Sciencewriters Archive

Reflections on Death, #1: Recycling of the Dead (An Excerpt from Death & Sex)

Wednesday, November 4th, 2009

The following is an excerpt from Death & Sex by Tyler Volk and Dorion Sagan. It has been adapted for the Web.

From chapter 4: Recycling of the Dead

When carbon ends its “lifetime” in the biosphere, it doesn’t stop being carbon. It merely passes into a deeper zone. One is reminded here of ancient myths that feature souls, victims, or heroes descending into the underworld, as a dramatic moment in the story. Like those mythic souls presumed to continue to live but in a new form, so carbon transported downward and outside the vibrant biosphere, after “burial,” continues to be carbon but somewhere deep and dark, and often hot.

Carbon is buried as detritus from dead marine plankton when it fluxes out of the dynamic surface system in the form of tiny calcium carbonate shells. The coal we mine to burn for electricity is the dead and highly compressed remains of giant ferns and mosses from dinosaur-era swamps. Our precious, diminishing reserves of oil were long, long ago the sediments underneath some of the world’s most productive marine areas ever. Verdant patches of algae grew, then fell into the sediments at such rapid rates of death that even the voracious bacteria alive there could not keep up with the rain from what was their heaven. The sites and rates of death that led to the fossil fuels upon which modern civilization came to depend were historically unique burial traps.

More commonly, carbon that was buried from organic tissue in the form of the bodies of plankton was finely dispersed. Today we see it as the black tincture in rocks such as shale, in contrast with the pervasive white of limestone rock that entombs once-living carbon in a paler shade.

All these buried forms of carbon can eventually spring back up, like the ancient Greek myth of Persephone emerging from the underworld to bestow life to the surface. She was said to rise up annually, as a rite of spring. But carbon’s stay below is typically millions to hundreds of millions of years. Its ports of reentry are the volcanoes and surfaces of rocks that dissolve when exposed to soil, rain, and weather, thereby returning carbon to the surface circulation of active cycles.

How dependent is life in the sunny biosphere upon this resurrected carbon? In the long run, very dependent. Without the reemergence—a kind of biogeochemical reincarnation, if you like—all carbon would slowly and surely exit from the interconnected surface system of life, air, soil, and water. Emergence would be limited to only truly primordial carbon that comes up as a portion of volcanic activity.

From chapter 7: Built from Death

Surpassing in some ways the wonders of death within the living animal body are the roles of the functional dead in sculpting the towering lives of trees. If you go inward from the bark, past a thin layer of cells called the phloem and another narrow layer of cells that are actively reproducing, you come to a notable layer called the xylem.

The xylem consists of tubular columns of dead cells that function to move mineral-laden water gathered by the roots up to the needles or leaves. Its special, dead cells are called tracheids. Tracheids (or, when grouped into units, tracheid elements) not only provide water and mineral circulation but also support the entire tree in its climb upward against gravity. Without tracheids there would be no forests or grasslands, no green life on land, except for some ground-hugging tiny mosses and a paltry soil coat of photosynthetic bacteria and algae. For not only do trees contain tracheids, so do all nonwoody herbaceous plants. Tracheids are in all stems, branches, and trunks of trees, in the shoots of grasses, in flower stalks (usually in their centers), and even in the veins of leaves. In all these instances, the dead are part of the living.

Without the evolutionary invention of tracheids just inside 400 million years ago, the land today would be virtually deserted. For more than 90 percent of Earth history, neither land plants nor their vital tracheids existed. And because tracheids are dead, in them we have an ideal example of how nature turns death into life to create organisms from cells.

Your night table will never look the same after this…

Tuesday, October 27th, 2009

Ever looked at your bedside table and thought–what can I rest on there? What can I read before bed that won’t give me nightmares, but may potentially arouse my intellect, twang on my heartstrings, or initiate some kind of pillow talk with my loved one that isn’t about who dropped a kleenex in the laundry machine? Perhaps you’re a science professor, or a lover of all things quirky…

Either way, you’re probably interested in death and sex. Right?

