Drawn together

Convergent evolution occurs when only distantly-related species are under the same selective pressures, and evolve to look alike.  A particularly good example of this is the North American flying squirrel (a rodent) and the Australian sugar glider (a marsupial).  Put them side-by-side, and they're hard to tell apart, and both have the distinctive kite-like flap of skin between the forelegs and hind legs, allowing them to catch a breeze and glide from tree to tree.

It's important to emphasize that while convergent evolution can result in organisms being similar in appearance or habits, it doesn't ever cause them to fuse into a single species.  Flying squirrels and sugar gliders maintain major differences in their genetic make-up, skeleton, dentition, and so on -- so however close the resemblance, they're still two separate species.

Convergence is actually fairly common in the natural world, which is why appearance is such a poor guide to determining who is related to whom.  There are only so many solutions to the problems posed by living in a particular environment, so it's inevitable that different lineages will happen on the same ones.  Flying, for example, has evolved independently at least four times -- birds, bats, pterodactyloids, and insects.  The structure and mechanics is different in each, which is indicative that they were independent innovations.

I was thinking about convergent evolution this morning as I read a paper in the journal Geodiversitas about the discovery of a remarkable fossil in Colombia.  It's the best-preserved and most complete skeleton ever found of Anachlysictis gracilis, a Miocene apex predator that belonged to a group called the sparassodontids.  (The name comes from the Greek σπαράσσειν, to tear to pieces, and ὀδόντος, tooth -- an indicator of how scary these animals were.)

Here's a photograph of the skeleton:

[Image courtesy of Daniella Carvalho and Aldo Benites-Palomino]

My guess is that looking at this, you're immediately reminded of the saber-toothed cats such as the famous Smilodon, which also were around during the Miocene Epoch but reached their pinnacle a few million years later, during the Pleistocene.  Surprisingly, this parallels my earlier example of the flying squirrel and sugar glider -- the saber-toothed cats were true felids, and thus placental mammals, while Anachlysictus and the other sparassodonts were marsupials.  The two species were drawn together by the forces of convergent evolution.  If you're a predator, having big nasty pointy teeth is a pretty good adaptation regardless what taxonomic group you belong to.

These striking carnivores were present in South America during what is called the "splendid isolation," prior to the tectonic shift that formed the Isthmus of Panama and allowed for the Pliocene Great Biotic Interchange.  South America had developed a unique biota, including not only the sparassodonts but a variety of other marsupial groups, most of which are now extinct.  Even the South American placentals didn't do so well, and were outcompeted (or hunted to death) by North American migrants.  Not long after the formation of Central America, a great many of the South American groups -- not only the sparassodonts, but the glyptodonts, litopterns, astrapotheres, pyrotheres, and xenungulates -- were gone forever.

The new fossil discovery will allow paleontologists to make some deductions about not only its anatomy, but its behavior. "In a future study we will address all the other bones in its body, which include various sections of the spine, ribs, hip, scapulae -- what we call 'shoulder blades' for humans -- and bones in its legs," said Catalina Suarez, of the Argentine Institute of Nivology, Glaciology and Environmental Sciences, who led the research team.  "This will allow us to explore aspects of how it moved, the position in which its neck held its head, whether it was a runner, whether it could climb, whether its hands could hold objects more easily, as many marsupials do when feeding, or whether it was a bit more difficult, as it is for example for a dog or a cat."

It's fascinating to learn more about these long-extinct animals, whose ecological role would be taken over by predatory placental mammals like wolves and the various big cats.  Even if they're extinct, their bones still have a story to tell -- of a saber-toothed marsupial who hunted in the forests of Colombia thirteen million years ago.

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Buried treasure

Maybe I need to get myself a metal detector.

The reason I say this is that it's apparently an auspicious time for treasure hunters, at least judging by two discoveries I found out about (once again!) from my friend and fellow writer Gil Miller, without whom in the last couple of weeks I wouldn't have had much to write about here.

The first one was a discovery in Norway made by an amateur treasure hunting enthusiast, using his newly-purchased metal detector for the first time (maybe there's something to beginner's luck after all...).  The fortunate fellow is named Ole Ginnerup Schytz, and I have to point out that (1) no, I am not making this name up, and (2), yes, this is from a reputable source, specifically the National Museum of Denmark.

