Sunshine Recorder

Bacteria were for a long time believed to exist as individual cells that sought primarily to find nutrients and multiply. The discovery of intercellular communication among bacteria has led to the realization that bacteria are capable of coordinated activity that was once believed to be restricted to multicellular organisms. The capacity to behave collectively as a group has obvious advantages, for example, the ability to migrate to a more suitable environment/better nutrient supply and to adopt new modes of growth, such as sporulation or biofilm formation, which may afford protection from deleterious environments. The “language” used for this intercellular communication is based on small, self-generated signal molecules called autoinducers. Through the use of autoinducers, bacteria can regulate their behavior according to population density. The phenomenon of quorum sensing, or cell-to-cell communication, relies on the principle that when a single bacterium releases autoinducers (AIs) into the environment, their concentration is too low to be detected. However, when sufficient bacteria are present, autoinducer concentrations reach a threshold level that allows the bacteria to sense a critical cell mass and, in response, to activate or repress target genes. Most of the bacteria thus far identified that utilize quorum-sensing systems are associated in some way with plants or animals. The nature of these relationships can be either amicable, as characterized by symbiotic bacteria, or adversarial, as seen with pathogenic bacteria. There are numerous bacteria that have components of a quorum-sensing system for which the phenotype regulated remains an enigma. Similarly, there are bacteria known to regulate a specific phenotype via quorum sensing for which one or more of the regulatory components have thus far eluded identification. 

A deep dive into how the most intelligent creatures in the ocean perceive their world.

There is almost nothing about a whale’s body that we can relate to. They breathe air like we do. They give birth to live young like we do. But the similarities seem to stop there. Their scale, body structure, and environment are all different.

But we do have a point of connection: the eyes. Both humans and whales are mammals, so our eyes are derived from a common ancestor. Not only can we look at whales and they can look back at us, but we know enough about optics to infer their eyes’ capabilities from their anatomy. Animal eyes can be imagined as technological systems evolved with biological materials.

“We will make the fairly bold claim that it is sensible to approach eyes in essentially the same way that an optical engineer might evaluate a new video camera,” write Michael Land and Dan-Eric Nilsson, the authors of the Oxford University Press treatment of our topic, Animal Eyes.

Their eyes capture light in ways we can understand. Their eyes have a focal length. Their eyes have a maximum resolution.

So, what does the world look like to a whale?

Here’s what got me pursuing this line of inquiry. The photographer Bryant Austin makes life-size composites of whales: humpbacks, sperm whales, minkes. The results are sublime. Each fin, each ridge in the skin, seems worth pondering. Austin is especially obsessed with photographing their eyes, and with good reason.

To create these images, Austin thought a lot about what kind of visual system could represent the experience of floating next to one of these creatures. Most whale photographers use wide-angle lenses to capture as much of the whale as possible at longer distances, but he realized that wide-angle lenses do not capture enough data to create high-resolution, life-size photographs of whales.

So, on a very fancy Hasselblad H3DII-50, Austin mounted an 80mm portrait lens with a narrow field of view. The consequences of that decision are startling: Austin has to get within ten feet of the whales, and he has to take many photographs from that distance in order to get enough photographs to stitch together the life-size portrait. In practice, that brought him eye-to-eye with these multi-ton animals time and again.

In his new book about his process, out next week, Beautiful Whale, he describes a moment where he came eye-to-eye with a sperm whale named Scar. “I lowered the camera so that our eyes could meet once again, I noticed his eye moving along the length of my body before returning to meet my gaze,” Austin wrote. “As I reflect upon that moment and reconsider the question, ‘What does it feel like [to be so close to whales]?’ the only word that comes to mind is ‘disturbing.’”

Why is it disturbing? Because, as Austin puts it, the whale challenges him “to reevaluate our perceptions of intelligent, conscious life on this planet.” This mammal’s eye—lens, cornea, pupil, retina, photoreceptors and ganglion nerve cells—is a direct passageway into its brain. And when we look at it, Austin can’t help but see an intelligence there, a connection to a brain that, perhaps, works enough like ours for us to understand each other.

… Whales, unlike nocturnal rodents or ourselves, see the world in monochrome. Leo Peichl at the Max Planck Institute for Brain Research co-authored a paper with the nearly tragic title, “For whales and seals the ocean is not blue.” Indeed, the first thing that we can know for sure about how whales see the world is that it exists only in shades of gray. The water we see as blue they would see as black. “They do want to see the background. They want to see animals on the background. And the animals on the background are reflecting light that’s not blue,” Johnsen explained. If we try to imagine what that might look like, Johnsen said perhaps we could picture a grayscale photograph of people wearing fluorescent clothes under a black light.

The revival of an extinct species is no longer a fantasy. But is it a good idea?