The following is an excerpt from Death & Sex by Tyler Volk and Dorion Sagan. It has been adapted for the Web.

Super-soft fur and slippery skin. Or is that lickable nipples and arguable kin? Or fun-filled frolicking in the name of sin? Whatever we call it, however high it flies on the rarefied notes of an aesthetic sensibility or low it sinks in the aftermath of familial responsibilities and limited options, the urge to merge—the lustful morass of feelings, emotions, and relationships around which mammalian sexuality swirls—begins and ends with bodies. To understand it, we must do a little time traveling. Fortunately, time travel itself is, so far, impossible. Fortunately because, if you were to go back and fall in lust with a fur-clad cave hunk or hottie, you might sire or give birth to a boy who grows to a man who kills your own ancestors. That would not only be a science-fiction paradox but also deprive you of the pleasure of reading this book.

But if we can’t go turn the clock back, or depend on evolutionists’ just-so stories, how can we find out what our ancestors were up to?

A powerful tool in reconstructing probable ancestral sex lives—less “just-so” than “might-be-so” stories—is comparative anatomy. By looking at now-living related organisms, we can see what traits they share and backtrack to determine probable features of an ancestor. The same can be done by comparing behavior, mating systems, and DNA sequences. There will be false leads, but, like the weight of circumstantial evidence carefully employed to re-create a crime scene, we can come up with a plausible picture. And unlike the prosecuting attorney, a scientist does not have to prove his case beyond a reasonable doubt. The continuum stretches not between crime and punishment, but between curiosity and discovery. New evidence will not get anyone out of prison, but it may release us from the subtler incarceration of received opinion.

In the 1980s, and although in the center of a full house near the front row, I walked out of a lecture by a creationist who was trying to make fun of evolutionists during the course of his slide show. “Evolutionists want you to believe,” he said, flashing a crude cartoon of a cow by the seashore, “that this”— and then our intrepid advocate flashed forward to a picture of a great whale in the water—“turned into this.”

Ovid, in his Metamorphoses, recounts some startling transformations. But a cow turning into a whale is not one of them, any more than it is for evolutionists. Caricatures and straw men do not an argument make. It is true that the ancestors of whales, dolphins, walruses, and seals were likely land mammals—more like goats than cows but in truth neither. Embryonic humans resemble embryonic mice and chickens— all three in utero look literally fishy: We have gill slits and tails before we come out of our mothers. Why would a creator give us gill slits in the womb, unless he used evolution to create, or was a prankster?

Anatomical similarities often reveal shared evolutionary roots. The evidence of common lineage is not limited to embryos. It is literally in our bones. The foreleg of a horse, the wing of a bat, the flipper of a whale, and the arm of a Moulin Rouge dancer all share a similar skeletal infrastructure.

Even the more honest creationist tactic of finding God in the gaps in the fossil record—emphasizing missing links— misses the point: What is remarkable is not what separates, but what connects us. Like a giant jigsaw all scientists are working on concurrently, missing pieces continue to be found. And they are profound. The 1850 Berlin discovery of the winged reptile Archaeopteryx would have delighted Darwin, in whose time the jigsaw puzzle, mostly due to the dearth of paleontological piece finders, had just begin. Today a slew of new fossils of feathered dinosaurs have been unearthed in China. Indeed, paleontologists now classify birds as dinosaurs: They lay eggs, have scales on their feet, and are technically reptiles. Paleontologist Jack Horner (an inspiration for the book/film Jurassic Park) even claims to be able to produce a modern-day mini dinosaur by interfering with embryonic development of a chicken, a small featherless dinosaur with teeth.

