Wilson and his wonderful ants

 kw: book reviews, nonfiction, science, natural science, naturalists, memoirs, ants, myrmecology

This is the most troublesome ant in the world. The 47 known species of leaf-cutter ants can form immense nests with millions of members, move tons of earth doing so, and strip entire trees of leaves overnight. In Tales From the Ant World, Edward O. Wilson, my favorite naturalist and nature writer, saves these ants for his last chapter. I don't have his patience.

Of all the social insects, leaf-cutter ants best deserve the moniker "superorganism". There are several distinct castes, and this photo (cropped from a much larger image) shows two of them. The workers that cuts the leaves and carry them are accompanied by smaller "minors", which ride along when the leaf bits are carried to the nest. They aren't freeloading. They keep away parasitic flies that would otherwise lay eggs on the workers. They are bodyguards.

Dr. Wilson, who studied at Harvard, taught there for 41 years, and is still affiliated as a Professor Emeritus, has been there for more than seventy years. From his many books we find that he didn't always spend much time there. Collecting and studying ants has taken him almost everywhere on Earth where ants live; effectively, everywhere except the polar ice caps and a few islands (ants are poor at crossing oceans).

When asked, "What do I do about ants in my kitchen?", he will typically reply,

"Watch your step, be careful of little lives, consider becoming an amateur myrmecologist, and contribute to scientific study. … They carry no disease, and may help eliminate other insects that do carry disease." —from the Introduction, p. 10.

If we all followed that advice, a lot more would be learned about ants in short order, and some pesticide companies would go broke.

The short chapters of Dr. Wilson's book are like adventure tales. We read of ants that sting worse than any wasp, ants that farm insects such as aphids for their honeydew, some that are ranchers (keeping "domesticated" insects to eat), and the many ants that enslave other ant species. Slavery has been around for 100 million years or more; humans didn't invent it.

This image, from a pest control company, shows some common ants to be found in temperate areas, such as most of the US. On my screen they are shown about 3x natural size. That would make the smallest, the "Crazy Ant", about 3mm (1/8") long, which is about right. Taken together, the ants in a typical yard weigh as much as one of the occupants of the house, perhaps more. Worldwide, the ants weigh more than all the billions of humans.

One chapter describes a few species of trap-jawed ants, such as the one shown here. They pull back their jaws past a cocking point. When they release the jaws they slam shut in a couple of milliseconds.

Such ants prey on insects such as springtails, which are much too fast to chase down or can jump (springtails also have a cocking mechanism and a lever to launch themselves). These ants move very slowly, to maneuver close enough to snap the jaws on their prey.

There are more than 15,000 species of ants so far described. Some are well known, but for others a physical description is all that is known besides where they were found. Sometimes, even knowing where a species was first found isn't much help if you don't take account of when. The author writes about searching in vain for some rare ants, only to learn later that they are only active in cold weather, and he'd had the misfortune to try to find them in the summertime.

Live and learn. He has a few chapters on his own path to becoming a naturalist, bolstered by a childhood in neighborhoods with a lot of natural places nearby, and parents who didn't mind him raising sundry critters or nests of insects in his bedroom. Yet after a working life that spans seven decades, he is still learning, and loving the learning. His books have the same goal, to share that love of learning from nature that has been his delight. His writing is happy writing because he is happy. Reading him makes me happy.

Of Course people are animals – get used to it

kw: book reviews, nonfiction, human nature, animal nature

My parents made sure I (and my brothers) knew that humans are animals from a very early age. They led us to understand that animals feel pain, fear and loss, and also joy, pleasure and fulfillment. We were not to be cruel. Of course, the peskiest insects and other vermin had to be expelled or killed, but we were to be humane about it, killing even an insect quickly.

Even as a believer in God, I learned the principles of the facts of evolution and the theory of natural selection when I was young, and from careful searching in the Bible I learned that evolution, specifically descent of humans from animals, does not threaten the reality of God, nor does it either prove or disprove His existence. I choose not to go further into detail here.

