Tooth and claw

The earliest living things, way back in the Precambrian Era, were almost certainly either autotrophs (those that could produce their own nutrients from inorganic chemicals) or else scavengers.  One of the reasons for this inference is that these early life forms had few in the way of hard, fossilizable parts, of the kind you might use to protect yourself from predators.  Most of the fossils from that era are casts and impressions, and suggest soft-bodied organisms that, all things considered, had life fairly easy.

But the Cambrian Explosion saw the rather sudden evolution of exoskeletons, scales, spines... and big, nasty, pointy teeth.  There's credible evidence that one of the main reasons behind that rapid diversification was the evolution of carnivory.  Rather than waiting for your neighbor to die before you can have a snack, you hasten the process yourself -- and create strong selection for adaptations involving self-defense and speed.

After that, life became a much dicier business.  I was discussing this just a couple of days ago with the amazing paleontologist and writer Riley Black (you should definitely check out her books at the link provided).  She'd posted on Bluesky about the terrifying Cretaceous mosasaur Tylosaurus proriger, which got to be a mind-blowing twelve meters long (around the length of a school bus).  This species lived in the Western Interior Seaway, which back then covered the entire middle of the North American continent.  I commented to her what a difficult place that must have been even to survive in.  "We always describe the Western Interior Seaway as 'a warm, shallow sea,'" Riley responded.  "Ahh, soothing -- and not like 'holy shit these waters are full of TEETH!'"

What's interesting, though, is that even though we think of predators as mostly being macroscopic carnivores, this practice goes all the way down to the microscopic.  The topic comes up because of a paper this week in Science about some research at ETH Zürich about a species of predatory marine bacteria called Aureispira.  These little things are downright terrifying.  They slither about on the ocean floor looking for prey -- other bacteria, especially those of the genus Vibrio -- and when they encounter one, they throw out structures that look like grappling hooks.  The hooks get tangled in the victim's flagella, and at that point it's game over.  The prey is pulled toward the predator, and when it's close enough, it shoots the prey with a microscopic bolt gun, and then chows down.

Aureispira isn't a one-off.  The soil bacterium Myxococcus xanthus forms what have been called "wolf packs" -- biofilms of millions of bacteria that can be up to several centimeters wide, that glide along soil particles, digesting any other bacteria or fungi they happen to run across. 

A "wolf pack" of Myxococcus xanthus [Image licensed under the Creative Commons Trance Gemini, M. xanthus development, CC BY-SA 3.0]

This one immediately put me in mind of one of the most terrifying episodes of The X Files; "Field Trip."  In this freaky story, people are put into a series of powerful hallucinations after inhaling spores of a microorganism.  The hallucinations keep the victim quiet -- while (s)he is then slowly digested.

Of course, the microbe in "Field Trip" isn't real (thank heaven), but there are plenty of little horrors in the world of the tiny that are just as scary.  Take, for example, the aptly-named Vampirococcus, which is an anaerobic aquatic genus that latches onto other bacterial cells and sucks out their cytoplasm.

But the weirdest one of all is the bizarre Bdellovibrio, which is a free-swimming aquatic bacterium that launches itself at other single-celled organisms, moving at about a hundred times its own body length per second, then uses its flagella to spin at an unimaginable one hundred revolutions per second, turning itself into a living drill.  The prey's cell membrane is punctured in short order, and the Bdellovibrio burrows inside to feast on the innards.

So.  Yeah.  When Alfred, Lord Tennyson said that nature is "red in tooth and claw," I doubt he was thinking of bacteria.  But some of them are as scary as the mosasaurs I was discussing with Riley Black.  The world is a dangerous place -- even on the scale of the very, very small.

****************************************

Death, with big nasty pointy teeth

One of the biggest mysteries in paleontology is what caused the Cambrian Explosion.

You probably know that the Cambrian Explosion is when, around 538.8 million years ago, all of the basic body plans of modern animals appeared in a relative flash.  Before that, there were various simple and soft-bodied forms; afterward, there were animals that were clearly arthropods, annelids (segmented worms), mollusks, echinoderms, corals, nematodes, and proto-vertebrates.