We are backboned animals with anatomical and sexual characteristics similar to other organisms that share our ancestry. The coccyx, the little tailbone at the bottom of our spine, serves no purpose for us now but it did when our simian ancestors swung from the trees. A grasping tail is an excellent tool if you are used to clinging to a branch as you call out for a furry friend. The great and lesser apes and Old World (African and Asian) monkeys all lack grasping tails. Some of the smaller New World (North and South American) monkeys, the smallest of which is the pygmy marmoset, a paltry lightweight at five ounces, have grasping tails. Unlike bigger Old World monkeys, the New World simians rarely come down to the ground, except for the occasional nut or cricket, preferring to scamper about from branch to branch (some, such as the marmosets, feeding directly on tree sap with special bark-piercing teeth) in the tropical forests in southern Mexico, Central and South America. Although it’s impossible for landlubbers to keep full account of the sixty-odd species of New World monkeys, their sexual and social relationships vary, with, for example, male tamarins and marmosets (whose females typically give birth to twins) carrying the infants most of the time, whereas daddy capuchins (the famous organ grinder monkeys) do not tend to take care of their offspring; some New World monkey species have harems with one male and several female consorts, while others, such as the callicebus monkeys (titis), tend to form long-term monogamous relationships. A similar variety marks the apes and Old World monkeys, who are more closely related to us.

The Platyrrhini, the ancestral stock that became the New World monkeys, may have arrived in South America on floating chunks of vegetation. They could have traveled on a natural raft like the floating mangrove forest islands that violent storms sometimes break off the coast of Africa. Geographic isolation—the separation of populations as the result of such events—was probably a major factor in the evolution of primates. A floating island, earthquake-separated patch of jungle, or primate tribe following fruit trees into a remote and distant valley and remaining there may separate members of a genetic stock. Physically separated, they no longer interbreed. Ultimately troops and tribes went their own way, evolving to the point that they could not form fertile offspring with members of the ancestral lineage even if they were still able and willing to mate with them. In this way new species, including our ancestors—who were mating long before there were humans—formed.

Genetic and fossil evidence suggests that the flat-nosed, branch-swinging New World monkeys split from the Old World monkeys—baboons, macaques, and many more— some forty million years ago. The island-hopping ancestors to the New World monkeys would have been aided in their journey on floating clumps of vegetation to the New World because Africa and South America were closer together thirtyseven million years ago in the Oligocene epoch.

The Old World monkeys, like us and apes, are catarrhines (Greek for “hook-nosed”) with downward-pointing nostrils. The biggest superficial difference among the three great primate groups closest to us—the Old World monkeys, the New World monkeys, and the African and Asian apes—is in the tails. The catarrhines, when they have tails, can’t hang, clutch, or hug with them as can the broad-nosed platyrrhines. Old World monkeys and the apes, like us, despite some vestiges here and there, have outgrown them. This could be because, unused, any changes that shortened tails had no material effect on survival, as our Old World ancestors gave up navigating the arboreal jungle gym for splendoring in the grass. Use it or lose it. But the true tale of the tail, as usual, is probably more complex. The coccyx, uterine tail, and occasional birth of children with tails indubitably suggest that our ancestors had tails and that, if we are made in God’s image and the devil an angel, they may also have been so endowed.

By looking more closely at the members of our evolutionary group, we can glean something of our shared ancestors’ sex lives—the erotic ape matrix of which human sex lives, despite their variety, are only a perhaps passing variation.

The evolutionary family Hominidae to which humans belong includes two species of chimp, the common and bonobo; three subspecies of gorilla, western and eastern lowland and mountain gorillas; and two species of orang, the Bornean and Sumatran. Immunological studies in the 1960s showed that the African apes are far more closely related to us than to Old World monkeys.

Although not directly answering the famous barb of Bishop Samuel Wilberforce in his 1860 debate with evolutionist Thomas Henry Huxley as to whether it was through his grandmother or his grandfather that he claimed descent from a monkey, a combination of fossil, immunological, and genetic evidence suggests the Old World monkeys split from the great ape lineage of which we are part some thirty million years ago. Various methodologies suggest that the orangutan line split off from the other great apes about fifteen million years ago, the gorillas about seven million years ago, and humans from common ancestors with chimps some five million years ago.