As a result of the above, I have always been puzzled by those who make charges of "anthropomorphism" whenever they encounter statements about the feelings or purposes of animals, whether domestic or wild. Nobody who understands evolution should think that only humans have a full range of emotions, or a feeling of purpose, or the ability to plan a course of action or decide between alternatives using reason. We have such faculties because our forebears had them! When any human does something another kind of animal can do, that is "zoomorphism"!! At best, there is a range of skills and competencies that we have developed further than any other animal.

The case for what I would call "advanced zoomorphism" is made by Melanie Challenger in How to be Animal: A New History of What it Means to be Human. Coming on the heels of a book I reviewed just a couple of weeks ago, MetaZoa by Peter Godfrey-Smith, it represents a healthy trend in recent writing.

Ms Challenger points out the hypocrisy of modern culture, which is still based on long-held opinion that humans are either not animals at all, or are categorically different in some way. Even as America, the most Biblically religious nation, turns away from that religion, and from its supposed denigration of animals in favor of Man (not so...stay tuned); even as American culture, and Western culture in general, becomes increasingly eco-centric and claims greater environmental sensitivity, that same culture destroys animals and entire species at an ever-increasing rate.

I must make a diversion here. Prior to the writing of Leviticus, everyone except a few slave-holders worked every day, from sunrise to sunset, and frequently long into the night. Domestic animals were worked to death, as were many slaves. There was a common practice that a domestic meat animal wasn't killed outright, but only partly dismembered, to keep most of it "on the hoof" to preserve the remaining meat; a 3-legged steer can still walk once it recovers. If any foreigners had the temerity to travel abroad, they were systematically exploited or mistreated and frequently enslaved, unless they traveled with a great band of bodyguards. Leviticus made huge social changes in God's name:

• One day in seven was to be a day of rest, not only for the people of Israel, but for their slaves, visiting or sojourning foreigners, and domestic animals. All were to enjoy a weekly Sabbath. That includes the household cook; on the Sabbath, everyone ate leftovers.
• Animals to be eaten (or sacrificed and then partly burned and partly eaten) were to be killed quickly, with a minimum of fuss, and the blood was to be poured out. The words against "eating the flesh with the blood" specifically forbid cutting part of an animal off to eat and leaving the animal alive.
• Visiting and sojourning foreigners had the same rights as all free persons.
• Slaves were to be indentured, not owned, unless a slave who had a particularly kind master volunteered to remain enslaved for life. "Bought with money", a phrase that appears a few times, refers to the work a slave could do in a typical term of six years or less, until the Sabbatical Year. The slaves' time was bought, not his or her body.

A big reason given for the destruction of the kingdoms of Israel and Judah was that they didn't do these things. The 70-year captivity was in part so "the land could enjoy her Sabbaths", which had been neglected for hundreds of years.

Back to the book, and I'll cut to the chase. All of the things that have been proposed as specially human gifts are found in animals, just to a lesser degree. Writers touted "Man the tool-using animal" until it was found that all apes make and use tools, as do many monkeys, also certain birds, plus some dolphins and a few species of fish. Only humans have language, others said, until a few apes were taught ASL; later it was found that certain species of parrot can learn our language well enough to hold simple conversations; prairie dogs don't have just one alarm call for "predator", but they distinguish hawk from snake from fox, and can indicate color and size (prairie dogs may have a small dictionary, but it includes a number of nouns, several adjectives, and a few verbs. That's language to me).

How to be Animal has lots of material about our fraught relationship with being animal. What it lacks is anything actionable. I was expecting some sort of manifesto, I suppose. But no, this is a catalog without anywhere to go. Sadly, it took me longer than I expected to read because the writing is rather dull. It doesn't carry one along, neither does it induce reflection as well as it might.

It is left for future writers to show the way to a new attitude, one that piques the conscience more keenly, and induces larger numbers of people to see animals for what they are, and see themselves for what they are.

