Microcosmos: Four Billion Years of Evolution from Our Microbial Ancestors

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 real

This is one of the best histories of life on earth that I have ever read. I highly recommend it. It covers much of the often ignored very early history of life (3.8 billion years ago to the appearance of animals) in better deatil than I have found in any other book written at the popular level. In particular, the importance of the eukaryotic/prokaryotic symbiosis is emphasized as well as the development of photosynthesis that released free oxygen into the earth's atmosphere 2-2.5 billion years ago. The information on the Eidiacara organisms is a little thin, and some of that later chapters are very speculative, but still I recommend the book. It's one of the very few books that I could say that I had a hard time putting it down.

This book is an excellent scientific account of how life originated on earth. It tells how the earth's environment came to host organic molecules, leading up to bacterial communities and on to higher organisms.Chapter by chapter, this book outlines the progression of life from it's origin 3.9 billion years ago up to present day. Very well written, and easy to understand, I found it to be very enjoyable. Microcosmos is a fine reference book for nonfiction, index and all, and I think it should be in everyone's private library.

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.

This is an outstanding and very readable book on the world of microbes. Beautifully written and filled with insights, it should be required reading for biology students. I couldn't put it down and I hated biology in high school! I takes you from the beginnings of our planet to the present time, showing the reader the crucial role of microbes in the creation and maintenance of all life. This book will also be of interest to any serious student of the Gaia hypothesis. Read it and you will never think of cells, bacteria and viruses the same way again. You will come away with a humbling and enlightened view on man's place in a world created, dominated, and maintained by microbes.For those of you who don't know, Lyn Margulis is the ex wife of the late Carl Sagan (prior to Ayn Druian) and Ms. Margulis is Dorian Sagan's mother.Together, they make an excellent writing team.