Look… Just because H. habilis was several branches back on the family bush doesn’t mean we’re supposed to stop being handy.
I get not carrying a pistol. It’s not for everybody and, if done with any level of seriousness, demands certain commitments and obligations that not everyone wants to undertake, and that’s cool. It’s still (mostly) a free country.
But how do you go through life without a flashlight and some kind of knife? Our most primitive ancestors carried sharp rocks around with them. Hell, carrying a sharpened rock around in case of future need is basically how we tell where the apes stop and the people start in our fossil family album. If they could have carried a light around without it burning their fingers or going out all the time, you bet they would have.
They make flashlights and knives small enough to accommodate any code, dress or legal, up with which you have to put.
Tamara Keel, “Look…”, View from the Porch, 2016-05-26.
October 13, 2018
QotD: Evolution
August 18, 2018
QotD: Adam Smith and Charles Darwin
… today few people appreciate just how similar the arguments made by Smith and Darwin are. Generally, Adam Smith is championed by the political right, Charles Darwin more often by the left. In, say, Texas, where Smith’s emergent, decentralised economics is all the rage, Darwin is frequently reviled for his contradiction of dirigiste creation. In the average British university, by contrast, you will find fervent believers in the emergent, decentralised properties of genomes and ecosystems who yet demand dirigiste policy to bring order to the economy and society. But if life needs no intelligent designer, then why should the market need a central planner? Where Darwin defenestrated God, Smith just as surely defenestrated Leviathan. Society, he said, is a spontaneously ordered phenomenon. And Smith faces the same baffled incredulity — How can society work for the good of all without direction? — that Darwin faces.
Matt Ridley, The Evolution of Everything, 2015.
July 28, 2018
Is Evolution Over? | Earth Lab
BBC Earth Lab
Published on 7 Jun 2013Are we still evolving? Have we stopped? How will we know? James May answers this burning question on evolution.
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James May’s Q&A: With his own unique spin, James May asks and answers the oddball questions we’ve all wondered about from ‘What Exactly Is One Second?’ to ‘Is Invisibility Possible?’
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April 16, 2018
Mass extinction or mass genesis? “The net result is that many more species are arriving than are dying out”
We often hear laments for the addition of another species to the endangered list, but that’s not the whole story as evolutionary biologist Chris Thomas explains:
Animals and plants are seemingly disappearing faster than at any time since the dinosaurs died out, 66m years ago. The death knell tolls for life on Earth. Rhinos will soon be gone unless we defend them, Mexico’s final few Vaquita porpoises are drowning in fishing nets, and in America, Franklin trees survive only in parks and gardens.
Yet the survivors are taking advantage of new opportunities created by humans. Many are spreading into new parts of the world, adapting to new conditions, and even evolving into new species. In some respects, diversity is actually increasing in the human epoch, the Anthropocene. It is these biological gains that I contemplate in a new book, Inheritors of the Earth: How Nature is Thriving in an Age of Extinction, in which I argue that it is no longer credible for us to take a loss-only view of the world’s biodiversity.
The beneficiaries surround us all. Glancing out of my study window, I see poppies and camomile plants sprouting in the margins of the adjacent barley field. These plants are southern European “weeds” taking advantage of a new human-created habitat. When I visit London, I see pigeons nesting on human-built cliffs (their ancestors nested on sea cliffs) and I listen out for the cries of skyscraper-dwelling peregrine falcons which hunt them.
Climate change has brought tree bumblebees from continental Europe to my Yorkshire garden in recent years. They are joined by an influx of world travellers, moved by humans as ornamental garden plants, pets, crops, and livestock, or simply by accident, before they escaped into the wild. Neither the hares nor the rabbits in my field are “native” to Britain.
July 15, 2017
The Scopes Trial in Dayton, Tennessee
As a long-time admirer of H.L. Mencken (since discovering Prejudices: A Selection in a used book store on Queen Street in the mid-1980s), I’ve always had an interest in the skullduggery around the “Scopes Monkey Trial” … and apparently so has Colby Cosh:
H.L Mencken celebrates the repeal of Prohibition, December 1933.
