Monday, February 27, 2006
Imagine a large, snowy mountain. One so large you'll never get off it. This ski run will last forever. At the summit, which direction will you go? Ridges and canyons stretch in all directions; gentle slopes, steeper slopes, crags and cliffs. It's not downhill everywhere. There are pockets and swales to be had, and the occasional deep, blind pocket. Some look inviting, perhaps places to rest, but there is a catch: you depend on gravity and inertia alone. If you come to rest in a low spot, that is the end of the run, forever.
You pick a direction and go. Soon you are schussing at a good clip, and it runs here and there, sometimes branching; you choose this branch, then that, reacting, barely thinking. At one point, a steep section levels off to a plain. Choices abound, here. You can creep along, almost at a standstill, pick a direction, and go off again.
Some runs are steep and rough, but single. There are no choices for a stretch, then choices abound. At some point, you think, "What if I had taken a different branch back there?" You are more likely to think that if a run levels out onto a pocket plain, surrounded by upslopes on all sides. There's no getting out of this one, no escape, no further progress. You're stuck. Eons pass, with no change. Perhaps you're lucky...slowly, the mountain slopes shift and change. Rare, sudden changes shift the landscape a little more. One day, there is an ever-so-narrow path that leads downward.
The inertia of being stuck so long is hard to overcome, but you do so. You glide slowly through the new gap that leads onward, then drop into a steep run, and you're off! Where to next?
Where indeed. We see around us the results of trillions of choices, made throughout the eons that life has existed here. The choices were not made by a brainy skier, but by happenstance. Once living things came into being—by what means we don't yet know—they multiplied, perhaps rather slowly at first. They could afford some slowness; "at first" there was probably little competition. But any pocket of living cells, perhaps remotely similar to bacteria, became the first few billion skiers dropped on the top of that mountain. When you are the first life on a planet, every direction represents progress.
It may be that RNA/DNA comprised the first and only genetic storage system that came about. Maybe not; it may be the sole winner of the oldest contest. But at some time, a genetic storage system gained a way to exist in a capsule and carry on metabolic activities (i.e. energy consumption). This probably happened nearly four billion years ago. We may imagine that these first living cells, however primitive, didn't stay that way very long. Light capture, by rhodopsin and chlorophyll, arose almost at once.
Many kinds of metabolism arose, specialized for different chemical regimes, gaining energy by reducing sulfates, or iron oxides, or (with light's help) carbon oxides. Some kinds got bigger, some stayed small or got smaller.
What took a long, long time, it seems, was for a bigger cell to engulf a number of smaller ones and enslave them. Little, single-purpose bacteria and photo-bacteria are very efficient at energy production and conversion. Somebody big was able to take advantage of their efficiency, to turn a single cell into a community, a "bacterial village" consisting of specialists in food gathering, energy production, DNA decoding, and many other tasks. As a result, that "somebody big" got bigger. Today's protozoa are the highly-advanced descendants of "somebody big". We'll give it a name, "Fat Albert." Or, just Albert. Albert isn't a single cell, but the presonification of the first Eukaryotic species. Eukaryotic cell fossils aged two billion years are known, and the innovation probably occurred within half a billion years before that.
Think of the mountain. Once Albert arose, he found himself on the slopes, in a broad, steep valley of his own. Stretching away to the sides were other ridges and valleys, covered with the little skiers, cousins of Albert's internal specialists. All were headed down the mountain, finding their way into this rille or that crack, past ridgeline and rock, all making what progress they could. Albert had his own valley. Nobody would enter it again, and he would never pass into any of the runs to either side. There was nowhere to go but down. Fortunately, because of the greater efficiency of the Albert-village, there were lots of ways down. Albert became Bertha, Carrie, Daniel, and many others, and took them all. A species can do that. Not all led to continued progress. Many got stuck, but many didn't.
At some point, a collection of Albert-villages—or maybe Valerie-villages—took a slope that led to numbers of them sticking together. A group became a whole. A lot of Valeries took a new name, Dallas, and became a small city composed of several villages. There were plenty of downhill directions Dallas could go. Of course, she took them all. This was probably 1.5 billion years ago.
As it turned out, there were so many, many ways Dallas and her siblings could go that for a time it seemed there was one member of each species on Earth. Various levels of efficiency, in the various environments in which Dallas-cities could live, resulted in quite a sorting-out, until just a few hundred varieties remained.
At some point, probably not long after the first Dallas was assembled, the development program in the DNA for some little wormy thing became well-enough organized that it could direct the staged development of a bilateral body, with certain intercellular messages used in a variety of ways in a segmented, or at least compartmentalized, body. Most of the naked-eye-visible animals we encounter today arose from little XingXing*.
