Unity in diversity

It was in my evolutionary biology class in college that I ran into a concept that blew my mind, and in many ways still does.

It was the idea that race is primarily a cultural feature, not a biological or genetic one.  There is more genetic diversity amongst the people of sub-Saharan Africa -- people who many of us would lump together as "Black" -- than there is in the rest of the world combined.  A typical person of western European descent is, our professor told us, closer genetically to a person from Japan than a Tswana man is to the !Kung woman he lives right next door to in Botswana, even though both have dark skin and generally "African features."

To reiterate: I'm not saying race doesn't exist.  It certainly does, and the social, cultural, and political ramifications are abundantly clear.  It's just that what we often think of as race has very close to zero genetic support; we base our racial classifications on a handful of characteristics like skin and eye color, the shape of the nose and mouth, and the color and texture of the hair, all of which can so easily undergo convergent evolution that it triggers us to lump together very distantly-related groups and split ones that lie much closer together on the family tree.

The reason this comes up today is a couple of bits of recent research highlighting the fact that the subject is way more complicated than it seems at first.  The first looks at the fragmentation that happened in Africa, on the order of twenty thousand years ago, that resulted in the enormous genetic diversity still to be found in sub-Saharan Africa today.  By analyzing DNA from both living individuals and the remains of people from long ago, researchers at Harvard University found that this was about the time that our ancestors stopped (for the most part) making extended walkabouts to find mates, and settled into being homebodies.  What triggered this is a matter of conjecture; one possibility is that this was in the middle of the last ice age, it could be that the colder and drier conditions (even in equatorial regions) made food scarcer, so long trips into unknown territory were fraught with more danger than usual.

Whatever the cause, the isolation led to genetic drift.  A general rule of evolutionary biology is that if you prevent genetic mixing, populations will diverge because of the accrual of random mutations, and that seems to be what happened here.  The fact that a Tswana person and a !Kung person (to use my earlier example) are so distinct is because they've been genetically isolated for a very long time -- something facilitated by a tendency to stay at home and partner with the people you've known all your life.

Interestingly, some research last year suggested that there are "ghost lineages" in the human ancestry -- groups that are ancestral to at least some modern humans, but are as yet unidentified from the fossil record.  The one studied in last year's paper were ancestral to the Yoruba and Mende people of west Africa, in which between two and nineteen percent of the genomes come from this ghost lineage -- but the phenomenon isn't limited to them.  The authors found analogous (but different) traces of ghost lineages in people of northern and western European and Han Chinese descent, and the guess is that all human groups have mysterious, unidentified ancestral groups.

The other bit of research that was published last week was an exhaustive study of the genetics of people around the world, with an ambitious goal -- coming up with a genetic family tree for every group of people on Earth. "We have basically built a huge family tree, a genealogy for all of humanity that models as exactly as we can the history that generated all the genetic variation we find in humans today," said Yan Wong of the University of Oxford, who co-authored the study.  "This genealogy allows us to see how every person's genetic sequence relates to every other, along all the points of the genome."

The researchers analyzed 3,609 individual DNA samples representing 215 different ethnic groups, and used software to compare various stretches of the DNA and assemble them using the technique called parsimony -- basically, creating a family tree that requires the fewest random coincidences and ad hoc assumptions.  The result was an enormous genealogy containing 27 million reconstructed common ancestors.  They then linked location data to the DNA samples -- and the program identified not only when the common ancestors probably lived, but where they lived.

I find this absolutely amazing.  Using modern genetic analysis techniques, we can assemble our own family tree, with roots extending backwards tens of thousands of years and encompassing lineages for which we have no archaeological or paleontological records.  With the number of connections the research generated, I have no doubt we'll be studying it for years to come, and have only started to uncover the surprises it contains.

But all part of living up to the maxim inscribed in the Temple of Apollo at Delphi -- γνῶθι σεαυτόν.

"Know thyself."

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The kites fly again

The iconic movie Jurassic Park has provided us with quite a number of quotable lines:

"I hate it when I'm always right."

"Clever girl."

"That is one big pile of shit."

"See?  Nobody cares."

"Hold onto your butts."

But as someone who has studied (and taught) evolution for decades, none of them has stuck in my mind like Ian Malcolm's pronouncement, "Life... uh... finds a way."

This short sentence sums up something really profound; however the Earth's ecosystems are damaged, they always bounce back.  Even after the catastrophic Permian-Triassic Extinction -- which by some estimates wiped out 90% of the existing taxa on Earth -- there was a recovery and rediversification.