In any case, the discovery, made a couple of months ago near the town of Jelling but only announced recently, is absolutely stupendous.  It's a collection of gold artifacts dating from the Danish Iron Age, about seventh century C.E.  It consists primarily of bracteates -- rune-decorated medallions thought to have not only a decorative but a magical purpose.  This new collection has bracteate designs the archaeologists say they've never seen before.

"It is the symbolism represented on these objects that makes them unique, more than the quantity found," explained Mads Ravn, director of research at the Vejle Museum.

As far as Schytz, he was as stunned as everyone else by his discovery.  "When the device activated, I knelt down and found a small, bent piece of metal," he said.  "It was scratched and covered in mud.  I had no idea, so all I could think of was that it looked like the lid of a can of herring."

One of the bracteates from the Jelling cache

"It was the epitome of pure luck," Schytz said.  "Denmark is 43,000 square kilometers, and then I happen to choose to put the detector exactly where this find was."

One thing I find fascinating about the discovery is that it contained gold coins from the Roman Empire that had been converted into jewelry, and a medallion depicting Constantine the Great (ruler of the Eastern Roman Empire from 306 to 337 C.E.).  So even though the cache seems to have been buried in the seventh century, some of the artifacts are a good three hundred years older than that.  Jelling, apparently, was the center of trade back then -- including trade from over two thousand kilometers away.

The second discovery was made on the other side of the world, in Colombia.  Recently archaeologists discovered a trove of gold and emeralds, filling eight ceramic jars of a type made by the Muisca people, an indigenous group known for their find goldsmithing (and who may have inspired the legend of the city of El Dorado).  The jars are thought to have been buried about six centuries ago, but this is much less certain than the Jelling cache's date, because there were no obvious historical benchmarks here as there were in Denmark.

One of the jars from the Muisca site

A lot of the pieces from this discovery are figurines in the shape of snakes and other animals, as well as people wearing headdresses and carrying staffs and weapons.  This has prompted the leader of the team which made the discovery, Francisco Correa, to conclude that the site may have been associated with the worship of ancestor spirits and animal totems.

In any case, both the Danish and the Colombian find are staggeringly precious, not just because of the monetary value of the gold and jewels, but because of what it tells us about the cultures that created these beautiful pieces.  So like I said, if you believe in auspices, maybe it's time to go out and get yourself a metal detector.

I probably won't bother.  Not only do I not believe in strings of good fortune, I don't think there's any gold buried around here.  About the only use I've seen people make of metal detectors in this area is sweeping the village fairgrounds after the annual fair wraps up, looking for lost pocket change.

And frankly, I don't think the return on that investment would be enough to justify the time and expense.

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Like graphic novels?  Like bizarre and mind-blowing ideas from subatomic physics?

Have I got a book for you.

Described as "Tintin meets Brian Cox," Mysteries of the Quantum Universe is a graphic novel about the explorations of a researcher, Bob, and his dog Rick, as they investigate some of the weirdest corners of quantum physics -- and present it at a level that is accessible (and extremely entertaining) to the layperson.  The author Thibault Damour is a theoretical physicist, so his expertise in the cutting edge of physics, coupled with delightful illustrations by artist Mathieu Burniat, make for delightful reading.  This one should be in every science aficionado's to-read stack!

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

Becoming human

I think one of the uniting characteristics of the topics that interest me is that they all have something to do with altering our perception of the commonplace reality around us.

This capacity for (in writer Kathryn Schulz's words) "seeing the world as it isn't" led me to writing fiction, but also to the weird and counterintuitive bits of quantum physics, the expansive vision of astronomy, and the fields studying that which no longer exists -- history, archaeology, paleontology.  It's this last one that brings this whole topic up, with a pair of discoveries revealed this week that leave me kind of awestruck.

The first, which came my way from my buddy Andrew Butters over at the wonderful blog Potato Chip Math, is about the discovery in South Africa of a two-million-year-old skull of Paranthropus robustus, a hominin considered a "cousin species" that coexisted with our direct ancestor species Homo erectus.