Today we recognize at least these five major stages in the evolution of bilateral animals: Prokaryotic cells arose from whatever went before (we have little clue so far), Eukaryotes came a billion years later, Metazoans another half-billion or less, and Bilateral animals that today comprise about thirty phyla a billion years or more ago. All "bilaterians" share a group of genes called the Homeobox, or just Hox, that regulate the development of a fertilized egg cell into an organized body. Non-bilaterians such as jellyfish have a very distant relative of Hox comprising two or four genes, half the minimum size of the Hox cluster.
The key feature of the mountain metaphor is, you can't go up, only ski down. Once you've entered one run, you'll never ski the run to its right or its left. Critics of evolution used to say things like, "You don't see rabbits evolving into cats or monkeys, do you?" Now, most of them know how abysmally stupid that question is. I think we understand the principle, that what we can do today depends on what we did in the past. If you were educated or trained for business, and you excel at marketing, you are unlikely to become an engineer, and vice versa. If you first begin a little recreational fencing at age thirty, you may become pretty good on the mat, but you'll never win Olympic gold for fencing; there, you'd face kids half your age who've fenced since they were four.
All this rumination was triggered by reading The Plausibility of Life: Resolving Darwin's Dilemma by Marc W. Kirschner and John C. Gerhart. I have read millions of words by and about evolutionary biologists (I know nearly all biologists are evolutionists, but some specialize in evolution itself). S.J. Gould was, to me, the best. He and Niles Eldredge developed "punctuated evolution" to explain why species seem to persist unchanged for periods of a few million to tens of millions of years, then either vanish or (rarely seen in the fossil record) change rapidly into a different species or radiate into several related species. This idea is typically discussed in anatomical or palaeontological terms. There has been much discussion of possible underlying mechanisms, including much by Gould in his columns (collected in a great series of books, the most memorable to me being "The Panda's Thumb"). Kirschner and Gerhart have provided a very plausible mechanism.
After noting the title and reading the introductory blurb, I was prepared to dispute the idea. They call their idea "facilitated variation". I immediately thought, "Facilitated by whom?" I am a facilitator of process modeling as part of my work. So I bring my history to the word. Having read the book, I understand, the denotation they are using is not my kind. Facilitation of the evolutionary process is active, but not conscious, nor purpose-directed.
Here was my epiphany: Evolvability is also subject to evolution. Variation of the genetics in a population is the source of the bodily variety among which natural selection makes its selections, and the ability to both vary and to tolerate greater degrees of genetic variation is also something that natural selection can work on. I saw this about halfway through, and found that the authors discussed it in their last two chapters. Oh, well. I had the brief illusion of a new idea...
Just seeing this was a result of some history. I have for a decade or so been considering the phenomenon of gene regulation. I did some work in the 1990s with chemical kinetics in interlocked networks of reactions, particularly the feedback loops that result. Then I connected the ideas to gene regulation. Here is the overview chapter in Wikipedia's article Gene regulatory network:
"A gene regulatory network (also called a GRN or genetic regulatory network) is a collection of DNA segments in a cell which interact with each other and with other substances in the cell, thereby governing the rates at which genes in the network are transcribed into mRNA."
I thought, are regulatory networks freestanding, or more deeply regulated? Regulating a gene depends on a tag near the "start" signal, that is recognized by a regulatory protein. A gene can have several of these. They are in what once was called "junk DNA." I can think of lots of uses for that "junk", but that's another rant!
After a lot of reading, I've concluded that there are at least three, and perhaps five or six, levels of gene regulation. Also, the machinery for exon/intron splicing, plus other protein or RNA splicing that combines smaller segments into larger proteins, explains how the human complement of about 23,000 "genes" can produce millions of proteins.
Thus, about fourteen human Hox genes suffice to regulate the development of our entire body. Mechanisms that are capable of development under the direction of relatively few regulatory signals can be trusted to grow bodies that are at least roughly proportionate, so that people have quite a range of variation (which keeps ergonomics folk in business), but not an infinite range (no 30-foot people, or 4-footers with 8-foot arms).
Kirschner and Gerhart have a compelling message. I think they have it right. Time will tell. They compiled and sorted a great mass of material to deliver a book that, while I had to read it slowly, kept me captive with clear examples and forceful logic. They go as deep "in the weeds" as they need to, to show how powerful and robust the evolution of the ability to evolve safely has rendered the living species with which we share the Earth today.
*Xing-Xing is Chinese for the Gemini.
Tuesday, February 14, 2006
kw: book reviews, nonfiction, science, astrobiology, space science
Peter Ward and his colleague Don Brownlee made a host of constituencies mad when they published Rare Earth four years ago. Their conclusion is that, while life in the form of microbes may be rather common throughout the Universe, complex animal life, however constituted, the kind of life that makes cities and spaceships and radio signals, is probably exceedingly rare. Read Rare Earth for a thorough, and thorougly entertaining, study of the requirements of complex life.