On July 30, 2003, a team of Spanish and French scientists reversed time. They brought an animal back from extinction, if only to watch it become extinct again. The animal they revived was a kind of wild goat known as abucardo, or Pyrenean ibex. The bucardo (Capra pyrenaica pyrenaica) was a large, handsome creature, reaching up to 220 pounds and sporting long, gently curved horns. For thousands of years it lived high in the Pyrenees, the mountain range that divides France from Spain, where it clambered along cliffs, nibbling on leaves and stems and enduring harsh winters.

Then came the guns. Hunters drove down the bucardo population over several centuries. In 1989 Spanish scientists did a survey and concluded that there were only a dozen or so individuals left. Ten years later a single bucardo remained: a female nicknamed Celia. A team from the Ordesa and Monte Perdido National Park, led by wildlife veterinarian Alberto Fernández-Arias, caught the animal in a trap, clipped a radio collar around her neck, and released her back into the wild. Nine months later the radio collar let out a long, steady beep: the signal that Celia had died. They found her crushed beneath a fallen tree. With her death, the bucardo became officially extinct.

But Celia’s cells lived on, preserved in labs in Zaragoza and Madrid. Over the next few years a team of reproductive physiologists led by José Folch injected nuclei from those cells into goat eggs emptied of their own DNA, then implanted the eggs in surrogate mothers. After 57 implantations, only seven animals had become pregnant. And of those seven pregnancies, six ended in miscarriages. But one mother—a hybrid between a Spanish ibex and a goat—carried a clone of Celia to term. Folch and his colleagues performed a cesarean section and delivered the 4.5-pound clone. As Fernández-Arias held the newborn bucardo in his arms, he could see that she was struggling to take in air, her tongue jutting grotesquely out of her mouth. Despite the efforts to help her breathe, after a mere ten minutes Celia’s clone died. A necropsy later revealed that one of her lungs had grown a gigantic extra lobe as solid as a piece of liver. There was nothing anyone could have done.

The dodo and the great auk, the thylacine and the Chinese river dolphin, the passenger pigeon and the imperial woodpecker—the bucardo is only one in the long list of animals humans have driven extinct, sometimes deliberately. And with many more species now endangered, the bucardo will have much more company in the years to come. Fernández-Arias belongs to a small but passionate group of researchers who believe that cloning can help reverse that trend.

The notion of bringing vanished species back to life—some call it de-extinction—has hovered at the boundary between reality and science fiction for more than two decades, ever since novelist Michael Crichton unleashed the dinosaurs of Jurassic Park on the world. For most of that time the science of de-extinction has lagged far behind the fantasy. Celia’s clone is the closest that anyone has gotten to true de-extinction. Since witnessing those fleeting minutes of the clone’s life, Fernández-Arias, now the head of the government of Aragon’s Hunting, Fishing and Wetlands department, has been waiting for the moment when science would finally catch up, and humans might gain the ability to bring back an animal they had driven extinct.

“We are at that moment,” he told me.

Hunter gatherers may have very egalitarian societies, but evolution says the human love of power and status runs deeper.

When The Spirit Level: Why Equality is Better for Everyone by Richard Wilkinson and Kate Pickett came out in 2009, it chimed well with the post-crash mood. The book claimed that higher levels of inequality were associated with a whole range of poor health issues, including lower life expectancy, increased obesity, and higher murder rates. It seemed that those fat cat bankers hadn’t just wrecked the financial system: they were making us all ill, too.

Subsequently, however, these claims came in for a great deal of criticism, especially from sociologists on the libertarian end of the political spectrum. Whether right or wrong, however, the original book has raised a deeper question, and one that is still wide open. By framing the debate about inequality in a biological context, The Spirit Level harked back to an older philosophical conundrum about human nature. Are we, fundamentally, an egalitarian species or a fiercely competitive one? Or are we perhaps so flexible that we can be equally at home in either kind of society?

Evolutionary biology casts considerable light on this question. Start with the fact that our species has spent more than 90 per cent of its existence living in highly egalitarian bands of hunter-gatherers. There is no room in this nomadic existence for the accumulation of property, and hence no great differences in material possessions. As the American anthropologist Marshall Sahlins observed in his 1968 essay on the ‘original affluent society’:

Of the hunter it is truly said that his wealth is a burden. In his condition of life, goods can become ‘grievously oppressive’ … and the more so the longer they are carried around. Certain food collectors do have canoes and a few have dog sleds, but most must carry themselves all the comforts they possess, and so only possess what they can comfortably carry themselves.

It was only when the first humans started farming, around 10,000 years ago, that it became possible for one person to accumulate many more possessions than another. Farmers are sedentary and can therefore store property in buildings, and stake a claim to land by building walls. Farming is also more efficient than hunting and gathering, so a division of labour can develop. Some grow enough food to support other people who have nothing to do with food production, such as artisans, soldiers, priests and kings. Inevitably, those who do not produce food end up far richer than those who do. Kings skim off the surplus production in the form of taxes and use it to finance armies, palaces and temples. Priests spin yarns about tithing to justify all this robbery in exchange for an income of their own. In just a few thousand years — a blink of an eye in evolutionary terms — humans have gone from living in small egalitarian bands to large-scale sedentary societies with extreme levels of inequality.