A recent genetic study that offers a clue about the fur gap between people and the other hominoids has to do with a protein. As shampoo ads sometimes mention, proteins are a major constituent of hair. In fact our bodies are mostly protein—blood, skin, organs, toenails, hair, and so on are all made of proteins. The main sort of proteins in hair are called keratins. The journal Human Genetics suggests that one of these proteins, human type I hair keratin, appears to be coded for by a gene that may have been inactivated some time after the divergence of Pan (chimps) and Homo (modern and extinct humans). This gene is one of the eighty that have been lost— thirty-six of which code for olfactory receptors allowing a better sense of smell. A disproportionate number of the other genes lost had to do with immune response, perhaps reflecting different pathogens in the primeval environments in which we and our soul-sister lineage evolved. But losing the type I hair keratin gene may have been the immediate cause of human body hair loss. The massive thinning and loss of our ancestors’ body hair is estimated to have occurred about 250,000 years ago, very recently in geological terms.

But behind the immediate genetic cause may well lie a deeper cause. Evolutionary biologists distinguish between ultimate and proximate cause. Proximate cause refers to immediate chemical or physical cause. Ultimate cause refers to evolutionary factors that can no longer be directly observed. One of the first to postulate an ultimate cause for human hair loss was the author Desmond Morris, who intriguingly suggested that sex was part of the story of why our ancestors lost their fur.

Death & Sex: Forbidden Fruit

Monday, October 19th, 2009

A playful exploration of the story behind the evolution of our sexuality based on hard (ahem) science, Dorion Sagan‘s Sex (part of the one-two punch known as Death & Sex) brings the author’s trademark wit and inquisitiveness to the endlessly fascinating subject of human copulation. In other words: a scientific look at boning.

And it’s available now. Head over to our bookstore to check it out. Here’s a sample to whet your appetite.

The following is an excerpt from Death & Sex by Tyler Volk and Dorion Sagan. It has been adapted for the Web.

When I was newly married, driving in Florida after a sparsely attended shotgun wedding (just the two of us and a justice of the peace), a preacher came on the radio. I listened because he was criticizing efforts to understand the evolution of sexuality while I was engaged, as a junior science writer, in writing a book on it (with, of all people, my mother, an evolutionary biologist). Scientists these days are taking it down to ridiculous levels, beyond the level of the flea, he said with scorn in his voice. By God, they were even trying to look to bacteria for answers! Listen, he continued. You don’t need to look at the birds and bees, let alone microorganisms, to understand sex. Everything you need to know about the subject is already there, written for you in black and white, in the Bible.

As a northerner in the Bible Belt I was perturbed. The Origins of Sex: Four Billion Years of Genetic Recombination had yet to come out. Highly technical, due to be published by Yale University Press, this book, just as the Christian broadcaster warned, took it down to the level of cells. Who was I, a twenty-six-year-old, to have such hubris?

Although I’d never read the Good Book cover-to-cover (I hear there are some bawdy parts), and had been brought up by scientists (astronomer father, chemist stepfather, and biologist mother), I could not help but feel accused by this stranger’s sermon. In Genesis, as I understood it, Adam is made by God in his image, Eve is taken from Adam’s rib, and they live happily ever after—at least until the Fall. As Jimmy Buffett sings (which you can also hear driving through Florida), some say a woman is to blame: The fall is Eve’s fault, as it is she who let the trickster snake whisper sweet somethings in her ear and yielded to the temptation to munch of the sumptuous fruit of the Tree of Knowledge of Good and Evil upon whose branches he hung. She took her fateful bite, and the rest is history.

Now, in English texts such as the King James translation of the Bible, the fruit she bit is an apple, but some say apricots, pomegranates, figs, or grapes were more likely the fruit of the one tree God prohibited the first couple from eating in Genesis 2:9. According to ethnobotanist R. Gordon Wasson, the “apple” may even have been a white-spotted red mushroom, Amanita muscaria, of the sort that the hookah-smoking snail sits upon in Alice’s Adventures in Wonderland. Forming a symbiotic partnership with the roots of trees, this fungus is a kind of “fruit.” It also qualifies as a candidate for the first bite on the grounds of being psychoactive and poisonous, although for sheer salacious lubriciousness in cross section it’s hard to top the apple.