Agree or disagree, you'll find they raise questions that need to be discussed even as we imagine a universe like that of Star Wars or Star Trek. My own conclusion is that this portion of the Galaxy has only recently begun to produce civilizations: Stars formed (in this region of the Galaxy) prior to our Sun have too few heavier materials with which to form rocky planets such as Earth, large enough to hold an ocean for five or ten billion years.
Also, stars formed only 1-2 billion years ago have larger amounts of rocky material, but even a larger proportion of heavy metals and radioactive materials; they are likely to form super-earths that hold too much water (no continents), and stay hotter longer. So there is a window of opportunity, which may be rather narrow, maybe not. I think we are on its leading edge.
OK, with that out of the way, I say, "Who better than Peter Ward to discuss the various kinds of life that may arise, both here and elsewhere?" Complex life of any kind may be rare...or not. But life analogous to bacteria and viruses is likely to be found nearly everywhere. In his new book, Life As We Do Not Know It, Dr. Ward warns that it may be hard to recognize as life.
His opening example is telling. When subsea hydrothermal vents were first found, there was a lot of thin, snotlike material floating around. It got in the way of observations of the big clams, crabs, and tube worms. The scientists often had to move around or wait for the water to clear so they could get nice looking photos. It was quite a while before anybody thought to capture some of the slime and look at it. It turned out to be bacterial life, in a profusion that probably outweighs the nice clams and worms. It happens to be their food, too!
It seems ludicrous. Any grazing or browsing animal weighs less than the biomass of forage needed to sustain its life. So what did they think the clams and tube worms were eating? But this is just the problem. We don't really know the limits of earthly life, in terms of temperature, pressure, or chemistry.
If you take a pinch of soil from your yard, and spread bits of it onto petri dishes containing the ten or so common nutrient mixes you can get from places like Cuisenaire or Cole-Parmer or Ward, you'll get dozens or hundreds of bacterial colonies, and if you're lucky, perhaps twenty or thirty different species. If instead, you shake that same soil sample with water, then screen for the portion smaller than two microns. Pulverize and use genetic probes, you'll find evidence that there were tens of thousands (or even millions) of different species present.
Here, this'll blow your mind: Ordinary ocean water, whether sampled shallow or deep, contains three or four parts per billion of viruses. Doesn't sound like much...it comes to 20 to 50 million virus particles per cc! Not only that, but almost every living thing on the planet contains a ppb or so of viruses, including you our me. I we had a kind of light that "saw" only viruses, the entire biosphere and all bodies of water would be outlined in a ghostly filigree of viruses, down to its last detail.
To jump to the chase, the author presents his reasons for considering viruses as living beings. Though they require living cells to reproduce, there are many species of animal parasites whose biochemistry is defective such that they cannot live outside their host.
Just to make you feel secure: the vast majority of animal species are parasites. Even though some, such as the follicle mites that live in the forehead hair follicles of at least 95% of us, are called "commensal" because they don't seem to do harm (How they might benefit us is totally unknown. Any benefit is strictly one-way, so I call them parasites).
What is life? We need enough of a definition that we'll recognize it...we just can't fall back on "I'll know it when I see it." My own formulation: "Life is a process that results when aperiodic crystals grow in an environment strongly out of equilibrium". Dr. Ward proposes, "Life metabolizes, life replicates, life evolves." Simple and functional, and more testable. It doesn't depend on a particular kind of genetic mechanism or "bio"chemistry.
What kinds of non-Earth life might we find, somewhere (even on Earth)? The author proposes Terroan to designate "life as we know it", so we can then distinguish as alien, "life as we do not know it." Terroan life is composed of cells with a lipid cell membrane, is based on Carbon, Hydrogen, Oxygen, and Nitrogen (CHON), employs water as the main solvent, and uses DNA to encode and RNA to translate genetic codes to proteins via the Universal Genetic Code (UGC). In order of increasing "alienness", we might list
- Certain bacteria that slightly violate the UGC. For example, some mycoplasmas use one of the "stop" codes (the U-G-A sequence) to encode for tryptophan.
- The parent organism of our Mitochondria; these organelles have their own, somewhat different, genetic code and reproduce independently.
- Organisms using one of the approximately 1075 other UGCs that might be devised, though only about 1050 of them keep redundant codes in groups. The mycoplasmas mentioned above could be included here also.
- Viruses, which are non-cellular.
- Organisms that use a solvent other than water, such as methane or a strong ammonia/water solution at very low temperatures, or hydrogen sulfate (sulfuric acid if excess water is present) at high temperatures.
- Organisms that use a polymer other than DNA to encode its genetics. (Note that silicate rocks consist of Si-O and Si-Al-O polymers. Feldspar life?)
I can think of one attribute that might make really alien life hard to recognize. Velocity. Let's look at plants. How do you tell the difference between a living and freshly-dead slice of Oak leaf? Oak trees are proverbially slow growing, though they grow leaves quickly enough each Spring. Within the cells of the leaf, though, under the microscope you can see cytoplasmic streaming going on. The insides of a cell seem to revolve complete every two or three seconds, in spite of the fact that it is encased in a porous cellulose box. Loose cells from the inside of your cheek also show streaming as long as Oxygen is present, though it is slower.
