible and are now using us too to spread onto the land and all over the planet and beyond from their original wet home in the ocean. Humans are defintely relegated to a secondary place within something much, much bigger that is (consciously?) evolving. This is a fascinating book which has radically changed the way I perceive life and the universe. I read it with great excitement and completed it with a new awe for those minute beings, the bacteria, which have, until now, had a very bad press. The best non-fiction book I've read this year.
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33 of 34 people found the following review helpful:
5.0 out of 5 stars
On microbes: the real rulers of the planet., June 20, 2003
Microcosmos is a natural history of the unseen beings upon whom we depend every moment for survival: the microbes. Margulis, who is currently Distinguished University Professor in the Department of Geology at the University of Massachusetts, did undergraduate work in biology and received her PhD in Genetics. She worked with James Lovelock on developing the Gaia theory, which posits that the earth can be regarded as a sort of super-organism. In Microcosmos we see all aspects of her education and sensibilities -- a close attention to scientific detail and a "big picture" approach to how living entities coexist. In the introduction she lays out her philosophy about life on earth, for which she was roundly criticized by many reductionist scientists. In the past, she writes, all life on Earth was traditionally studied as being merely a prelude to the appearance of humans. Now, overwhelming evidence suggests that microbes (one-celled organisms) not only inhabit every known living thing on earth, they are also indispensable to the survival of all living things. They, not human beings, are the most important beings on the planet. Furthermore, in opposition to one of the most accepted tenets of Neo-Darwinism, Margulis states that life did not colonize the planet by competition so much as by networking. Cooperation between one-celled creatures led, over billions of years, to the evolution of beings such as ourselves, who possess the capability for self-conscious awareness. Our human consciousness, of which we are so proud, "may have been born of the concerted capacities of millions of microbes that evolved symbiotically to become the human brain." Strong words! Yet, Margulis sets forth compelling evidence in the remainder of her book to support her bio-philosophical ideas. Along the way, we learn many amazing things. For instance, we get a perspective on what upstart newcomers we are: the continents we inhabit now appeared in their present locations only in the last tenth of a percent of Earth's history. We learn that bacteria invented genetic engineering. Thus, when ultraviolet light damaged early microbes' DNA, the creatures produced repair enzymes to remove the damaged portions and copy new replacement DNA. This is a natural form of gene splicing. Sometimes, the DNA used in gene splicing was borrowed from neighboring bacteria of different strains, thus affording these critters a prodigious adaptability. This borrowing still goes on today. Through intermediaries, two very different bacteria can share genetic information. Why is this important? Because it allows the distribution of genetic information in the microcosm with a speed "approaching that of modern telecommunications--if the complexity and biological value of the information being transferred is factored in." This speed makes bacteria the biosphere's first responders in dealing with planetary changes. In responding to change, bacteria end up altering and shaping their environments. Few people realize that the entire earth's atmosphere, which we depend on for our life's breath, was created, and is maintained, by microbes. This is a good thing to remember next time you feel like spraying down your bathroom or kitchen with anti-microbial spray. Our fear of bacteria is misplaced. Yes, some are harmful to us, but most are beneficial. Indeed they are a lot more helpful to us than we are to the rest of the planet! This book isn't an easy read, but it will broaden one's outlook on our place in the natural world. Even if bacteria are not in the end responsible for the intricacies of our human brain and consciousness, we still owe them many debts. This book unveils the smallness of humans before the vast and minute workings of nature, and encourages a sense of humility before the greater Life that surrounds us.
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15 of 15 people found the following review helpful:
4.0 out of 5 stars
Don't miss the beginning . . ., January 12, 2003
Margulis and Sagan return us to the days of life's inception. It's a journey in time and scope, travelling far back and down in size. Looking at the microbial world might seem unrewarding, but they escort us through a rich trove of information. The knowledge contributes to our understanding of how we work. Although mysteries remain hidden in that distant time, the authors clearly demonstrate the logic of how early life has developed into ourselves and our animal and plant neighbours on this planet. The title suggests that the journey must necessarily occur at high speed, but they demonstrate that if we don't appreciate the beginning the remainder of the trip will be undertaken in obscurity. A better knowledge of the origins, they suggest, will also give us better insight into what the future heralds. After some preliminary discussion of how life started, the authors move into the realm of cellular organisms. The various ideas of life's origins are fascinating, but not until it achieved the level of individual micro-organisms does life take on meaning. The authors describe the events occurring during the long reign of the prokaryotes. These simple organisms were little more than a bag containing some genetic information. Yet, their emergence was the start of true life. While it's easy to think this "primitive" organism has faded into oblivion with the passage of time, the authors remind us that all our bacterial neighbours [and some inhabiting us!] are of that distant family. When conditions varied in certain localities, these simple creatures performed some amazing tricks. One of these resulted in a devastating event the authors term The Oxygen Holocaust. The original prokaryotes thrived on hydrogen, making useful compounds of it and other elements. Since the best available source was water, the resultant waste product was oxygen. As this pollutant entered the atmosphere many organisms were forced to change their lifestyle or die out. The massive changes resulting increased the complexity of many organisms that began adding new protective devices to their structures. According to the authors, some cells had already initiated a new survival technique - the merging of various prokaryotic cells resulting in a new type. The new cell packaged its genetic material in a nucleus, creating the form known as the eukaryotes. Eukaryotic cell structure led down the long evolutionary track to complex creatures like ourselves. There is a goal behind their descriptions of life's evolution. They remind us that textbook illustrations of individual bacteria are misleading. All Bacteria "clump" in some form or another as part of their survival strategy. Because these tiny organisms encounter so many environments and because their genetic makeup allows astonishing variation, many bacteria form communities with various groups performing specific tasks. These roles may include shielding the rest of the community from environmental hazards, processing food and waste or mobility. This revelation also points up a major theme of this book - cooperation has played a greater role in evolution than has competition. Cooperation is a survival strategy whereas competition may leave too few winners to ensure perpetuation of the species. How far can the cooperation extend in a planet of highly varying environments? That question is answered in their concluding chapter. In it, they extend their previous narrative to reinforce the case for James Lovelock's Gaia thesis. In their view, Gaia is a "superorganism" extending throughout the entire biosphere. It is self correcting and self-regulating - indeed, the role of evolution is but the "operating system" of this global organism. Since the oxygen we breathe came from waste-expelling microbes, more than lifeforms are contained within Gaia. The atmosphere and oceans aren't habitats and support systems for life, but an integral part of a grander structure, one thoroughly integrated. One can only wonder what Darwin might have thought of this extrapolation of his idea of evolution by natural selection. This is not the place to debate Lovelock's thesis. While Gaia has been strenuously challenged by other commentators, Margulis and Sagan weave a tightly knit support for the idea. They do it earnestly and with clarity, and their view should be given some consideration. Strangely, however, while they have no qualms about describing certain theories about life's evolutionary progress as "still a mystery" or "controversial," this aspect of the book is presented as a given. The inconsistency is glaring, but shouldn't detract from the worth of the book as a whole.
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