It would hardly be surprising then if the sudden appearance of inequality didn’t have deleterious consequences for the human mind and body. Other novelties associated with the advent of farming, such as the constant proximity of domestic animals and higher population density, exposed our ancestors to new threats for which they were unprepared, such as the rise of infectious diseases. Evolutionary psychologists have speculated that our ancestors found the new landscape of social inequality similarly damaging, and that there has not yet been enough time for natural selection to adapt us to it, if it ever will.

According to the social competition hypothesis of depression, humans are exquisitely sensitive to small differences in social status. Such sensitivity was vital when our ancestors lived in smaller bands of hunter-gatherers, where status differences were relatively slight. But in today’s world, where the global elite earn thousands of times more than those at the bottom of the economic heap and have completely different lifestyles, our status detectors go into overdrive. Hence a sensitivity that evolved to help low-status individuals signal obedience would, in today’s world, produce pathological results.

Support for this idea is provided by studies of dominance hierarchies in other primates. Low-ranking vervet monkeys, for example, have serotonin levels that are half those of the alpha males, and low-status yellow baboons have elevated levels of the stress hormone cortisol. Both of these physiological responses are found in depressed people, so perhaps inequality does literally get under our skin. A study of British civil servants found that those in lower-grade jobs showed significantly higher levels of the cortisol-awakening response (the difference between cortisol levels at waking and 30 minutes later, which is thought to be linked to the hippocampus’s preparation to face anticipated stress) than those in higher grades. Contrary to popular belief, then, it seems that those at the top of the pyramid, who tend to have the most decision-making responsibility, have the least stressful lives. One theory is that, the lower one is in the chain of command, the less control one has over one’s daily life. Taking orders, rather than giving them, results in raised heart rate, stress hormones, and blood pressure.

Inequality is not a negative-sum game — in which everybody ends up worse off — but a zero-sum game, in which the poorer health of those at the bottom of the pile is offset by the health gains of those at the top. There is nothing like the sight of a beggar to make one feel rich. It is not enough to succeed, as Gore Vidal said; others must fail.

Evolutionary psychologists have also looked to experimental psychology for evidence that we are naturally averse to inequality. In the ultimatum game, for example, two strangers are paired and given a sum of money. One of them — usually referred to as the ‘proposer’ — has to decide how to divide the money. The proposer might suggest a 50-50 split, or they might offer only 10 per cent and keep the lion’s share. The other player can then either accept or reject this offer. If the responder accepts the offer, each player walks away with the share suggested by the proposer. If the responder rejects the offer, each player walks away with nothing.

According to game theory, a rational proposer should always offer the smallest amount possible, and a rational responder should always accept the proposer’s offer, no matter how small it is. After all, some money is better than none. But this isn’t what people actually do when they play this game. Instead of offering the smallest possible amount, most proposers offer between 40 and 50 per cent of the money. And on the few occasions that proposers offer less than 20 per cent, responders reject about half of those offers, despite the fact that this means both lose.

Such findings have been interpreted as evidence that people naturally dislike inequality and will sacrifice some personal gains to avoid it. However, when the experiment has been carried out with indigenous people with a low degree of market integration, the results are very different. Machiguenga farmers in Peru, for example, offer very little, and accept almost every offer, no matter how derisory. In the cultures least exposed to the influence of capitalism, people behave almost as greedily as game theory suggests they should. This does not bode well for the idea that inequality aversion is part of our DNA.

The parasite my lab is beginning to focus on is one in the world of mammals, where parasites are changing mammalian behavior. It’s got to do with this parasite, this protozoan called Toxoplasma. If you’re ever pregnant, if you’re ever around anyone who’s pregnant, you know you immediately get skittish about cat feces, cat bedding, cat everything, because it could carry Toxo. And you do not want to get Toxoplasma into a fetal nervous system. It’s a disaster.

In the endless sort of struggle that neurobiologists have — in terms of free will, determinism — my feeling has always been that there’s not a whole lot of free will out there, and if there is, it’s in the least interesting places and getting more sparse all the time. But there’s a whole new realm of neuroscience which I’ve been thinking about, which I’m starting to do research on, that throws in another element of things going on below the surface affecting our behavior. And it’s got to do with this utterly bizarre world of parasites manipulating our behavior. It turns out that this is not all that surprising. There are all sorts of parasites out there that get into some organism, and what they need to do is parasitize the organism and increase the likelihood that they, the parasite, will be fruitful and multiply, and in some cases they can manipulate the behavior of the host.

Some of these are pretty astounding. There’s this barnacle that rides on the back of some crab and is able to inject estrogenic hormones into the crab if the crab is male, and at that point, the male’s behavior becomes feminized. The male crab digs a hole in the sand for his eggs, except he has no eggs, but the barnacle sure does, and has just gotten this guy to build a nest for him. There are other ones where wasps parasitize caterpillars and get them to defend the wasp’s nests for them. These are extraordinary examples.

