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Liaisons of Life P
A fascinating exploration of symbiosis at the microscopic level and its radical extension of Darwinism
Microbes have long been considered dangerous and disgusting-in short, "scum." But by forming mutually beneficial relationships with nearly every creature, be it alga with animals or zooplankton with zebrafish, microbes have in fact been innovative players in the evolutionary process. Now biologist and award-winning science writer Tom Wakeford shows us this extraordinary process at work. He takes us to such far-flung locales as underwater volcanoes, African termite mounds, the belly of a cow and even the gaps between our teeth, and there introduces us to a microscopic world at turns bizarre, seductive, and frightening, but ever responsible for advancing life in our macroscopic world. In doing so he also justifies the courage and vision of a series of scientists-from a young Beatrix Potter to Lynn Margulis-who were persecuted for believing evolution is as much a matter of interdependence and cooperation as it is great too-little-told tales of evolutionary science.
Microbes have long been considered dangerous and disgusting-in short, "scum." But by forming mutually beneficial relationships with nearly every creature, be it alga with animals or zooplankton with zebrafish, microbes have in fact been innovative players in the evolutionary process. Now biologist and award-winning science writer Tom Wakeford shows us this extraordinary process at work. He takes us to such far-flung locales as underwater volcanoes, African termite mounds, the belly of a cow and even the gaps between our teeth, and there introduces us to a microscopic world at turns bizarre, seductive, and frightening, but ever responsible for advancing life in our macroscopic world. In doing so he also justifies the courage and vision of a series of scientists-from a young Beatrix Potter to Lynn Margulis-who were persecuted for believing evolution is as much a matter of interdependence and cooperation as it is great too-little-told tales of evolutionary science.
224 pages, Paperback
First published January 1, 2001
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Displaying 1 - 3 of 3 reviews
May 16, 2009
Cheesy title, but very cool stuff about how microbes have been a major driving force in evolution. I believe that research into microbial symbionts is gonna cause a major paradigm shift in biology during the next century, mostly because of how it recasts evolutionary biology and the forces that shape it. There aren't a whole lot of books on this and this one is very readable for the non-microbiologist - and well researched.
October 15, 2016
_Liaisons of Life_ by Tom Wakeford is a well-researched and very readable book on the importance of symbiosis in ecology and in evolution. Actually, to be more specific, it is a book about the importance of organisms' symbiosis with microbes (whether microbes with microbes or microbes with macroscopic organisms). The central tenets of this wonderful work are first that microbes (be they bacteria, protozoa, or fungi) are one of the most important innovative factors in evolution and are key parts of any ecology; Wakeford believed that the importance of the gene has been overemphasized. Secondly, interdependence among organisms is at least as important (if not more important) than competition between them; most organisms survive only by the "constant management" of their relationships with the microbes in and around them. Far from constant competition, it is often difficult to tell where one organism ends and another begins. Thirdly, this is a dynamic relationship; relationships can change, partners in symbiosis come and go, and the mutalist of today can become the parasite of tomorrow.
The acceptance of the importance of symbiosis and the beneficial role of microbes has been a long time coming. In the nineteenth century microbes first came to the attention of scientists thanks to the efforts of Louis Pasteur. It was he coined the word "germ" and single-handedly brought about the "antibacterial age," a time that lasted for several decades in which scientists saw microbes as things only to be eradicated. Additionally, views about symbiosis became tied up with the politics of the 1920s and 1930s, with bacteria and symbiotic relationships regrettably and very unscientifically becoming tied up with fears about Communism. It did not help that many pioneers in the field hailed from Germany and Russia.
Those who pointed out evidence of symbiosis often were met with derision and ignorant prejudice. Beatrix Potter was hounded out of biology in the 1890s for her views that lichens were made up of the alliance of two organisms; when the London scientific community treated her with disdain if not hatred she became instead a noted children's author and illustrator. Earlier in 1869 the Swiss botanist Simon Schwendener offered his "dual hypothesis" for the taxonomy of lichen, noting that they were both a fungus and an alga; his theories and works were treated with contempt and for a time calling someone a "Schwendenerist" was a term of abuse, meaning someone who waffled between two competing explanations for something. The idea that symbiotic organisms could be passed from one generation to another was for a time discredited thanks to associations with pre-Darwinian French evolutionist Jean-Baptiste Lamarck.
