kw: book reviews, nonfiction, biographies, scientists, botanists, adventurers, agriculture
Had your kale lately? How about some quinoa in your soup? Do you like navel oranges, mangoes, or avocados? Have you been to Washington, DC (or several other cities in the region) in the springtime to see the cherry trees in bloom? Thank David Fairchild. His life and adventures are shown in The Food Explorer: The True Adventures of the Globe-Trotting Botanist Who Transformed What America Eats by Daniel Stone.
As a young scientist in the 1890's, David Fairchild caught the interest of a wealthy, globe-trotting dilettante and raconteur, Barbour Lathrop. The rich man claimed to have circled the world many times (the number varied with the telling, usually around 20-40), but his life was otherwise aimless.
Fairchild had met Alfred Russell Wallace, who entranced him with tales of his travels in Malaysia and Indonesia, particularly Java, and the strange and wonderful plants and animals he'd encountered in the tropics. For a Kansas boy, it seemed a faraway planet. A few years later he spoke of it to Lathrop—when he could get a word in edgewise—and Lathrop remembered it; later on he visited Fairchild with an offer to sponsor a plant-collecting trip to Java. Fairchild was at the time in the employ of the infant Department of Agriculture; he eventually quit his job in favor of globetrotting plant collecting, but retained ties to the Department so as to have somewhere to send his discoveries.
Eventually, Lathrop and Fairchild traveled together for several years, giving more purpose to Lathrop's life, and affording Fairchild the opportunity to gather new species and new varieties of plants, in hopes that American farmers and orchardists could enrich the variety of foods on offer.
I didn't know that all the citrus fruits we enjoy, in such amazing variety, were all bred from just four progenitor species: citron, pomelo, mandarin, and papeda (a bitter fruit, but one parent of the Key lime). Nor that there are hundreds of varieties of avocado—yet only a few that can be shipped—or mango—ditto. I'd heard of Meyer lemons, and even had a dwarf Meyer lemon tree in a container for many years, but in this book I read about Frank Meyer, hired by Fairchild to scour China for plant varieties, including new citrus hybrids.
Every good story has a nemesis. The best man at Fairchild's wedding, his boyhood friend Charles Marlatt, serves the rôle here. He was an entomologist, fighting crop pests, particularly those that came from elsewhere. When Fairchild arranged to have Japanese Yoshido flowering cherry trees brought to Washington, D.C.in 1910, Marlatt found them infested with at least 8 pathogenic insects and a fungus or two. The entire shipload (2,000 young, mature trees!) was burned on orders of President Taft. The Japanese were very apologetic, and prepared a new shipment of trees, grown in "virgin soil" and carefully tended, that were brought in 1912, 3,000 this time, and planted around the Tidal Basin, along the Mall, and extras sent to nearby cities. The real "damage" incurred from Marlatt, in Fairchild's eyes, came with legislation such as various Quarantine Acts. They restricted plant exploration by requiring so much paperwork and inspection that most of the plant explorers that were following in Fairchild's footsteps went on to other pursuits.
However, there is a certain amount of right on both sides of the introduce-versus-ban dichotomy. After all, Fairchild introduced Kudzu, grew it in his own yard, then found he had to go to a lot of trouble to exterminate it! Too bad he didn't get it all. It is a scourge in the southern half of the U.S. But more good than bad has come of plant exploration and introduction. We need both Fairchild (and Meyer et al) and Marlatt.
Kudos to Daniel Stone for reminding us of David Fairchild and others, who may have been famous in their generation, but are nearly forgotten. Remember him the next time you enjoy a mango.
Wednesday, November 28, 2018
Sunday, November 25, 2018
Spiders hiding their tracks
kw: blogging, spider scanning
In the past 24 hours, 210 hits have been registered that I consider spider scans:
The 133 from "Unknown Region" match the 133 that originated in Linux systems. Linux offers more tools for hiding identity. The 77 from Russia apparently match the 77 that used IE on Windows, but I can't all that a definite match. The "real" traffic, hopefully of people with some scant interest in reading the blog, is around 25. I hope y'all aren't just bumping into me by accident and skipping out in a heartbeat!
Anyway, Cheers to all, and I hope the 5 Americans who passed this way had a Happy Thanksgiving.
In the past 24 hours, 210 hits have been registered that I consider spider scans:
Anyway, Cheers to all, and I hope the 5 Americans who passed this way had a Happy Thanksgiving.
Friday, November 23, 2018
Removing the straitjacket of non-causation in statistics
kw: book reviews, nonfiction, statistics, probability, causation, mathematics
In 1926, during the height of the eugenics movement in the U.S., a researcher who has been nearly forgotten studied the relationship between the intelligence of children and that of parents. This is the core debate, even today, regarding the "nature-nurture" dichotomy. Which is more important, upbringing or inheritance?
Step back a minute, and consider, with the current popularity of "big data", how this might be tackled. It is no longer difficult to gather enormous amounts of data regarding the IQ of numerous children, adults, and societal indicators such as neighborhood of residence. Do all the math you might wish, with regressions and correlation diagrams, and what might you find? No doubt some kind of correlation will show up, perhaps very obviously. But what does it mean? What has "caused" the greater intelligence of some children, and the lesser intelligence of others?
The word "cause" was forbidden in statistical monographs for decades. For many researchers even today, the mantra (I chose that word with malice aforethought) is, "Correlation does not imply causation." While this is indeed true, even a tautology, it is not all there is to it. We naturally think of nearly everything in cause-and-effect terms, and work done in the past couple of generations now makes it possible for researchers to discuss causes without losing tenure, grants, etc.
For the young researcher, Barbara Burks, the mantra was nonsense. She sought causes. To this end, she gave IQ tests to every member of 204 households that included foster children, and 105 households without foster children. For 1926, this was pretty big data. The choice of studying both foster children and natural children along with the adults was clever. Even more clever was the little diagram she used to analyze her results:
The arrows imply causation. Here, the "X" factor that might influence both the level of intelligence of the child, and the social status of the household, was thought to be the "heritage", including genetic inheritance, of the family. The parents, in whatever measure they benefit (or not) from "heritage", will have their own X factor, which could have been added as Y, off to the left perhaps.
Note that two of the arrows have heads at both ends. This indicates feedback effects between the social status and the intelligence of all members of the family (I imagine a family of "ordinary" intelligence having a very, very bright kid, and this leading to an improvement in social standing, for example).
Such a diagram embodies a "causal model", in the terminology of Judea Pearl, in The Book of Why: The New Science of Cause and Effect. Such a diagram, and mathematical processes invented by Pearl and his students, provide what is missing in non-causal statistics: the understanding that some things really do cause other things. By the way, Ms Burks's conclusion: genetics provides 35% of the observed differences in the intelligence of children. This was a disappointment to eugenicists, including Ms Burks. In particular, Louis Terman, an inventor of the Stanford-Binet IQ test, also famous for his "genius" studies, rejected it outright. He was quite certain that genetics were behind "nearly all" the differences in IQ. One might imagine him, upon seeing her results and conclusions, huffing, "Impossible!"