In addition, there were also a number of groups of uncertain relationship to better-known lineages, and which went extinct by the end of the Cambrian Period.  One of the weirdest is Opabinia:

[Image licensed under the Creative Commons Nobu Tamura (http://spinops.blogspot.com), Opabinia BW2, CC BY 3.0]

This kind of rapid diversification is usually an indication that something drastic has changed.  One event that sometimes causes this is a large extinction -- leaving behind open niches that the survivors can adapt to fill.  But there appears to have been no major extinction immediately prior to the Cambrian Explosion.

One of the most plausible explanations has its basis in the observation that a lot of the new forms had fossilizable parts -- shells, exoskeletons, teeth, stiff fins and tails adapted for rapid swimming, and so on.  These more durable body parts mostly are either of a defensive or offensive nature.  So perhaps the Cambrian Explosion was triggered when formerly scavenging species realized they didn't have to wait for their friends and neighbors to die to have dinner, and predation was invented.  At that point, there's a hell of a selective pressure for said friends and neighbors to develop structures that protect them from being on the day's menu -- or turn them into predators themselves.

That theory about the origins of the Cambrian Explosion got a significant boost with the recent discovery of a fossil in Charnwood Forest, near Leicester, England, which is the oldest clearly predatory animal known -- and dates to 560 million years ago, so about twenty million years prior to the spike in biodiversity.

It's a relative of modern sea anemones, and was christened Auroralumina attenboroughii, "Attenborough's dawn lantern," after naturalist David Attenborough, who said he was "truly delighted" by the honor.  

[Image licensed under the Creative Commons F. S. Dunn, C. G. Kenchington, L. A. Parry, J. W. Clark, R. S. Kendall & P. R. Wilby, Auroralumina attenboroughii reconstruction, CC BY-SA 4.0]

It's wildly inaccurate to say that "this is the species that caused the Cambrian Explosion," but it certainly is suggestive that predators evolved not that long before the burst in biodiversity began.  "It’s generally held that modern animal groups like jellyfish appeared 540 million years ago, in the Cambrian Explosion, but this predator predates that by twenty million years," said Phil Wilby of the British Geological Survey, who co-authored the study.  "It’s the earliest creature we know of to have a skeleton.  So far we’ve only found one, but it’s massively exciting to know there must be others out there, holding the key to when complex life began on Earth."

It's amazing to think of what the Earth was like back then.  The only life was in the sea, and the vast continents were nothing but bare rock and sand without a single living thing anywhere.  Into that world was born an animal that was one of the first of its kind, a predatory beast with a protective skeleton to make sure that it wouldn't get turned into lunch itself -- launching the evolution of a dizzying array of structures that allowed for fleeing, attacking, and self-protecting, including all of the big, nasty, pointy teeth we see in predatory animals today.

****************************************

The song of the bat

My favorite animal is the flying fox.

(Don't tell my dogs.)

[Image licensed under the Creative Commons Andrew Mercer (www.baldwhiteguy.co.nz), Grey headed flying fox - AndrewMercer IMG41848, CC BY-SA 4.0]

What's not to like?  They can fly, they get to eat dates and figs all day, and they have the cutest faces ever.

[Image licensed under the Creative Commons Anton 17, Lesser short-nosed fruit bat (Cynopterus brachyotis), CC BY-SA 4.0]

Fruit-eating sky puppies, is how I think of them.

I have to admit, though, that the fruit bats and flying foxes ("megachiropterans," which is Greek for "big hand-wing") are not as astonishingly weird as their cousins, the "microchiropterans" ("little hand-wing") such as the little brown bat (Myotis lucifugus) familiar to us here in the northeastern United States as a nocturnal insect hunter.  I was thinking about these fascinating animals because I'm reading the book Sensory Exotica by Howard C. Hughes, which is about animal sensory systems, and after I said, "Wow!" for the tenth time, I thought they deserved a post.