In a merely procedural sense, the Scopes Monkey Trial in Dayton, Tennessee, ended on July 21, 1925 with the conviction of biology teacher John T. Scopes on the charge of instructing students that “man has descended from a lower order of animals.” But of course the real Monkey Trial is eternal, winding its way anew through American life, decade after decade. The carefully staged publicity stunt in Tennessee was merely one occasion in a longer struggle over the nature of man and the limits of his knowledge. I know this is an old-fashioned romantic ACLU-liberal view of the matter, but I hold to it.
As I write this column, county officials in Dayton are unveiling a statute of Clarence Darrow, the garrulous, crooked lawyer who represented Team Enlightenment in the original 1925 contest between Darwinian evolution and the Scriptures. In 2005, the citizens of Dayton, where Monkey Trial tourism is now a crucial industry, erected a statue of William Jennings Bryan on the grounds of the immortal Rhea County courthouse. Bryan had been the chosen hero of evangelical Christianity in the trial, dying less than a week after its conclusion, and is the namesake of a local bible college, which paid for the statue.
[…]
I became a serious student of the Scopes Trial as an undergraduate. Like anybody else, I had seen the 1960 Hollywood rendering of the play about the trial, Inherit The Wind, which represents Bryan as an ignorant windbag, Darrow as a tired, patient figure of ostentatious nobility, and a thinly disguised H.L. Mencken as a cruel nihilist newspaperman. Today, I suppose I would regard Mencken as the real hero of the show. He was privy to the ACLU’s engineering of the trial as a publicity stunt, but he also always said that Tennessee was within its constitutional rights to forbid the teaching of evolution — to be, in his view, just as backward as its people wished.
Inherit The Wind makes its pseudo-Mencken a heartless guttersnipe mostly as a device for elevating a sympathetic Darrow even further. This is part of the movie’s major liberty with the events of the trial: it has Bryan drop dead in mid-rant at the moment of its culmination, instead of waiting a few days. What I discovered as a student was that, aside from this excusable concession to theatrical unity, the film probably deserves some kind of prize for general fidelity to historical events.
March 10, 2017
BAHFest Sydney 2016: Dr. James O’Hanlon “Why do males have nipples?”
Published on Feb 26, 2017
Watch Dr. James O’Hanlon discuss how nipples are actually rudimentary balance organs that detect the bodies orientation in space assisting terrestrial mammals stay upright.
The first BAHFest Sydney took place at the Museum of Applied Arts and Sciences on Friday, August 19th 2016.
For more info about BAHFest and upcoming shows in your part of the world, visit http://www.bahfest.com
February 14, 2017
QotD: Explaining why men tend to be slobs, but women very much don’t
The central fact that controls the the preferences of both sexes is that bearing children is difficult and dangerous for women, but fertilizing a woman is almost trivially easy for a man. Furthermore, the female investment in childbearing is front-loaded (proportionally more of the risk is before and at birth) while the male investment is back-loaded (proportionately more of the risks and costs are incurred after birth).
Moderns living in a largely disease-free environment seldom realize how cruel and pressing these differences were over most of our species history. But before modern sanitation, death in childbirth was so common that men wealthy enough to afford it expected to have several wives during their lifetimes, losing many of them to childbed fever and other complications.
Also relevant is the extremely high rate of childhood death from infectious diseases and parasites that was characteristic of premodern societies. Disease resistance in humans is highly variable and generally increases with genetic mixing (the same reason a mongrel puppy or kitten is less likely to catch a disease than a purebreed). Thus, both men and women have instincts intended to maximize genetic variety in their offspring in order to maximize the chances that some will survive to reproductive age.
Our instincts evolved to cope with these patterns of life and death. The next piece we need to understand those instincts is what physical beauty means. Recent anthropology revealing strong cross-cultural patterns in the perception of pulchritude is helpful here.
