Looking past old bones

 kw: book reviews, nonfiction, science, geology, paleontology, plants, evolution

Cyanobacteria, which were called "blue-green algae" when I was taking Freshman botany more than sixty years ago, arose about 2.7 billion years ago. The Earth started to become green. Before that it was primarily orange. The greening of Earth began in earnest once certain cyanobacteria became incorporated into the cells of an Archaean species to become chloroplasts in the first eukaryotic cells. Multicellularity, in the sense that among a bunch of cells that were sticking together, the cells began to have different functions, came about perhaps 1.5 billion years ago. By 1.2 billion years ago a proto-alga we call Bangiomorpha was the tallest plant in the shallows of the Precambrian ocean, being all of 2 mm tall, towering over micron-sized prokaryotes.

Bangiomorpha features in the first chapter of When the Earth was Green: Plants, Animals, and Evolution's Greatest Romance by geologist Riley Black. The chapter is titled "Sex in the Shallows" because it is pretty certain that Bangiomorpha was among the first organisms to reproduce via sexual differentiation of gametes and gamete fusion.

Side note, not related to the content of the book: The preference in nature to use DNA rather than RNA for long-term storage and retrieval of genetic information is based on its stability. RNA copying is much more prone to error, and the lack of pairing of RNA strands makes an "RNA world" very fragile. However, RNA is essential for helping DNA make copies of itself, and for translating sections of DNA into proteins. The fact that the biosphere was extremely slow to change during the first billion years after life began indicates that DNA is "too slow"! The mix-and-match processes of meiosis and gametogenesis sped things up appropriately, so that complex life could arise before the Sun burned out (not that "nature" had any idea it had such a deadline). Sex combines a level of stability much greater than an RNA basis allows, while also providing mechanisms for making changes more rapidly, particularly when small populations are isolated under adverse conditions. As you might imagine, biological theorists are still arguing strenuously about the pace of evolutionary change at various levels.

Back to the book: The fifteen chapters each tell a story of a particular organism or ecosystem, focusing on the plants. Most of paleontology is "shells and bones". Having done my time clambering over desert landscapes all over North America—as Riley Black is still doing, lucky kid!—I relate strongly to the tendency to focus on the hard bits. It is easy to climb a cliff that was a marine reef in the Pennsylvanian Era and snatch up brachiopods, bryozoans, clams, snails, and corals. The plants that accompanied them are simply not in evidence; they don't fossilize well in the gritty sands that surround the structures of the reef. And why collect fossils in deserts? I live in Delaware now, and most rocks containing fossils are buried under tens of feet of soil. In Nevada, there are lots of rocks right at the surface.

Some of the chapters tell stories that feature sundry animals, retaining the emphasis on the plants they lived among, and often upon. For example, Chapter 13, "Far from the Tree" has a proto-hyena watching two monkeys squabble on the branch of a tree in late Miocene Ethiopia, hoping one will fall. The tree is the "hero" of the story, along with the effects tree dwelling had on the morphology of the little primates. The focus of the chapter is the gradual spread of grasses as the forests retreat. 

By the way, it is stated that grasses have C3 photosynthesis, making them more efficient than trees at turning CO2 and water into carbohydrates. This is an error. Grasses are the primary C4 plants, while most shrubs and trees use the older C3 photosystem. I don't know if this is a typo; it should have been caught by the copy editor at very least (The author had a copy editor, who is named in the Acknowledgements). Anyway, to my point: Prior to the evolution of C4 photosynthesis, CO2 content of the atmosphere was nearly always between 500 ppm and 2,000 ppm. C3 plants thrive best with at least 500 ppm. C4 plants can draw down CO2 below 100 ppm, at which point most trees won't grow at all. So, you folks out there that want to grow stuff to draw down CO2, use grasses, not trees. Even at today's CO2 level of 440 ppm, the trees are struggling.

My favorite chapter is 3, "The Forest Primeval", in which the author lyrically describes aspects of life in the Carboniferous Era (as it is called in Europe; in North America this era is divided into the Mississippian and Pennsylvanian Eras).

This image I generated using Seedream V4.5 in OpenArt is not as densely packed with trees as I wanted, but it shows the alienness of the treelike species that existed at the time. Of course, I had to include an eagle-sized dragonfly. The rapid profusion of plants and their equally rapid burial, which formed our coal beds, led to a very high level of atmospheric oxygen. As the author points out, the larva of the dragonfly needed to be larger to reduce oxygen toxicity. Yet the extra oxygen also fueled the energy needed for the adult to thrive at its meter-sized length.