This reminds me of the first of Arthur Clarke's laws: "When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong." Dr. Pearl writes of his own Odyssey of discovery. He did not come to causal reasoning easily. But now he and his students have developed "causal calculus", which is introduced in The Book of Why, by Judea Pearl and Dana MacKenzie.
I must confess, though my long career as a scientific programmer led me into statistical work again and again, I never became comfortable with the formulas of probability. When I see the term P(Y|X), I have to think a moment to get my head around, "The Probability of Y occurring (or existing), given the occurrence (or existence) of X". In non-causal terms, you can freely substitute "daybreak" and "rooster crowing" for X and Y, either way: "The probability of daybreak, given that the rooster crowed" and "The probability of a rooster crowing, given that day is breaking." Hold that thought.
Dr. Pearl has added the "do" operator, which implies an intervention, so that P(Y|do(X)) means "The probability of Y occurring, given that the intervention X was made, compared to X not being done". This is the reasoning behind the randomized controlled trial (RCT) in medicine, but it was not stated in a formula before. Indeed, in older medical journals the authors use all kinds of locutions and verbal gymnastics to avoid saying, "Medicine X caused a Z% reduction in death rate due to disease Y". Many still do so.
Thus far, I can follow along. Dr. Pearl freely ignores the folklore that each mathematical expression used in a book reduces its audience by half. Now, I like math, but it would take a great deal of study for me to become conversant with causal calculus. In an example called "DO-CALCULUS AT WORK" on page 236, we find expressions such as
Dr. Pearl's work has great benefits for those researchers who can wrap their minds around these concepts and formalisms. For example, the decades-long struggle to determine to what extent smoking causes lung cancer, the subject of a major chapter, was undertaken in the face of determined and well-funded opposition to the concept, but might have been shortened to a year or a few years if causal language had been allowed. This stricture was as if the scientists studying smoking and cancer, those who were not in the pay of the tobacco companies, tied both hands behind their backs and had to perform their work with their toes and tongues. Now causal language is out of the closet.
An early chapter discusses the Ladder of Causation, from Association (what we observe), to Intervention (what we do to see what happens), to Counterfactuals (what we imagine might happen if X were not so). It appears that only humans can perform counterfactual reasoning, such as, "Will the day break if we get rid of all the roosters?" or, as a song says, "What if we gave a War and nobody came?"
We can't always figure out what is a cause and what is an effect. But where we can, the language of causation helps us model an event, such as by the use of a diagram such as the one above. Also, Do-Calculus now provides a mathematical way to treat cause and effect in a meaningful and quantitative way. It adds power to Design of Experiments logic, so that a researcher is more likely to correctly determine the appropriate set of causative factors and winkle out just how important each is, in producing the effect being studied.
As difficult as the reading was, due only to my unfamiliarity with the jargon and formulas, reading the book was very enjoyable. The winding path Dr. Pearl took to get past the hamstrung statistical reasoning of half a century ago, on through Bayesian analysis, and on to develop causal reasoning in a formal way, with the appropriate formalisms of the mathematical language of Do-Calculus, make for a quest saga every bit as gripping as the search for a hidden city.
In 1926, during the height of the eugenics movement in the U.S., a researcher who has been nearly forgotten studied the relationship between the intelligence of children and that of parents. This is the core debate, even today, regarding the "nature-nurture" dichotomy. Which is more important, upbringing or inheritance?
Step back a minute, and consider, with the current popularity of "big data", how this might be tackled. It is no longer difficult to gather enormous amounts of data regarding the IQ of numerous children, adults, and societal indicators such as neighborhood of residence. Do all the math you might wish, with regressions and correlation diagrams, and what might you find? No doubt some kind of correlation will show up, perhaps very obviously. But what does it mean? What has "caused" the greater intelligence of some children, and the lesser intelligence of others?
The word "cause" was forbidden in statistical monographs for decades. For many researchers even today, the mantra (I chose that word with malice aforethought) is, "Correlation does not imply causation." While this is indeed true, even a tautology, it is not all there is to it. We naturally think of nearly everything in cause-and-effect terms, and work done in the past couple of generations now makes it possible for researchers to discuss causes without losing tenure, grants, etc.
For the young researcher, Barbara Burks, the mantra was nonsense. She sought causes. To this end, she gave IQ tests to every member of 204 households that included foster children, and 105 households without foster children. For 1926, this was pretty big data. The choice of studying both foster children and natural children along with the adults was clever. Even more clever was the little diagram she used to analyze her results:
Note that two of the arrows have heads at both ends. This indicates feedback effects between the social status and the intelligence of all members of the family (I imagine a family of "ordinary" intelligence having a very, very bright kid, and this leading to an improvement in social standing, for example).
Such a diagram embodies a "causal model", in the terminology of Judea Pearl, in The Book of Why: The New Science of Cause and Effect. Such a diagram, and mathematical processes invented by Pearl and his students, provide what is missing in non-causal statistics: the understanding that some things really do cause other things. By the way, Ms Burks's conclusion: genetics provides 35% of the observed differences in the intelligence of children. This was a disappointment to eugenicists, including Ms Burks. In particular, Louis Terman, an inventor of the Stanford-Binet IQ test, also famous for his "genius" studies, rejected it outright. He was quite certain that genetics were behind "nearly all" the differences in IQ. One might imagine him, upon seeing her results and conclusions, huffing, "Impossible!"
This reminds me of the first of Arthur Clarke's laws: "When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong." Dr. Pearl writes of his own Odyssey of discovery. He did not come to causal reasoning easily. But now he and his students have developed "causal calculus", which is introduced in The Book of Why, by Judea Pearl and Dana MacKenzie.
I must confess, though my long career as a scientific programmer led me into statistical work again and again, I never became comfortable with the formulas of probability. When I see the term P(Y|X), I have to think a moment to get my head around, "The Probability of Y occurring (or existing), given the occurrence (or existence) of X". In non-causal terms, you can freely substitute "daybreak" and "rooster crowing" for X and Y, either way: "The probability of daybreak, given that the rooster crowed" and "The probability of a rooster crowing, given that day is breaking." Hold that thought.
Dr. Pearl has added the "do" operator, which implies an intervention, so that P(Y|do(X)) means "The probability of Y occurring, given that the intervention X was made, compared to X not being done". This is the reasoning behind the randomized controlled trial (RCT) in medicine, but it was not stated in a formula before. Indeed, in older medical journals the authors use all kinds of locutions and verbal gymnastics to avoid saying, "Medicine X caused a Z% reduction in death rate due to disease Y". Many still do so.
Thus far, I can follow along. Dr. Pearl freely ignores the folklore that each mathematical expression used in a book reduces its audience by half. Now, I like math, but it would take a great deal of study for me to become conversant with causal calculus. In an example called "DO-CALCULUS AT WORK" on page 236, we find expressions such as
Σt P(c|do(s),do(t))P(t|do(s))This is the second of seven formulas in a derivation. At that point I realized I probably ought to devote my few remaining years to something besides learning how to not only parse such statements, but to create and perform them!