The parasite my lab is beginning to focus on is one in the world of mammals, where parasites are changing mammalian behavior. It’s got to do with this parasite, this protozoan called Toxoplasma. If you’re ever pregnant, if you’re ever around anyone who’s pregnant, you know you immediately get skittish about cat feces, cat bedding, cat everything, because it could carry Toxo. And you do not want to get Toxoplasma into a fetal nervous system. It’s a disaster.

The normal life cycle for Toxo is one of these amazing bits of natural history. Toxo can only reproduce sexually in the gut of a cat. It comes out in the cat feces, feces get eaten by rodents. And Toxo’s evolutionary challenge at that point is to figure out how to get rodents inside cats’ stomachs. Now it could have done this in really unsubtle ways, such as cripple the rodent or some such thing. Toxo instead has developed this amazing capacity to alter innate behavior in rodents.

If you take a lab rat who is 5,000 generations into being a lab rat, since the ancestor actually ran around in the real world, and you put some cat urine in one corner of their cage, they’re going to move to the other side. Completely innate, hard-wired reaction to the smell of cats, the cat pheromones. But take a Toxo-infected rodent, and they’re no longer afraid of the smell of cats. In fact they become attracted to it. The most damn amazing thing you can ever see, Toxo knows how to make cat urine smell attractive to rats. And rats go and check it out and that rat is now much more likely to wind up in the cat’s stomach. Toxo’s circle of life completed.

This was reported by a group in the UK about half a dozen years ago. Not a whole lot was known about what Toxo was doing in the brain, so ever since, part of my lab has been trying to figure out the neurobiological aspects. The first thing is that it’s for real. The rodents, rats, mice, really do become attracted to cat urine when they’ve been infected with Toxo. And you might say, okay, well, this is a rodent doing just all sorts of screwy stuff because it’s got this parasite turning its brain into Swiss cheese or something. It’s just non-specific behavioral chaos. But no, these are incredibly normal animals. Their olfaction is normal, their social behavior is normal, their learning and memory is normal. All of that. It’s not just a generically screwy animal.

You say, okay well, it’s not that, but Toxo seems to know how to destroy fear and anxiety circuits. But it’s not that, either. Because these are rats who are still innately afraid of bright lights. They’re nocturnal animals. They’re afraid of big, open spaces. You can condition them to be afraid of novel things. The system works perfectly well there. Somehow Toxo can laser out this one fear pathway, this aversion to predator odors.

We started looking at this. The first thing we did was introduce Toxo into a rat and it took about six weeks for it to migrate from its gut up into its nervous system. And at that point, we looked to see, where has it gone in the brain? It formed cysts, sort of latent, encapsulated cysts, and it wound up all over the brain. That was deeply disappointing.

But then we looked at how much winds up in different areas in the brain, and it turned out Toxo preferentially knows how to home in on the part of the brain that is all about fear and anxiety, a brain region called the amygdala. The amygdala is where you do your fear conditioning; the amygdala is what’s hyperactive in people with post-traumatic stress disorder; the amygdala is all about pathways of predator aversion, and Toxo knows how to get in there.

Next, we then saw that Toxo would take the dendrites, the branch and cables that neurons have to connect to each other, and shriveled them up in the amygdala. It was disconnecting circuits. You wind up with fewer cells there. This is a parasite that is unwiring this stuff in the critical part of the brain for fear and anxiety. That’s really interesting. That doesn’t tell us a thing about why only its predator aversion has been knocked outwhereas fear of bright lights, et cetera, is still in there. It knows how to find that particular circuitry.

So what’s going on from there? What’s it doing? Because it’s not just destroying this fear aversive response, it’s creating something new. It’s creating an attraction to the cat urine. And here is where this gets utterly bizarre. You look at circuitry in the brain, and there’s a reasonably well-characterized circuit that activates neurons which become metabolically active circuits where they’re talking to each other, a reasonably well-understood process that’s involved in predator aversion. It involves neurons in the amygdala, the hypothalamus, and some other brain regions getting excited. This is a very well characterized circuit.

Stem cells have generated such an enormous amount of interest, in part, because of their applications related to areas such as fertility and genetics. In that same light, their interest for solving reproductive challenges has also generated a great deal of controversy. This is particularly true in the application of stem cells to facilitate reproduction for gay couples.

At present, there are a number of research laboratories that are focused on the creation of cells that are genetically male but have been produced from eggs. Alternately, they are also trying to create sperm from female eggs. If the research proves to work, the consequences are particularly important for gay and lesbian couples that wish to have children. The idea is, however, an extremely controversial one that mixes in with politics, religion and ethics. Many individuals oppose same-sex reproduction while gay and lesbian couples - as well as heterosexual members of the public - argue that gay persons should have the right to produce and raise biological children if the opportunity becomes available.