In both sexes, the most important beauty indicators include symmetrical features and a good complexion (clear skin without blemishes, warts, etc.). It turns out these are indicators of resistance to infection and parasites, especially resistance in childhood and during adolescent growth. Good hair is also a health indicator.
In men, physical signs of strength, dexterity, and agility are also favored; this reflects the value female instinctive wiring puts on male specializations in burst exertion, hunting, and warfare. In women, signs of fertility and fitness to bear are favored (healthy and generous breasts, a certain range of hip-to-waist ratios).
Men fixate on physical beauty and youth because under primitive conditions it is a leading indicator of the ability to bear and suckle children. Through most of history, plain or ugly women were bad risks for the next round of infectious diseases — and their children, carrying their genes, were too.
The last piece of the puzzle is that men and women have asymmetrical information about the parentage of their children. A woman is seldom in doubt about which children are the issue of her womb; a man, by contrast, can never be as sure which are the fruit of his seed. Thus, genetic selfishness motivates the woman in a mated pair to sacrifice more for her children than it does the man. This is why women abandon their children far less often than men do.
While women do respond to male good looks, it’s not the agenda-topper for them that it is for men. To understand why this is, it helps to know that the optimal mating strategy for a woman begins with hooking a good provider, a man who will stick around to support the kids in spite of not being as sure that he’s their father as the woman is of being their mother. Where men look for fitness to bear children, women seek the capability and willingness to raise them.
Thus, robust health and infection resistance, while desirable in a potential husband, are not the be-all and end-all. Behavior traits indicating attachment, loyalty, nurturance, and kindness are more important than a tight six-pack. Men instinctively worry about these things less because they know women are more certain of parentage and thus more tightly bonded to their children. Fitness-to-raise also means that indicators of success and social status count for more in men. Men marry health and beauty, women marry security and good prospects.
There is, however, one important exception — one circumstance under which women are just as physical, beauty-oriented, and “shallow” in their mating preferences as men. That’s when they’re cheating.
Both sexes have a genetic-diversity incentive to screw around, but it manifests in different ways. Again, the reason is parentage uncertainty. For a man, diversity tactics are simple — boff as many hot babes as possible, accepting that you don’t know which of their kids are yours and counting on stronger maternal bonding to ensure they will have at least one devoted parent around. Because a woman can be more sure of who her offspring are, her most effective diversity tactic is different — get married to a good provider and then cheat on him.
Under those circumstances, she doesn’t have to value good character in a mating partner as much; hubby, who can’t tell the kids aren’t his, will supply that. Thus the relative value of handsomeness goes up when a woman is taking a lover on the sly. Marrying the lord and screwing the gardener is an old game, and from a genetic-selfishness point of view a very effective one.
Eric S. Raymond, “A Unified Theory of Male Slobbishness and Female Preening”, Armed and Dangerous, 2005-01- 06.
February 6, 2017
The “beer before bread” theory gains strength
The received wisdom about the transition from hunter-gatherer to agrarian societies is that clans or tribes stopped being nomadic in order to grow crops and secure their food supply more consistently … that growing grain for bread was one of the strongest underlying reasons for the change in lifestyle. That theory is being challenged by researchers who believe the real reason was to produce grains for brewing instead:
The story of humanity’s love affair with alcohol goes back to a time before farming — to a time before humans, in fact. Our taste for tipple may be a hardwired evolutionary trait that distinguishes us from most other animals.
The active ingredient common to all alcoholic beverages is made by yeasts: microscopic, single-celled organisms that eat sugar and excrete carbon dioxide and ethanol, the only potable alcohol. That’s a form of fermentation. Most modern makers of beer, wine, or sake use cultivated varieties of a single yeast genus called Saccharomyces (the most common is S. cerevisiae, from the Latin word for “beer,” cerevisia). But yeasts are diverse and ubiquitous, and they’ve likely been fermenting ripe wild fruit for about 120 million years, ever since the first fruits appeared on Earth.