Dr. Pearl's work has great benefits for those researchers who can wrap their minds around these concepts and formalisms. For example, the decades-long struggle to determine to what extent smoking causes lung cancer, the subject of a major chapter, was undertaken in the face of determined and well-funded opposition to the concept, but might have been shortened to a year or a few years if causal language had been allowed. This stricture was as if the scientists studying smoking and cancer, those who were not in the pay of the tobacco companies, tied both hands behind their backs and had to perform their work with their toes and tongues. Now causal language is out of the closet.
An early chapter discusses the Ladder of Causation, from Association (what we observe), to Intervention (what we do to see what happens), to Counterfactuals (what we imagine might happen if X were not so). It appears that only humans can perform counterfactual reasoning, such as, "Will the day break if we get rid of all the roosters?" or, as a song says, "What if we gave a War and nobody came?"
We can't always figure out what is a cause and what is an effect. But where we can, the language of causation helps us model an event, such as by the use of a diagram such as the one above. Also, Do-Calculus now provides a mathematical way to treat cause and effect in a meaningful and quantitative way. It adds power to Design of Experiments logic, so that a researcher is more likely to correctly determine the appropriate set of causative factors and winkle out just how important each is, in producing the effect being studied.
As difficult as the reading was, due only to my unfamiliarity with the jargon and formulas, reading the book was very enjoyable. The winding path Dr. Pearl took to get past the hamstrung statistical reasoning of half a century ago, on through Bayesian analysis, and on to develop causal reasoning in a formal way, with the appropriate formalisms of the mathematical language of Do-Calculus, make for a quest saga every bit as gripping as the search for a hidden city.
Monday, November 12, 2018
The warmest and fuzziest -- with big claws!
kw: book reviews, nonfiction, animals, animal behavior, pets, wildlife
It takes extraordinary experiences to set the stage for a wild animal to become bonded to a person. In the case of a bobcat, soon to be named Trooper, these experiences included being the only survivor of his family's massacre by coyotes and getting stuck in a patch of cholla; for Johnson, they included a life that led to particular love for wild places and wildlife, and a temperament that just matched the bob-kitten's need. Basically, Johnson found the dying kitten, extracted him from the cholla (a most dangerous cactus), and took him to a veterinarian who was able to meet his medical needs and, even more, knew just how to prepare the kitten and Johnson for a life together in and around the home Johnson and his wife had created. Thus begins Trooper: The Bobcat Who Came in from the Wild by Forrest Bryant Johnson.
Years later, when a self-styled animal activist accused Johnson of "imprisoning" the cat, he was able to show her that Trooper came and went as he pleased and was never caged except when he needed to be taken to see the vet. Trooper loved the vet, just not the car ride. He also preferred to sleep snuggled against Johnson's arm.
At the risk of spoiling, although Trooper was a gentle companion and friendly to people, he kept enough of his wild nature to kill a coyote that began to stalk him and other animals around the Johnson mini-ranch. It was a collaboration: Johnson and neighbors first killed all the coyotes but one of a small pack that "moved into the neighborhood" and began preying on pets and even stalking children. Trooper finished off the last one.
In the years between, Trooper and Johnson learned from each other. Johnson ruminates, somewhat ruefully, that he knew Trooper thought of him as a rather inept cat. Not for Trooper the notion of being a "person". The book is full of stories of cat and man, and the man's wife, grown daughter and other family members. Of the time his wife good-naturedly tried to hire a "home-call" grooming service to "bathe" Trooper, and the way Trooper so thoroughly intimidated the groomer, without harming him in the slightest, that the groomer simply turned and left. Of the time a great horned owl knocked itself silly against a window, and Trooper brought it inside, not to eat, but perhaps hoping for a new kind of playmate; it was a job and a half getting the irate owl back out the door! Of the time the alarm service kept phoning Johnson that there was an intruder tripping the light beam in the house's hallway, but nobody was ever found. What was found? Trooper and another (ordinary) cat that had come to live there, jumping off furniture and interrupting the beam; the alarm company removed that particular sensor.
There are still many people who say animals are totally instinctual and cannot think, or plan, or feel pain. Such people have never owned a pet, never watched it plan, perhaps for days, how to attack a particular kind of prey or enemy. They've never thought through the fact that animals seem to easily learn a number of our spoken words, but we learn hardly any of theirs, or none at all. Even the most inbred, bred-for-looks-not-for-smarts Pomeranian pup or Persian cat shows these attributes. Johnson found that a bobcat, that must live by its wits, had quite a lot going on in that big, fuzzy head of his.
This book gets my Heart-Warming, Heartstring-Tugging, Drippy-Nose Award for the year!
It takes extraordinary experiences to set the stage for a wild animal to become bonded to a person. In the case of a bobcat, soon to be named Trooper, these experiences included being the only survivor of his family's massacre by coyotes and getting stuck in a patch of cholla; for Johnson, they included a life that led to particular love for wild places and wildlife, and a temperament that just matched the bob-kitten's need. Basically, Johnson found the dying kitten, extracted him from the cholla (a most dangerous cactus), and took him to a veterinarian who was able to meet his medical needs and, even more, knew just how to prepare the kitten and Johnson for a life together in and around the home Johnson and his wife had created. Thus begins Trooper: The Bobcat Who Came in from the Wild by Forrest Bryant Johnson.
Years later, when a self-styled animal activist accused Johnson of "imprisoning" the cat, he was able to show her that Trooper came and went as he pleased and was never caged except when he needed to be taken to see the vet. Trooper loved the vet, just not the car ride. He also preferred to sleep snuggled against Johnson's arm.
At the risk of spoiling, although Trooper was a gentle companion and friendly to people, he kept enough of his wild nature to kill a coyote that began to stalk him and other animals around the Johnson mini-ranch. It was a collaboration: Johnson and neighbors first killed all the coyotes but one of a small pack that "moved into the neighborhood" and began preying on pets and even stalking children. Trooper finished off the last one.
In the years between, Trooper and Johnson learned from each other. Johnson ruminates, somewhat ruefully, that he knew Trooper thought of him as a rather inept cat. Not for Trooper the notion of being a "person". The book is full of stories of cat and man, and the man's wife, grown daughter and other family members. Of the time his wife good-naturedly tried to hire a "home-call" grooming service to "bathe" Trooper, and the way Trooper so thoroughly intimidated the groomer, without harming him in the slightest, that the groomer simply turned and left. Of the time a great horned owl knocked itself silly against a window, and Trooper brought it inside, not to eat, but perhaps hoping for a new kind of playmate; it was a job and a half getting the irate owl back out the door! Of the time the alarm service kept phoning Johnson that there was an intruder tripping the light beam in the house's hallway, but nobody was ever found. What was found? Trooper and another (ordinary) cat that had come to live there, jumping off furniture and interrupting the beam; the alarm company removed that particular sensor.
There are still many people who say animals are totally instinctual and cannot think, or plan, or feel pain. Such people have never owned a pet, never watched it plan, perhaps for days, how to attack a particular kind of prey or enemy. They've never thought through the fact that animals seem to easily learn a number of our spoken words, but we learn hardly any of theirs, or none at all. Even the most inbred, bred-for-looks-not-for-smarts Pomeranian pup or Persian cat shows these attributes. Johnson found that a bobcat, that must live by its wits, had quite a lot going on in that big, fuzzy head of his.