The techniques purported to allow same-sex reproduction have yet to be successful but they do hold promise. They include methods of cellular reprogramming and even techniques such as artificial chromosomes. While they have not been shown to work at present, they do hold potential for the future of same-sex reproduction. One particular technique involves the creation of sperm from human stem cells. In a recent experiment, bone marrow stem cells were extracted from men and they were then triggered into spermatogonia. These cells are able to develop into immature sperm cells. The experiment was widely reported in the news but has not yet been published or successfully replicated.

In another experiment, spermatogonia were triggered to begin meiosis after being cultured with cells known as Sertoli cells. These cells are found in the testes and are important because they support developing sperm. While the research team for this particular experiment has yet to obtain these kinds of results with the production of eggs, a team in Brazil does cite that they have created sperm and eggs from embryonic stem cells. Whether or not the eggs can actually produce viable offspring, however, is the most vital aspect of this type of experimentation. Still, the work does still show that potential for same-sex reproduction exists, and it will likely spur further research in this area.

How do you design a utopia? In 1972, John B. Calhoun detailed the specifications of his Mortality-Inhibiting Environment for Mice: a practical utopia built in the laboratory. Every aspect of Universe 25—as this particular model was called—was pitched to cater for the well-being of its rodent residents and increase their lifespan. The Universe took the form of a tank, 101 inches square, enclosed by walls 54 inches high. The first 37 inches of wall was structured so the mice could climb up, but they were prevented from escaping by 17 inches of bare wall above. Each wall had sixteen vertical mesh tunnels—call them stairwells—soldered to it. Four horizontal corridors opened off each stairwell, each leading to four nesting boxes. That means 256 boxes in total, each capable of housing fifteen mice. There was abundant clean food, water, and nesting material. The Universe was cleaned every four to eight weeks. There were no predators, the temperature was kept at a steady 68°F, and the mice were a disease-free elite selected from the National Institutes of Health’s breeding colony. Heaven.

Four breeding pairs of mice were moved in on day one. After 104 days of upheaval as they familiarized themselves with their new world, they started to reproduce. In their fully catered paradise, the population increased exponentially, doubling every fifty-five days. Those were the good times, as the mice feasted on the fruited plain. To its members, the mouse civilization of Universe 25 must have seemed prosperous indeed. But its downfall was already certain—not just stagnation, but total and inevitable destruction.

Calhoun’s concern was the problem of abundance: overpopulation. As the name Universe 25 suggests, it was not the first time Calhoun had built a world for rodents. He had been building utopian environments for rats and mice since the 1940s, with thoroughly consistent results. Heaven always turned into hell. They were a warning, made in a postwar society already rife with alarm over the soaring population of the United States and the world. Pioneering ecologists such as William Vogt and Fairfield Osborn were cautioning that the growing population was putting pressure on food and other natural resources as early as 1948, and both published bestsellers on the subject. The issue made the cover of Time magazine in January 1960. In 1968, Paul Ehrlich published The Population Bomb, an alarmist work suggesting that the overcrowded world was about to be swept by famine and resource wars. After Ehrlich appeared on The Tonight Show with Johnny Carson in 1970, his book became a phenomenal success. By 1972, the issue reached its mainstream peak with the report of the Rockefeller Commission on US Population, which recommended that population growth be slowed or even reversed.

But Calhoun’s work was different. Vogt, Ehrlich, and the others were neo-Malthusians, arguing that population growth would cause our demise by exhausting our natural resources, leading to starvation and conflict. But there was no scarcity of food and water in Calhoun’s universe. The only thing that was in short supply was space. This was, after all, “heaven”—a title Calhoun deliberately used with pitch-black irony. The point was that crowding itself could destroy a society before famine even got a chance. In Calhoun’s heaven, hell was other mice.

(Source: sunrec)

During an epoch of dramatic climate change 200,000 years ago, Homo sapiens (modern humans) evolved in Africa. Several leading scientists are asking: Is the human species entering a new evolutionary, post-biological inflection point?

Paul Davies, a British-born theoretical physicist, cosmologist, astrobiologist and Director of the Beyond Center for Fundamental Concepts in Science and Co-Director of the Cosmology Initiative at Arizona State University, says in his new book The Eerie Silence that any aliens exploring the universe will be AI-empowered machines. Not only are machines better able to endure extended exposure to the conditions of space, but they have the potential to develop intelligence far beyond the capacity of the human brain.

“I think it very likely – in fact inevitable – that biological intelligence is only a transitory phenomenon, a fleeting phase in the evolution of the universe,” Davies writes. “If we ever encounter extraterrestrial intelligence, I believe it is overwhelmingly likely to be post-biological in nature.”

In the current search for advanced extraterrestrial life SETI experts say the odds favor detecting alien AI rather than biological life because the time between aliens developing radio technology and artificial intelligence would be brief.  

