Sunday, June 28, 2015

Ghosts in the Landscape

Photo by author
Not long ago, I was driving across the Colorado high plains when a pair of pronghorn crossed the road. When they saw me coming they ran, and I pulled over to admire their retreat. I was thinking, "Those things might be faster than deer." And then, as if affronted by the comparison, they decided to stop messing around and run. I've never seen any animal run that fast before. Later, I looked them up and found that they're the second-fastest land animal in the world. Only the cheetah is faster.

And that's odd, if you think about it. Why do pronghorn need to be that fast--far faster than any predator on the plains? Nature doesn't usually give its creatures abilities beyond their needs, so the pronghorn's excessive speed is a puzzle.

The poet Robinson Jeffers offers a hint of an answer:
What but the wolf’s tooth whittled so fine
The fleet limbs of the antelope?
Wolves were certainly important predators of pronghorn, but they probably aren't the whole story. Pronghorn can run 20 miles per hour faster than wolves, which means they may be built to outrun an even faster predator. And just such a predator once existed: the American cheetah, or false cheetah. Until about 12,000 years ago, there was a big cat in North America that fit into the same "turbocharged grassland predator" niche that modern African cheetahs occupy. As the name "false cheetah" suggests, it wasn't closely related to African cheetahs. It's an example of convergent evolution--it resembled a cheetah because it evolved to fill a similar ecological niche. It's also an example of what the science writer Connie Barlowe called a "ghost of evolution": a species that's now gone, whose legacy we can still see reflected in other species.

Photo by Greg Hume,
Wikimedia Commons
Ghost species aren't just reflected in other animals. You can also see their spectral outlines in the shape of some plants. For example, honey locust trees are covered with vicious, branched thorns as long as daggers. Why? Why do they need that kind of armament? The answer, most likely, is that they don't need it anymore, but they once did--when mastodons and sloths the size of cars used to eat their seeds. In fact, that may be why honey locust seeds are honey-sweet--to attract large mammals, which would eat the seeds, and then disperse them later along with a nice dollop of fertilizer. The trees needed to encourage the big beasts to eat their seeds, but they needed to discourage them from pushing them right over in their zeal. So they grew thorns big enough to repel a mastodon.

Some of the other ghosts in the landscape come from much farther back in time. If you look closely at certain rocks at the edge of the Rocky Mountains, near the Mile High City of Denver, you may get lucky and find a shark tooth. Of course, actual sharks are rare these days in the Rockies. The fossilized teeth are actually older than the mountains. They're reminders that Colorado was once covered by a sea, where sharks patrolled alongside giant aquatic reptiles that went extinct along with the dinosaurs.

Cretaceous Shark Tooth from Colorado. Photo by Author
Some of nature's most influential ghosts were never actually alive, but they left a far more visible legacy than the sharks and mastodons did. The other day I hiked into the mountains outside Denver and saw the incredible wall of rock in the picture below. The trees clinging to its left side give an idea of its scale--it's hundreds of feet tall; sweeping up in a great curve from the valley floor. Why is it shaped like that? Why isn't there just a tree-covered slope like you might find in the Appalachians? The answer is that it was carved by glaciers--a whole series of glaciers that crept down the valley every when the climate got really cold every hundred thousand years or so. The glaciers are gone from Colorado today (except for a few small ones in sheltered cirques) but their handiwork is visible everywhere; in sharp ridges, glacial lakes, and walls of bare rock framing U-shaped canyons. Their work is as alive today as Michelangelo's, and unlike Michelangelo, they may come back someday.

Glacial Cliffs near Chicago Lakes, Colorado. Photo by Author
When you look closely, you find ghosts everywhere in the landscape. In fact, you can even see entire phantom landscapes if you know how to look for them. Many geologists do their job by learning to see such ghost landscapes; looking out across the modern terrain and seeing outlines in their mind's eye of long-gone features like volcanoes and mountain ranges. In the picture below, for example, we see a mesa near Golden made of ancient lava that once flowed from volcanoes into a valley. The valley walls and the volcano eroded away, but the hardened lava resisted erosion, and now stands above the surrounding plains. It's a beautiful scene, but it's more than that, too: It's also a reflection of an older, equally beautiful landscape; a landscape that's now nothing but a ghost.

Table Mountain, Golden, Colorado. Photo by Ross Mays, ancient landscape drawing based on Drewes, 2008


More details on giant sloths, locust trees, and the mesa above:

Thorn Trees, Avocados, and VLS's (Very Large Sloths)

How a Valley Became a Mesa, and Why a River Runs Through It

Table Mountain Shoshonite Porphyry Lava Flows and Their Vents,Golden, Colorado / Harald Drewes, 2008

Saturday, June 20, 2015

Believing Kenny: Listening to African-Americans about Racism

In the few days since the horrific murders at a black church in Charleston, one of the many things that's disturbed me is the initial reluctance of some white people to believe the attack could have been motivated by racial hatred. This was especially true among certain conservatives--to a degree that was shocking to me. Fox News jumped to the conclusion that the attack was an attack on Christianity, not black people, and called it "extraordinary" that it was being investigated as a hate crime. The governor of South Carolina and certain Republican presidential candidates were also weirdly reluctant to say what the attack obviously was: a hate crime against African-Americans.