An astrophysicist comes in from the dark

 kw: book reviews, nonfiction, memoirs, science, astrophysics, widowhood, exoplanets

Dr. Sara Seager, an astrophysicist, designed something called Starshade, which NASA may build to allow a spaceborne telescope see a planet next to a star. This illustration by NASA shows the shape of the shade, which would actually be a great distance from the orbiting telescope, tens of thousands of kilometers away.

She fell in love with the night sky as a young child, as many of us do. She never fell out. During graduate school she became obsessed with exoplanets, planets around other stars. She was into them before they were cool. Her fervent desire is to discover the first planet that is enough like Earth that "someone" could be living there.

Her journey to become an astronomer, and her journey through life, are told in The Smallest Lights in the Universe, a memoir and scientific discovery journal all in one. She didn't have it easy, getting into her chosen field, but the trials were minor compared to what life handed her. Nearing age forty, with two very young sons, she was widowed. I surmise that the title of the book has a secondary meaning, of the way she thought of herself, being ground to powder by an uncaring universe.

Dr. Seager is incredibly talented, but was overwhelmed, and at a time of desperate need she had the great good fortune to meet a set of friends, all young widows like herself, whom she calls the Widows. From her telling, they sound like the best support group ever. Their help didn't make her transit through grief easy, they just made it possible. She also gathered others who could help care for the boys, backstop her slender housekeeping skills, and help her navigate the million little terrors of "the real world". I won't mention any names, because in the introduction she states that names were changed to protect them. Those she has to name, such as her (very supportive) advisors and mentors, of course, are named. I wish I'd had a few of those in grad school!

Her husband died of cancer, a cancer related to one that I survived 21 years ago. I was lucky to survive. I remember going into surgery, wondering how my wife, in her 50s, and our teenage son, would do, because I gave myself a slim chance of survival. Had I lost that battle, I like to think my widow might have found help at the level this book describes. It's no sure thing.

Finding happiness amidst enormous grief is harder than finding a planet "out there." When the author began studying the first exoplanets, only a handful had been found, and most astronomers were very skeptical of the work. It took a few years, and several more discoveries, for the majority of them to be convinced that exoplanets were indeed being located. In a few more years, as technology advanced and better tools were created, finding these tiny orbs got easier, and now a few thousand have been located.

A key element of their discovery was the Kepler telescope. I spent many a pleasant hour perusing light curves via the Zooniverse Project, along with thousands of other "citizen scientists", looking for that subtle dip that indicates a planet has crossed in front of its star, from our perspective. A not-so-subtle dip usually indicates a companion star (AKA an eclipsing binary), or sometimes, a "hot Jupiter", a big planet, not enough like Earth to be of interest except for statistical purposes. The Kepler instrument was intended to find planets not too much bigger than Earth, far enough from their stars to be possible sites of life. Among the discovered planets, there is at least one with my handle attached, along with at least a dozen other citizen scientists who also flagged it as a possible planet.

Dr. Seager works at a level that enables people like me to get in on the fun. She is a kind of mother hen to hundreds of planets. She also led the work to get a satellite built called ASTERIA. It was a proof-of-concept for a family of small satellites that just might locate a sister Earth, or a few of them. Planets, not just the right size and the right temperature, but with the right atmospheric chemistry to make them good candidates for having a biosphere.

Starshade hasn't been built yet, though models up to half size have been. The final shade would have to unfurl in space, "growing" into shape with an accuracy in the thousandth-of-an-inch range. In the 1970s I worked on a team that was building a radio telescope that had to have similar accuracy, but was much smaller; its diameter is 10 meters (34 feet, and it is still in use). Starshade's full diameter will be 34 meters (111 feet), and the central disk is 20 meters across.

I haven't done the math yet, so I'll do some on the fly to see what the parameters need to be for Starshade to work.