You probably know that the nocturnal insectivorous bats hunt using sonar -- they emit sounds, then by the echoes locate their prey and scoop it up.  But what you may not have considered is how stunningly complicated this is.  Here are a few things they have to be able to accomplish:

1. Use the echoes from a tiny object like an insect to tell not only what direction it is, but how far away it is.
2. Determine whether the insect is moving toward them or away from them.
3. Determine whether the insect is straight ahead, or to the right or left of them.
4. Decide if the thing they're detecting is an insect at all -- i.e., food -- or something inedible like a fluttering leaf.
5. Given that most bats live in groups -- in the case of the Mexican free-tailed bat (Tadarida brasiliensis) groups of millions in the same cave system -- they have to be able to distinguish the echoes of their own calls from the echoes (and the calls themselves) of their neighbors.
6. Since an echo is much fainter than the original noise, they have to call loudly.  Microchiropteran bats emit calls at about 130 decibels, which is louder than a nearby jet engine or an overamplified rock band.  If their calls weren't so high-pitched -- usually between 30,000 and 40,000 hertz, while even a human with excellent hearing can only detect frequencies lower than 20,000 hertz -- their noises would be deafening.  So how don't they deafen each other, or themselves?

The first one -- the prey range -- they figure out by the delay between the call and the echo.  The closer the insect is, the faster the echo comes back.  We're talking about tiny time intervals, here; for an insect 3.4 meters away, the echo would arrive ten milliseconds after making the call.  So as something gets closer, the echo and the call actually overlap, and the degree of overlap tells the bat it's heading in the right direction.

As far as whether the insect is flying toward or away from the bat, they do this by picking up the Doppler shift of the echo as compared to the pitch of the original call.  You've all heard the Doppler shift; it's the whine of a motorcycle engine suddenly dropping in pitch as it passes you.  So if the pitch of the echo is higher than the pitch of the original call, the insect is coming toward the bat; if it's lower, it's flying away.

Even more astonishing is that they can tell whether an insect is to the right, left, or straight ahead by computing the delay between the echo arriving at their ears.  If it arrives at the right ear first, the insect is the the right, and vice versa; if the echo arrives at both ears simultaneously, it's straight ahead.  Here, we're talking even smaller time intervals; the delay they're sensing is less than a thousandth of a second.

Experiments have shown that bats actually are so sensitive to the quality of the echo that they can tell not only if the sound has echoed off an insect or something else, but if it's an insect, what kind of insect it is.  Experiments have shown that horseshoe bats (Rhinolophus spp.) prefer moths over other types of nocturnal insects, and their sound analysis systems are able to tell the echo coming from the large flapping wings of a moth from the echo coming from the smaller and faster wingbeats of a mosquito or fly.

Okay, now into the part that to me, almost defies belief.  How do they detect their own calls and echoes, and distinguish them from those of their friends?  Each bat recognizes its own call because each call is tuned to a slightly different frequency, and the bat's brain learns to respond to that one frequency and no other.  They can detect a difference between sounds that are only three hertz apart (remember, their calls are in the range of thirty to forty thousand hertz).  But this engenders a problem, the solution to which is mind-boggling.

Remember the Doppler shift?  The echo changes frequency depending on whether the object they're echolocating is coming toward them or away from them.  So how does this not move the frequency of the sound outside of the range the bat is sensitive to?  Put another way, how do they tell that what they're hearing is an echo of their own voice, and not the call of a bat who vocalizes at that (different) frequency?

The answer is that they tune their voices as they go, and do it with a pinpoint accuracy beyond what any trained opera singer could accomplish.  If they hear a sound that could be an echo or could be the voice of a nearby bat, they test it by changing the pitch of their voice.  If the pitch of the echo also changes, it's their voice, not that of another bat.  Further, they tune their voices so that the highest brain response occurs if the conditions are optimal; the echo is exactly what would indicate that it's a bug of the right species coming toward them at a particular speed.  When the frequency of the echo drops into that range, it's like Luke Skywalker using the targeting computer in his X-wing fighter.  Target locked in!  Bam!

Lunchtime.

If you think that's wild, consider the last one.  How does a bat not deafen itself, if its calls are loud enough to create an echo from a tiny object that its sensitive ears can pick up?  Seems like it's a self-limiting system: if the calls aren't loud enough, the echo is too faint; if the calls are sufficiently loud, the call itself will be disastrously loud for the bat's own ears.