I don't exactly understand why they wanted to deny that racism was to blame. I'm truly puzzled by the motives there. What I can understand, though, is why white people might not realize the full extent of racist aggression that African-Americans face in their daily lives. We don't realize it, because it doesn't happen to us. Whatever the extent of white-on-black racial aggression, if you're a non-racist white person with non-racist friends, you're not going to see much of it firsthand. If you hardly ever see it happen, it's easy to assume it hardly ever happens. It's easy, but it's wrong.

I'm convinced it's quite common for blacks to experience racism from whites. In fact, I believe it happens to many of them every day. I came to this conclusion years ago, after another racially-charged incident that shook up the whole country. I was a student at a small liberal arts college in Arkansas when the Rodney King beating and trial happened. The afternoon the news broke that the police had been acquitted, an African-American student invited everybody on campus to gather in front of the library and discuss what had happened.

A few dozen people showed up, and what was said doesn't concern us here, except for one brief exchange I'll never forget. A white student asked this question to all the African-Americans present: "Here's what I want to know: How often do you actually experience racism in your daily life?" Then a guy I knew named Kenny stood up and spoke for the first time.

He said, "Every day, man. Every single day."

Now, here's the thing about Kenny: When he said it, I believed it. I admit that if some of the other African-American students had said it, I wouldn't have. Some of them, in my opinion, had too much of a chip on their shoulder about race. I thought they might see racist slights when none were intended. But not Kenny. He was one one of the friendliest people I've ever met--he seemed to be friends with everybody, black and white, and I had never heard him say a negative word about anyone or anything. So when Kenny said it happened to him every day, I believed it. I still do.

After he said it, I started thinking about other times I had realized that how people treat me isn't necessarily how they treat everybody. I had noticed it before; not about race, but social class and reputation. I grew up in a small town in the Ozarks where almost everybody was white. My parents were very respectable--a veterinarian and a teacher--and I didn't get in much trouble, so the adults around town were really nice to me. But I had friends who did get in trouble occasionally, and who didn't come from such respectable families, and I started noticing that some of the other respectable adults (not my parents) weren't so nice to them. Around them, they turned into different people. Their smiles vanished. Their eyes hardened. That's when I realized that people who seemed perfectly friendly to me can turn nasty to others.

Another thing I already knew, of course, is that some people are racist. You don't hear nearly as much racist talk in the Ozarks as you hear in the deep south (partly because there are hardly any black people there) but you still hear plenty of it--or at least you did a couple decades ago. Some people casually threw the n-word around, and there were always a handful of people who seem to trace every problem in the country back to black people...even though they hardly ever encountered one.

I actually don't remember ever seeing a white person say something racist to a black person in my home town, but that means next to nothing, because as I said, hardly any black people lived there. I don't know how much racism I would have seen if I had grown up in a more diverse town. I suspect it would be much more, but I also suspect it would be much less than what was actually happening, and I wasn't seeing.

Anyway, after hearing what Kenny said, and thinking about how many racists I knew, and how people could be nice to me and nasty to others, I started thinking about how those racists might act when they encountered a black person, and thought nobody else was watching. Weighing up all these things, I decided that Kenny was surely right--black people must experience a lot of racism that most white people never even notice (unless they're the ones doing it.) We don't notice it because it happens when we aren't watching, and it's not happening to us.

People are sneaky, and they can be surprisingly nasty when they think nobody is watching. I know that's true, because I've heard the stories from people I trust. However, once again, it's not usually about racism. It's about sexism. But don't worry! I'm not about to go off on a different tangent--one hot-button issue per post is plenty. I just think the sexism I do hear about is analogous to the racism I don't hear about. I have a lot of female friends, and I've been stunned my whole adult life by stories they tell me about what some guys do when they think nobody else will see: the catcalls, the elevator eyes, the flat-out sexual propositions. I think it's a similar situation as with Kenny--I don't see it happening, and I wouldn't even believe it if I wasn't hearing it from someone I trust.

But I do believe it, because I do trust them. Yes, some guys really do say those things. And if that's true, and it's also true that some people are racist, then it's not a stretch to think African-Americans of both sexes are in a similar situation to women: they see a lot of nastiness that I'm completely unaware of. It doesn't happen to me, and it doesn't usually happen around me. But it does happen. When Kenny says it happens every day, I believe him, and I think other white Americans should believe him too.