Note that I'm not saying that means it was a good thing.  The end Permian extinction event was, it is believed, caused by an unimaginably huge series of volcanic eruptions, followed by a major spike in the carbon dioxide content of the atmosphere -- leading to a jump in the global temperature and catastrophic oceanic anoxia.

So yeah.  "Life survived" doesn't mean it'd have been a fun event to live through.  But it should give us hope that the damage humans can do to the Earth as a whole is, in the grand scheme of things, short-lived.

As an encouraging example of this, take a recent study out of the University of Florida on snail kites.  These birds, related to hawks and falcons, are serious food specialists; they eat only one species of snail, found in salt marshes like the Everglades (and also parts of Central America; I first saw snail kites in Belize).  When things are stable, being a specialist is a good thing -- you pretty much corner the market on a particular resource, like the South American hummingbird species whose bills are shaped to fit one and only one species of flower.  The snail kite's food finickiness is this same sort of thing, and as long as the Everglades was undamaged and had an abundant supplies of snails, all was well.

[Image licensed under the Creative Commons Bernard DUPONT from FRANCE, Snail Kite (Rosthramus sociabilis) Poconé, Mato Grosso, CC BY-SA 2.0]

But when the environment is rapidly changing, either through human effects or because of natural events, being a specialist is seriously precarious.  When a new species of snail -- the island apple snail -- was introduced to the Everglades, its larger size and voracious appetite outcompeted the native snails, and the snail kites were in trouble because their bills weren't large and heavy enough to tackle the bigger prey.

Snail kites were already on the Endangered Species List, given that the Everglades has been massively damaged by human activity.  This, it seemed, might be the death blow to the Florida population of this striking bird.

But... life, uh, finds a way.

The snail kite, in a near-perfect reenactment of the bill diversification in Darwin's finches in the Galapagos, had a variety of bill sizes.  Genetic diversity, despite their extreme specialization.  Before the introduction of the island apple snail, bill size probably didn't make much difference, positive or negative, to the individual birds.  But now, large bills were a serious advantage.  The birds with the biggest bills could tackle the larger snail species -- meaning they had a copious food source that their smaller-billed cousins couldn't utilize.

And in the thirteen years since the introduction of the island apple snail, the average bill size has gone up dramatically -- and the overall population is rebounding.

"Beak size had been increasing every year since the invasion of the snail from about 2007,” said Robert Fletcher, who co-authored the study.  "At first, we thought the birds were learning how to handle snails better or perhaps learning to forage on the smaller, younger individual snails...  We found that beak size had a large amount of genetic variance and that more variance happened post-invasion of the island apple snail.  This indicates that genetic variations may spur rapid evolution under environmental change."

As I said earlier, this is not meant to give the anti-environmental types another reason to say, "Meh, we don't have to change what we're doing, things'll be okay regardless."  Most species aren't as fortunate as the snail kites, already having the genetic diversity to cope with a sudden change.  Much more likely, if we keep doing what we're doing, the specialist species in the world will simply be wiped out.

Whether we'll be able to survive in such a changed world remains to be seen.

But one thing is nearly certain; even if we catastrophically damage the global ecosystem, it will rebound eventually.  Which is hopeful, as far as it goes.  Even after Homo sapiens is another fossilized footnote in the Earth's geological history, life will persist -- once more generating, in Darwin's immortal words, "endless forms most beautiful and most wonderful."

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 Many of us were riveted to the screen last week watching the successful landing of the Mars Rover Perseverance, and it brought to mind the potential for sending a human team to investigate the Red Planet.  The obstacles to overcome are huge; the four-odd-year voyage there and back, requiring a means for producing food, and purifying air and water, that has to be damn near failsafe.

Consider what befell the unfortunate astronaut Mark Watney in the book and movie The Martian, and you'll get an idea of what the crew could face.

Physicist and writer Kate Greene was among a group of people who agreed to participate in a simulation of the experience, not of getting to Mars but of being there.  In a geodesic dome on the slopes of Mauna Loa in Hawaii, Greene and her crewmates stayed for four months in isolation -- dealing with all the problems Martian visitors would run into, not only the aforementioned problems with food, water, and air, but the isolation.  (Let's just say that over that time she got to know the other people in the simulation really well.)