This book gets my Heart-Warming, Heartstring-Tugging, Drippy-Nose Award for the year!
Saturday, November 10, 2018
Our data are doomed
kw: book reviews, nonfiction, internet, internet security
I have read the Schneier on Security blog on and off almost since I began this blog. As far as gurus of internet security go, he is IT. So when I ran across Schneier's latest book, I nabbed it, in part to see whether it would be a collection of blog posts (it isn't). His writing is great, his ideas are spot-on, and the subject is rather depressing.
Click Here to Kill Everybody: Security and Survival in a Hyper-connected World, by Bruce Schneier, is scary as hell, and the author isn't selling anything…not to us at least. He is indeed trying to "sell" policy ideas to the U.S. government, and in part this book is aimed at getting us to put pressure on our representatives to pay more attention to this issue.
The Internet is rapidly becoming the Internet of Things (IoT), in which to say, everything in the home that would have been bought after a certain date is not just a toaster, light bulb, or easy chair, but a computer that cooks toast and Pop-Tarts (and remembers), a computer that talks to the light switch and learns your schedule and can set mood lighting at your request, or a computer that offers you a comfy seat and records your weight and heartbeat and maybe massages you (it may also inform your doctor of your day-to-day state of health). Almost any new car is not just a computer, but a collection of computers that control a transportation machine, more or less at your demand, keep track of its own maintenance schedule, record where you go and your driving habits; in the future it will know your mood, not only from your driving habits but from your temperature, smell, and perhaps level of noise you make (do you yell at other drivers when they annoy you...or at the radio?).
What the car, light bulb, and chair may know about us is one thing. Because they all connect via the Internet, or the coming, enhanced Internet that he calls Internet+, anybody with a modicum of hacking skills can know what they know. Your phone already knows your buying habits and perhaps banking habits. Who else would you be just tickled about if they knew also? Nobody? I thought so. Well, what will you do about it? What CAN you do about it?
If you believe the book's current explanation of the state of Internet security, the answer is, "Nearly nothing." Firstly, most people will be unwilling to go to the least trouble to "do something about it." Secondly, for those few who would be willing, there is precious little they can do. And that, my friends, is the message of Click Here.
The title is intended as click bait, but its message is not entirely hype. The book begins with three scenarios, and returns to them from time to time.
Now consider item #3. Suppose someone hacks into a 3D printer, and has it print a booby trap to injure or kill the owner, when next he/she turns on the light in the room where it is kept? Suppose a 3D bio-printer is hacked to produce a super-flu like the 1918 bug that killed about 4% of the human population that year? How about every insecure 3D bio-printer? This extended scenario is behind the title of the book.
The author thinks only government can deal with this effectively. No other entity has the scope to do so. But at the moment, every powerful player in the Cyber arena has a vested interest in an Internet that is not too secure:
Not only that, the Internet is the most prolific espionage tool to be developed since the microdot camera. When new vulnerabilities in common software are discovered, say by someone at NSA, they don't inform the software company. No, they add the knowledge to their "virtual arms locker", as a took to be used offensively, until someone more civic-minded or someone at the company stumbles across it and it gets fixed.
So, nobody with any power has much interest in better security. Tools to help make security better have languished on the shelf for decades, unused. Schneier explains why.
If you want your own end-to-end encryption, perhaps you can get Tor, but be aware that all the world's governments keep tabs on Tor users because so many of them are criminals. That in itself argues that we all ought to have such tools available by default. In the U.S., the Second Amendment assures that, if we want to own a gun for our protection, we can do so. That way, it is not presently so that "only criminals and cops have guns." But on the Internet, and even more, the nascent Internet+, you can't find a gun anyway, so only the criminals have guns, and most of the cops have at best rather inferior ones.
Will this get better? The author thinks so. He is optimistic enough to think it can get better in just a decade or two. Maybe. It probably won't get better, at least from a governmental intervention standpoint, until a Scenario #3 leads to a few dozen, or thousand, or even million, deaths. That's what it takes to get major policies created or changed. Good luck, y'all…keep your head low.
I have read the Schneier on Security blog on and off almost since I began this blog. As far as gurus of internet security go, he is IT. So when I ran across Schneier's latest book, I nabbed it, in part to see whether it would be a collection of blog posts (it isn't). His writing is great, his ideas are spot-on, and the subject is rather depressing.
Click Here to Kill Everybody: Security and Survival in a Hyper-connected World, by Bruce Schneier, is scary as hell, and the author isn't selling anything…not to us at least. He is indeed trying to "sell" policy ideas to the U.S. government, and in part this book is aimed at getting us to put pressure on our representatives to pay more attention to this issue.
The Internet is rapidly becoming the Internet of Things (IoT), in which to say, everything in the home that would have been bought after a certain date is not just a toaster, light bulb, or easy chair, but a computer that cooks toast and Pop-Tarts (and remembers), a computer that talks to the light switch and learns your schedule and can set mood lighting at your request, or a computer that offers you a comfy seat and records your weight and heartbeat and maybe massages you (it may also inform your doctor of your day-to-day state of health). Almost any new car is not just a computer, but a collection of computers that control a transportation machine, more or less at your demand, keep track of its own maintenance schedule, record where you go and your driving habits; in the future it will know your mood, not only from your driving habits but from your temperature, smell, and perhaps level of noise you make (do you yell at other drivers when they annoy you...or at the radio?).
What the car, light bulb, and chair may know about us is one thing. Because they all connect via the Internet, or the coming, enhanced Internet that he calls Internet+, anybody with a modicum of hacking skills can know what they know. Your phone already knows your buying habits and perhaps banking habits. Who else would you be just tickled about if they knew also? Nobody? I thought so. Well, what will you do about it? What CAN you do about it?
If you believe the book's current explanation of the state of Internet security, the answer is, "Nearly nothing." Firstly, most people will be unwilling to go to the least trouble to "do something about it." Secondly, for those few who would be willing, there is precious little they can do. And that, my friends, is the message of Click Here.
The title is intended as click bait, but its message is not entirely hype. The book begins with three scenarios, and returns to them from time to time.
- Control of an auto from ten miles away, via an Internet-connected laptop. This was first done in 2015.
- Shutdown of a power plant in Kiev, presumably by Russian hackers, in 2016.
- A hacker took control of 150,000 printers on insecure networks in 2017, and had them print taunting messages. This is a 'near-white-hat' attack. I wonder how many of the printers' owners took steps to secure their equipment?
Now consider item #3. Suppose someone hacks into a 3D printer, and has it print a booby trap to injure or kill the owner, when next he/she turns on the light in the room where it is kept? Suppose a 3D bio-printer is hacked to produce a super-flu like the 1918 bug that killed about 4% of the human population that year? How about every insecure 3D bio-printer? This extended scenario is behind the title of the book.