Thursday, June 11, 2015

The Mayfly and the Pyramid: Seeking Perspective in the Rockies

Long's Peak. Rocky Mountain National Park. Photo by Author
People visiting the Rockies or the Alps often remark that the mountains make them feel small. That's not how they affect me. Their enormity is staggering, of course, but I don't really compare myself to them that way, so they don't make me feel small. I do, however, compare myself to them in terms of age. And that does make me feel small--not small in stature, but small in years. "Ephemeral" is the word that always comes to mind. Standing on the side of a snow-capped mountain makes me feel like a mayfly on the Great Pyramid.

Bristlecone pine in Colorado. Photo from US Forest Service
We humans like to scoff at the mayfly's day-long life, but we're pretty short-lived creatures ourselves by some standards. Even trees can make our lives seem brief. I'm 43 years old, and there are bristlecone pines where I live in Colorado that are over 50 times as old as I am. The oldest one known sprouted in 442 BC, the year Sophocles wrote Antigone. It's older than the Roman Colosseum, but only half as old as some of its cousins in California.

Bristlecone pines are ancient things, but they, in turn, are ephemeral on longer scales. For example, the most recent glaciers that chiseled the cirques and rounded the valleys in the high mountains of Colorado were at their greatest extent about 18,000 years ago. They lasted for 20,000 years--ten times as long as Colorado's ancient pines. Some of them were almost thirty miles long, and heavy enough to bore mountain valleys into U-shaped troughs (these valley glaciers would have looked similar to the one below, in Switzerland) They were monsters that dwarfed us in size as well as longevity.

Photo by Dirk Beyer Click for photo credit and information
And today, they're just ghosts--recognizable only by their handiwork. But they'll be back one day. The glaciers of 18,000 years ago were just the latest in a long series of glacial cycles going back 2.5 million years. We're living in a brief warm period in a long ice age--one that's a thousand times older than the oldest bristlecone pines in Colorado, or the plays of Sophocles.

But even the ice age has been brief compared to the mountains themselves. The Rockies were here long before the first glaciers began to carve them. The Colorado Rockies began to rise about 70 million years ago, which means they were young when the dinosaurs went extinct, and have presided over the 65-million-year rise of mammals. I said above that my age compared to the Rockies is like a mayfly's compared to the Great Pyramid. That's not an exaggeration. If a mayfly lives a day, the Great Pyramid--built around 2600 BC--is about 1.6 million times as old as the mayfly. That's almost exactly how much older the Colorado Rockies are than me (the size comparison isn't far off, either).

And yet, even the mountains come and go. The Rockies aren't nearly as old as the rocks they are made of. The metamorphic rocks that compose much of Colorado's Front Range were formed about 1.7 billion years ago, when even older sedimentary rocks were compressed and heated in the formation of a long-vanished mountain range. That makes them 24 times as old as the Rockies. They're old enough to been part of a succession of mountain ranges. As James Michener said in the novel Centennial (set in Colorado), "Only the rocks live forever".

Of course, even rocks don't live forever, but compared to us, they might as well. The universe itself is only a few times as old as these rocks are, and they could still survive for billions of years to come. Compared to that, we're far more ephemeral than mayflies.

Some people may find that depressing. In fact, millions of people refuse to accept it at all, preferring to believe the whole Earth is only slightly older than a bristlecone pine. It isn't, thank goodness. It's so much older, bigger, and grander than that. That's why I don't think it's depressing to compare myself to the rocks, or the mountains, or the glaciers, or the ancient trees. When I go into the mountains, I do feel my own mortality--my own fleetingness--but in a good way. Yes, I'm small and ephemeral, but only because the world is so grand and ancient, and I become larger by going out and losing myself in it.

Besides, there's a whole lot more to life than size and longevity. Humans have something the rocks, mountains, and glaciers don't: a conscious mind. We can go up into the mountains and marvel at them, and at the epic sweep of the processes that made them. We're lucky enough to be among the parts of nature capable of appreciating itself. Not only that, but we live in a time when science is showing us just how immense and ancient nature really is. It's an enormous privilege, if you think about it. So, no, it's not at all depressing to me that our lives are so fleeting compared to the rocks and mountains. The mountains are blind--they can't appreciate their own grandeur. But we can, and it's glorious. We may not be here long, but we have an incredible world to explore while we're here.

Saturday, June 6, 2015

The Best Defense: Thoughts on Arguing with Creationists

Rising in Noah's Ark, Aurelio Luini, 1556. 
Arguing with creationists? Don't do it! That way lies madness!