Who could blame Eve, surrounded by all those arrogant males, for taking a bite of the forbidden fruit? Even if the main thing learned from that luscious bit of nutriment was the revelation that they were naked. Nonetheless, for her contagious disobedience in partaking of such a licentious snack, God the Father doled out a suitably agricultural punishment: They were to toil with the soil, and grow their own, rather than continuing on as freeloaders in a paradise they didn’t appreciate, blithely violating divine edicts, like the prohibition against education.

According to the Bible, this was the female-precipitated ur-disaster for which we continue to pay. There was also said to be a Tree of Life in the Garden that conferred immortality, but God made sure that Adam and Eve, given their sinful natures, didn’t get a piece of that. Instead, they were expelled from the Garden, fell to Earth (or, more allegorically, into incarnation and time), and were subject henceforth to aging and death.

Well, maybe. There does seem to be a connection, and not just in the Bible, between sex and death. The tiny ameboid microbes that preceded all animals have chromosomes with DNA in the nuclei of their cells. Such cells, bigger than bacteria, don’t all mate, but some do. And when they do, parts of the cell of one, the oxygen-using mitochondria, must be “put to death” by the other. When an egg and sperm merge, like a young couple moving into a Manhattan apartment, they can’t take everything with them. Some stuff, such as his DNA-containing mitochondria, never make it into the fertilized cell. Of the trillions of cells of our bodies, only a few sperm and eggs survive into the next generation. In coming together in reproductive sex, the sex cells leave male and female bodies behind to grow a fresh being. It is the reproductive cycle, not the individual animal, that is selected for over evolutionary time. After the midair mating of a queen by a horny honeybee, the latter goes pop, audibly, as its penis breaks off inside her (blocking passage to other would-be suitors) while the rest of his body plunges to its death. It may seem tragic to have life cut short in such flagrant fashion. But then the honeybee exploding immediately prior to death is lucky relative to his fellows, who can number up to twenty-five thousand, all virgins whose efforts to compete for the queen’s sexual favors fail, their entire lives an exercise in frustration.

Evolution travels light. Sex and death do go together, although the colorful stories of Genesis, written more than two thousand years ago, favor the story of a talking serpent over the fact of serpentine DNA, whose structure was deduced only in March 1953. Scientific stories about sex are not necessarily as pretty as Scarlett Johansson, as romantic as a honeymoon on O’ahu, or as memorable as Adam’s de-ribbing. But exploring the evolutionary story of our sexual nature based on science will help us get to the bottom of this topic better than the radio sermonizer’s version of religion.

If we are to be punished for Eve’s congress with the twisting reptile of the Tree of Knowledge, we should at least relish each morsel of wisdom that her sinking her incisors into the ripened red ovary of the flowering Malus domestica—the fruit of the apple tree—has made possible for us.

LISTEN: Random Mutation Responsible for Evolution? Not a Chance, Says Lynn Margulis

Saturday, October 10th, 2009

“I don’t see myself as controversial. I see myself as right.”

Nevertheless, a lot of people did consider Professor Lynn Margulis to be a controversial figure in the world of evolutionary science—that is, until her theories were proven right. Professor Lynn Margulis (Dazzle Gradually: Reflections on the Nature of Nature) explains the theory of symbiogenesis, and reveals her view that the separation of the plant kingdom from the animal kingdom is really just political, in this interview with BlogTalkRadio’s Jay Ackroyd.

Listen Now

Evolution Explains Human Nature Quite Well

Thursday, April 16th, 2009

Lynn Margulis, author of Luminous Fish: Tales of Science and Love and co-author of Mind, Life, and Universe: Conversations with Great Scientists of Our Time, participated in the John Templeton Foundation’s “Big Question” celebration of the bicentennial of Charles Darwin’s birth by answering the following question, “Does evolution explain human nature?”