Both animals and plants of Terroan life exhibit at some scale, motions that can be observed directly by our 20-frames-per-second visual systems. That is anything from a speed just faster than the minute hand on a wall clock to velocities that blur like a spinning figure skater. But suppose we find objects in an environment whose kinematics disallow motions of such rapidity, or that are composed of much stiffer material?
A science fiction story I read was about an odd rock in an astronaut's collection, kept in a terrarium with other rock specimens from the apparently desert planet he'd visited. Every week or so, it seemed this rock had moved a little. Finally, after setting up a time-lapse camera, he was able to see that, over a few months, the odd rock moved away from the more lighted part of the terrarium, then moved to the glass side and began slowly (very slowly) grinding at it, seemingly in an attempt to escape. Perhaps it "lived" on a time scale that to it, seemed like running to a barrier and grinding through in the space of a few moments. I wonder what the astronaut seemed like from its viewpoint?
We know, kinematically, living creatures that live ten or a hundred times faster are implausible. But there is no limit to how slow one may go.
There is a point to the book. We need to expand the "tree of life" to include viruses and RNA life, at the very least, so as to include all Earth-originated and/or -developed life. We think RNA life is extinct, if it originated at all. But it may be created soon in the laboratory. Bacteria with added DNA codes have been created in the laboratory, so they are aliens. Mars probably once hosted living creatures, at least bacteria or something similar; and it may do so today, some distance below ground. Europa might have life, though the energetics are forbidding. Titan seems to have a "just right" mix of energetics and complex chemistry, that life of some kind is likely.
Thus, Dr. Ward proposes that we send people to Mars and to Titan, to look for it. Because of the differing probable history, and the known differences today, a Paleontologist needs to go to Mars and a Biochemist to Titan (better, more than one of each!). Mars is likely to have fossils, and a Paleontologist by definition is good at finding fossils. Titan doesn't seem to have anywhere on its surface that could contain fossils, but is likely to have a strong chemical signature of life processes in many places. Just what a Biochemist is prepared to determine.
You know, that's a pair of really good ideas. I hope we do it. The biggest hurdle? We have to get used to the idea that a Saturn/Titan mission is definitely one-way. Radiation there is less than near Jupiter, but still deadly over the span of a few months at most (Jupiter orbit is a DOA environment at any arrival speed less than 0.1c). Mars is probably one-way also. Can we afford to send heavy digging equipment to Mars, so astronauts can get dug in before they die of radiation poisoning? Just getting there, the DNA in 1/3 of the body cells gets damaged per year of exposure to the interplanetary environment. You gotta get a hole dug first (10m deep at least), then go there fast. Then, there is a chance to return. Send a backhoe to Mars first!
Though I was a bit put off by Rare Earth, I understand the reasoning. I find Life As We Do Not Know It much more optimistic.
Monday, February 13, 2006
kw: book reviews, nonfiction, history, western hemisphere
Who were the Indians in 1491, and before?
- They were a Stone Age people, living by hunting and gathering.
- They were a highly cultured people, living a complex political and religious life.
- They were sophisticated agriculturalists.
- They were noble and wise, living lightly on a vast land.
- They lived in the most primitive of conditions.
- They built great cities.
- They managed their environment to make life easier.
- They overran their resources and destroyed their environment.
- They were a people without history, unchanged for millennia.
- They were illiterate savages.
- Their written languages were complex and expressive.
All these statements are true. All are false. All were true at some times, for some groups. None was true of all.
In the prior three posts, I discussed things I found interesing in 1491: New Revelations of the Americas Before Columbus by Charles C. Mann. The history of the Indians of the Western Hemisphere has been hard to discover and harder to publish. The first two hundred years of Indian-European contact resulted in near-destruction of Indian populations by disease, the subjugation of many to unequal trade practices, and the collapse of many of their cultures. The next two hundred years of "Indian wars" resulted in near-depopulation of North America and less intense, but quite devastating reduction in the populations of Central and South America.
By about 1900 AD, most U.S. and Canadian Indians lived on reservations or had been forcibly "assimilated" into white society. Mexican and Central American Indians had been chased into "waste places" the neo-Spanish society didn't care about. The Indians of South America, at least the northern half, were marginalized and mainly ignored by a larger Spanish- and Portuguese-speaking majority.
Once the film industry in the U.S. really got going, about the 1920s, huge numbers of popular films had a "Western" theme, mainly about noble whites prevailing over wily savages. When I was growing up in the 1950s, the only non-negative Indian on a popular TV series was Tonto, who regularly got beat up whenever he went into town. Bill Cosby had it right, "You go to Hell, Lone Ranger!"