The author thinks only government can deal with this effectively. No other entity has the scope to do so. But at the moment, every powerful player in the Cyber arena has a vested interest in an Internet that is not too secure:
- The NSA and other agencies want access to anything, anywhere, with little fuss.
- Businesses would rather spend to make new products than to add security to existing ones. Neither do they have incentive to design security into their new products.
- To the biggest presences on the Internet, from Google, Yahoo, Facebook, Instagram, Alibaba, Dianping..., all have as their primary product YOU, the user, and the information you post or reveal by your posting habits. They want to sell this stuff, not secure it.
Not only that, the Internet is the most prolific espionage tool to be developed since the microdot camera. When new vulnerabilities in common software are discovered, say by someone at NSA, they don't inform the software company. No, they add the knowledge to their "virtual arms locker", as a took to be used offensively, until someone more civic-minded or someone at the company stumbles across it and it gets fixed.
So, nobody with any power has much interest in better security. Tools to help make security better have languished on the shelf for decades, unused. Schneier explains why.
If you want your own end-to-end encryption, perhaps you can get Tor, but be aware that all the world's governments keep tabs on Tor users because so many of them are criminals. That in itself argues that we all ought to have such tools available by default. In the U.S., the Second Amendment assures that, if we want to own a gun for our protection, we can do so. That way, it is not presently so that "only criminals and cops have guns." But on the Internet, and even more, the nascent Internet+, you can't find a gun anyway, so only the criminals have guns, and most of the cops have at best rather inferior ones.
Will this get better? The author thinks so. He is optimistic enough to think it can get better in just a decade or two. Maybe. It probably won't get better, at least from a governmental intervention standpoint, until a Scenario #3 leads to a few dozen, or thousand, or even million, deaths. That's what it takes to get major policies created or changed. Good luck, y'all…keep your head low.
Sunday, November 04, 2018
Spiders around the world
kw: blogs, blogging, spider scanning
Oh, this is cute:
The one-hour spike on 11/1/18 is 99 hits; the one a half day later is 37 hits. The former, just before midnight my time, is probably from Turkey, and the other from Ukraine.
The low hump on 11/3/18 mostly represents interest in a post on making pumpkins pies. It got a lot of hits over several hours' time. It is a pity I don't get stats on locations hitting particular posts. I'd be interested to see if the pie-making post was checked out by anyone overseas. I took pains to include Celsius temperatures, but I didn't convert cups to ml. Oh, well. My cup measures have both fl.oz. and ml scales, and I suspect people everywhere will know how to convert. But I don't think pumpkin pie is of much interest outside the U.S. But whatever pie someone might want to make, the pie crust recipe and instructions produce a crust that is without peer.
Oh, this is cute:
The one-hour spike on 11/1/18 is 99 hits; the one a half day later is 37 hits. The former, just before midnight my time, is probably from Turkey, and the other from Ukraine.
The low hump on 11/3/18 mostly represents interest in a post on making pumpkins pies. It got a lot of hits over several hours' time. It is a pity I don't get stats on locations hitting particular posts. I'd be interested to see if the pie-making post was checked out by anyone overseas. I took pains to include Celsius temperatures, but I didn't convert cups to ml. Oh, well. My cup measures have both fl.oz. and ml scales, and I suspect people everywhere will know how to convert. But I don't think pumpkin pie is of much interest outside the U.S. But whatever pie someone might want to make, the pie crust recipe and instructions produce a crust that is without peer.
Saturday, November 03, 2018
Pumpkin Pie Season at my place
kw: photo essays, pies, pie crust, how to
Grab a cuppa, this is long…
Above are the ingredients and equipment needed to make two pumpkin pies, using the crust recipe from the 1962 edition of Betty Crocker's New Good and Easy Cookbook, published by Golden Press. It is the one my Mom used to teach me to cook and bake; also the recipe from the side of a can of "Libby's 100% Pure Pumpkin". I have ground up my own pumpkin in the past, but it is a lot of trouble, when a good commercial product is so affordable.
The crust recipe for "1-2-3 Pastries" has these ingredients, per single-crust pie:
I put the flour in a glass bowl and shape a hollow in it using a fork:
Pour the oil in the hollow and fold in:
When fully mixed it will be a little crumbly:
Sprinkle the water over the mix and fold in thoroughly. Press the dough together and let it sit to homogenize while preparing to roll the crusts.
The crusts are rolled between sheets of waxed paper. To make the lower sheet of waxed paper stick to the table, get it very clean and then moisten it well:
Put a piece of waxed paper on the wet table, shiny side up (it'll curl upward). Take half of the dough and shape it into a ball in your hands, and then press it onto the waxed paper.
Put a second piece of waxed paper on top, shiny side down, and press with your hand (at this point I wipe my hands with a paper towel). Then roll it. I roll it in all directions to get it as round as possible.
Here it is, ready to be put in the pan:
Slowly peel off the top sheet of waxed paper. Dry all around with a paper towel, then lift the front edge partway and dry underneath.
Slip the pie pan in there and gently lift the pie crust. Then invert it onto the pan:
This process is just a fiddly bit of gradually pulling the edges up and getting nearly all the air out fron under the crust. I got the wrong camera angle; near my left hand is a bit of crust pulled up to let air out as I maneuver the rest into place:
Gather the overlapping stuff around the edge into a rim that you press into a raised rim. The pie recipe will not fit inside without this step:
While rolling the second crust I got a photo of a useful step: rolling around the edge with the end of the roller on the table, to give it a slight taper. You can leave this step out, for a little more thickness at the rim.
Here are the two crusts ready for filling:
Here is the filling recipe:
These cans for two pies used to have 30 ounces of pumpkin. That made pies that were just a bit deeper, but somewhat harder to carry over to the oven. The finished filling is very goopy and slops out of the crust if you wiggle even a little. So you'll have the ingredients in text form, in the order I use:
This shows the 4 eggs ready to beat (not whip! this isn't an omelette), and the spices sitting on the sugar ready to stir in. I stir them in and then add after I add the pumpkin and mix it with the eggs. Before any of that I heat the oven to 425°F (~220°C).
Here I am stirring the eggs.
In goes the pumpkin:
After stirring in the sugar-spice mix, I add the evaporated milk, half a can at a time:
I use a big plastic ladle to spoon alternately into the two pie shells. At the end, I eyeball what is half and drag that into one shell, then use a rubber spatula to get the rest into the other.
Two pie shells, loaded and ready to cook. I first move them to the countertop next to the oven.
Then I put them in the oven. I hold them so that when I put the pie on the oven grate I don't get a burn.
The recipe says to lower the temperature after 15 minutes, but with two pies I use 20 minutes. I kept the oven open longer, so it takes longer to re-heat. So I lower it to 350°F (175°C) and cook for 45 minutes. Then I check it, which is what I am doing here, by poking the tip of a knife into the center. If nothing sticks to the knife, they are done. If only a tiny bit sticks, I give then another 5 minutes, otherwise I give them another 10 minutes and re-check.
Here they are, all done, pulled out of the oven, sitting on racks. You can see that they began to crack around the edge, which is a good sign that the filling is cooked and properly stiff.