From our modern point of view, ethanol has one very compelling property: It makes us feel good. Ethanol helps release serotonin, dopamine, and endorphins in the brain, chemicals that make us happy and less anxious.
To our fruit-eating primate ancestors swinging through the trees, however, the ethanol in rotting fruit would have had three other appealing characteristics. First, it has a strong, distinctive smell that makes the fruit easy to locate. Second, it’s easier to digest, allowing animals to get more of a commodity that was precious back then: calories. Third, its antiseptic qualities repel microbes that might sicken a primate. Millions of years ago one of them developed a taste for fruit that had fallen from the tree. “Our ape ancestors started eating fermented fruits on the forest floor, and that made all the difference,” says Nathaniel Dominy, a biological anthropologist at Dartmouth College. “We’re preadapted for consuming alcohol.”
[…]
Flash forward millions of years to a parched plateau in southeastern Turkey, not far from the Syrian border. Archaeologists there are exploring another momentous transition in human prehistory, and a tantalizing possibility: Did alcohol lubricate the Neolithic revolution? Did beer help persuade Stone Age hunter-gatherers to give up their nomadic ways, settle down, and begin to farm?
The ancient site, Göbekli Tepe, consists of circular and rectangular stone enclosures and mysterious T-shaped pillars that, at 11,600 years old, may be the world’s oldest known temples. Since the site was discovered two decades ago, it has upended the traditional idea that religion was a luxury made possible by settlement and farming. Instead the archaeologists excavating Göbekli Tepe think it was the other way around: Hunter-gatherers congregated here for religious ceremonies and were driven to settle down in order to worship more regularly.
H/T to Tamara Keel for the link.
August 15, 2016
Evolved sexual differences
Amy Alkon on the reason men and women value different attributes in one another:
Why Does Feminism Mean “You Can’t Say That About Women!”?
Feminism, too often these days, means treating women like eggshells, not equals.If you talk about a woman’s looks — and maybe criticize how much she cares about her looks — you are stomping on hallowed ground, and you’re in for a media reaming (if you make your criticism at all publicly).
By the way, we care about women’s looks — and women care about caring for and showing off their looks — because of our evolved sex differences. Women prioritize status and power in a man and men prioritize physical attractiveness.
This isn’t all we care about in a partner, and it isn’t all we use to judge another person, but these preferences evolved to promote our mating and survival, not out of nowhere. We are living in a modern world with pretty antique psychology — perfect for life in an ancestral environment — so these sex differences in our psychology remain.
I write about these differences in our preferences in my science-based book, Good Manners for Nice People Who Sometimes Say F*ck:
Many women think men are pretty rude to care so much about a woman’s looks. In a just world, men would have the hots for women simply for the beautiful people they are on the inside. Unfortunately, in the real world, this is just not how male sexuality works. (The penis is not a philanthropic organization and will not get hard because a woman bought a homeless guy a sandwich.)
Because male sexuality is all about the visuals, men’s magazines are filled with pictures of naked women with freakishly large breasts and women’s magazines are filled with pictures of beauty products and ass-cantilevering $2,000 stilettos. Men evolved to go for signs of reproductively hot prospects — an hourglass figure, youth, clear skin, symmetrical faces and bodies, and long shiny hair: all indicators that a woman is a healthy, fertile candidate to pass on a man’s genes. Women co-evolved to try to make themselves look reproductively hot, though that’s not how we think of it.
July 12, 2016
QotD: Did our distant ancestors select for intelligence?
This is a special case of one of my favorite Damned Ideas, originally developed by John W. Campbell in the 1960s from some speculations by a forgotten French anthropologist. Campbell proposed that the manhood initiation rituals found in many primitive tribes are a selective machine designed to permit adulthood and reproduction only to those who can demonstrate verbal fluency and the ability to override instinctive fears on verbal command.
Campbell suggests that all living humans are descended from groups of hominids that, having evolved full-human mental capability in some of their members, found the overhead of supporting the dullards too high. So they began selecting for traits correlated with intelligence through initiation rituals timed for just as their offspring were achieving reproductive capacity; losers got driven out, or possibly killed and eaten.