Now this is a question that, if posed to me, would be met with a confident, “uh…sure?” Luckily for the thinking readers of this blog, the question was posed to Lynn—one of the greatest scientific minds of our time. Here answer, which was originally posted here, is below.

Ever since Bishop Wilberforce asked, in a debate with Thomas Huxley, whether it was from his grandmother or grandfather that he claimed descent from a monkey, the sufficiency of evolutionary theory to explain humanity’s spiritual and moral qualities has been in question. Then, as now, the evolution of humans was a touchy subject, and after the publication of On the Origin of Species, Darwin devoted a separate work, The Descent of Man, to untangling how evolutionary understanding could be applied to humans and their special traits.

Since his account of “descent with modification” leaned heavily on natural selection of the individual, Darwin wondered how moral behaviors – which focus on others – evolved. When lying, cheating, manipulation, greed, and other less than admirable qualities seemed to benefit those individuals who practiced them, how could their opposites evolve? Pointing out that he “who was ready to sacrifice his life . . . would often leave no offspring to inherit his noble nature,” Darwin pondered how members of a tribe became endowed with moral attributes.

His simple answers still apply. One who aids his fellows commonly receives aid in return. Darwin called this a “low motive” because it is self-regarding. So-called reciprocal altruism – I’ll carry your baby if you take my son on the hunt tomorrow at dawn – is operative in species whose members are capable of recognizing each others’ faces. More important is the praise we love and the blame we dread, instincts that help bind tribe members who work together. Reciprocal acts of kindness and aid underlie families, tribes, and religious groups; they ensure survival and reproduction as “naturally selected” perpetuating, living entities.

Our human sort of mutual care, along with the strong feeling of life we have in the presence of sexual partners, family, friends, colleagues, classmates, and fellow citizens (in short, in the company of meaningful others), necessitates frequent communication: symbols, language, music, teaching, learning, etc. Do these activities fundamentally distinguish us from the non-human life forms with whom we share the planet and upon whom we depend for our survival? I doubt it.

This may sound inadequate to true believers in human uniqueness, especially on religious grounds. But religion serves an obvious evolutionary function: it identifies, unifies, and preserves adherents. Admonitions to desist from the seven deadly sins inhibit behaviors that threaten group solidarity and survival. Greed, for example, privileges the individual in seasons of limited resources. Lust – the biblical coveting of the neighbor’s wife (in its male-centered perspective) – interferes with ideals for the nurture of healthy children and effective warriors. Prohibiting sloth enhances productive work intrinsic to survival and reproduction of the social unit. Anger, perhaps useful in battle, destroys family and other social relationships. Envy and pride promote individual interests above those of the larger social unit. The survival value of prohibiting sin seems obvious.

By contrast, “love thy neighbor,” interpreted from an evolutionary point of view, is an algorithm for social connectedness. The touted virtues of chastity, moderation, compassion, diligence, patience, moral commitment, and humility provide touchstones for effective group action. The intellectual historian Karen Armstrong, a former nun and the author of books on Christianity, Judaism, and Islam, argues that compassion is the crucial link among the major religions. The golden rule of Jesus, Confucius, and others is that we should not do to others what we would not want them to do to us. Is this not a clear precept for the evolutionary perpetuation of specific cohesive groups in familiar habitats?

We differ from other species in that fewer rules of social behavior are communicated only by shout, groan, touch, and facial expression and more by verbal explication. But all tend to maintain and perpetuate unity of the pack, gaggle, or herd. We people share a linguistic version of the universal tendency toward socio-ecological wisdom measurable in life forms at every level. After my collaborative scientific work for over a half century to detail the genetics, microscopy, and biochemistry of cells that adhere in their lives together, I consider the neo-Darwinist overemphasis on competition among selfish individuals – who supposedly perpetuate their genes as if they were robots – to be a Victorian caricature. Disease microbes that kill all their victims perish themselves as a result of their aggression.