I support cookie sheets with whatever is handy (pill bottles, cup cozies…) to keep dust off while they cool for an hour or so, no more than two hours. They'll still be warm if you serve them right away. Otherwise, refrigerate them.
I cover them to put in the refrigerator. The first layer is waxed paper. I cut a piece a little longer than the width of the pie, and fold it in half, then half again, then fold a triangle as shown here. One more fold is coming.
Here is the piece, folded four times so the arc is 1/16th. I am holding it where I plan to cut. I cut a slight arc that crosses both edges of the triangle at a right angle.
Unfolded, that yields a circle. Put this on top of the pie so it won't stick to plastic wrap.
Both pies are covered (one cover is not pressed on yet), ready to wrap in plastic wrap and refrigerate.
The Libby's recipe makes a great-tasting pie, better than if you use "pumpkin pie spice", and this kind of crust is the flakiest I've ever encountered. It is also much lighter than a crust made with lard or another solid fat. Enjoy!
Grab a cuppa, this is long…
Above are the ingredients and equipment needed to make two pumpkin pies, using the crust recipe from the 1962 edition of Betty Crocker's New Good and Easy Cookbook, published by Golden Press. It is the one my Mom used to teach me to cook and bake; also the recipe from the side of a can of "Libby's 100% Pure Pumpkin". I have ground up my own pumpkin in the past, but it is a lot of trouble, when a good commercial product is so affordable.
The crust recipe for "1-2-3 Pastries" has these ingredients, per single-crust pie:
- 1 cup + 2 tbsp. unbleached flour (2 tbsp. = 1 fl. oz.)
- ⅓ cup vegetable oil (I use canola oil)
- 2 tbsp cold water
I put the flour in a glass bowl and shape a hollow in it using a fork:
Pour the oil in the hollow and fold in:
When fully mixed it will be a little crumbly:
Sprinkle the water over the mix and fold in thoroughly. Press the dough together and let it sit to homogenize while preparing to roll the crusts.
The crusts are rolled between sheets of waxed paper. To make the lower sheet of waxed paper stick to the table, get it very clean and then moisten it well:
Put a piece of waxed paper on the wet table, shiny side up (it'll curl upward). Take half of the dough and shape it into a ball in your hands, and then press it onto the waxed paper.
Put a second piece of waxed paper on top, shiny side down, and press with your hand (at this point I wipe my hands with a paper towel). Then roll it. I roll it in all directions to get it as round as possible.
Here it is, ready to be put in the pan:
Slowly peel off the top sheet of waxed paper. Dry all around with a paper towel, then lift the front edge partway and dry underneath.
Slip the pie pan in there and gently lift the pie crust. Then invert it onto the pan:
This process is just a fiddly bit of gradually pulling the edges up and getting nearly all the air out fron under the crust. I got the wrong camera angle; near my left hand is a bit of crust pulled up to let air out as I maneuver the rest into place:
Gather the overlapping stuff around the edge into a rim that you press into a raised rim. The pie recipe will not fit inside without this step:
While rolling the second crust I got a photo of a useful step: rolling around the edge with the end of the roller on the table, to give it a slight taper. You can leave this step out, for a little more thickness at the rim.
Here are the two crusts ready for filling:
Here is the filling recipe:
- 4 large eggs, beaten in a big bowl
- 1 can (29 oz.) pumpkin
- 1½ cups sugar with spices mixed in:
- 2 tsp ground cinnamon
- 1 tsp ground ginger
- ½ tsp ground cloves
- 2 cans Evaporated Milk
This shows the 4 eggs ready to beat (not whip! this isn't an omelette), and the spices sitting on the sugar ready to stir in. I stir them in and then add after I add the pumpkin and mix it with the eggs. Before any of that I heat the oven to 425°F (~220°C).
Here I am stirring the eggs.
In goes the pumpkin:
After stirring in the sugar-spice mix, I add the evaporated milk, half a can at a time:
I use a big plastic ladle to spoon alternately into the two pie shells. At the end, I eyeball what is half and drag that into one shell, then use a rubber spatula to get the rest into the other.
Two pie shells, loaded and ready to cook. I first move them to the countertop next to the oven.
Then I put them in the oven. I hold them so that when I put the pie on the oven grate I don't get a burn.
The recipe says to lower the temperature after 15 minutes, but with two pies I use 20 minutes. I kept the oven open longer, so it takes longer to re-heat. So I lower it to 350°F (175°C) and cook for 45 minutes. Then I check it, which is what I am doing here, by poking the tip of a knife into the center. If nothing sticks to the knife, they are done. If only a tiny bit sticks, I give then another 5 minutes, otherwise I give them another 10 minutes and re-check.
Here they are, all done, pulled out of the oven, sitting on racks. You can see that they began to crack around the edge, which is a good sign that the filling is cooked and properly stiff.
I support cookie sheets with whatever is handy (pill bottles, cup cozies…) to keep dust off while they cool for an hour or so, no more than two hours. They'll still be warm if you serve them right away. Otherwise, refrigerate them.
I cover them to put in the refrigerator. The first layer is waxed paper. I cut a piece a little longer than the width of the pie, and fold it in half, then half again, then fold a triangle as shown here. One more fold is coming.
Here is the piece, folded four times so the arc is 1/16th. I am holding it where I plan to cut. I cut a slight arc that crosses both edges of the triangle at a right angle.
Unfolded, that yields a circle. Put this on top of the pie so it won't stick to plastic wrap.
Both pies are covered (one cover is not pressed on yet), ready to wrap in plastic wrap and refrigerate.
The Libby's recipe makes a great-tasting pie, better than if you use "pumpkin pie spice", and this kind of crust is the flakiest I've ever encountered. It is also much lighter than a crust made with lard or another solid fat. Enjoy!
Learning of life as never before
kw: book reviews, nonfiction, natural history, geological history, life, evolution
Hmm, let's see, will this do?
Probably not. The little blob represents an amoeba. When did amoebas first appear on Earth? Probably around 800 million years ago. Amoebas are quite advanced. Life began with pre-bacteria (or pre-archaea) cells some time between 3,500 and 4,200 million years ago, so eons of evolutionary progress occurred before protozoans such as amoebas came into being. On the scale of this diagram, there would be another 35-40 things strung out to the left, for about two feet, all looking a lot like the period at the end of this sentence, or maybe a tiny oval of similar size.
So, just how has life progressed since it first appeared on earth? To find out, read a wonderful new book by Dr. Peter Ward and Joe Kirschvink, A New History of Life: The Radical New Discoveries About the Origins and Evolution of Life on Earth. Geology has not stood still since I studied it in the 1970's and early 1980's. Neither has biology, nor genetics. In fact, our understanding of DNA and genetics has advanced more in the past decade than in all of prior history…and we realize that we still know something like 1% (or a lot less) of what we thought we would know by now.