Wakeford provided numerous fascinating examples of symbiosis in nature. Many species of orchids for instance are so dependent upon fungal symbionts in their roots that they cannot survive without them. In fact mycorrhizal fungi - underground fungi that exist in a symbiotic relationship with the roots of plants - are essential in allowing many plants to get enough of many nutrients (notably phosphate). So essential are they that 90% of the plants on Earth have domesticated their own species of fungus. Mycorrhizal fungi can form vast underground networks, often linking more than one plant together. One researcher by the name of David Perry has said that the sharing of fungal symbionts between trees is so important they form a superorganism, what he termed a "guild." These fungal symbionts are known to allow one tree - perhaps suffering by being overly shaded - to draw upon the nutrients of another tree, thereby constituting a "mycorrhizal welfare state."
In addition to colonizing roots symbionts can colonize other parts of the plant; tall fescue grass, a dominant grass in the United States, has a species of fungus (_Acremonium_) that grows in the spaces between the grass's cells. This symbiont offers resistance to drought, increases seed production, and produces toxic alkaloid compounds that put off plant-eaters. So intimate is the relationship that grass seeds are infected while still in the seed coat.
Other examples of symbiosis in nature include the relationships of deep sea organisms with bioluminescent symbiotic bacteria, chemosynthetic symbiotic sulfide bacteria living in _Riftia_ tube worms around hydrothermal vents, the bacteria that allow shipworms and termites to digest wood (or in the case of anobiid beetles, it is a yeast-like fungus that allows them to eat wood), and the bacteria and protozoa ecosystem that exists in the four-chambered stomachs of ruminants such as cattle, sheep, and deer that allow these animals to digest grass. The most important examples of symbiosis though are undoubtedly the acquisition in eukaryotic cells of chloroplasts and mitochondria, a momentous evolutionary event, an example of an extremely intimate and permanent form of intracellular symbiosis which Wakeford skillfully explained.
Many species very actively manage their microbial associates. Corals bleach themselves - bleaching being the loss of the coral's symbionts, called _Symbiodinium_ - as a natural strategy to deal with changing environmental conditions. They do this to alter the makeup of their symbionts, to allow themselves to be repopulated by a new type of associate, one that perhaps is better suited for a changed environment. Researchers have discovered that leaf-cutter ants are continually domesticating new varieties of fungi by taking them into their nests; 862 types of nest fungi have been discovered, with evidence that ants periodically swap crop varieties with their neighbors.
As noted, the continuum between beneficial symbiont and parasite is a rather fuzzy continuum. Orchids for instance produce natural fungicides to keep their root symbionts from colonizing their stems; these and other plants can be overrun by their symbionts if they become weakened or malnourished. David Philip, the famous "bubble boy," had to live in a sterile environment because his body had no ability to cohabit with the numerous microbial associates in the human body (symbiotic bacteria make up a tenth of our body's weight and totaling 90 trillion cells outnumber our own body cells nine to one). If the intestines of any human are damaged formerly beneficial symbiotic microbes can create a life-threatening infection called sepsis.
The acceptance of the importance of symbiosis and the beneficial role of microbes has been a long time coming. In the nineteenth century microbes first came to the attention of scientists thanks to the efforts of Louis Pasteur. It was he coined the word "germ" and single-handedly brought about the "antibacterial age," a time that lasted for several decades in which scientists saw microbes as things only to be eradicated. Additionally, views about symbiosis became tied up with the politics of the 1920s and 1930s, with bacteria and symbiotic relationships regrettably and very unscientifically becoming tied up with fears about Communism. It did not help that many pioneers in the field hailed from Germany and Russia.
Those who pointed out evidence of symbiosis often were met with derision and ignorant prejudice. Beatrix Potter was hounded out of biology in the 1890s for her views that lichens were made up of the alliance of two organisms; when the London scientific community treated her with disdain if not hatred she became instead a noted children's author and illustrator. Earlier in 1869 the Swiss botanist Simon Schwendener offered his "dual hypothesis" for the taxonomy of lichen, noting that they were both a fungus and an alga; his theories and works were treated with contempt and for a time calling someone a "Schwendenerist" was a term of abuse, meaning someone who waffled between two competing explanations for something. The idea that symbiotic organisms could be passed from one generation to another was for a time discredited thanks to associations with pre-Darwinian French evolutionist Jean-Baptiste Lamarck.