Had I been the publisher's editor, I might have amended the book's title to just The Earth was Green. This image of the Blue Ridge in Tennessee, from a panorama by the National Park Service, shows that Earth is very green even today:

Riley Black is a trans woman, who put the pronouns "she/they" in the author bio. Since she is at least halfway through a full physical transition, I'm willing to say "she". "They"? Not so much. I care about singular and plural. Her pronoun confusion extends to the grammar of the book, where it is applied to the creatures. Sentences with wording such as, "Now that the monkey can reach the fruit, they can…" are simply solecisms. The common usage is "it can…", which is at least genderless. Similar grammatical errors are found numerous times per chapter. It is sad. Apparently her copy editor shares her grammatical mis-education.

Ms Black's writing is lyrical and enjoyable. She has published several earlier books, and I understand all are popular. And I envy her access to so many prime fossil localities!

One last quibble: In the first chapter, describing how DNA data are mutated, the analogy of a copy of a copy of a copy in a photocopier is used. It's a very bad analogy. The successive copies gradually fuzz into meaninglessness. No new letters appear. In DNA, every "word" is exactly three letters. Every possible combination is meaningful. A DNA copy error doesn't make any fuzz, it exchanges one letter for another, or it may even add or delete a letter, causing a frame shift (frame shifts are fatal flaws).

When is a drug really a drug

 kw: book reviews, nonfiction, drugs, entheogenic chemicals, plants

About 90% of the human race uses caffeinated drinks, including coffee, tea, "energy drinks", and caffeinated soft drinks. Every culture has some kind of stimulant(s) to keep intelligent people "on task" as they slog through their daily grind. Before caffeine became ubiquitous, Asia-Pacific areas had Betel, tropical South America had cocaine, and North America had tobacco (which is still the second-most-used stimulant). All of these are still in use, with caffeine thrown in for good measure.

Caffeine is the centerpiece (literally and physically) of This is Your Mind on Plants by Michael Pollan. He makes a case that Western civilization was largely enabled by its stimulation, as it replaced alcoholic drinks. Formerly, alcohol was needed to make as beverage safe to drink. Boiling water to make tea or coffee also kills germs, and the resulting drink was energizing rather than stupefying.

Personally, I don't like hot drinks and I abhor the taste of coffee (a good way to ruin a teaspoon of cream), so if I want caffeine, I use one of the more robust soft drinks such as Mountain Dew or Jolt (where it can be found). However, since I retired, I stopped using "cold caffeine", which I'd needed to keep going at work, particularly during meetings when the lights would be turned low for PowerPoint presentations. I guess even then, I wasn't ingesting as much caffeine as coffee drinkers, because I didn't suffer any withdrawal symptoms. The author did a 3-month caffeine break, and withdrawal affected him quite a lot. When he had his first cup of Espresso after the break, it was like a first hit of cocaine to him. Thanks, I'll pass.

The first third of the book is about opium. Many cultures also have their favored pain-killers (willow comes to mind), but the opium poppy spread far and wide, long ago. Much of that section dwells on his early experiments with growing poppies (which is legal!), and the kinds of trouble he could have gotten into if, at the height of the War on Drugs, he had "crossed the line" by so simple a matter as drying a few seed heads and brewing tea with them. There's much information on the history of poppies and opium.

When I was in college, you could still buy Paregoric (4% opium in alcohol, with a couple of other ingredients). It was "Grandmother's helper" with colicky or teething infants. The author mentions Laudanum, which is stronger; I never saw it in drug stores. I couldn't relate to much of what he wrote. I wasn't willing to break the drug laws, but he had fewer qualms, though he writes of having a few qualms!

The third plant is actually a family of cacti that includes Peyote ("mescal buttons"), with the active ingredient mescaline. While peyote is soon to be an endangered species—it's getting too popular and is very slow-growing—another group of cacti called San Pedro (among numerous other names) is much more common, easier to grow (Pollan had some in his garden without knowing it), and different species have varying amounts of mescaline. It made me think, just as with marijuana, if mescaline gets much more popular, growers of San Pedro will breed more potent varieties.

Peyote is legal to use only for certain religious groups of American Indians. As the author found, they have a cultural mindset that is less analytical, which helps them use the plant more appropriately, as a medicinal rather than recreational substance. The author writes of the effects of environment and attitude, on one's experience with mescaline in particular. Indians get quite huffy if peyote is called a drug. To them it is medicine for the soul. It is being called "Entheogenic", meaning it reveals (or produces: "-genic") the god within ("En-theo"). That's an attempt to remove the stigma of the "drug" designation.