Geological history and biological history go together. Only the first era of Earth, called the Hadean, during which there were no solid rocks, was without life. A period called Late Heavy Bombardment (LHB) ended the Hadean Eon and partially overlapped the first appearance of living cells. Life may have arisen a few times, only to be melted out of existence when a rocky body about the size of Texas would cause most of the crust to melt, again. So what we call "the origin of Earthly life" actually began just after the last successful total extinction event. The remaining history of Earth and of Earthly biology is divided into eras marked by partial extinction events. Five (plus one, shown below, in my accounting) are major, in that more than 50% of all living species were eliminated. Others caused many more extinctions in a short time than the background rate, but less than 50% at a blow.
To be clear: "Event" is a comparative term. When referring to geological time, anything that happens in less than a million years, if it is more than 50-100 million years in the past, can be called an event. So let us set a time scale, primarily of these extinction "events", based on what is currently known:
Now it is time for terminology about the kinds of living cells.
The authors draw on new discoveries in every area of geological and biological sciences imaginable. The various eons, eras, periods and so forth, delineated in the outline above, had an array of living creatures, both plant, animal, fungal, and prokaryotic, that differed significantly from those in any other. For example, before about 120 ma, were you to visit in your pocket time machine, you could not go about smelling the flowers because the few that had existed for the prior 30-40 million years didn't have nectar or perfume yet. There weren't any bees to attract. Jump back to the middle Cambrian, say, 520 ma, and there was nothing living on land except some bacterial crusts here and there. The main sea-bottom creatures were scuttling shrimp-like and isopod-like things including trilobites, also mollusks and clam-like brachiopods. Tentacled things such as ammonites weren't yet present, but there were numerous creatures we would probably not recognize, scuttling and swimming about.
The kinds of living things that existed, and the transitions from one kind of biosphere to another afforded by the various cataclysms, form the main subject of the book. I am overwhelmed by the sheer mass of information the authors packed into some 360 pages. Even many of the end notes, those that weren't just strings of references, made fascinating reading.
To pick one significant learning from the book as a whole: several of the extinction events are classified as "greenhouse events". Certain periods were characterized by temperatures beyond tropical. Given that the Sun was several percent less bright half a billion years ago, and 40% dimmer around 3,000 ma, carbon dioxide alone could not produce global temperatures that would have exceeded 35°C (95°F) nearly everywhere, day and night. Methane eruptions, possibly from warming of methane clathrates in the shallower seabeds, were involved.
Certain geologic cycles, such as the formation or breakup of a supercontinent such as Pangaea or Rhodinia, cause large excursions in the level of carbon dioxide in the atmosphere. While that level was around 280 ppm a century or so ago, and is 400 ppm today, it was 1000 ppm or higher, sometimes much higher, during much of prehistory. A period of warming when carbon dioxide rises can trigger methane release. Methane doesn't last more than a few years in the atmosphere, because it can be oxidized. But sometimes, oxygen has been low at the same time as high carbon dioxide and methane, and then the methane lasts much longer and accumulates. The Triassic contained one such ultra-hot period.
And a fun fact: The present oxygen content of the atmosphere is 21%. At certain earlier times it was as high as 35%, which had several effects: the amount of nitrogen was the same as ever, so air pressure was ~15% higher; the extra oxygen provided extra energy to animals, and could in particular penetrate more deeply into the semi-passive respiratory systems of insects; and these two things led to some insects getting very large, such as a dragonfly with a meter-wide wingspan. The atmosphere was smokier, though, because of great forest fires. But the oxygen level was kept high by the rapid burial of organic debris that didn't get much chance to rot during that period. So...a dragonfly as big as a crow. Wow!
You don't have to specialize in geology or biology to enjoy this book. It is intended for us all, and the authors are very good at explaining what their jargon means.
(I won't go into detail about a few copy-editing errors I ran across. That's for a private letter. But I must comment that good proofreading and copy-editing are becoming less common. Authors out there, and editors, you can't just rely on a spell-checker. How else to account for the word "Cambria" where "cambium" was meant? The former is the historic name of Wales, and the latter is the living tissue in a tree.)
Hmm, let's see, will this do?
Probably not. The little blob represents an amoeba. When did amoebas first appear on Earth? Probably around 800 million years ago. Amoebas are quite advanced. Life began with pre-bacteria (or pre-archaea) cells some time between 3,500 and 4,200 million years ago, so eons of evolutionary progress occurred before protozoans such as amoebas came into being. On the scale of this diagram, there would be another 35-40 things strung out to the left, for about two feet, all looking a lot like the period at the end of this sentence, or maybe a tiny oval of similar size.
So, just how has life progressed since it first appeared on earth? To find out, read a wonderful new book by Dr. Peter Ward and Joe Kirschvink, A New History of Life: The Radical New Discoveries About the Origins and Evolution of Life on Earth. Geology has not stood still since I studied it in the 1970's and early 1980's. Neither has biology, nor genetics. In fact, our understanding of DNA and genetics has advanced more in the past decade than in all of prior history…and we realize that we still know something like 1% (or a lot less) of what we thought we would know by now.
Geological history and biological history go together. Only the first era of Earth, called the Hadean, during which there were no solid rocks, was without life. A period called Late Heavy Bombardment (LHB) ended the Hadean Eon and partially overlapped the first appearance of living cells. Life may have arisen a few times, only to be melted out of existence when a rocky body about the size of Texas would cause most of the crust to melt, again. So what we call "the origin of Earthly life" actually began just after the last successful total extinction event. The remaining history of Earth and of Earthly biology is divided into eras marked by partial extinction events. Five (plus one, shown below, in my accounting) are major, in that more than 50% of all living species were eliminated. Others caused many more extinctions in a short time than the background rate, but less than 50% at a blow.
To be clear: "Event" is a comparative term. When referring to geological time, anything that happens in less than a million years, if it is more than 50-100 million years in the past, can be called an event. So let us set a time scale, primarily of these extinction "events", based on what is currently known:
- 4,570 ma ("ma" means "millions of years ago") - Completion of Earth's accretion, and beginning of the Hadean Eon, during which the entire planet was molten, and which ended when solid crustal rocks began to form.
- 4,100 to 3,600 ma - Late Heavy Bombardment, when most of the craters on the Moon, Mercury and Mars were formed. One relic on Earth is possibly the Nastapoka Arc in Hudson's Bay in Canada. Anything smaller has been eroded away. The first glimmers of life, and earliest putative fossils, date from the end of this era. There are also chemical signals in rocks aged 3,800 ma, that indicate photosynthetic life existed at that time. The Archean Eon is considered to have begun 4,000 ma. The Last Total Extinction.
- 2,450 ma - Oxidation Catastrophe. During the Archean Eon life originated and soon became photosynthetic. For a billion years or more oxygen was immediately taken up by reduced minerals such green iron oxide (Ferrous Oxide, FeO2) and pyrite (FeS2), which produced red iron oxide (Ferric Oxide, Fe03) and iron sulfates such as FeSO4 and Fe2(SO4)3. Once all the reduced minerals had been oxidized, oxygen began to accumulate in the atmosphere, killing nearly everything. Those living things that evolved the ability to survive in the presence of oxygen, and later, to even use oxygen for producing cellular energy through respiration, took over the earth during the ensuing Proterozoic Eon. This was probably the nearest thing to a total extinction since the series of total extinctions at the end of the Hadean Eon. Great Extinction #1.