Wakeford provided numerous fascinating examples of symbiosis in nature. Many species of orchids for instance are so dependent upon fungal symbionts in their roots that they cannot survive without them. In fact mycorrhizal fungi - underground fungi that exist in a symbiotic relationship with the roots of plants - are essential in allowing many plants to get enough of many nutrients (notably phosphate). So essential are they that 90% of the plants on Earth have domesticated their own species of fungus. Mycorrhizal fungi can form vast underground networks, often linking more than one plant together. One researcher by the name of David Perry has said that the sharing of fungal symbionts between trees is so important they form a superorganism, what he termed a "guild." These fungal symbionts are known to allow one tree - perhaps suffering by being overly shaded - to draw upon the nutrients of another tree, thereby constituting a "mycorrhizal welfare state."
In addition to colonizing roots symbionts can colonize other parts of the plant; tall fescue grass, a dominant grass in the United States, has a species of fungus (_Acremonium_) that grows in the spaces between the grass's cells. This symbiont offers resistance to drought, increases seed production, and produces toxic alkaloid compounds that put off plant-eaters. So intimate is the relationship that grass seeds are infected while still in the seed coat.
Other examples of symbiosis in nature include the relationships of deep sea organisms with bioluminescent symbiotic bacteria, chemosynthetic symbiotic sulfide bacteria living in _Riftia_ tube worms around hydrothermal vents, the bacteria that allow shipworms and termites to digest wood (or in the case of anobiid beetles, it is a yeast-like fungus that allows them to eat wood), and the bacteria and protozoa ecosystem that exists in the four-chambered stomachs of ruminants such as cattle, sheep, and deer that allow these animals to digest grass. The most important examples of symbiosis though are undoubtedly the acquisition in eukaryotic cells of chloroplasts and mitochondria, a momentous evolutionary event, an example of an extremely intimate and permanent form of intracellular symbiosis which Wakeford skillfully explained.
Many species very actively manage their microbial associates. Corals bleach themselves - bleaching being the loss of the coral's symbionts, called _Symbiodinium_ - as a natural strategy to deal with changing environmental conditions. They do this to alter the makeup of their symbionts, to allow themselves to be repopulated by a new type of associate, one that perhaps is better suited for a changed environment. Researchers have discovered that leaf-cutter ants are continually domesticating new varieties of fungi by taking them into their nests; 862 types of nest fungi have been discovered, with evidence that ants periodically swap crop varieties with their neighbors.
As noted, the continuum between beneficial symbiont and parasite is a rather fuzzy continuum. Orchids for instance produce natural fungicides to keep their root symbionts from colonizing their stems; these and other plants can be overrun by their symbionts if they become weakened or malnourished. David Philip, the famous "bubble boy," had to live in a sterile environment because his body had no ability to cohabit with the numerous microbial associates in the human body (symbiotic bacteria make up a tenth of our body's weight and totaling 90 trillion cells outnumber our own body cells nine to one). If the intestines of any human are damaged formerly beneficial symbiotic microbes can create a life-threatening infection called sepsis.
September 2, 2019
We and the microbes are one
This book is about symbiosis and how prevalent it is. It is also about how politicized the concept has been historically. From the experience of nineteenth-century biologist and illustrator Beatrix Potter whose identification of lichen as symbionts went against the established dogma as filtered through the ideas of Pasteur, to "anti-communist" biology as practiced by some Western scientists who saw symbiosis as supporting the collective, it is amazing how purely political ideas successfully censored the scientific. Symbiosis has even been thought of as "feminine" and contrary to the noble interpretation of Darwinism as the survival of the fittest.
But Wakeford is able (after a fashion) to go beyond the politics and demonstrate in a most convincing manner that the symbiotic way of life is vastly more important and enormously more widespread than is usually imagined. Most of us know that legumes work symbiotically with rhizobia bacteria to fix nitrogen in the soil so that it is available to the plant, but what surprised me is to learn that 90 percent of plants host mycorrhizal fungi (p. 167) and are therefore symbionts. As Wakeford asks on the same page, "Can we continue to simply call them plants without acknowledging their fungal dimension? Is a cow an animal or a microbial fermentation vessel, when without the microbes, the cow would not exist?"
Good questions, and indeed, what about humans who have microbes in our guts that help us to digest our food? Are we in symbiosis with those microbes? Without the beneficial bacteria in our guts, the harmful bacteria would run rampant and we would be led to disease. Ants are not merely ants, they are farmers who harvest fungi gardens. They and the fungi are in symbiosis, living together, dependent upon one another for their survival. And what about termites, creatures who harbor microbes to digest the wood they eat? The broad, general message of this book is that cooperation between species is at least as important in evolution as is competition.