This is solved by an ingenious mechanism.  When the bat vocalizes, a set of tiny muscles connected to the bones of the inner ear (which are the same as ours, the hammer, anvil, and stirrup) pull on the bones and move them away from each other, temporarily diminishing the bat's ability to hear.  As soon as the call is made, the muscles relax and the bones move back together, restoring the bat's hearing.  This needs to happen in an astonishingly short amount of time; recall that the time between call and echo is measured in milliseconds.  But this is what they do -- induce deafness for a fraction of a second, and restore hearing in time to pick up the echo!

So that's our look at the astonishing coolness of nature for the day.  We should appreciate bats; not only are they not the bad guys depicted in horror fiction, they are fantastic predators on animals a lot of us don't like -- nocturnal insects.  Microchiropteran bats can eat on the order of three hundred insects an hour, all night long; at night, hunting is pretty much all they do.  The aforementioned enormous colonies of Mexican free-tailed bats are estimated to eat five hundred thousand kilograms of insects every night.

Which, I have to admit, puts even my favorite fruit-eating flying foxes to shame.

***********************************

Saber-toothed tigers.  Giant ground sloths.  Mastodons and woolly mammoths.  Enormous birds like the elephant bird and the moa.  North American camels, hippos, and rhinos.  Glyptodons, an armadillo relative as big as a Volkswagen Beetle with an enormous spiked club on the end of their tail.

What do they all have in common?  Besides being huge and cool?

They all went extinct, and all around the same time -- around 14,000 years ago.  Remnant populations persisted a while longer in some cases (there was a small herd of woolly mammoths on Wrangel Island in the Aleutians only four thousand years ago, for example), but these animals went from being the major fauna of North America, South America, Eurasia, and Australia to being completely gone in an astonishingly short time.

What caused their demise?

This week's Skeptophilia book of the week is The End of the Megafauna: The Fate of the World's Hugest, Fiercest, and Strangest Animals, by Ross MacPhee, which considers the question, and looks at various scenarios -- human overhunting, introduced disease, climatic shifts, catastrophes like meteor strikes or nearby supernova explosions.  Seeing how fast things can change is sobering, especially given that we are currently in the Sixth Great Extinction -- a recent paper said that current extinction rates are about the same as they were during the height of the Cretaceous-Tertiary Extinction 66 million years ago, which wiped out all the non-avian dinosaurs and a great many other species at the same time.  

Along the way we get to see beautiful depictions of these bizarre animals by artist Peter Schouten, giving us a glimpse of what this continent's wildlife would have looked like only fifteen thousand years ago.  It's a fascinating glimpse into a lost world, and an object lesson to the people currently creating our global environmental policy -- we're no more immune to the consequences of environmental devastation as the ground sloths and glyptodons were.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!] 

Black as the night

You wouldn't think that fish living three miles deep in the ocean, far beneath the level that sunlight can penetrate, would worry much about being seen.

Well, I'm not sure they're worried, exactly.  But they still have the problem that if they do somehow get seen, they're likely to get eaten.

This lies at the heart of the reason that bioluminescence exists in the deep ocean.  You probably know that bioluminescence is the ability of some organisms to use chemical reactions in their bodies to emit light.  (Fireflies are a common example.)  In the deep ocean, it was thought the main reason animals might do this is to create a lure; the illuminated "fishing pole" of the grotesque angler fish brings in curious smaller fish, which then get turned into lunch.

[Image licensed under the Creative Commons Masaki Miya et al., Bufoceratias, CC BY 2.0]

There are other functions for light-emitting structures besides lures.  Squid that live in shallow water have ink they squirt into the water then they're attacked, creating a dark cloud to confuse the predator, thus allowing the squid to escape.  But if you live at a depth where its perpetually dark, black ink is fairly useless; so there are deep-sea squid that emit luminescent ink, creating a burst of light to startle the predator and give the would-be dinner a chance to live for another day.

Last week in Current Biology, though, there was a paper wherein I learned about another reason for bioluminescence in the deep ocean.  In "Ultra-black Camouflage in Deep-Sea Fishes," by Alexander L. Davis, Sönke Johnsen, and Karen J. Osborn (Duke University), Kate N. Thomas (The London Museum of Natural History), Freya E. Goetz (Smithsonian National Museum of Natural History), and Bruce H. Robison (Monterey Bay Aquarium Research Institute), we read about fish like the evocatively-named fangtooth, Pacific blackdragon, and black swallower, whose skin is amongst the blackest naturally-occurring substances, reflecting less than 0.5% of the light the falls on it.

