What is Life?: The Eternal Enigma [Paperback]

The quote "knock up against each other and work things out." is used by the reviewer to knock
down Margulis and Sagan's book. This line is taken from the last half of the first sentence in a five sentence summary of chapter six. These chapter summaries are intended to be playful and poetic, not dry and lifeless remarks. The implication that tough-minded biologists would laugh at this book is nonsense and should be completely dispelled by Niles Eldrege's forward.

The Gaia theory does permeate the book at many levels. The theory is controversial, but
Margulis has not been one to shrink from biological controversies. Her symbiotic theories of the origins of mitochondria and chloroplasts were also controversial when she put them forward, however, she was right then and she may be right now. I would not find much fault with her support of the Gaia theory even if it is not elevated to textbook status. To take a specific example, the suggestion that coccolithophorid algal blooms generate dimethyl sulfide and this causes cloud cover to form and cool the planet has not been supported by satellite observations reported this year. Yet, the Gaia hypothesis is greater than this one example, and there is something to be said for backing an idea if you think it is
worthy.

The final blow in the Kirkus review is that few readers would persevere through the whole text.
This is hardly relevant to the quality of the book, but more to the quality of the reader. There are many books that are highly praised, yet are seldom read from cover to cover. One that comes to mind is Godel, Escher, Bach, an Eternal Golden Braid, winner of the 1980 Pulitzer Prize for general non-fiction. How many of us have started that book, only to become stalled part way through?

As a biochemist with an interest in evolution, I found this book to be fascinating. The examples
are fresh. I had never heard of the Rio Tinto in Spain, with its unusual fungi. I did know about the 37 acre fungal clone in Michigan, but I did not know about the quaking aspen forest with 47,000 trunks that is a single organism, probably the largest on earth. One does not have to read far into this book to realize the breadth and depth of knowledge relevant to life's history. Trichoplax, a living minimalist animal is
presented as a glimpse of what the first animals might have been like. Thermoplasma acidophilum, an archeabacterium with histones (found almost exclusively in eukaryotes) suggests we need to consider the ancestors of these types of bacteria as precursors of modern eukaryotes.

One area that is particularly strong in this book is the early history of life. A 10 page timeline scrolls across the top of Chapter 3, giving one of the most detailed summaries of important events in life's progression. Margulis is of course the authority on symbiosis of cells to generate more complex life forms, and Chapter 5 on this subject is one of the best in the book. If you are looking for answers to some mystical or metaphysical notion about life, or if you want a quick definition, do not read this book! If you
want to gain some insight about life from an expert in the field, then read What is Life. This is a luscious book.

David R. Nelson, Ph.D.
Assistant Professor
Dept. of Biochemistry
University of Tennessee, Memphis

Lynn Margulis does not serve up any final answer to her title's question. There are a couple of ongoing themes: that wherever there is life, there is what she calls "autopoiesis", the definition of a boundary between self and other, together with the absorption and expenditure of free energy to maintain the self. (A process, as she notes, which not only doesn't violate the second law of thermodynamics, but actually accelerates the rate at which overall entropy increases.) A second theme is, that life's self-organization goes on at progressively higher levels of integration: from cells to colonies and to symbiotic unions that make one complex cell out of several; from complex cells to multicellular animals, plants, and fungi; from multicellular beings to societies and ecosystems; from ecosystems to the biosphere. Margulis believes that biology impoverishes itself by insisting, as Steven Jay Gould does, that evolution has no "direction," simply because no master designer is imposing a direction on it from outside.

But ultimately, according to Margulis, life can't be defined because it keeps on defining itself, and coming up with new definitions. It is better to step back from our skewed view of primates and vertebrates as the most typical living beings, and look at the broad range of specific ways of being alive that evolution and symbiosis have produced so far. So her book is largely organized into chapters describing the history and nature of each of the five kingdoms, in chronological order: bacteria, protoctists (single celled organisms with nuclei), animals, fungi, and plants.

Did you know that it takes two eggs and three sperm to make a flowering plant? That the cell walls of fungi are made from the same material as lobster skin? That photosynthesis evolved independently several times among bacteria?

As stimulating as the book's parade of facts about the wild profusion of ways of being alive is its parade of speculations: that cilia and flagella are the remnants of spirochete bacteria which took up residence in other cells; that the first fertilization event was the result of a failed attempt at cannibalism; that species-jumping genes from fungi taught flowering plants how to make fruit. Another startling hypothesis surfaces every few pages. Some of these speculations are seriously defended, some are tossed out for what they're worth, but they're all fascinating.

I do wish the footnotes had been more extensive. It would be good, for example, to read up on Kwang Jeon's ameba experiments, in which those amebas that didn't die of a bacterial infection wound up incorporating the bacterial genes - and after a few years of lab reproduction, became unable to survive without them. That experiment is the most vivid support Margulis gives for her thesis that genetic material continues to be regularly exchanged across kingdom boundaries; but it's not among the items for which she chose to provide citations.

But this book is far more than a random collection of facts. Margulis and her collaborators do an amazing job of assembling an understandable model of life using parts carefully selected from a vast body of biological knowledge. While a one-sentence definition is still elusive, the reader builds up a picture of life's most pertinent characteristics, as exhibited by the truly astounding diversity of living things on this planet. By the time I finished, I was satisfied that the authors had answered the question.

You don't need to be a biologist to understand and enjoy this book. Its beauty is that the greatest scientific thinking on the most complex topics has been presented in common english, with necessary scientific terms explained as they are introduced. If you are intrigued by the question of life, I doubt there's a more complete, accurate, understandable, and enjoyable answer available than this book.