If you were to take an Egyptian of the 15th Century BC and drop him near Cahokia, Illinois, he'd be on familiar ground. "These guys are building a big pyramid, like my ancestors did...only bigger!"
Take a village farmer from 13th Century AD England or France, and drop him in coastal Peru. He'd quickly learn a few things, and soon be itching to go home and get better yields from his own field.
Take a courtier from the court of Louis IX of France, say in 1215 AD, and drop him among the New York Mohawks, of the Haudenosaunee (Iroquois) confederacy. Their "Great law of peace" was but seven decades old, but he would find the intrigues and power by-play quite familiar and invigorating. A number of the "founding fathers" of the U.S. and its constitution claim inspiration from the egalitarian principles of the Haudenosaunee.
Which had the greater population in 1200 A.D., Paris or Tikal (in the Yucutan)? Where were the better-managed forest lands, Spain or pre-Bolivia? Was there, anywhere in Europe, a culture that developed a "long count" to rival that of the Mayas: a cycle that contains 1,872,000 days, or more than 5,000 years? (Considering that their "day zero" was in 3114 BC, the cycle will end in 2112 AD, which is of great interest to all kinds of cultists.)
Of all the statements at the beginning of this post, I consider the following to me "most true, most of the time":
- They were a highly cultured people, living a complex political and religious life.
- They were sophisticated agriculturalists.
- They managed their environment to make life easier.
In other words, they were people, like people everywhere.
When I was twelve or so, I was walking in a forested area in late Summer. I began to notice apples on the ground, then cherries. I looked up, and there was fruit everywhere. Not on every tree, but on many, particularly a number of old, gnarly trees. It didn't take long to figure out that this piece of now-public land was once a farmer's informal orchard: half a dozen apple trees, some cherry trees, and I found a stand of small plums.
Visitors from temperate areas (mainly Europe and North America) who visit the tropics often remark that life must be easy, you can pick fruits and other foods almost anywhere. Contrary to my childhood experience, though, very few consider that they might be in ancient orchards. As it happens, writes Charles C. Mann in 1491, the poster child of tropical forests, the Amazon "jungle," is actually at least one-ninth "'anthropogenic'—directly or indirectly created by humans."
The tropics are rich, no doubt. In "unmanaged" forest, about 20 percent of the plants bear edible fruit. But over large, widespread areas, fully half the plants are sources of food. It is likely that many of the "20-percenter" forests were once managed, but have been fallow since the epidemics of 500 years ago.
And what of the great American grasslands, the Western steppes and Mideastern tall grass prairies? Or the large open areas in the "impenetrable" forests of the East? Early reports tell of the Indians' use of fire, to prepare agricultural land, to create charcoal for enriching fields, for managing the species that would grow, and for keeping the forest open for travel. The open, cathedral-like forests once seen from Pennsylvania (Penn's Woods...except they weren't his) to Minnesota and south to Kentucky were burned yearly by their earlier inhabitants. By the late 1500s, the cathedral-like aspect had pretty much vanished, and white homesteaders cut down and burned off the now-impenetrable forest for farmland.
If a forest burns every year, the grasses, forbs, and shrubs of the understory burn and char, and the trees are little affected. It is only when the understory gets overgrown that fire can endanger trees. If you want to turn a meadow in Pennsylvania into forest, as quickly as possible, first let it burn over in Autumn. In the Spring, scatter acorns and seeds of elm, ash, maple, and other trees. Then wait a few years until you have a few hundred 15- to 25-foot hardwood trees per acre and burn it, again in Autumn. If a lightning strike starts a fire before that, let it burn. Either way, many of the trees will survive. Thereafter, burn the underbrush yearly. You'll have a nice, open forest with dense shade within a decade or so. Thereafter, the "ceiling" will rise by a few feet per decade until it tops out at 50-60 feet.
Further west, the central North American grasslands are a product of fire. The Corn Belt was once covered with "buffalo grass," that fed browsing prey. Prior to 1492, there were comparatively few bison; their population explosion in the 1700s was a symptom of environmental collapse once the "burners" died off and the plants changed. The resulting Sioux and other bison-hunting cultures were no more than a century old when Custer was lured to his death in Montana. Rather, the older culture mixed grain growing with the hunting of pronghorn and deer, and perhaps were taking steps to domesticate the larger Whitetail deer, much as the Lapps domesticated Caribou to create Reindeer. We'll never know.
I live in Delaware. In some of the State parks, there are hardwood trees 18 to 24 inches in diameter and forty feet tall, and in wetter areas, 40-inch sycamores sixty feet tall. A little inquiry determines that none of these trees is a century old. An oak that died in a bit of forest near my home, which was two feet in diameter (at breast height, where trees are properly measured), died of root fungus and was felled. Its stump has sixty growth rings. My house is 62 years old, so that tree was planted or first sprouted two years after my development was built. In my yard I have two oaks and a maple, all about 18 inches in diameter, that are 44 years old, which I know because my neighbor told me the year she saw them planted.