Campbell pointed out that the common elements of tribal initiations are (a) scarring or cicatricing of the skin, opening the way for lethal infections, (b) alteration or mutilation of the genitals, threatening the ability to reproduce, and (c) alteration of the mouth and teeth, threatening the ability to eat. These seem particularly well optimized for inducing maximum instinctive fear in the subject while actually being relatively safe under controlled and relatively hygenic conditions. The core test of initiation is this: can the subject conquer fear and submit to the initiation on the basis of learned (verbal, in preliterate societies) command?
Campbell noticed the first order effect was to shift the mean of the IQ bell curve upwards over generations. The second-order effect, which if he noticed he didn’t talk about, was to start an arms race in initiation rituals; competing bands experimented with different selective filters (not consciously but through random variation). Setting the bar too low or too high would create a bad tradeoff between IQ selectivity and maintaining raw reproductive capacity. So we’re descended from the hominids who found the right tradeoff to push their mean IQ up as rapidly as possible and outcompeted the groups that chose less well.
It doesn’t seem to have occurred to Campbell or his sources, but this theory explains why initiation rituals for girls are a rare and usually post-literate phenomenon. Male reproductive capacity is cheap; a healthy young man can impregnate several young women a day, and healthy young men are instinct-wired to do exactly that whenever they can get away with it. Female reproductive capacity, on the other hand, is scarce and precious. So it makes sense to select the boys ruthlessly and give the girls a pass. Of course if you push this too far you don’t get enough hunters and fighters, but the right tradeoff pretty clearly is not 1-to-1.
Eric S. Raymond, “Selecting for intelligence”, Armed and Dangerous, 2003-11-14.
June 14, 2016
QotD: Romantic love … what is it for?
It’s all about the encephalization, really. Millions of years ago our hominid ancestors stumbled onto a novel adaptive strategy: be smart, adaptable, and capable of learning rather than purely instinct-driven. Make tools; use fire; invent language.
This strategy required much, much more of our nervous systems. Because intelligence was in fact a winning strategy, we were selected for growing more complex brains capable of doing more information processing. But increasing the logic density of brains is hard; there probably isn’t a path to it through the design space that is rapidly exploitable by small point mutations. So selective pressure made our brains larger, instead.
The fossil record shows that the hominid line encephalized at a breakneck speed compared to the usual leisurely pace of evolutionary change. This had huge consequences; much of human biology is a series of hacks and kluges to support that encephalization, often in stupidly suboptimal ways.
The one that’s relevant here starts from the limited width of the birth canal. Limited, that is, by the pelvic girdle surrounding it. A skull that’s too large won’t fit through. Therefore, the genetic lines that survived were those in which babies are born with small skulls but the ability to grow them much larger by maturity. (And even so, the size of a baby’s skull pushes that limit pretty hard; this is why birth is so much more difficult and dangerous for human females than it is for other primates).
That design (be born with a small skull and upgrade it outside the womb) implied a long juvenile period between birth and physical maturity. In fact the human brain doesn’t completely finish configuring and rewiring itself until around age 25. And the long juvenile period probably also explains the exceptionally long human lifespan; whatever had to be altered in the development clock to defer stabilization into the final adult configuration probably also delayed the inset of senescence. (Direct evidence for this theory is the rare disease “progeria”).
And the dominoes kept falling. The long juvenile period implied offspring that would be incapable of fending for themselves for an unprecedently long time – on the order of decades rather than the few months to a year typical for other mammals. Consequently the selective value of extended cooperation between the parents went way, way up relative to even our nearest animal kin.
Romantic love works as an an evolved mechanism for keeping mated pairs cooperating long enough to raise multiple children. Here again, selection favors those who love more because they get to launch more offspring. We are, in fact, made to fall in love – and it would only be surprising if the mechanism for establishing it were not simple, robust, and easily triggered.