“If we build a machine with the intellectual capability of one human, then within 5 years, its successor is more intelligent than all humanity combined,” says Seth Shostak, SETI chief astronomer. “Once any society invents the technology that could put them in touch with the cosmos, they are at most only a few hundred years away from changing their own paradigm of sentience to artificial intelligence,” he says.

ET machines would be infinitely more intelligent and durable than the biological intelligence that created them. Intelligent machines would be immortal, and would not need to exist in the carbon-friendly “Goldilocks Zones” current SETI searches focus on. An AI could self-direct its own evolution, each “upgrade” would be created with the sum total of its predecessor’s knowledge preloaded.

“I think we could spend at least a few percent of our time… looking in the directions that are maybe not the most attractive in terms of biological intelligence but maybe where sentient machines are hanging out.” Shostak thinks SETI ought to consider expanding its search to the energy- and matter-rich neighborhoods of hot stars, black holes and neutron stars. 

Before the year 2020, scientists are expected to launch intelligent space robots that will venture out to explore the universe for us.

“Robotic exploration probably will always be the trail blazer for human exploration of far space,” says Wolfgang Fink, physicist and researcher at Caltech. “We haven’t yet landed a human being on Mars but we have a robot there now. In that sense, it’s much easier to send a robotic explorer. When you can take the human out of the loop, that is becoming very exciting.”

As the growing global population continues to increase the burden on the Earth’s natural resources, senior curator at the Smithsonian National Air and Space Museum, Roger Launius, thinks that we’ll have to alter human biology to prepare to colonize space. 

Launius  looks at the historical debate surrounding human colonization of the solar system. Experiments have shown that certain life forms can survive in space. Recently, British scientists found that bacteria living on rocks taken from Britain’s Beer village were able to survive 553 days in space, on the exterior of the International Space Station (ISS). The microbes returned to Earth alive, proving they could withstand the harsh environment. 

Humans, on the other hand, are unable to survive beyond about a minute and a half in space without significant technological assistance. Other than some quick trips to the moon and the ISS, astronauts haven’t spent too much time too far away from Earth. Scientists don’t know enough yet about the dangers of long-distance space travel on human biological systems. A one-way trip to Mars, for example, would take approximately six months. That means astronauts will be in deep space for more than a year with potentially life-threatening consequences.

Launius, who calls himself a cyborg for using medical equipment to enhance his own life, says the difficult question is knowing where to draw the line in transforming human biological systems to adapt to space.

Does success spell doom for Homo sapiens?

The problem with environmentalists, Lynn Margulis used to say, is that they think conservation has something to do with biological reality. A researcher who specialized in cells and microorganisms, Margulis was one of the most important biologists in the last half century—she literally helped to reorder the tree of life, convincing her colleagues that it did not consist of two kingdoms (plants and animals), but five or even six (plants, animals, fungi, protists, and two types of bacteria).

Until Margulis’s death last year, she lived in my town, and I would bump into her on the street from time to time. She knew I was interested in ecology, and she liked to needle me. Hey, Charles,she would call out, are you still all worked up about protecting endangered species?

Margulis was no apologist for unthinking destruction. Still, she couldn’t help regarding conservationists’ preoccupation with the fate of birds, mammals, and plants as evidence of their ignorance about the greatest source of evolutionary creativity: the microworld of bacteria, fungi, and protists. More than 90 percent of the living matter on earth consists of microorganisms and viruses, she liked to point out. Heck, the number of bacterial cells in our body is ten times more than the number of human cells!

Bacteria and protists can do things undreamed of by clumsy mammals like us: form giant supercolonies, reproduce either asexually or by swapping genes with others, routinely incorporate DNA from entirely unrelated species, merge into symbiotic beings—the list is as endless as it is amazing. Microorganisms have changed the face of the earth, crumbling stone and even giving rise to the oxygen we breathe. Compared to this power and diversity, Margulis liked to tell me, pandas and polar bears were biological epiphenomena—interesting and fun, perhaps, but not actuallysignificant.

Does that apply to human beings, too? I once asked her, feeling like someone whining to Copernicus about why he couldn’t move the earth a little closer to the center of the universe. Aren’t we specialat all?

This was just chitchat on the street, so I didn’t write anything down. But as I recall it, she answered that Homo sapiens actually might be interesting—for a mammal, anyway. For one thing, she said, we’re unusually successful.

Seeing my face brighten, she added: Of course, the fate of every successful species is to wipe itself out.

Why and how did humankind become “unusually successful”? And what, to an evolutionary biologist, does “success” mean, if self-destruction is part of the definition? Does that self-destruction include the rest of the biosphere? What are human beings in the grand scheme of things anyway, and where are we headed? What is human nature, if there is such a thing, and how did we acquire it? What does that nature portend for our interactions with the environment? With 7 billion of us crowding the planet, it’s hard to imagine more vital questions.

One way to begin answering them came to Mark Stoneking in 1999, when he received a notice from his son’s school warning of a potential lice outbreak in the classroom.