But as with the squid ink, why bother to evolve such dark skin if there's no light there to reflect?  The answer turns out to be that there is light there to reflect; the bioluminescence emitted by other predatory fish.  If you're in the complete darkness, even the reflection of a tiny amount of light from your body might give away your position.  So this is a third reason for deep-sea bioluminescence; not as a lure, nor a distraction, but as a searchlight.

These fish, however, are so dark that even in bright sunlight they look like black silhouettes, as study co-author Karen Osborn found out when she tried to photograph them.  This confers a significant advantage over other fish, even if there's only a marginal difference in the skin blackness.  The authors write:

At low light levels, as is the case with a fish reflecting <2% of an already dim source (i.e., a bioluminescent flash, lure, glow, or searchlight), against the black deep-sea background, the model predicts that the sighting distance is proportional to the square root of the number of photons being reflected back to the viewer.  Using this relationship, we find that reducing skin reflectance from 2% to 1% reduces sighting distance by 29% and that decreasing further to 0.5% or 0.05% reflectance reduces sighting distance by 50% and 84%, respectively.  Because visual predators typically search a volume of space, and this reduction in sighting distance is linear, the camouflage benefits of ultra-black skin may be even greater than the reduction in sighting distance calculated here.  Given the small size of the fishes studied here, it is likely that predator-prey interactions occur over short distances, where even small differences in sighting distance can have meaningful effects on interaction outcomes.

I've read that we know less about the abyssal regions of the ocean than we do about the surface of the Moon.  I don't know if that's true -- it's a little hard to quantify what we don't know about something -- but what's certain is that the deep ocean harbors some astonishingly weird creatures.  I'll end with a quote from H. P. Lovecraft, in whose writings the ocean represents everything that is dark and mysterious about the universe: "But more wonderful than the lore of old men and the lore of books is the secret lore of ocean...  The process of delving into the black abyss is to me the keenest form of fascination."

*************************************

This week's Skeptophilia book recommendation of the week is about as cutting-edge as you can get, and is as scary as it is fascinating.  A Crack in Creation: Gene Editing and the Unthinkable Power to Control Evolution, by Jennifer Doudna and Samuel Sternberg, is a crash course in the new genetic technology called CRISPR-Cas9 -- the gene-editing protocol that Doudna herself discovered.  This technique allows increasingly precise cut-and-paste of DNA, offering promise in not just treating, but curing, deadly genetic diseases like cystic fibrosis and Huntington's disease.

But as with most new discoveries, it is not without its ethical impact.  The cautious are already warning us about "playing God," manipulating our genes not to eliminate disease, but to enhance intelligence or strength, to change personal appearance -- or personality.

A Crack in Creation is an unflinching look at the new science of gene editing, and tries to tease out the how much of what we're hearing is unwarranted fear-talk, and how much represents a genuine ethical minefield.  Doudna and Sternberg give the reader a clear understanding of what CRISPR-Cas9 is likely to be able to do, and what it won't, and maps out a direction for the discussion to take based on actual science -- neither panic and alarmism, nor a Panglossian optimism that everything will sort itself out.  It's a wonderful introduction to a topic that is sure to be much in the news over the next few years.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Sparkling camouflage

Natural selection is such an amazing driver of diversity.  As Richard Dawkins showed so brilliantly in his tour-de-force The Blind Watchmaker, all you have to have is an imperfect replicator and a selecting agent, and you can end up with almost any result.

The only requirement is that the change has to enhance survival and/or reproduction now.  Evolution is not forward-looking, heading in the direction of whatever would be a cool idea.  (It'd be nice if it were; I've wanted wings for ages.  Big, feathery falcon wings from my shoulders.  It'd make wearing a shirt impossible, but let's face it, I hate wearing shirts anyway so that's really not much of a sacrifice.)

Anyhow, the trick sometimes is figuring out what the benefit is, because it's not always obvious.  The extravagant tail of the peacock is clearly an attractant for females, although at this point the male peacocks may have maxed out -- reached the point where the tail's advantage of attracting females is counterbalanced by the disadvantage of being so cumbersome that it makes it harder to escape predators.  When two competing selecting agents hit that balance point, the species -- with respect to that trait, at least -- stops evolving.