The find is remarkable from a number of perspectives, not least that a complete skull of any hominin is pretty unusual.  "Most of the fossil record is just a single tooth here and there so to have something like this is very rare, very lucky," said Angeline Leece, who participated in the research.  She added an evocative description of what the world was like when the owner of this skull was still alive and loping around on the African savanna.  "These two vastly different species, Homo erectus with their relatively large brains and small teeth, and Paranthropus robustus with their relatively large teeth and small brains, represent divergent evolutionary experiments,"  Leece said.  "Through time, Paranthropus robustus likely evolved to generate and withstand higher forces produced during biting and chewing food that was hard or mechanically challenging to process with their jaws and teeth — such as tubers.  Future research will clarify whether environmental changes placed populations under dietary stress and how that impacted human evolution."

It's fascinating to imagine what the world was like to these creatures, during a time when there were several intelligent hominin species coexisting.  I remember my evolutionary biology professor making that point; a lot of our attitude that species are these hard-and-fast little cubbyholes comes from the fact that we have no near relatives still alive.  Much more common in the natural world are groups of closely-related species all competing and coexisting.

But it's still a little hard to picture wandering around the place and seeing other human-like, but not-quite-human, animals out there doing their thing.

It also bears keeping in mind that the other animal species they'd have been around weren't like the ones today, either.  This point was driven home by the second discovery revealed this week, of a twelve-thousand-year-old frieze of cliffside paintings in Cerro Azul, Colombia, that show not only the usual assemblage of South American animals -- snakes, alligators, turtles, bats, monkeys, porcupines -- but mastodons, giant sloths, camelids, and some sort of three-toed ungulate with a trunk.

"These really are incredible images, produced by the earliest people to live in western Amazonia," said Mark Robinson, an archaeologist at the University of Exeter, who participated in the study.  "The paintings give a vivid and exciting glimpse in to the lives of these communities.  It is unbelievable to us today to think they lived among, and hunted, giant herbivores, some which were the size of a small car."

A small part of the Cerro Azul frieze

The size, scope, and detail of the drawings is phenomenal.  The paintings were made with ochre, a yellowish or reddish mineral, and cover the cliff face not only for miles horizontally, but for almost twenty meters vertically.  Whatever the purpose of this art -- whether it was purely decorative or had some kind of magical or symbolic significance -- the artists certainly were highly motivated.  Some parts of the frieze would have required ladders or climbing equipment to create, pretty impressive for what was at the time a more or less pre-technological society.

"These rock paintings are spectacular evidence of how humans reconstructed the land, and how they hunted, farmed and fished," said archaeologist José Iriarte, also of the University of Exeter.  "It is likely art was a powerful part of culture and a way for people to connect socially.  The pictures show how people would have lived amongst giant, now extinct, animals, which they hunted."

I find it fascinating that even back then -- at the tail end of the last Ice Age, when merely surviving must have been a challenge -- people were creating art.  And the fact that much of that art was depicting animals no longer extant adds a whole other layer of mind-boggling to the find.  This, and the South African skull discovery, give us a window into understanding how we became human -- how we went from savanna-dwelling apes to intelligent beings who have art, music, literature, science, and technology.

It's a journey that took us from the East African Rift Valley to pretty much every point on the surface of the Earth -- and has driven us along the way to look with wonder into the unknown vastness of the universe.  As Carl Sagan so poignantly put it, "We are a way for the cosmos to know itself."

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One of the most compellingly weird objects in the universe is the black hole -- a stellar remnant so dense that it warps space into a closed surface.  Once the edge of that sphere -- the event horizon -- is passed, there's no getting out.  Even light can't escape, which is where they get their name.

Black holes have been a staple of science fiction for years, not only for their potential to destroy whatever comes near them, but because their effects on space-time result in a relativistic slowdown of time (depicted brilliantly in the movie Interstellar).  In this week's Skeptophilia book-of-the-week, The Black Hole Survival Guide, astrophysicist Janna Levin describes for us what it would be like to have a close encounter with one of these things -- using the latest knowledge from science to explain in layperson's terms the experience of an unfortunate astronaut who strayed too close.

It's a fascinating, and often mind-blowing, topic, handled deftly by Levin, where the science itself is so strange that it seems as if it must be fiction.  But no, these things are real, and common; there's a huge one at the center of our own galaxy, and an unknown number of them elsewhere in the Milky Way.  Levin's book will give you a good picture of one of the scariest naturally-occurring objects -- all from the safety of your own home.

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

Holy chemtrails, Batman!