Podcast (20 minutes): From a suburban sidewalk in southern California, Jad and Robert witness the carnage of a gruesome turf war. Though the tiny warriors doing battle clock in at just a fraction of an inch, they have evolved a surprising, successful, and rather unsettling strategy of ironclad loyalty, absolute intolerance, and brutal violence.

David Holway, an ecologist and evolutionary biologist from UC San Diego, takes us to a driveway in Escondido, California where a grisly battle rages. In this quiet suburban spot, two groups of ants are putting on a chilling display of dismemberment and death. According to David, this battle line marks the edge of an enormous super-colony of Argentine ants. Think of that anthill in your backyard, and stretch it out across five continents.

Argentine ants are not good neighbors. When they meet ants from another colony, any other colony, they fight to the death, and tear the other ants to pieces. While other kinds of ants sometimes take slaves or even have sex with ants from different colonies, the Argentine ants don’t fool around. If you’re not part of the colony, you’re dead.

According to evolutionary biologist Neil Tsutsui and ecologist Mark Moffett, the flood plains of northern Argentina offer a clue as to how these ants came to dominate the planet. Because of the frequent flooding, the homeland of Linepithema humile is basically a bootcamp for badass ants. One day, a couple ants from one of these families of Argentine ants made their way onto a boat and landed in New Orleans in the late 1800s. Over the last century, these Argentine ants wreaked havoc across the southern U.S. and a significant chunk of coastal California.

In fact, Melissa Thomas, an Australian entomologist, reveals that these Argentine ants are even more well-heeled than we expected - they’ve made to every continent except Antarctica. No matter how many thousands of miles separate individual ants, when researchers place two of them together - whether they’re plucked from Australia, Japan, Hawaii … even Easter Island - they recognize each other as belonging to the same super-colony.

But the really mind-blowing thing about these little guys is the surprising success of their us-versus-them death-dealing. Jad and Robert wrestle with what to make of this ant regime, whether it will last, and what, if anything, it might mean for other warlike organisms with global ambitions.

The scientific identification of the key components of sexual reproduction – eggs and sperm – took place during an amazing decade of discovery in the 1660s and 1670s. The names of many of the people involved are now forgotten, and yet their work, and the difficulties they faced and the conflicts they endured, resonate strongly to the present day. Despite this period of innovation, the respective roles of egg and sperm remained unclear for another 170 years. Why did this take so long? And what did people think before these discoveries? By tracing the contours of this major milestone in human knowledge, we can also gain insight into our current knowledge, and the boundaries we may be unwit- tingly trapped by.

The 17th century discovery of the role of egg and sperm in reproduction can be traced to two letters, written 7 years apart, each by a remarkable man who is largely forgotten today. Those letters heralded an amazing decade of discovery that eventually shaped the way we now understand life.

In April 1665, Melchisedec The ́ venot (c.1620–92), a French patron of the sciences, wrote to his friend Christiaan Huygens (1629–95), a Dutch mathematician and astronomer: ‘We took the opportunity provided by the cold of recent months and applied ourselves to dissections and to investigating the Generation of animals’ (The ́ venot 1665). The ‘we’ referred to two of The ́ venot’s prote ́ ge ́ s, the Dutchman Jan Swammerdam (1637–1680) and the Dane Niels Stenson (‘Steno’) (1638–86). This was the start of a process of discussion, dissection and experimentation that would soon lead Swammerdam and Steno to the conclusion that all animals – including humans – come from eggs.

The second letter was sent 9 years later, in April 1674. It was written by Henry Oldenburg (c.1615–77), the German secretary of the Royal Society (Hall 2002) and was sent to a Delft draper, Leeuwenhoek (1632–1723). In the letter, Oldenburg asked Leeuwenhoek to use his microscope to study semen, saliva, chyle, sweat and other bodily fluids. With this inspiration, in 1677, Leeuwenhoek would make one of the most stupendous discoveries in the history of science: the observation of spermatozoa.

To understand why these two letters were so impor- tant, we need to unlearn all that we know about reproduction, beginning with that word. The term ‘reproduction’ was first introduced by Buffon in 1749 (Roger 1997). Up until then, people spoke about ‘generation’, and this was taken to include both how organisms grow apparently from nothing, and how male and female contributed to new life (Cole 1930).

Although the simple answer to the question ‘where do babies come from?’ is fairly obvious – they come out of the female vagina – arriving at an explanation of how the baby got there in the first place proved quite difficult (Cobb 2006a). It seems very likely that early human populations did not know that intercourse led to babies. There are number of reasons for thinking this. Firstly, how could they know? The link between intercourse and pregnancy is not at all clear or immediate – people can easily have intercourse without the woman getting pregnant and the first signs of pregnancy may not be seen for weeks after the act. This surprising supposition is supported by the widespread existence of matrilineal communities in hunter-gatherer societies, which suggests that men’s role in generation was uncertain.