A good bunch of the wild colorations you find in nature have to do with sex.  Not only attracting mates in animals, but colorful flowers attracting a specific pollinator -- because pollination is (more or less) plant sex.  But not all; the stripes of the Bengal tiger are thought to break up its silhouette in the dappled sunlight of its forest home, making it less visible to prey.  The bright colors of the dart-poison frogs are warning colorations, advertising the fact that they're highly poisonous and that predators shouldn't even think about it if they know what's good for them.  A recent study concluded that one advantage of stripes in the zebra is that it confuses biting flies, including the dangerous tsetse fly (carrier of African sleeping sickness) -- horses that were draped with striped cloth (mimicking the zebra's patterns) were far less susceptible to horsefly bites.  It's probable that the stripes also confuse predators such as lions, which frequently try to target one animal in a fleeing herd and separate it from the rest, a task that's difficult if the stripes make it hard to tell where one zebra begins and the other ends.  So zebra stripes may be a twofer.

Sometimes, though, the reason for a bright coloration isn't obvious.  In the summer here in upstate New York we often see brilliant little tiger beetles, named not for stripes (most of them don't have 'em) but for their role as a voracious predator of other insects.  The ones we have here are a glistening emerald green, which I always figured camouflaged them on plant leaves -- but there are ones that are an iridescent blue, and one species is green and blue with orange spots.

Hard to call that camouflage.

[Image licensed under the Creative Commons Ryan Hodnett, Six-spotted Tiger Beetle (Cicindela sexguttata) - Mississauga, Ontario 01, CC BY-SA 4.0]

Turns out that even the non-green ones might be using their sparkling colors as camouflage, however implausible that sounds.  A study that appeared this week in Current Biology, led by Karin Kjernsmo of the University of Bristol, concluded that the iridescence itself confuses predators, as much as it seems like it would attract attention.

Kjernsmo was studying the aptly-named Asian jewel beetles, which like our North American tiger beetles come in a wide range of glittering colors.  She took the wing cases of jewel beetles, both the iridescent and the matte species, and baited them with mealworms to see if birds had a preference.  85% of the targets with matte wings (of various colors) were picked off by birds, while only 60% of the iridescent ones were.

"It may not sound like much," Kjernsmo said, "but just imagine what a difference this would make over evolutionary time."

Her next question, though, was why.  This is much harder to determine, mostly because you can't ask a bird why it picked a particular insect for lunch.  (Well, you can ask.)  So what she did was a simple but suggestive experiment using human subjects -- she stuck various-colored wing cases to leaves at eye level on a forest trail, and had thirty-six human subjects walk the trail and see how many they could find.  They found 80% of the matte ones -- and only 17% of the iridescent ones!

It's a surprising result.  It may be that the shifting, sparkling surface of an iridescent insect confounds the ability of your visual cortex to make sense of what it's seeing by rendering it more difficult to perceive the edges, and therefore the shape, of what you're looking at.  The result: you can see the colors, but you don't recognize it as a beetle.  It's a plausible guess, but it will take more research to find out if it's the correct one, and if the reason the humans couldn't see iridescent wings is the same as why birds didn't eat them.

But once again, we're left with a slight difference in selection by a predator leading to what Darwin called "endless forms most beautiful and most wonderful."  The natural world is deeply fascinating, and is even more wonderful when you not only can appreciate its beauty -- but understand where that beauty may have come from.

**********************************

The brilliant, iconoclastic physicist Richard Feynman was a larger-than-life character -- an intuitive and deep-thinking scientist, a prankster with an adolescent sense of humor, a world traveler, a wild-child with a reputation for womanizing.  His contributions to physics are too many to list, and he also made a name for himself as a suspect in the 1950s "Red Scare" despite his work the previous decade on the Manhattan Project.  In 1986 -- two years before his death at the age of 69 -- he was still shaking the world, demonstrating to the inquiry into the Challenger disaster that the whole thing could have happened because of an o-ring that shattered from cold winter temperatures.