The author's experiences with mescaline sound intriguing, but I think I'll pass here also, for the same reason I gave up alcohol before the age of 21: I don't like anything messing with my mind.

Michael Pollan self-experiments. We have here his record of some of those experiments. It is also an approach to a manifesto of sorts, against the war on drugs. I agree that the Federal government badly overreacted over the past 2/3 century (basically, most of my lifetime). What are the chances they will pull back? Although most US states have "decriminalized" marijuana use and possession, the Feds have not, putting the states in a curious position. The process is slow; perhaps, drug by drug, various "substances" will be removed from their "Schedule". It could take decades.

She is not only ape about apes.

kw: book reviews, nonfiction, plants, memoirs, polemics

Jane Goodall is known for her lyrical writing, and her new book—which hardly mentions chimpanzees!—is, if anything, even more lyrical. With the help of Gail Hudson, she has written Seeds of Hope: Wisdom and Wonder From the World of Plants. At first, a reader may wonder why a primatologist would write about plants. As she tells us in the opening chapter, her first love was a tree, a beech (named Beech) in which she sat and read or drew or wrote for many a childhood hour. That is not all.

By the second half of the book, her hortatory purpose emerges in full. She has seen a good deal more of the world than most of us ever will. Everywhere, among the wonder and beauty, there is damage and tragedy. Of course, her beloved chimps are in danger, but their greatest peril is the shrinking forest. Where 50 years ago the tiny Gombe reserve was surrounded by forest and a piece with it, now it is an isolated enclave, with bare ground, or monoculture farm fields, right up to the boundary. If we save and restore the forest, we will also save the apes…if not, not.

This is happening everywhere. At one time, the First World exemplified the "taming of the wilderness" in favor of agriculture and agribusiness. For example, nearly every acre of the United States that is arable is devoted to that purpose. While this comes to just under half the total land area, and cities and roads and other pavements take up only about 5%, much of the rest is logged or otherwise exploited, including an increasing proportion of our national parks and monuments. And this is the "new world"! Now the Third World is going full steam ahead, building, plowing and planting, polluting, and generally straining to outdo all our worst sins.

The first half of the book is descriptive, of the author's life and of a systematic trek through the plant world, from the various aspects of the plants themselves to the uses made of them by animals and humans. Starting in chapter 11, things turn dark. Its title is "Plants that can harm". Why do plants make so many chemical substances? Many, many of them are insecticides, bitterants (to discourage browsing mammals) or downright poisons. Some of these substances can be used as medicines (the subject of Chapter 10); indeed, nearly every medicine is either extracted from a plant or chemically derived from a plant chemical. But so are many poisons and "recreational" drugs. All the ways a plant can heal or harm are a product of human redirection of chemicals the plants make for self defense.

But even "good" crops are not without their dark side. In the West, we may have outlawed slavery, which was largely agricultural, but agriculture, particularly the picking of fruits and vegetables, is still an area rampant with abuses, of workers, of the land, and of domestic animals. And in "developing" countries the abuses are the worst, including continued slavery. Think about that the next time you buy cotton underwear without checking whether it was both organically and ethically grown.

The last five chapters describe suggestions for taming agriculture itself. It has become the master and we the slaves. This can be turned around, and the featured initiatives, including Roots & Shoots, which Ms Goodall and a group of teens started in Tanzania 22 years ago, show at least part of the way. Crops such as coffee and cacao (chocolate) grow poorly in monoculture, compared to polyculture with appropriate plant companions. With more time and research, we are likely to find that many crops share this characteristic. This in not new: read Malabar Farm by Louis Bromfield; the farm has been in operation since 1939. One tidbit: corn grows better when it shares the field with alfalfa. Other innovative ways of growing crops, some of them thousands of years older than agribusiness, just might feed more people than the current "big business" way we have fallen into in the West.

Even at her most polemical, Jane Goodall writes lyrically, and manages to avoid being too "preachy". But we need out preachers. She is one of the best.

Wallflowers they are not

kw: book reviews, nonfiction, natural history, plants, weeds

Many years ago, I was doing a bit of gardening when my cousin and her husband came by. On the way in I told them I was transplanting a couple of Oxalis plants from the lawn into a corner of a flower bed. "Oxalis!" the husband sniffed, "Get rid of it. That's a noxious weed!" I refrained from pointing out that, among some 800 species of Oxalis, we find the Shamrock and a number of other species that are valued for rock gardens. The common California species have attractive trefoil foliage year-round (in Pasadena anyway), and small, pretty yellow flowers once the rainy season gets going.