• The shade's radius is 17 meters. It needs to block the glaring light of a star so that a nearby planet becomes visible. 
• The sunflower-petal design is needed to cancel out the diffraction rings that would form if a simple circle were used.
• A parsec is 3.26 light-years. The term is from "parallax-arc-second", and represents the distance to a star which has a parallax of one arc second as viewed from Earth. That is 31 trillion km.
• The distance to the nearest star, Proxima Centauri, is 4.25 light years, or 1.3 parsecs.
• From Proxima Centauri, the maximum elongation of Earth from the Sun is 1/1.3 or 0.77 arc seconds.
• The tangent of one arc second is about 1/206,000. The tangent of 0.77 arc seconds is about 1/270,000.
• 270,000 x 17m = 4,590 km.

That's the absolute minimum distance between Starshade and the telescope it serves. The system would barely be able to detect a planet at that distance that was the same distance from its star as we are from ours (a unit called one Astronomical Unit, or 1 AU), and only for a couple of days in the year. There are more than 100 stars within about eight parsecs from Earth. Most of them are smaller than the Sun, and thus dimmer, and thus their "Goldilocks zone" of earthlike temperature is smaller. A factor of 16 makes sense to me, to look for planets at least 0.5 AU from their stars, up to 8 parsecs away.

• 16 x 4,590 ≈ 73,400 km.

That's almost one-fifth of the way to the Moon! It is just a little less than the diameter of the synchronous orbit.

Hmm. Perhaps the two craft, the one carrying the Starshade (and able to move it about and orient it properly) and the one carrying the telescope (ditto), should be in synchronous orbit, maybe at a 120° spacing so the Earth doesn't intrude. That would limit their bailiwick to a narrow band of sky near the celestial equator. But it would make communications with them easier. I sure hope it gets built! In the current political climate, NASA gets no respect, and the chances are pretty slim…for the time being.

I'll leave it to you to read the book to learn of the other quite literally one-in-a-billion chance that life handed Sara Seager, to bring her out of the night of the soul.

Is one percent of a mind still a mind?

kw: book reviews, nonfiction, psychology, zoology, animals, experience

The title and cover art (a Leafy Dragon, a kind of seahorse) of MetaZoa: Animal Life and the Birth of the Mind, by Peter Godfrey-Smith promise good thing inside, and that promise is abundantly kept. Thinking about thinking is the highest human art, and while Sturgeon's Dictum ("90% of everything is junk") holds especially true in this field, when the right ideas come together, the synergy is wonderful.

Dr. Godfrey-Smith has a prior book particularly on the mind of the octopus, Other Minds, and the work there is a springboard to his thinking about the full range of cognition, from the first evolution of neurons onward. MetaZoa begins with the eukaryotic cell—it could have begun with prokaryotes, but that would have added little and taken much more space—, a cell that senses and reacts to the environment, and is complex in its own right. However, there seems to be nothing we can do (so far) to determine whether amoebas, or critters like Euglena and Paramecium, have "experiences" or a "sense of being" in any way comparable to ours. Thus, the discussion proper begins with the simplest metazoans, those without nervous systems (so far as we know): sponges and placozoans.

A sponge is a metazoan—a multicellular creature—at its most basic: a collection of cells of three (some say four) types of cells, that produce spicules composed of either calcite or silica to stiffen a roughly vase-shaped "body". There seems to be a very simple system of cell-to-cell communication that allows the animal to react, quite slowly, to certain stimuli, perhaps including light. We still don't know much about sponges. Working with them is very difficult. 

A placozoan is one of nature's great secrets: an animal typically smaller than one millimeter in diameter and 1/10 millimeter thick, that creeps among sand and silt grains using cilia for locomotion. This also implies some kind of cell-to-cell communication to coordinate the cilia. There are no cells with long projections that could serve as nerves for longer-range communication across the body. They eat by creeping atop a bit of algae and excreting enzymes to digest it outside the body, absorbing the products of digestion directly. These are even harder to work with than sponges.