James Gleick's Genius: The Life and Science of Richard Feynman gives a deep look at the man and the scientist, neither glossing over his faults nor denying his brilliance.  It's an excellent companion to Feynman's own autobiographical books Surely You're Joking, Mr. Feynman! and What Do You Care What Other People Think?  It's a wonderful retrospective of a fascinating person -- someone who truly lived his own words, "Nobody ever figures out what life is all about, and it doesn't matter.  Explore the world.  Nearly everything is really interesting if you go into it deeply enough."

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Ecological micro-management

Even if I sometimes present a rather cynical front, I really have a deep belief in the fundamental goodness of human nature.  Most of us, most of the time, mean well.  All we want is to have our basic needs met; food, shelter, companionship, security.  Despite what you see on the nightly news -- news that has been selected deliberately to be eye-catching, i.e., usually violent or upsetting -- the vast majority of the human race is peaceful, caring, and kind.

That said, we do have a regrettable tendency to suffer from hubris, mainly with respect to the rest of the inhabitants on Earth.  We often feel like we have the right to twist the environment and its non-human inhabitants to our own desires, and expect that because of our big brains we should be able to predict all outcomes (and avoid any negative ones).  Burn fossil fuels, increase the amount of carbon dioxide in the atmosphere?  Pshaw, how could that cause a problem?  Overhunt, overfish, feed the world with big industrial farms that require millions of tons of fertilizer each year just to remain productive?  No problem.  We have to eat, right?

Of course, right.

Few people think all that deeply about how interlocked the ecosystem is, and how complex.  You cannot affect one piece of it without affecting them all, often in unpredictable ways.  We are dealing with multi-variable analysis of a system we only partly understand, and acting as though we should be able to control it, acting as though we are somehow outside the system ourselves.

A vivid demonstration of this came in the early 1990s with the inauguration of Biosphere 2, the fascinating (and forward-thinking) ecology project in the Arizona desert, which consisted of a huge dome housing a variety of ecosystems.  It was constructed, and populated with plants and animals, so as to be self-sustaining, just as the Earth's system ("Biosphere 1") is.  Chemists, biologists, and ecologists combined their knowledge in the planning process, trying to get the initial balance exactly correct.  Then, in 1991, eight human scientists agreed to be locked inside the dome for two years, with no access to anything that wasn't locked in there with them.

Biosphere 2 experienced problems right from the get-go, and eventually the mission had to be cancelled:

Biosphere 2 suffered from CO2 levels that "fluctuated wildly" and most of the vertebrate species and all of the pollinating insects died.  Insect pests, like cockroaches, boomed.  In practice, ants, a companion to one of the tree species (Cecropia) in the Rain Forest, had been introduced.  By 1993 the tramp ant species Paratrechina longicornis, local to the area, had been unintentionally sealed in and had come to dominate...  [A] number of pollinating insects were lost to ant predation and several bird species were lost.

The oxygen inside the facility, which began at 20.9%, fell at a steady pace and after 16 months was down to 14.5%.  This is equivalent to the oxygen availability at an elevation of 4,080 meters (13,400 ft)...  A mystery accompanied the oxygen decline: the corresponding increase in carbon dioxide did not appear. This concealed the underlying process until an investigation by Jeff Severinghaus and Wallace Broecker of Columbia University's Lamont Doherty Earth Observatory using isotopic analysis showed that carbon dioxide was reacting with exposed concrete inside Biosphere 2 to form calcium carbonate, thereby sequestering both carbon and oxygen.

Now, I'm not criticizing the experiment, mind you; we learned a tremendous amount from it.  It's just that I think it serves primarily as an illustration that we don't know nearly enough to undertake ecomanagement on a large scale.

All of this is simply a preamble to my thoughts about an article sent to me by a friend, called "The Radical Plan to Eliminate Earth's Predatory Species."  In it, we hear the proposal by a British philosopher, David Pearce, who believes that because predation of all sorts causes suffering to sentient beings, we have a moral obligation to eliminate predators if we can.

[image courtesy of photographer Colin M. L. Burnett and the Wikimedia Commons]

Pretty radical.  Pearce says:

Sentient beings shouldn't harm each other.  This utopian-sounding vision is ancient.  Gautama Buddha said "May all that have life be delivered from suffering".  The Bible prophesies that the wolf and the lion shall lie down with the lamb.  Today, Jains sweep the ground in front of their feet rather than unwittingly tread on an insect. 