My mother was a reader, more than a TV watcher, and I've followed her footsteps. One series of adventure novels she relished features a hero called the Scarlet Pimpernel. This name would be sniggered at today. As it happens, the pimpernels, scarlet, blue, and a few other colors, are familiar roadside weeds in England, though rarely found in the Americas.

We have a hedge about our yard, so I don't use "weed and feed" or other chemical-warfare methods to control non-grass plants in my lawn. It would harm the privet plants. As a result, we have an interesting variety of ground covers, forbs and other species in the turf. Wild strawberry, with its creeping habit, is pretty in a corner or two, but we pull it from the middle of the yard. There are other plants we try to stay ahead of. We have a scattering of wild violets, which I really like, but my wife insists on digging them out. I do my passive-aggressive thing about that, and just ignore them, pulling other weeds instead.

It was with great delight, then, that I read Richard Mabey's lovely book Weeds: In Defense of Nature's Most Unloved Plants. While discussing the general concepts of native plants, wanted or unwanted, he has structured his book with a round dozen chapters, each based on a particular plant or family of plants, including the infamous (and imaginary) Triffids, from John Wyndham's 1951 novel The Day of the Triffids.

Really, though, what is a weed? Simply put, it is a plant that thrives in a place you'd rather it wasn't. Our next-door neighbor has a bird feeder. She uses uncooked birdseed, so below the feeder various plants are constantly popping up, most notably Millet, also known as Sorghum, a fast-growing, aggressive, tall grassy plant. Of course, she regularly rips everything out except the few wisps of lawn grass that survive the onslaught. When we lived in South Dakota, a farmer's field across the road was used to grow Millet every year. In 1984 a tornado zipped through the field, scattering stuff over the whole neighborhood. The following year, everyone had Millet growing in their yards. We didn't mind. We knew our rocky soil had low fertility and the grass would soon crowd it out. It did. But if the tornado had run through my flower bed and blown some poppy seeds into the Millet field, the farmer would likely have hoed them out once they grew.

There were no weeds before there was agriculture. There is no thought of a plant being out of place when you have no concept that certain plants "belong" in certain places. Now, many standard practices of "modern" agriculture are found wanting. Many years ago, at Malabar Farm in Ohio, it was found that growing a clover or alfalfa crop among the corn in a cornfield was more effective weed control than blasting everything with pre-emergents, post-emergents, and targeted glyphosate sprays. Also, the legume fertilized the corn. Few have picked up on the Malabar Farm experience, but a few farmers have begun to re-learn this lesson. And clover isn't just good for corn. The healthiest looking yard in our neighborhood is full of white clover (just like the yard was where I grew up half a century ago). I'm encouraging the clover patches in my yard. They reduce the need for fertilizer, and squeeze out some of the weeds we've been hand-pulling.

Mabey discusses an interesting matter: Many English plants have been brought to North America and become invasive weeds. Very few American plants have successfully made the reverse migration. He attributes this to the historical fact of Europe's high population density. While there were a great many more Native Americans prior to 1492 as compared to the number in the 1600s once smallpox and measles had killed 95% of them, the population density was always lower than that of Europe and England for at least 1,500 years. Intensive agriculture has caused the English native plants, which are now quite different from those of pre-Roman times, to be adapted to frequent disturbance, primarily by weeding practices. By contrast, pre-Columbian agriculture in the Americas was based on using fire as a "pre-emergent herbicide", but pretty much leaving a field alone once a crop was established. Thus, English plants have a long history of resisting the hoe. American plants don't.

Many of the stories in Weeds recount the author's wanderings and observations of native plants all over England. Some grow quickly and set seed almost before you find out they are there. Some grow best in cracks in stone walls, and have, for example, traveled along walled roadways, even throughout the storied universities of London and Cambridge. He tells of a study done a century or more ago, that found more than 360 plants growing in, around and over the Roman Coliseum, until they were assiduously removed by the Garibaldi administration. I suspect if the old place were left alone for a few decades, most would return.

Throughout the book, the plants are referred to by vernacular names, and there is a glossary in the back, nine pages worth (!), to document the binomial names. I find myself chagrined that I know only a couple of dozen native plant names; Mabey knows hundreds. But I do enjoy seeing the various plants in their seasons. I still like having some Oxalis around. The East Coast species differ from those I knew in California, but are just as pretty. As the seasons pass, one after another, the native plants, and their English companions, provide a backdrop or frame to the more cultivated flower beds in my neighborhood. I am glad there is movement afoot to recognize the value of some of the plants that we've been conditioned to destroy on sight. I hope Weeds is but the vanguard of a movement towards a more rational and measured response to the plants that insist on making themselves our companions.