Some of the former farms in northern Delaware were farmed, abandoned, farmed again...four cycles since the 1600s. Today large trees grow on those lands, but you can see old walls running through. The upshot is, not having visited the Pacific northwest, I've never seen "virgin" forest...but what I have seen looks pretty good to me.
The author concludes in one section, "Until Columbus, Indians were a keystone species in most of the hemisphere. Annually burning undergrowth, clearing and replanting forests, building canals and raising fields, hunting bison and netting salmon, growing maize, manioc, and the Eastern Agricultural Complex, Native Americans have been managing their environment for thousands of years."
kw: book reviews, nonfiction, history, western hemisphere
I lived in Ohio in my high school years. On a family trip to the southern part of the state, we visited Serpent Mound, near Peebles. I was sixteen, and six feet tall already, and it seemed quite a bit taller. Of course, it is on the top of a ridge. It takes about five minutes to walk along its length; about a quarter mile. Its serpentine shape would make a walk along the spine of the Serpent quite a bit longer.
The first image here shows Serpent Mound from above. The second is a post card from about the time I visited, around 1960.
Continuing my review of 1491 by Charles C. Mann, I find it amazing that there is so much archeological richness in America, more than 99% overlooked or unrecognized. I recall visiting a relative in North Carolina, who took me digging for arrowheads. It isn't hard: Any road cut shows hundreds of yellowish flint chips along the older soil horizon a few inches below "modern" soil. We went into a field where we dug and sifted a couple cubic feet of dirt. There were hundreds of chips, a few dozen flake tools, and four arrow points. The site was a hunting camp, and has been dated to 8,000 years ago. It was used seasonally between that time and about 1200 AD. Even allowing for 7,000 years of use, there are huge numbers of artifacts. Agricultural areas nearby have few of the sought after "points", but much larger accumulations of various chips and flakes, made on the spot for various household uses, then discarded when dulled.
At one time Serpent Mound was one of more than 10,000 mounds built by various peoples all over the Midwest and South. Most of them have been destroyed, plowed over or carted off for fill. While many were burial mounds, some such as Serpent Mound were "high places" or meeting centers, and some, such as Monk's Mound near Cahokia, Illinois, were for ceremonial use. The volume of Monk's Mound is substantially bigger than that of the Great Pyramid at Giza. It is often said of Giza that millions of slaves must have been employed for centuries. I wonder how many people it took to build Monk's Mound and its nearby, somewhat smaller (only by comparison!) companion mound?
Looking further south, the spread of maize after its development before 1000 BC can be followed in proxy by mapping the successive high-population cultures that followed, the Olmec followed by the Maya and Aztec in Mesoamerica, and the Wari followed by the Aztecs in and near the Peruvian Andes. They built impressive cities. Machu Picchu, shown here, is the most famous in Peru...though the hardest to get to!
Severe climate shifts after about 1250 AD seem to have greatly reduced the population the land would support. The century of famines in Europe (1304-1390) is probably a related phenomenon.
Yet great cities such as this one, Chan Chan in Peru, continued nearly until the Spanish conquest. Chan Chan itself was conquered by the Inca in about 1450, and declined rapidly. The Inca fell, first to smallpox, then to genocide, two generations later. Few stone cities are to be found in North America, though Tuzigoot (shown below) and the "Anasazi" cliff dwellings of the American southwest are awe-inspiring today. "Anasazi" is Navajo for "enemy ancestors"; they had a different name for themselves, now unknown.
Finally, the presence of trade goods throughout all areas testifies to numerous vibrant, sophisticated, interlocking cultures. Kentucky Flint is found throughout the Hopewell areas from Minnesota to Pennsylvania and Louisiana, Arizona pottery was traded into Utah and Idaho to the north and Mexico to the south, and copper was traded up and down the East coast of the (pre-)U.S. by Mandoag middlemen from North Carolina.
All of this speaks to a much greater cultural attainment than many care to think of. Lacking only iron tools, the Indians of North, Central and South America had all other accoutrements of a culture as complex and sophisticated as any European culture of the day.
See the following posts.
At the climax of H. G. Wells's War of the Worlds, just as the Martians are poised to take over the earth, they are extinguished by a fatal disease against which they have no resistance. I guess we're lucky that Earthlings weren't similarly prone to catching a Martian cold.
Something like the wildfire spread of a "Martian cold" seems to have raged through the Americas in the 16th Century. Only it was worse than a cold: Prior to 1570 AD, five epidemics of smallpox roared through mid-South America, where we have the best documentation (1524, 1533, 1535, 1558, and 1565). The area was also ravaged by Typhus (or a similar disease) in 1546, influenza in 1558—which killed many that survived smallpox—, diphtheria in 1614, and measles in 1618. Nine epidemics, each killing from 20% to 50% of the population then existing...estimates of the proportion that remained range down from 20% to less than 5%, all within about two generations.