I disagree with neo-Darwinist zoologists who assert that the accumulation of random genetic mutations is the major source of evolutionary novelty. More important is symbiogenesis, the evolution of new species from the coming together of members of different species. Symbiogenesis is the behavioral, physiological, and genetic fusion of different kinds of being; it leads to the evolution of chimeric new ones. One example is of originally pathogenic bacteria that invaded and killed many amoebae in the University of Tennessee laboratory of Kwang Jeon in the 1970s. He selected survivors, and eventually different amoebae with new species characteristics appeared among them. These had retained 40,000 bacteria in each amoeba!

A new type of fruit fly evolved after it acquired an insect-loving bacterium that prevented it from successfully mating with its old partners. Indeed, the only documented cases of the “origin of species” in real time involve not selfish genes but “selfless” mergers of different forms. Chemical and genetic evidence suggests that even mitochondria, bodies inside all of our cells that suffocate without oxygen, came from ancient mergers, truces between oxygen-respiring bacteria and the nearly poisoned cells of other kinds of microscopic beings. The mergers, naturally selected, survived to thrive and spread across the planet.

Gifted with large brains that permit us great neurological processing power, we humans plan further into the future. We recognize more of our own kind with whom, now via global communication, we establish relationships of identity and trust. But on a crowded planet, there has always been a premium on effective togetherness. Our moral nature reflects rather than conflicts with nature.

Free will may also be nature-deep. Large single-celled forams choose from brightly colored sand grains the correct ones with which to make shells. Aware of shape and color, they make choices and reproduce their kind. Awareness in some form has been naturally selected for at least 550 million years. For me, our spirituality and moral nature help perpetuate our living communities, just as similar attributes aided previous living communities whose evolution is chronicled in the fossil record.

Related Posts:

New Species and The Progeny of Elephants

Monday, March 23rd, 2009

Lynn Margulis, author of Luminous Fish: Tales of Science and Love and Mind, Life, and Universe: Conversations with Great Scientists of Our Time, recently sat for an interview with Suzan Mazur at Scoop, an independent news site from New Zealand. Here’s an excerpt.

Suzan Mazur: Can you shed some light on what’s going on regarding the status and meaning of natural selection?

Lynn Margulis: I think I see the problem clearly. There is absolutely no doubt that natural selection itself can be measured every minute of the day in every population of organisms. Darwin was brilliant to make “natural selection” a sort of godlike term, an expression that could replace “God”, who did it — created life forms. However, what is “natural selection” really? It is the failure of biotic potential to be reached. And it’s quantitative.

Biotic potential is the intrinsic ability of any population to overgrow its environment by production of too many offspring. Whether born, hatched, budded or sporulated, all organisms potentially produce more offspring than can survive to reproduce themselves. Natural selection is intrinsically an elimination process. I’ll give you some specific examples.

My favorite one – I show this in a film and people just gasp. An ordinary bacterium – Proteus vulgaris – divides at the rate of every 15 minutes.

I have a time-lapse view of Proteus vulgaris where I show two hours of growth – 1, 2, 4, 8, 16, 32, 64, etc., until it fills the screen. I explain that if Proteus vulgaris continued to grow at this rate, not once a minute or once every 10 seconds, but once every 15 or 20 minutes, i.e., the way it really grows when it’s not limited, this bacterium would reach the mass of the Earth over a weekend.

It’s easy to show that the biotic potential measured as “number of offspring per unit time” (convertible of course into its equivalent “number of offspring per generation”) is never reached. Ever.

Darwin said the whole Earth could be covered by the progeny of a single pair of elephants.

Read the full article here.