Green means everything

kw: book reviews, nonfiction, evolutionary theory, plants

In 1980 Plate Tectonic theory was sufficiently established to be accepted dogma (as it still is) but new enough that great uncertainties surrounded nearly every major hypothesis. One entire course was devoted to studying when plate motions began and how plate tectonics might have evolved through time. As I recall, the fact that radioactive heating of the earth was six times greater than now, some four billion years ago, was never mentioned.

However, it is a smaller incident that comes to mind today. In a follow-on course I happened to remark that the existence of life, that is the actions of the biosphere, must have had a great effect on the rates of weathering and sedimentation, and may have actually multiplied the rate at which the continents accumulated. The professor objected to this point strongly, and the debate led, over time, to my receiving a B in the course rather than my customary A. This was but one of two Geology courses for which I did not receive the top mark while in graduate school.

As it happens, for more than half the history of life on earth, the biosphere has consisted primarily of bacteria. But by two billion years ago (and perhaps still at one billion), though the oceans were bluish-green with cyanobacteria, the visible color of Earth's continents was still the grayish brown of completely inorganic soils. How things have changed!

Algae of many colors must have brightened up coastal margins, but it was only with the evolution of true plants that living beings came ashore and began to colonize the land. The green-on-blue look of Earth today, shown here in a GOES-8 image from NASA, illustrates that more than 95% of the biomass is now plant life. In The Emerald Planet: How Plants Changed Earth's History author David Beerling explains the part plant life has played, primarily over the past half billion years, and argues for a greater understanding of plants as one of the great driving forces of planetary evolution.

Plants harvest sunlight and so form the basis of all non-bacterial life on earth. So imagine a planet without them, and perforce, without any animals either. Oh, there are perhaps stromatolites in the ocean shallows, and similar bacterial mats in pools and streams of fresh water. But the land surface is no different from that of Mars: brown or reddish-brown, sandy and dusty, or gritty-muddy on a rainy day (as Mars's land would be if it would ever rain there). The cloudiness of the skies might be quite different...I can't say just how. But there would be probably ten to twenty times as much carbon dioxide in the atmosphere, and at most one-third of the oxygen seen today. This bacterial world would be much, much different.

However, I would make one change to the book's title: ...How Plants Determined Earth's History. This is not too strong an expression. For most of the past half billion years, particularly since the evolution of leaves about 450 million years ago, plants have covered much of the land, greatly increasing weathering rates with organic acids, yet holding soils so that bulk erosion rates decreased even as chemical erosion increased.

Carbon dioxide has been successively drawn down, though not at a steady rate. Rates of volcanism are a primary driver of CO₂ production, and particularly during the Carboniferous and Permian, this fertilizing gas was produced at much greater rates than at present. In addition, plant remains were being incorporated into sediments at unprecedented rates, which led on the one hand to the Coal Measures, and on the other to a much greater level of Oxygen in the atmosphere, and thus to a higher atmospheric pressure.

Various studies have confirmed that oxygen, which today forms one-fifth of the air, was greater than one-third some 300 million years ago. The nitrogen amount was the same, so this thicker, energy-rich air supported an age of gigantic insects, such as the three-foot wing span dragonfly Meganeura. A gigantic mass extinction episode 250 million years ago nearly eliminated the biosphere, and put an end to the era of big bugs.

200 million years later, the continents were differently configured, and various factors combined to add "extra" greenhouse gases such as nitrous oxide and ozone to the lower atmosphere, multiplying the effect of a rising amount of carbon dioxide. This "Eocene optimum" (optimum for who? I wonder) produced alligators in arctic and antarctic areas, and tropical forests that, paradoxically, had to survive months-long winter darkness, but not winter cold. The average temperature of the planet was 18°C greater than today, primarily because of greater polar warmth.

Finally, the evolution of C₄ grasses, which use a more effective type of photosynthesis, led eight million years ago to the spread of savannas in place of dry land forests, and into some semi-arid areas that could not be forested. The author does not mention this, but I wonder if the spread of savannas led to certain chimp-like apes finding it beneficial to stand upright, so they could see over the grasses. Chimps today live in the forest, where there aren't tall grasses to overtop; they would gain little advantage by standing up. Is Grass a parent of Humanity?

And a final question: Is the current series of Ice Ages fundamentally a result of the great draw-down of carbon dioxide that began eight million years ago, and if so, will it continue until the Sun heats up enough to overcome it? Our "global warming" fears ought to center not on the gases we emit, but on the Sun on which we depend.