Reading this made me think that perhaps the idea of competition in evolution is merely an anthropomorphic delusion. Certainly Wakeford shows that our notions about parasites and who is feeding on whom, may be in error. He writes, "Rather than discrete categories, the terms mutualist, parasite, and pathogen are better seen as fuzzy points on a continuum, along the length of which an association between two organisms may fluctuate. For many associations, the point they occupy on this continuum is as difficult to assess as it is to say who gains more...in a marriage between two human partners." (p. 184)
There is an old saying, that I got from somewhere years ago. It is, "Everything works toward a symbiosis." This book not only supports that idea, it even, taken further, supports the idea of Gaia, namely that all the living creatures on this planet form a single organism. I don't necessary believe this, the "strong" Gaia hypothesis, but I think the distinction between a planet that harbors organisms and a planet that is itself part organism, may be more a semantic distinction than anything else.
Because of all we have learned about microbial life in recent decades, it is becoming clearer and clearer that no organism is an island, and indeed, all of life is in symbiosis with the microorganisms that constitute the largest, most viable life form on this planet. Realizing this while reading Wakeford's fascinating arguments, I had a thought: the little green men from outer space are probably symbionts themselves, but more fully realized ones, like lichen, part "animal" and part "plant," deriving their energy directly through photosynthesis. And suddenly I had a vision of beings all seated as in meditation, taking a break to open the top of their heads, filled not with brains, but with cells capable of turning light into nourishment. How primitive and clumsy we might appear by comparison!
--Dennis Littrell, author of “The World Is Not as We Think It Is”
This book is about symbiosis and how prevalent it is. It is also about how politicized the concept has been historically. From the experience of nineteenth-century biologist and illustrator Beatrix Potter whose identification of lichen as symbionts went against the established dogma as filtered through the ideas of Pasteur, to "anti-communist" biology as practiced by some Western scientists who saw symbiosis as supporting the collective, it is amazing how purely political ideas successfully censored the scientific. Symbiosis has even been thought of as "feminine" and contrary to the noble interpretation of Darwinism as the survival of the fittest.
But Wakeford is able (after a fashion) to go beyond the politics and demonstrate in a most convincing manner that the symbiotic way of life is vastly more important and enormously more widespread than is usually imagined. Most of us know that legumes work symbiotically with rhizobia bacteria to fix nitrogen in the soil so that it is available to the plant, but what surprised me is to learn that 90 percent of plants host mycorrhizal fungi (p. 167) and are therefore symbionts. As Wakeford asks on the same page, "Can we continue to simply call them plants without acknowledging their fungal dimension? Is a cow an animal or a microbial fermentation vessel, when without the microbes, the cow would not exist?"
Good questions, and indeed, what about humans who have microbes in our guts that help us to digest our food? Are we in symbiosis with those microbes? Without the beneficial bacteria in our guts, the harmful bacteria would run rampant and we would be led to disease. Ants are not merely ants, they are farmers who harvest fungi gardens. They and the fungi are in symbiosis, living together, dependent upon one another for their survival. And what about termites, creatures who harbor microbes to digest the wood they eat? The broad, general message of this book is that cooperation between species is at least as important in evolution as is competition.
Reading this made me think that perhaps the idea of competition in evolution is merely an anthropomorphic delusion. Certainly Wakeford shows that our notions about parasites and who is feeding on whom, may be in error. He writes, "Rather than discrete categories, the terms mutualist, parasite, and pathogen are better seen as fuzzy points on a continuum, along the length of which an association between two organisms may fluctuate. For many associations, the point they occupy on this continuum is as difficult to assess as it is to say who gains more...in a marriage between two human partners." (p. 184)
There is an old saying, that I got from somewhere years ago. It is, "Everything works toward a symbiosis." This book not only supports that idea, it even, taken further, supports the idea of Gaia, namely that all the living creatures on this planet form a single organism. I don't necessary believe this, the "strong" Gaia hypothesis, but I think the distinction between a planet that harbors organisms and a planet that is itself part organism, may be more a semantic distinction than anything else.
Because of all we have learned about microbial life in recent decades, it is becoming clearer and clearer that no organism is an island, and indeed, all of life is in symbiosis with the microorganisms that constitute the largest, most viable life form on this planet. Realizing this while reading Wakeford's fascinating arguments, I had a thought: the little green men from outer space are probably symbionts themselves, but more fully realized ones, like lichen, part "animal" and part "plant," deriving their energy directly through photosynthesis. And suddenly I had a vision of beings all seated as in meditation, taking a break to open the top of their heads, filled not with brains, but with cells capable of turning light into nourishment. How primitive and clumsy we might appear by comparison!
--Dennis Littrell, author of “The World Is Not as We Think It Is”
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