The book doesn't discuss that favorite of experimenters, the nematode Caenorhabditis elegans (usually C. elegans), which is less than 1/10th the mass of a placozoan but is much better organized. About a third of its 959 cells constitute its nervous system, including a 56-cell brain. The author chose instead to move right along to coral polyps and to cnidarians in general, which have a minimal nervous system (in terms of percent of body mass), a neural net (no brain) that coordinates swimming motions in swimming polyps and grasping motions in sessile polyps, and also feeding behaviors.

A point the author makes repeatedly in the first several chapters: we shouldn't think of sponges, placozoans, corals or jellyfish (or any other animals) as "primitive". They have four billion years of evolution in their history, the same as we do. They are successful in their environments, or they'd have been eliminated.

With these simple animals, their similarities and contrasts, we begin a journey around (not necessarily "up"!) the tree (or network) of life. The author wished to puzzle out the origin of experience. Looking from "our" end of things, we, and a number of other animals (maybe a very large number), have something we call "consciousness", sometimes described as a "here I am" feeling. Are there animals that don't have this feeling? The smaller an animal is, the less we think it is "like us", and therefore capable of consciousness. Is this so?

Our pet calico cat is rather touchy, even peevish: it doesn't take much of a transgression on my part for her to give me a hurt look and stalk off. Another cat I had long ago would run across a carpeted room onto the linoleum in the hallway, and find himself skidding past the turn into the bedroom. Once he came to a stop, he would stroll, the picture of dignity, in the direction of the skid, as though he'd intended to go there all along. Unflappable aplomb! These animals have a definite sense of being "who they are". I call it consciousness, even if it is simpler than a human's.

Now, let us jump almost to the other extreme. A honeybee has much more brain than a nematode, about a million neurons. Even though the bee brain is tinier than a pinhead, it is well organized. This drawing, from an article in ResearchGate by Eleni Vasilaki and others, has this title: 

"Basic anatomy of the honey bee brain showing the major pathways involved in odor classification and olfactory learning."

Think about that: olfactory learning. It sounds like a lot can go on in the brain of a honeybee. But does the bee have a sense of "here I am" or "this is me"? While it cannot have such a sense at a human level, or even a mammal level, perhaps it does.

An aspect that Dr. Godfrey-Smith turns to in the last two chapters is gradualism. My statement above, "…even if it is simpler…" is along this line. Much is made of the phrase, "the lights are on". Some claim consciousness is like pregnancy: "Can you be a little bit pregnant?" I think to take such a purist attitude is misguided. 

There may be a threshold effect. Is the neural net of a coral polyp (there is no brain) enough to generate a sense of presence, of "I am here"? Are the 56 neurons of a C. elegans brain enough? The million neurons of a honeybee's brain? Right in the middle of such a spectrum is the octopus, which has half a billion neurons.

The octopus's brain is quite different from a vertebrate brain. A ring of nerve tissue surrounding the gullet contains about 140 million neurons. A ganglion near the big end of each arm has about 45 million; those 360 million (45x8) plus those in the ring brain add up to 500 million. There is a lot of text in MetaZoa about whether this is a 1+1 situation, or 1+8, because the eight arms seem to act semi-independently. As I read, I remembered that 75% or more of human brain neurons are in the cerebellum, which runs the body, the "autonomic system". Our vaunted reasoning abilities, plus systems for vision, speech, sound, and the interpretation of our senses use 20% or so (16-18 billion neurons), and our emotions primarily reside in the limbic system, which has around a billion neurons. That in itself indicates that, if our feelings are entirely in the neurons, and primarily those of the limbic system (this is by no means certain), we use two whole octopus nervous systems to run our emotional being. So of course, octopus emotions (and they definitely have some!), belong to a much smaller set of neurons. But the octopus does behave as we'd expect of an animal that has a sense of self. Does a fish, or a bee? We can't say "Definitely not." Not yet, anyway.

Here I lean a lot on a concept I developed over many years. It is not anthropomorphism to attribute feelings and thoughts to animals. I look at it from the other end. The reason humans have feelings, thoughts, a sense of presence, and so forth is because our genetic ancestors had them, as do the other descendants of those ancestors. Have we developed all these things further than the rest? Some of them, at least, but perhaps not all!