If there's one thing I've learned from nine years of writing here at Skeptophilia, it's that there is no idea so weird that someone can't alter it so as to make it way weirder.

On Saturday, we looked at the woman in Japan who is convinced that the way to get rid of pesky ghosts is to buy a high-quality air purifier.  This would put ghosts in the same class as indoor air pollutants and that greasy smell left behind when you fry bacon, which is not how I'd like to be remembered by my nearest and dearest.  "Gordon's back!  Turn on the air purifier!" is not what I'd want to hear, if I was a ghost.

But according to a Roman Catholic bishop in Colombia, there's another way to get rid of evil spirits.  Have an airplane fly over and create a "chemtrail"...

... out of holy water.

I'm not making this up, but I kind of wish I was, because I did some repeated headdesks while researching this post while trying to find out if it was actually true or the result of someone trying to trap me (and others) in Poe's Law.  Sadly, it appears that the whole thing is real.  Monsignor Rubén Darío Jaramillo Montoya, bishop of the city of Buenaventura, is distressed by the unpleasant stuff that goes on down in this port city of 340,000 inhabitants.  So far this year there have been 51 murders, says Monsignor Montoya, which is double what occurred during an equal-length time interval last year.  So the only answer is to douse the entire city in holy water, to "take out these demons that are destroying the city's port."

[Image is in the Public Domain]

Amazingly enough, the powers-that-be in Buenaventura are all-in on this idea, and plan on spraying the city on July 13 or 14.   "In Buenaventura we have to get rid of the devil to see if we return the tranquility that the city has lost with so many crimes, acts of corruption with so much evil and drug trafficking that invades our port," a church representative told reporters.

There's no doubt that Buenaventura is kind of a mess.  Besides the murders, which are certainly shocking enough, there's the fact that it's a major hub of the drug trade (especially of cocaine) heading north to the United States.  Efforts by the government to clean the place up have been largely ineffective, and a lot of the city is controlled more by the Cali cartel than it is by law enforcement and elected officials.

On the other hand, mass exorcisms to get rid of crime and drug trafficking have been tried before, and the results were fairly unimpressive.  Back in 2015, Mexican "renowned exorcist" Father José Antonio Fortea organized an "Exorcismo Magno" to evict the demons that were behind all the murders and mayhem and drug trade, and as far as I can tell Mexico is still as dangerous as it ever was.  So as far as I can tell, exorcisms aren't that great a solution to crime and drug trafficking, ranking right behind building a wall to stop the Bad Hombres from getting in.

So sadly, loading up holy water in a crop duster isn't likely to do much, either.  I suppose it falls into the "no harm if it amuses you" department, although it must be said these sorts of "thoughts and prayers"-type solutions are problematic in that they give people the impression that you're doing something when you really aren't.

But that's not going to stop Monsignor Montoya and the rest of the Holy Chemtrails Squad from doing their thing the second week of July.  I'm just as glad I won't be there when it happens.  If I got sprayed with holy water, I'd probably spontaneously combust, which would be unpleasant for me, even if it might be entertaining for any onlookers.

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Richard Dawkins is a name that often sets people's teeth on edge.  However, the combative evolutionary biologist, whose no-holds-barred approach to young-Earth creationists has given him a well-deserved reputation for being unequivocally devoted to evidence-based science and an almost-as-well-deserved reputation for being hostile to religion in general, has written a number of books that are must-reads for anyone interested in the history of life on Earth -- The Blind Watchmaker, Unweaving the Rainbow, Climbing Mount Improbable, and (most of all) The Ancestor's Tale.

I recently read a series of essays by Dawkins, collectively called A Devil's Chaplain, and it's well worth checking out, whatever you think of the author's forthrightness.  From the title, I expected a bunch of anti-religious screeds, and I was pleased to see that they were more about science and education, and written in Dawkins's signature lucid, readable style.  They're all good, but a few are sheer brilliance -- his piece, "The Joy of Living Dangerously," about the right way to approach teaching, should be required reading in every teacher-education program in the world, and "The Information Challenge" is an eloquent answer to one of the most persistent claims of creationists and intelligent-design advocates -- that there's no way to "generate new information" in a genome, and thus no way organisms can evolve from less complex forms.

It's an engaging read, and I recommend it even if you don't necessarily agree with Dawkins all the time.  He'll challenge your notions of how science works, and best of all -- he'll make you think.

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