Contemporary records by Europeans show the trend. Prior to 1520, from Maine to Yucatan to Peru and Chile, described the land as well-settled, with a dense, active population of agriculturalists. Writings made after 1600 report an empty land covered with the ruins of abandoned villages, and small numbers of people subsisting by hunting and gathering in scattered, roaming bands.
Piecing together many accounts, and the best of recent scholarship, Charles C. Mann opens his new book 1491: New Revelations of the Americas Before Columbus with a study of the de-peopling of the Americas. While our children are taught an outdated view of a nearly empty continent just begging to be settled, scholars for the past generation have determined that the Americas of 1491 rivaled Europe in population, civilization, and sophistication. People are more similar than they are different.
White American culture has two opposed views of Indians, particularly the Indians prior to contact with Europeans (Mr. Mann presents his reasons for using the term "Indians," including the fact that the Indians seem to prefer it. I follow his
example. While it is not accurate, it appears to be the least inaccurate term). They are seen as "noble savages": people who made no cultural or technological progress since the glaciers melted some 12,000 years ago; people without history, mostly without agriculture, without cities or even settled homes, living by hunting and gathering on a land that was edenic and pristine. They are also seen as incurable vicious barbarians: wily, stealthy, warlike bands that kept white armies at bay for generations, only succumbing when nearly annihilated.
Thirty or forty years ago, the pre-1492 population of North America was confidently declared to be "about a million," a figure thought to be little changed for thousands of years. The forests of the East and Midwest and the grasslands of the West were considered nearly pristine. Today, the "low counters" struggle to maintain the plausibility of a pre-Columbus population estimate of around five million, while the "high counters," the majority, support figures in the ten- to fifty-million range, or higher.
Today, there are about 2.5 million Indians in the U.S., and another 1.6 million who are part Indian. I don't think of myself as part Indian, my best estimate of proportion being about 1/64th. The most inclusive tribe, the Cherokees, require 1/32d for membership, so they and I agree I am not "Indian enough to count." Most of those "counted" have one or two full-Indian grandparents.
U.S. census figures show 44,021 "American Indian, Eskimo, and Aleut" in 1860; before that year, they weren't counted. The Census of 1890 shows two figures: 58,806 "excluding Indian Territory and reservations", and 248,253 including them. So the total for 1860 was actually about 186,000. There were 31.44 million people in the U.S. in 1860, so Indians comprised 0.6% of the population. Today they total 0.9% (just the 2.5 million).
I favor a figure for North America of about twenty million in 1492, and fifty million in all of the Americas. The 17th Century estimates of a million or so Indians in North America, north of Mexico, represents a 5% survival after a century of European plagues. Then in the 19th Century we find less than a 20% survival after a century and a half of "Indian Wars," including further plagues caused by weapons such as "smallpox blankets".
Studies of immune system haplotypes indicate that the Indians derive from just four, three of which are found throughout Siberia today (along with many others). By contrast, there are dozens of European haplotypes. This is one indication that their ancestors began with a very small population and multiplied. They went through a "genetic bottleneck". However, it may be that much of the bottleneck occurred in the 1500s, as well. Two successive reductions of population by 90% would have eliminated many minor haplotypes.
The evidence for large populations in South America and Mesoamerica is much more abundant and compelling...to most. "Small counters" still argue against hemispheric populations larger than a few millions. It is hard to ignore the incredibly abundant Mesoamerican ruins. It isn't so easy to determine what happened in the Andes or Amazon areas, but archeologists now recognize very large-scale, widespread evidence for large populations.
Just in the Beni area of northeast Bolivia, the example with which Mann begins the book, there are thousands of raised areas with causeways between, raised areas composed of huge numbers of artifacts that indicate not only long-term occupation by large numbers of people, but deliberate manipulation of the soil to better support their agriculture. In areas with poor soil, broken pottery is a kind of "artifical gravel" that releases mineral nutrients into the soil much as the glacial gravels found in the northern U.S. and Canada do. Admixed charcoal, both fire leavings and charcoal deliberately produced and stirred in, further enrich the soil. Similar accumulations abound in the Amazon area.
Yet, Central and South America were ravaged by European plagues, then felled by Indian-European warfare, just as thoroughly as in the North. Introduced diseases, particularly smallpox, ran through the continents so rapidly that most Indian societies were demolished a generation or two before they saw their first white man.
Let's reconsider the stone-age, naked-savage view of early Indians. Except for a few Spaniards in ~1500, nobody saw Indians in anything like a normal condition or setting. By the early 1600s, Europeans newly arriving in America encountered indigenous peoples who were more like the survivors of a few generations in a concentration camp.
This sets the stage for further investigation of Indian society in 1491. See the successive posts.