OK, that's just my first impulse. Honestly, I think there are times when it's worthwhile to argue with creationists. Not because you'll convince them of anything, mind you--you almost certainly won't. Most of them are entirely unpersuadable. In fact, changing anybody's mind about anything is extremely rare, so if your goal is to change minds, you're mostly going to be disappointed. (I've never fully learned this lesson.)

But there are still a couple of reasons having the argument could be worthwhile anyway. One is that most creationists can at least be shaken out of their smugness a little, and that's a good thing. It's possible to give them pause, and make them think--just for a second--that their claims might not be as solid as they think, and that established scientific theory might not be as shaky and fraudulent as they think. It's also common that they will say something that shows they don't understand what the theory of evolution actually says; e.g. "If we came from monkeys, why are there still monkeys?" Many creationists don't actually understand basic science. They've read just enough creationist literature to think they know how to refute it.

Which brings us to the second, and far more important reason, it can be worthwhile to have the argument: other people are usually watching, and they may still be sitting on the fence. The person you're arguing with probably won't change their mind, but some of the people overhearing it might.

But this is risky, because if you don't know your stuff, it may be the creationist who sounds more convincing. A creationist who's spent a lot of time learning how to deny science can easily win an argument over someone who doesn't know how to defend it. Let's face it--most people who believe in science don't know enough to defend it well, and even someone who knows a lot about science can be stumped temporarily by some of the claims creationists throw out. That's because it's much, much easier to cast doubt on a complex theory than it is to defend it. This is especially true if the person casting the doubt is willing to be dishonest (or just repeating dishonest or delusional claims, which is more common), or if the people listening don't know science very well. As Alberto Brandolini put it, "The amount of energy necessary to refute bullshit is an order of magnitude bigger than to produce it."

It gets worse. Even if you DO know the science well, creationists will always be able to ask questions you can't immediately answer. If they throw out a wild claim about some purported finding that contradicts evolution, it takes a lot of work to track it down and figure out what's wrong with it. Nobody, not even professional scientists, knows enough to instantly refute every claim someone might make. There are dozens of such claims that have been answered here, but there will always be more of them. It's always easier to knock a theory down than to prove it, even if the theory is true.

The point is, the person attacking a complex idea usually has an advantage over the person defending it.* So what can you do? My suggestion is that at a certain point, you have to stop playing defense and go on the offensive. I don't mean you should be offensive--that's usually counterproductive, and in fact, it's probably best to be extra polite, since people get offended over religion three times as fast as any other topic. I'm just saying we need to turn the tables. If creationists want to talk evidence, then great, let's talk evidence--including their evidence.

When you start doing that, most creationists get pretty quiet, and for good reason. True Biblical literalists believe some pretty wild things. They believe there was once a snake who talked. They believe Adam was made from dust, and Eve was made from one of his ribs. They believe that every animal on Earth--including kangaroos from Australia, raccoons from North America, and penguins from Antarctica--somehow made it to the Middle East, and then squeezed together, by the millions, onto a wooden boat (and what about plants, fungi, bacteria, protists, and viruses? Surely they were passengers too?) Creationists believe Noah lived over 900 years, that floodwaters once topped Everest, and that people speak different languages because they tried to build a tower into the sky and God didn't like it.

So let's ask them this about all those things. Let's ask them things like: What's your evidence that a snake really talked? How do you know that women were created from a rib? Is there some genetic signature of these things? Do snakes have some sort of vestigial speech organs you can see in a dissection? Do women show genetic signs of being physiologically based on bone tissue? And how did Noah make sure every strand of bacteria and virus got on the ark? How did those raccoons get across the Atlantic? What's the evidence that people once lived for hundreds of years? Or that all languages can be traced to the Middle East?

Whatever holes creationists think they can poke in science, the holes in their theories are much, much bigger. And besides, turnabout is fair play. If creationists want to ask us about our evidence...great! We've got it, and lots of it. Museums, journals, rocks and DNA are full of evidence that backs us up. All of nature backs us up. Now let's ask them about their evidence. Let's hear what they've got on that talking snake and the 900-year-old man. I'm all ears.


* That's why, if a creationist asks me for the evidence for evolution or the age of the earth, I'm going to give it to them, but I know they will find fault with it. I can't help that, and there aren't enough hours in the day to explain why their objections are wrong--especially since they won't believe it anyway. It's enough for me to know that the only people who deny things like the accuracy of radiometric dating, stratigraphic methods, the constancy of the speed of light, and the authenticity of most fossils are people with a strong religious motivation to do so. The standard view of all these things is good enough for the US Geologic Survey, NASA, the National Science Foundation, the Royal Society, and dozens of other scientific bodies listed here. It's also good enough for oil companies who just want to find oil and make money. If you read what petroleum geologists write, you'll see references to million-year time spans, geologic ages, and the ancient environments that today's rocks came from. You won't see anything about Noah's flood.