It is possible that the domestication of animals provided the key. In all domesticated animals, mating takes place only during oestrus (Potts and Short 1999). Placing the animals together to allow mating would have been an important step in domestication and in ensuring the survival of the animals and of the human group that owned them. According to an un-testable hypothesis, this could have had two inter-linked conse- quences: it may have revealed the role of male animals (and, by extension, of men) in generation, and also created an economic surplus. And once wealth became widespread, the question of paternity became funda- mental for society. 

FiveBooks interviews asks writers, academics, and experts to list recommended books on a given topic.

The science writer and award-winning blogger discusses the strangeness of life, from viruses to manipulative flatworms.

What is it that draws you to explore the ‘strangeness of life’?

The idea of the strangeness of life has been preoccupying me ever since I was a kid. I just didn’t articulate it until I was making a living writing about it. The most important thing science can do is to show that when you look around, you are only really seeing the surface of things. Reality is very different, and it is not what your intuition is telling you. You see the animals and the plants around you but there is also another world of life you can’t see. And even though you think you understand the animals and plants, you probably don’t.

Your first choice is Armand Leroi’s Mutants, which is about a biologist who recounts the lives of people with extreme deformities.

That’s right. Armand Leroi is a biologist at Imperial College, London. And this is a really wonderful book because Leroi takes what could have just been a freak show and turns it into a really amazing experience. He writes about these people as people. He finds wonderful portraits of individuals – for example, some of them are covered in hair and look like wolves – and he tells the story of their lives in quite beautiful prose. He also uses their conditions to talk about the rules of development.

And what does he reveal about those rules?

What is important is that mutants are not random. You don’t get a random range of deformities; they have certain patterns. So you don’t see people developing an eye on their hands, for example. That just doesn’t happen. But it is possible for two eyes to become one. So, why is it that you don’t see eyes developing on hands but you do see two eyes becoming one? And why do Siamese twins form in particular patterns and not others? You don’t see twins joined at the toe.

The reason is that our development follows a pretty tight path. When the genes that are governing our development are mutated, they don’t get disrupted in all that many different ways.

These regularities in disruptions can reveal to you what is going on underneath. This is a tried-and-true method in biology. When people are trying to understand how the brain works, one of the most important things they can do is to study people who have different kinds of psychological disorders. People can lose their ability to use language but not their ability to perceive music, and that starts to show that, actually, there are networks for these different kinds of cognition.

The same thing goes with development. Three biologists won the Nobel Prize in 1995 for studying how fruit flies sometimes develop extra wings or sprout legs on their heads. Those kinds of deformities let them zero in on genes that define a body from head to tail. They studied it in fruit flies – and then, lo and behold, it turns out that we actually have the same genes. They govern our anatomy. When those genes mutate in us, we can end up with extra fingers.  And so again there is a hidden unity under there.

Which he is exploring.

Yes. And he does such a beautiful job of showing that and doing it with poetry. He is able to show the beauty in a birth deformity.

Your next choice is Rebecca Skloot’s Immortal Life of Henrietta Lacks. This is almost a detective story – it’s about the woman who unknowingly helped create the polio vaccine and uncover the secrets of cancer.

Yes. This is a fascinating book on so many different levels. It is really compelling as the story of the author trying to uncover the history of the woman from whom all these cells came.

Who was known as ‘HeLa’.

She had cervical cancer, and samples were taken from her body. Scientists who were trying to culture human cells discovered that her cells could just grow and grow and grow. It had never been seen before.

Why do you think that was?

That is one of the things that I find particularly fascinating. What happened to Henrietta Lacks is that she was infected with human papillomavirus. Now lots of people get infected with this virus. It is very common on people’s skin, for example. A lot of people carry it and don’t even know it; in some cases, it causes a small wart. But if it is spread sexually, women can develop cervical cancer from it. 

And it is amazing what this virus does. We usually think of viruses as infecting cells and making new copies of themselves until the cells explode and die. All the new viruses then go off and kill other cells. But that’s not what all viruses do. I am obsessed with viruses.

I know you have just written a book about them.

For me, part of the fascination with Rebecca’s book is that it is the story about what viruses can do. The papillomavirus infects a cell in the skin or other kinds of lining in the body. But it doesn’t try to kill the cell; it actually does the opposite. It actually produces proteins that link onto the proteins in the cell and speed up its growth and division. Basically, its strategy is: If there are more host cells that are infected with the virus, that means there are more viruses.

The reason most of us can have this type of virus and not be harmed by it is that we are constantly shedding the top layer of our skin.

But with Henrietta, there was no balance.

Exactly. For people with cervical cancer, the virus just speeds things up too much. Once you get that kind of uncontrolled growth, you have cancer. In the case of Henrietta Lacks, the virus created a kind of super-cancer, because it could not only grow rapidly in her body, but also grow rapidly in a Petri dish.  So it is continuing to grow today, even though she has been dead for some 50 years.