This sense of being we have, which I consider belongs also to many animals, how far back does it go? When did an animal first experience it? We get a hint from electrical activity in brains themselves. When any neuron-containing animal is idle, a kind of synchronized cycling occurs throughout the nervous system. In humans, when we close our eyes we soon enter a state called "alpha", characterized by an overall brain rhythm around 10 Hz (it ranges from 8-13). Open the eyes, and the frequency roughly doubles to the "beta" rhythm. Pay attention to something, or get into problem-solving mode, and it doubles again, or more; the "delta" rhythm ranges from 30-140 Hz, usually centering around 40Hz. Do these patterns have meaning?

I immediately thought of regeneration and superregeneration in radio receivers (I am a radio amateur). Regeneration occurs when a tuned system oscillates in the absence of a signal. That is bad for radio reception, though it is what we want to happen in the signal generator of a radio transmitter. Regeneration also happens if a weak signal arrives in a system tuned to nearly self-oscillate; it is quickly triggered to oscillate. The stronger the incoming signal is, the more rapidly the oscillation begins. A superregenerative radio receiver is set to just barely self-oscillate, but the power supply is interrupted frequently (in old CB radios, this "squelch" occurred 30,000 times per second). During each short period, the oscillation's strength depends on the strength of the weak signal the receiver is tuned to detect. The resulting series of little peaks is filtered to remove the high frequencies (usually, above 5,000 or 10,000 Hz), and what comes through the filter is the audio that was carried on the incoming signal. This may sound complicated, but it is a cheap way to make a very sensitive receiver. It is an example of the use of a "keep alive" signal to enhance the system's performance. I suspect the various brain rhythms are akin to this, the beta rhythm being the main "detector". It is well known that our basic reception is limited to noticing fewer than 20 things per second, and the beta rhythm may be why.

I want to comment on one other matter. Vertebrate brains in particular are divided, at least in their upper sections, the cortex in mammals for example (the limbic system is only partly divided). When the connections between the cerebral hemispheres are cut, as is sometimes done to treat epilepsy, a split-brain person sometimes behaves as if there are two minds in one body. Certainly, if the brain of any smaller animal has sufficient "heft" to support a mind, there is room in half a human brain for a distinct mind. In an endnote to the chapter on the octopus, the author mentions a neuroscientist, Semir Zeki, who defends the view that we have several, or even many, distinct consciousnesses. Whether that is so, it does open the door to considering what happens in dissociation, in which a person develops "extra personae" as a response to extreme abuse. This used to be called multiple-personality disorder, but is now called dissociative disorder. The notion of true multiple personalities is mostly pooh-poohed, but it does seem to exist in some cases.

This and all notions that one brain can host multiple consciousnesses lend weight to gradualism. If there is a threshold below which a brain cannot support consciousness, it must be less than one-third of the 16-18 billion neurons of the typical human cortex, based on The Three Faces of Eve by Thigpen and Cleckley. I wouldn't have a clue where to place such a threshold, and Dr. Godfrey-Smith also declines to do so. He points out that, if lab rats and other smaller animals have a sense of self, we need to develop a better set of ethical standards for how we treat them. We have come a long, long way from the day René Descartes kicked a dog at a lecture and claimed that its cries of distress were "automatic" and did not signal pain or suffering.

It is worth considering that a smaller brain may actually be capable of thoughts that we would consider very high level, but they just take a lot longer to occur, given the smaller amount of "machinery" involved. However, time and time again our author expresses that more is going on than raw computation, and he explicitly denies strong AI, and equally denies that "uploading" the contents of a brain to a supercomputer will allow someone's consciousness to continue to run, unimpeded by having been removed from the body. Maybe we must have the computer also simulate all the rest of the body (endocrine systems at least!) for uploading to work, but I don't think so even then. That is a philosophical end of things that gets beyond how the mind came to be. It'll take another book (I hope he will) to delve into the future of the mind.