Eric S. Raymond, “Love is the simplest thing”, Armed and Dangerous, 2015-01-15.
June 1, 2016
QotD: The evolutionary advantage of conformity
In the environment of evolutionary adaptedness (EEA) an individual could not survive outside the group of their birth and so conformity was a matter of life and death. Conform or be cast out. Conformity to arbitrary convention was not in fact arbitrary but signalled affiliation. Conformity banded groups together.
Today, however, conformity is often counter-productive. Trying to enforce the arbitrary conventions of one’s in-group impedes social cooperation on the scale that makes modernity possible. Conformity also slows the development of new ideas and new ways of doing things — the essence of growth and progress. Even though conformity is now counter-productive the desire to conform and to enforce conformity is buried deep–the atavism of social justice.
Individualism and liberalism are foundational ideas for modernity but these adult ideas battle the desire to conform in our childish hearts.
Alex Tabarrok, “The Developmental Roots of Conformity Bias”, Marginal Revolution, 2016-05-20.
March 19, 2016
QotD: Dieting as a substitute religion
A current New York Times news story, What If It’s All Been A Big Fat Lie, entertainingly chronicles the discovery that low-fat diets are bad for people. More specifically, that the substitution of carbohydrates like bread and pasta and potatoes for meat that we’ve all had urged on us since the early 1980s is probably the cause of the modern epidemic of obesity and the sharp rise in diabetes incidence.
I have long believed that most of the healthy-eating advice we get is stone crazy, and the story does tend to confirm it. One of my reasons for believing this is touched on in the article; what we’re told is good for us doesn’t match what humans “in the wild” (during the 99% of our species history that predated agriculture) ate. The diet our bodies evolved to process doesn’t include things like large amounts of milled grain or other starches. Our hunter-gatherer ancestors ate wild vegetables (especially tubers) and meat whenever they could get it.
[…]
But the evolutionary analysis only tells us what we probably should be eating. It doesn’t explain how the modern diet has come to be as severely messed up as it is — nor why the advice we’ve been getting on healthy eating over the last twenty years has been not merely bad but perversely wrong.
The answer is, I think, implicit in the fact that “health food” has a strong tendency to be bland, fibrous, and nasty — a kind of filboid studge that we have to work at convincing ourselves we like rather than actually liking. Which is, if you think about it, nuts. Human food tropisms represent two million years of selective knowledge about what’s good for our bodies. Eating a lot of what we don’t like is far more likely to be a mistake than eating things we do like, even to excess.
Why do we tend to treat our natural cravings for red meat and fat as sins, then? Notice the similarity between the rhetoric of diet books and religious evangelism and you have your answer. Dietary mortification of the flesh has become a kind of secular asceticism, a way for wealthy white people with guilt feelings about their affluence to demonstrate virtue and expiate their imagined transgressions.
Once you realize that dieting is a religion, the irrationality and mutual contradictions become easier to understand. It’s not about what’s actually good for you, it’s about suffering and self-denial and the state of your soul. People who constantly break and re-adopt diets are experiencing exactly the same cycle of secondary rewards as the sinner who repeatedly backslides and reforms.
This model explains the social fact that the modern flavor of “health”-based dietary piety is most likely to be found in people who don’t have the same psychological needs satisfied by an actual religion. Quick now: who’s more likely to be a vegetarian or profess a horror of “junk food” — a conservative Christian heartlander or a secular politically-correct leftist from the urban coasts?
Eric S. Raymond, “Diet Considered as a Bad Religion”, Armed and Dangerous, 2002-07-17.
January 19, 2016
QotD: Male brutality as an evolutionary advantage
Perhaps more important than piling up more examples to attest the phenomenon is giving a little thought to why female masochism occurs. Like other sex traits, it is an evolutionary adaptation. I am going to go way out on a limb and suggest that early hominid males may not have been quite so delicate as Tom Fleming, who becomes ill at the very thought of a woman being struck. African men are, by all accounts, pretty quick with their fists to this day. Gallantry is an achievement of civilization, not a part of our primitive nature.