In Once Upon a Time I Lived on Mars: Space, Exploration, and Life on Earth, Greene recounts her experience in the simulation, and tells us what the first manned mission to Mars might really be like.  It makes for wonderful reading -- especially for people like me, who are just fine staying here in comfort on Earth, but are really curious about the experience of living on another world.

If you're an astronomy buff, or just like a great book about someone's real and extraordinary experiences, pick up a copy of Once Upon a Time I Lived on Mars.  You won't regret it.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

The path to acceptance

Lately, it's been mighty hard to stay upbeat.  Insularity, fear, intolerance, and suspicion have ruled the day, along with their inevitable outcomes -- racism, homophobia, and other forms of bigotry.

Even so, I've always been optimistic about humanity in general.  Yes, we're capable of some horrifying actions, but there are just as many (or more) cases where people acted with astonishing selflessness.  We're a complex species, and we often don't respond the way you'd think -- in fact, sometimes we even surprise ourselves.

What a lot of social scientists would like to know is how to decrease the former and increase the latter.  And new research in Proceedings of the National Academy of Sciences, by Miguel R. Ramos, Matthew R. Bennett, Douglas S. Massey, and Miles Hewstone, supports a contention I've had for years; that it's very hard to stay prejudiced against a group when you start interacting with members of the group.

[Image licensed under the Creative Commons Frerieke from The Hague, The Netherlands, Diversity and Unity, CC BY 2.0]

In a paper published last week called "Humans Adapt to Social Diversity Over Time," Ramos et al. describe an interesting tendency.  Faced with changes to what had been a homogeneous population, through immigration or a change in the acknowledgment of a group (as in LGBTQ individuals coming out), initially there's resistance, but over time the original population responds by adjusting and becoming more accepting overall.

The authors write:

Humans have evolved cognitive processes favoring homogeneity, stability, and structure.  These processes are, however, incompatible with a socially diverse world, raising wide academic and political concern about the future of modern societies.  With data comprising 22 [years] of religious diversity worldwide, we show across multiple surveys that humans are inclined to react negatively to threats to homogeneity (i.e., changes in diversity are associated with lower self-reported quality of life, explained by a decrease in trust in others) in the short term.  However, these negative outcomes are compensated in the long term by the beneficial influence of intergroup contact, which alleviates initial negative influences.  This research advances knowledge that can foster peaceful coexistence in a new era defined by globalization and a socially diverse future.

In other words, bigotry can be cured.  I know more than one case of a family where one of the individuals was seriously homophobic -- until someone they're close to came out.  At that point, the bigoted individual has to adjust those negative stereotypes to what (s)he knows of the person (s)he loves and has known for years.  It's hard to hate someone once you recognize their common humanity, when you see they laugh, love, hurt, and bleed just like you do.

Of course, it can go the other way.  There are all too many cases of bigotry that has survived contact with members of the disparaged group, of coworkers and neighbors and family members who have still been targeted, of becoming victims of people they've known for years.  But the hopeful message of the Ramos et al. paper is that this reaction is far less common than an increase in acceptance, trust, and understanding.

It's easy to focus on the negative, and certainly the media encourages that.  Outrage increases readership, and (let's face it) there's still a lot to be outraged about.  But this research gives us a way to combat those tendencies for humans to be insular, suspicious, and prejudiced.  And it also is a hopeful note for our own society, which is becoming more heterogeneous whether we want it to or not.  What Ramos et al. suggests is that we can expect to see some growing pains -- of the sort that is exemplified by our current leadership -- but that over time, we will come to accept, and even appreciate, our diversity, to look upon it as a strength rather than as a threat.

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When the brilliant British neurologist and author Oliver Sacks died in August of 2015, he was working on a collection of essays that delved into some of the deepest issues scientists consider: evolution, creativity, memory, time, and experience.  A year and a half ago, that collection was published under the title The River of Consciousness, and in it he explores those weighty topics with his characteristic humor, insight, and self-deprecating humility.

Those of us who were captivated by earlier works such as The Man Who Mistook His Wife for a Hat, Musicophilia, Awakenings, and Everything in its Place will be thrilled by this book -- the last thoughts of one of the best thinkers of our time.

[Note:  If you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Unity in diversity

A couple of days ago, NPR ran a piece about conservatives who are leaving liberal areas so they can live amongst like-minded folks.  The article, by Vanessa Romo, is entitled "Texas Becoming a Magnet for Conservatives Fleeing Liberal States Like California," and tells the story of people like 36-year-old Tim Stokes, who is upping stakes and moving along with his pregnant wife and three children.