Lynn Margulis Awarded Illustrious Darwin-Wallace Medal

Friday, February 20th, 2009

Scientist and author Lynn Margulis (Luminous Fish: Tales of Science and Love; Mind, Life, and Universe: Conversations with Great Scientists of Our Time; Dazzle Gradually: Reflections on the Nature of Nature) was recently honored by the Linnean Society of London with the Darwin-Wallace Medal for “major advances in evolutionary biology.”

Until 2008, the Darwin-Wallace Medal was awarded to only a select few, every 50 years, beginning 1908, the fiftieth anniversary of Charles Darwin and Russel Wallace’s reading of the joint paper “On the Tendency of Species to form Varieties; and the Perpetuation of Varieties and Species by Natural Means of Selection” July 1, 1858.

We here at Chelsea Grenn send Lynn our most enthusiastic congratulations on receiving this great honor. It’s no stretch to call it a once-in-a-lifetime achievement.

From Professor Margulis’s bio:

Margulis’s theory of species evolution by symbiogenesis, put forth in Acquiring Genomes (co-authored with Dorion Sagan, 2002), describes how speciation does not occur by random mutation alone but rather by symbiotic détente. Behavioral, chemical, and other interactions often lead to integration among organisms, members of different taxa. In well-documented cases some mergers create new species. Intimacy, physical contact of strangers, becomes part of the engine of life’s evolution that accelerates the process of change. Margulis works in the laboratory and field with many other scientists and students to show how specific ancient partnerships, in a given order over a billion years, generated the cells of the species we see with our unaided eyes.The fossil record, in fact, does not show Darwin’s predicted gradual changes between closely related species but rather the “punctuated equilibrium” pattern described by Eldredge and Gould: a jump from one to a different species.

Here’s the full list of 2008 Silver Medal Winners (the Gold was awarded once only, in 1908):

Nick Barton
Mark Chase
Bryan Clarke
Joseph Felsenstein
Stephen Jay Gould (posthumous)
P. R. Grant & Rosemary Grant
James (Jim) Mallet
Lynn Margulis 
John Maynard‐Smith (posthumous)
Mohamed Noor
H. Allen Orr
Linda Partridge

WATCH: Author Dorion Sagan Teaches Love of Science Through Magic

Monday, December 8th, 2008

Dorion Sagan, author of Notes from the Holocene: A Brief History of the Future, enjoys blurring the line between science and magic. “After science, comes magic,” he explains to his captive audience while performing for friends at an after-dinner party.

Dorion’s show makes clear, to a young volunteer from the audience, that science is magic and that the line we believe that separates the two is a social construct that can be played with, distorted, and done away with altogether. The video below highlights an evening performance of Dorion’s magic and humor.

Margulis: Bacteria do everything ‘cept the talking

Friday, April 11th, 2008

If ever there was a single article that captures the spirit and intellect of Lynn Margulis, this profile in the Daily Collegian may be it. It simply underscores all the reasons why we here at Chelsea Green love Lynn and why we are proud to work with her on the Sciencewriters Books imprint.

Just take these few choice lines:

“The answer to all my questions is always bacteria, except talking—they don’t do talking.”


“When I was in [elementary school], I was bad because I was bored. I’ve always had trouble doing what I’m supposed to do. I just laughed at goodie-goodies, and made trouble, and chased boys, and I was bad.”

Or, my personal favorite when talking about her days at the University of Chicago:

“I got my critical ability to detect bullshit. I’m really good at that.”

And, dear readers, let me concur that if ever you have bullshit that needs detecting, Lynn’s the one you want on your side.

Scientist, Chelsea Green author calls for new 9/11 investigation

Tuesday, August 28th, 2007

Just in time for it’s sixth anniversary, Lynn Margulis—co-author of the forthcoming Dazzle Gradually and author of Luminous Fish—has joined a long line of scientists, thinkers, 9/11 survivors and family members in the United States who question the official story of 9/11. Margulis, Distinguished University Professor in the Department of Geosciences, University of Massachusetts at Amherst, is also calling for a new investigation into the events of the day.

Her complete statement, posted on the website Patriots Question 9/11, reads below the fold:


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