Thursday, February 09, 2006
While preparing a series of posts for a history book, I read Running from the Deity by Alan Dean Foster, one of his "Pip and Flink" series. A mix of space opera and cautionary tale, Deity has Philip Lynx becoming a god as an unanticipated side effect of avoiding boredom while his ship repairs itself on a "Class IVb" planet.
Philip, AKA Flinx, suffers from an excess of empathy, or rather telempathy. He can't turn it off—though it comes and goes capriciously—, so visiting populated areas is quite uncomfortable for him. Pip is a minidrag, a small (meter-length?) flying reptile that spits poison, but most importantly, is also a telempath that can link with Flinx (I had to!), and is a comforting companion.
Flinx is also a thief, so must keep one step ahead of the law. Fortunately, he did a big favor for members of an advanced species, and they built him a starship, one of the few that can land on a planet. Nice trillion (quadrillion?)-credit bonus, that! So, he bombs around the galaxy, in a loose league with a few sympathetic humans and thranx, who are trying to save the universe from an evil bigger than a galaxy cluster.
Foster writes like a house afire. This has the great benefit that his most suspenseful scenes don't drag on too long. On the other hand, I wonder to what extent he thinks things through. This novel has Flinx at his most blindlingly naïve ever. He seems compelled to spill his guts to every interviewer, trusting his ability to read emotions. Of course, he can't discern accompanying thoughts, so how is he to know the joy a creature feels is to his benefit? I'd be suspicious of Stalin's joy, for example.
Anyway, a fun book, with yet another nonhuman sentient species to show for it. The author is one of the better inventors of aliens.
Thursday, February 02, 2006
It is like Earth but not Earth; they are called human and may be human, maybe not; their society is like semiurban America...usually. In a story told from the nonhuman viewpoint, Michael Blumlein, MD, presents in The Healer a narrative of a society wholly dependent for the health of its citizens on rare, gifted individuals from a despised race.
They are usually called "tesques," short for Grotesque. And grotesque they are, having misshapen skulls and an extra organ system—attached to an extra orifice on the rib cage—by which one tesque in ten can extract nearly any disease from a human, compact it into a grisly "concretion," and excrete it for disposal. This is the setting for a tragic novel of rare beauty.
Payne, perhaps the most gifted healer of his generation, or of all generations, finds healing easy and pleasurable. Indeed, it replaces all other passions, whether he is working on the roughshod miners in an isolated camp, the (temporarily) high-society denizens of a mirror of Las Vegas, or the hardest cases, near-moribund victims of "sixth level" illnesses. He is, like Orson Scott Card's overly-moral heroes, an innocent in a rough-and-tumble world that he never does understand.
Healers don't heal healers. Payne tries, once, and condemns a friend to an agonizing living death. At the instigation of his brother's human paramour—his brother Wyn was also a gifted healer—he tries once more, and succeeds in healing his brother. But at that point, the book departs into a full-fledged fantasy, having Payne re-live one of his people's creation myths. I found this ending profoundly disappointing. The author's point is clearly to provide a means to change from the outside a society that cannot be changed from within. The book closes with this hope plainly implied.
But I'd have preferred a less-mystical means of getting there. Ending with Payne in pursuit of his brother's snake-like 6th-level concretion would have left Dr. Blumlein with the room needed to develop a more satisfying transition to a second society in a sequel.
That's the trouble with the triple-point boundary between Science Fiction, Speculative Fiction (where I place most of this novel), and Fantasy. Begin invoking magic, and it will run away with you.
Wednesday, February 01, 2006
In the middle of reading a number of heavier works, both fiction and nonfiction, Starship: Mutiny by Mike Resnick was pure escapist space opera for me. Heavy on the dualism: military discipline vs subversive righteousness; "the Republic" (which seems to be anything but) I vs an ill-defined "Toroni Federation" enemy; white hats and black hats all around.
I like the protagonist/hero, Wilson Cole, a thinker and doer. The byplay between him and various "by the book" adversaries makes any of them the poster child for my maxim (viz. M. Twain), "Someone who is unwilling to think is no better than someone who cannot think" and its corollary, "...and is probably much worse." Cole doesn't bother to outgun an adversary, but out-thinks him or her (boneheads of both sexes, and several species, abound).
Cole is assigned as a mid-rank officer on an aging starship staffed by malcontents. Sort of a halfway house. It doesn't take him long to make a tidy collection of both friends and enemies, nor to find "the enemy" active in a corner of space that nobody expected. As his successes pile up and his popularity (with the brass) plummets, Cole is in his element.
As someone who has built a career—a rather good one—by doing for customers what I've been ordered not to do, I know right where Cole is coming from. Like him, I've been tempted to hoist the Jolly Roger a time or two. Considering that the second volume in the proposed quintology is Starship: Pirate, it'll spoil nothing to tell you that Cole finally does just that.
Mike Resnick is just a couple years older than I am. I expect the quintology to get into print at a rate of about a volume each year or two. It's gonna be a fun decade.