The reason, Stokes said, is that he is tired of "feeling like an outsider" in his hometown.  He's a Republican, has staunchly supported conservative causes, and has the sense of being marginalized in a community that is largely liberal Democrat.  And he's not alone; the article projects that by 2050, twenty million people will have left their home states to be in places that align better with their political stances and religious beliefs.

It's not that I don't understand this.  I tend to have a liberal bent (which, I'm sure, will come as no shock to regular readers of Skeptophilia), although I try to avoid politics when I can because I find arguing about it to be rather pointless.  I live in an area where liberals outnumber conservatives, although if you continue down the highway where I live toward the south and the city of Watkins Glen, the numbers flip completely.  During the last election, if you took the road past my house, you could see the blue Clinton signs thinning as the red Trump signs increased in numbers, mile after passing mile.

I get that it's nice to have like-minded folks near you.  Believe me, being a liberal atheist from southern Louisiana, I know what it's like to feel like you're on the fringe in your own home, and the situation must feel similar for conservatives in strongly liberal areas.

But I think what Tim Stokes and his family (and, apparently, a great many other people) are doing is unequivocally a bad idea.

We need to be around people who disagree with us, who challenge and question us.  I'm not saying we should seek out hostile interactions, or (worse) provoke them; but I contend that if you live in the contented, self-satisfied little bubble of only hearing the opinions you already have reflected back at you, you will never have the opportunity to suss out places where your thinking is wrong-headed -- or things that you haven't thought about at all.

Fortunately, there are influential people who are saying exactly this.  George Fuller, the (conservative) mayor of McKinney, Texas (near Dallas), said of what Stokes and others are doing, "I think instead of just trying to kind of put together pockets of the like-minded, I would think energy is better spent trying to figure out how to live and exist together and find productive solutions going forward versus insulating yourself from different thoughts and ideologies."

Norman Rockwell, Golden Rule (1961) [image courtesy of the Wikimedia Commons]

Which is it exactly.  If there's one thing I've found to be consistently true, it's that it's much easier to demonize someone if you have no personal contact with them.  Over and over, I've seen stories of the devoutly religious who hated LGBT individuals -- until a child or a friend came out to them.  They're forced into realizing that the labels and the hatred allow them to ignore the humanity of an entire group, and that they're being presented with a choice between love and narrow-minded bigotry.  (I realize those situations don't always end this way, and there are cases where the bigoted choose to embrace their prejudice instead; but it's encouraging the number of times it's gone the other way.)

In fact, prejudices of all kinds evaporate when you take the time to get to know people different than you are, and realize that your commonalities far outweigh your differences.  And if you segregate yourself voluntarily into a little echo chamber where everyone looks like you, votes like you, and attends the same church as you, you'll never have the chance to do what Kathryn Schulz calls "moving outside of that tiny, terrified little bubble of having to be right about everything."

In fact, I'll go a step beyond that; you should not only be accepting of opportunities to interact with people who aren't like you, you should seek them out.  The leaders of our country are, by and large, accelerating the polarization of the American people, pushing us into believing that anyone who isn't like you is either a hopeless idiot, or else an evil creature dead-set on destroying the very fabric of the United States.

We have to work tirelessly against this mindset.  And, for cryin' in the sink, don't you think we'd get it by now?  We're a nation that in the past has prided itself on being a "melting pot."  I'm a good example; I have in my ancestry recent immigrants from the southeast of France, Jewish refugees from Alsace, Cajuns exiled from Nova Scotia, Dutch settlers who came to New Amsterdam in the 1600s, and Scottish peasants who ended up in the hill country of southwestern Pennsylvania.  Virtually all of us are the product of such amalgams.  And yet, the way things are going, we're rapidly heading toward a society where we not only don't interact with people who aren't like us, we almost never see them.

So do yourself a favor.  Find some people of different ethnicity, religion, sexual orientation, age, or political values, and sit down with them to have a conversation over your favorite libation.  Don't just talk; listen.  Chances are good that you'll find out that this person, so different than you are, just wants the same things you want; a secure home, food on the table, a safe environment to raise children, the freedom to speak without judgment, the freedom to be who they are without fear of censure, ridicule, or violence.

And who knows?  Maybe you'll come away not only having learned something, but having made a friend.