Now, females in our “environment of evolutionary adaptation” were dependent on males for mating, protection, and access to resources. These males were bigger and stronger than females and could easily hurt them if angered or displeased. If our female ancestors had been delicate snowflakes unable to endure life with such brutes, we would not be here today. In other words, women adapted to male brutality, including occasional violence, learning how to get through or around it.
Think for a moment, men, how you would learn to behave if you were dependent for survival on an unpredictable and often violent creature larger and stronger than yourself. You would learn not simply to take what you wanted. You would learn to act when his back is turned, to use indirection, deception, manipulation. You would learn to conceal your true thoughts and keep Big Boy confused as to your true intentions. You would, in short, learn to act like a woman.
The battle of the sexes is a contest of force vs. cunning. Yes, civilized men learn to control their aggressive impulses and not beat women up every time they feel irritation with them. In the modern West, men have largely renounced the use of their natural weapon for controlling women, i.e., force. Have women renounced the use of their own weapons against men? Certainly we cannot expect women to shed millennial evolutionary adaptations automatically the instant men learn to behave.
F. Roger Devlin, “The Question of Female Masochism”, Counter-Currents Publishing, 2014-09-17.
April 24, 2015
Framing every conservation issue in terms of “extinction” is counter-productive
Stewart Brand wants us to stop presenting so many conservation concerns in the headline-grabbing “Fluffy Bunnies At Risk!” format:
The way the public hears about conservation issues is nearly always in the mode of ‘[Beloved Animal] Threatened With Extinction’. That makes for electrifying headlines, but it misdirects concern. The loss of whole species is not the leading problem in conservation. The leading problem is the decline in wild animal populations, sometimes to a radical degree, often diminishing the health of whole ecosystems.
Viewing every conservation issue through the lens of extinction threat is simplistic and usually irrelevant. Worse, it introduces an emotional charge that makes the problem seem cosmic and overwhelming rather than local and solvable. It’s as if the entire field of human medicine were treated solely as a matter of death prevention. Every session with a doctor would begin: ‘Well, you’re dying. Let’s see if we can do anything to slow that down a little.’
Medicine is about health. So is conservation. And as with medicine, the trends for conservation in this century are looking bright. We are re-enriching some ecosystems we once depleted and slowing the depletion of others. Before I explain how we are doing that, let me spell out how exaggerated the focus on extinction has become and how it distorts the public perception of conservation.
Many now assume that we are in the midst of a human-caused ‘Sixth Mass Extinction’ to rival the one that killed off the dinosaurs 66 million years ago. But we’re not. The five historic mass extinctions eliminated 70 per cent or more of all species in a relatively short time. That is not going on now. ‘If all currently threatened species were to go extinct in a few centuries and that rate continued,’ began a recent Nature magazine introduction to a survey of wildlife losses, ‘the sixth mass extinction could come in a couple of centuries or a few millennia.’
The fossil record shows that biodiversity in the world has been increasing dramatically for 200 million years and is likely to continue. The two mass extinctions in that period (at 201 million and 66 million years ago) slowed the trend only temporarily. Genera are the next taxonomic level up from species and are easier to detect in fossils. The Phanerozoic is the 540-million-year period in which animal life has proliferated. Chart created by and courtesy of University of Chicago paleontologists J. John Sepkoski, Jr. and David M. Raup.
The range of dates in that statement reflects profound uncertainty about the current rate of extinction. Estimates vary a hundred-fold – from 0.01 per cent to 1 per cent of species being lost per decade. The phrase ‘all currently threatened species’ comes from the indispensable IUCN (International Union for Conservation of Nature), which maintains the Red List of endangered species. Its most recent report shows that of the 1.5 million identified species, and 76,199 studied by IUCN scientists, some 23,214 are deemed threatened with extinction. So, if all of those went extinct in the next few centuries, and the rate of extinction that killed them kept right on for hundreds or thousands of years more, then we might be at the beginning of a human-caused Sixth Mass Extinction.