- 2,400-2,100 ma - Huronian Glaciation, probably the first "snowball earth" period, unless it was "only" a near-snowball, a "slushball" with a narrow equatorial unfrozen belt. A Significant Extinction Event.
- ~1,650 ma (maybe 2,000 ma) - Origin of Eukaryotes, large, complex cells and later on multicellular life composed of such cells; to be discussed later.
- 780 (720?)-635 ma - Three better-studied Snowball Earth extinctions of the Cryogenian Era, in the late Proterozoic Eon. Each would have made most of Earth unlivable for all but the hardiest creatures. Three Extinction Events, each lasting several million years.
- 542 ma - End-Ediacaran Extinction, A Significant Extinction Event. Early soft-bodied, multicellular creatures, and a few with hard parts, abruptly vanished. Possibly caused when predators arose that could eat the Ediacaran animals. The period that followed is the Cambrian Period, the first period of the Paleozoic Era of the Phanerozoic Eon, which is still going on.
- 488 ma - late Cambrian Extinction Event (AKA SPICE, for Steptoean Positive Carbon Isotope Excursion, a technical designation indicating a dramatic chemical change in the atmosphere and ocean).
- 450-440 ma - Ordovician-Silurian events, a series of global cooling events, possibly ice ages, that wiped out 70% of species. Great Extinction #2.
- 375-360 ma - Late Devonian volcanism. Over a few million years, half of all animal and plant genera became extinct, and perhaps 75% or more of all species. Great Extinction #3.
- 252 ma - End Permian Mass Extinction, the greatest of the "Big 5", which actually starts with #2 in this list. A confluence of several causes, including inconceivably enormous amounts of lava that erupted to form the Siberian Traps ("trap" is a kind of volcanic rock). At least 90% of all species wiped out. Great Extinction #4.
- 201 ma - End Triassic Mass Extinction, triggered when a less intense extinction caused by trap volcanism was augmented by an asteroid impact. At least 50% of species became extinct. Great Extinction #5.
- 65 ma - End Cretaceous Mass Extinction, primarily caused by an asteroid impact, but trap volcanism was also occurring around this time in India (Deccan Traps). Wiped out most of the dinosaurs, leaving only birds, and also the pterosaurs and marine reptiles such as the plesiosaurs. The most famous of the "Big 4", Great Extinction #6.
- 2.5-0 ma - The ongoing Pleistocene-Holocene Mass Extinction. Initially a result of the ice ages that began when North and South America became connected at the isthmus of Panama, it is not yet clear whether this is, or will, rank with the "Big 5". What was begun by continental glaciation is apparently continuing due to human interference with the biosphere, possibly including causing a big boost in carbon dioxide. A Significant Extinction Event. If we outdo ourselves, it could become #7.
Now it is time for terminology about the kinds of living cells.
- Prokaryote is meant to convey "prior to the nucleus", where "kary" refers to the nucleus in cells that have them. There are two major domains:
- Archaea, which until recently were considered to be bacteria. But they have an odd mix of primitive and advanced features that bacteria don't have at all. For example, their ribosomes, which translate DNA codes into proteins, are complex and very similar to those of Eukaryotes. Bacteria have simpler ones.
- Bacteria include all other prokaryotes, including all known pathogenic prokaryotes. Some (including me) consider Bacteria a younger offshoot of Archaea, and others consider it the other way around.
- Eukaryote means "good nucleus". The cells are much larger, and contain mitochondria, which are prokaryote-sized energy-producing organelles that are considered to be descended from prokaryotes that were engulfed by a larger one but, rather than being digested, kept, "enslaved", and eventually became an internal part of all eukaryotic cells. Alternatively, the smaller prokaryote may have begun as an endoparasite to a larger species, that developed into an endosymbiont. Anyway, every cell in your body (except red blood cells) contains from hundreds to thousands of these little organelles, and you'd die in a matter of seconds if they were somehow killed off.
The authors draw on new discoveries in every area of geological and biological sciences imaginable. The various eons, eras, periods and so forth, delineated in the outline above, had an array of living creatures, both plant, animal, fungal, and prokaryotic, that differed significantly from those in any other. For example, before about 120 ma, were you to visit in your pocket time machine, you could not go about smelling the flowers because the few that had existed for the prior 30-40 million years didn't have nectar or perfume yet. There weren't any bees to attract. Jump back to the middle Cambrian, say, 520 ma, and there was nothing living on land except some bacterial crusts here and there. The main sea-bottom creatures were scuttling shrimp-like and isopod-like things including trilobites, also mollusks and clam-like brachiopods. Tentacled things such as ammonites weren't yet present, but there were numerous creatures we would probably not recognize, scuttling and swimming about.
The kinds of living things that existed, and the transitions from one kind of biosphere to another afforded by the various cataclysms, form the main subject of the book. I am overwhelmed by the sheer mass of information the authors packed into some 360 pages. Even many of the end notes, those that weren't just strings of references, made fascinating reading.
To pick one significant learning from the book as a whole: several of the extinction events are classified as "greenhouse events". Certain periods were characterized by temperatures beyond tropical. Given that the Sun was several percent less bright half a billion years ago, and 40% dimmer around 3,000 ma, carbon dioxide alone could not produce global temperatures that would have exceeded 35°C (95°F) nearly everywhere, day and night. Methane eruptions, possibly from warming of methane clathrates in the shallower seabeds, were involved.
Certain geologic cycles, such as the formation or breakup of a supercontinent such as Pangaea or Rhodinia, cause large excursions in the level of carbon dioxide in the atmosphere. While that level was around 280 ppm a century or so ago, and is 400 ppm today, it was 1000 ppm or higher, sometimes much higher, during much of prehistory. A period of warming when carbon dioxide rises can trigger methane release. Methane doesn't last more than a few years in the atmosphere, because it can be oxidized. But sometimes, oxygen has been low at the same time as high carbon dioxide and methane, and then the methane lasts much longer and accumulates. The Triassic contained one such ultra-hot period.
And a fun fact: The present oxygen content of the atmosphere is 21%. At certain earlier times it was as high as 35%, which had several effects: the amount of nitrogen was the same as ever, so air pressure was ~15% higher; the extra oxygen provided extra energy to animals, and could in particular penetrate more deeply into the semi-passive respiratory systems of insects; and these two things led to some insects getting very large, such as a dragonfly with a meter-wide wingspan. The atmosphere was smokier, though, because of great forest fires. But the oxygen level was kept high by the rapid burial of organic debris that didn't get much chance to rot during that period. So...a dragonfly as big as a crow. Wow!
You don't have to specialize in geology or biology to enjoy this book. It is intended for us all, and the authors are very good at explaining what their jargon means.
(I won't go into detail about a few copy-editing errors I ran across. That's for a private letter. But I must comment that good proofreading and copy-editing are becoming less common. Authors out there, and editors, you can't just rely on a spell-checker. How else to account for the word "Cambria" where "cambium" was meant? The former is the historic name of Wales, and the latter is the living tissue in a tree.)
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