My own conceptual framework and ethics are secular — more Bentham than Buddha.  I think we should use biotechnology to rewrite our genetic source code; recalibrate the hedonic treadmill; shut down factory farms and slaughterhouses; and systematically help sentient beings rather than harm them... 

Humans already massively "interfere" with Nature in countless ways ranging from uncontrolled habitat-destruction to captive breeding programs for big cats to "rewilding".  Within the next few decades, every cubic metre of the planet will be computationally accessible to surveillance, micro-management and control.  On current trends, large nonhuman terrestrial vertebrates will be extinct outside our wildlife parks by mid-century.  So the question arises.  What principle(s) should govern our stewardship of the rest of the living world?  How many of the traditional horrors of "Nature, red in tooth and claw" should we promote and perpetuate?  Alternatively, insofar we want to preserve traditional forms of Darwinian life, should we aim for an ethic of compassionate stewardship instead.  Cognitively, nonhuman animals are akin to small children.  They need caring for as such.

In answer to the inevitable charge of hubris, Pearce responds:

Inevitably, critics talk of "hubris".  Humans shouldn't "play God."  What right have humans to impose our values on members of another race or species?  The charge is seductive but misplaced.  There is no anthropomorphism here, no imposition of human values on alien minds.  Human and nonhuman animals are alike in an ethically critical respect.  The pleasure-pain axis is universal to sentient life.  No sentient being wants to be harmed — to be asphyxiated, dismembered, or eaten alive.  The wishes of a terrified toddler or a fleeing zebra to flourish unmolested are not open to doubt even in the absence of the verbal capacity to say so.

My criticism of Pearce's proposal -- which, he says, should be accomplished by genetic manipulation, selective breeding, and monitoring of animal populations with microchips -- does not rest on any high-flown philosophy.  It has, in fact, little to do with morals or values.  He is correct that we are already "playing god," and have been for millennia, with our selective breeding and large-scale ecological manipulation for food production and living space.  What I question is purely pragmatic; if we don't know enough to manage even a three-acre simulated biosphere, using the skills, insight, and planning of the world's best ecologists, how in the hell do we think we're smart enough to micromanage the entire globe?

Pearce's motivation, and ultimate goal -- eliminating pain and suffering, even from less-cognitively-developed animals like insects -- is, on one level, laudable.  I've been a biologist long enough that I can consider an incident like a cheetah killing an antelope as positive in the larger sense of keeping the eco-community in balance.  At the same time, I'm compassionate enough that I feel sorry for the antelope, and pity the victim for the fear and pain that it experienced as its life ended.  That emotional reaction is not sufficient, however, to fool me into thinking that we as a species know enough to overturn the predator-prey interaction, evolved for billions of years, in some sort of misguided attempt to make things better.

Pearce says, "A few centuries from now, if involuntary suffering still exists in the world, the explanation for its persistence won't be that we've run out of computational resources to phase out its biological signature, but rather that rational agents — for reasons unknown — will have chosen to preserve it.
"  I think this is not only wrong, but dangerously wrong.  The hubris of his position is not that presumes human moral superiority; it is that it presumes a far greater comprehension of this planet's systems than we have, or are likely to have in the foreseeable future, even considering the expansion of our scientific understanding over the last couple of centuries.

Our ecological management of the world is rife with examples of actions undertaken with the best of intentions, and which had drastic and unexpected consequences.  Pearce might well label me as immoral for accepting the inevitability of predation, and therefore suffering, in the world; but his position -- that we could use our scientific and technological capacities to eliminate it -- isn't just the words of an optimist who makes Pollyanna look like a cynic.  It exemplifies the attitude that got us to the disastrous place where we currently are -- in the beginning of the Sixth Great Extinction, facing radical climate change, facing the collapse of the ocean's fisheries -- all resulting from the stance that "we know what we're doing."

Only Pearce's vision, of micromanagement of the whole world, goes one step beyond blind eco-optimism; it puts us in the position of pulling all of the Earth's strings.  And, I believe, it opens up the possibility of fucking things up on a scale the likes of which we've never seen before.