Thursday, August 28, 2014

My Fun Evolution Trip Part Five: A Visit to a Prairie Dog Town

On the next day of the evolution trip (see previous entries below), my companions and I visited the Badlands, about fifty miles east of the Black Hills, in the driest part of the short grass prairie. We drove through Scenic, a nearly abandoned town where the now-closed bar catered to some Lakota men who had a lot of time on their hands. I remember these men from the 1990s, and they were nice and interesting people.

I have lots of bad things to say about soil erosion, but it can be starkly beautiful in the Badlands, where it occurs slowly enough that the plants and animals have been able to adjust to it.

The Badlands consists of mountains and cliffs of dirt, but it is dirt from the Cenozoic Era, sediments (sometimes with large mammal fossils) that never consolidated into rock. Some of the sediments were bright yellow and red, because they were deposited during a period of drier climate when the iron oxidized more.

The best part was when we drove a few miles out on a dirt road to the prairie dog town. Prairie dogs are not dogs; they are sort of like ground squirrels. Their most notable feature is their communal system of interconnected tunnels in which they live, relatively free from predators. There are a few predators, such as the black-footed ferret, which can slink down into the tunnels, grab sleeping prairie dogs, and chew them into a bloody mess. Do the prairie dogs have any defense against such predators?

Yes, and that defense is altruism, regarding which I have written many times and will write many more times. Some of the prairie dogs stand guard at tunnel entrances, and if a predator (or a human whom they think might be) approaches, they give a warning chirp and dive into the tunnel. In so doing, they put themselves at increased risk of getting caught by the predator. But even if the guard gets killed, his genes make it into the next generation because his relatives may reproduce more. That is, even a guard that gets killed may have enhanced inclusive fitness. In this case, the guards seemed more curious than alarmed and approached me, perhaps hoping for some food. This particular prairie dog town gets a constant stream of human visitors. Was it my imagination that they were trying to be cute? This is an evolutionary strategy that worked for cats.

Besides the evolutionary story of altruism, a prairie dog town is a good place to study the ecological effects of animals on their ecosystems. Without prairie dogs, the short grass prairie has a thick sod of grass stems and roots, into which a little seedling has little chance of growing. Most of the annual wildflowers (such as the scarlet globemallow, no longer in bloom when we visited) grow only in areas where the sod has been disturbed. This occurs where the prairie dogs dump their excavated soil (and fertilize it with droppings), and where the bison wallow. Bison do not have hands and cannot scratch parasites so they have to wallow around on the ground for relief. In the photo, note the prairie dog on the mound of disturbed soil with globemallows, and the bison in the distance.

The prairie dogs even have an effect on other animals. Burrowing owls do not dig their own burrows but nest in prairie dog tunnels.

The wind was extreme when we visited the prairie dog town, so the videos at that site were worthless. But two days later, at Devil’s Tower, my videographer Sonya Ross made an excellent recording which I will post in due time on YouTube.

Prairie dogs are not popular among ranchers, who like to poison them. The reason is that bison are smart enough to not step in the holes, but cows are stupid and step in the holes and break their legs. Prairie dogs are routinely poisoned on private land, and have occasionally been poisoned on federal land leased by ranchers from the government. Ranchers generally consider federal land to be theirs, rather than the property of all American citizens, and in some cases ranchers have protested for the right to graze their cattle on these lands for free. (They call this private enterprise rather than communism.) But at least, as far as I could see, the prairie dogs actually within the borders of Badlands National Park are safe.

As we left the park, we saw a herd of bighorn sheep, including a mother with a kid that was just learning how to jump around on the cliffs. With twenty cars and a dozen photographers around for this impromptu show, the sheep seem to have lost some of their fear of humans.

Monday, August 25, 2014

My Fun Evolution Trip Part Four: East Meets West in the Black Hills

The Black Hills is also a good place to study biogeography. While no place is as good as Wallace’s line in modern Indonesia, you might find the Black Hills of South Dakota to be more accessible.

The Black Hills (so named because the ponderosa pines look black from a distance) are a small mountain range that formed separately from other nearby ranges and hills, such as the Bear Lodge Mountains, Bighorns, and Bear Butte. They are entirely separate from, and a hundred miles east of, the Rockies. The Rockies form a rough dividing line of eastern from western species: they have mostly western species. But the Black Hills has a mixture of eastern and western species. This is a perfect illustration of biogeography over evolutionary time. The species that migrated from the west include:

·         Ponderosa pines (Pinus ponderosa)
·         Limber pines (Pinus flexilis)
·         Many wildflower species
·         Violet-green swallows
·         Bighorn sheep
·         Mountain goats

It is obvious from this list that I know more about plants than about animals.

But other species migrated from the east. Western North America has tree species such as the Fremont poplar and many of its own species of oaks, but in the Black Hills you will find:

·         Bur oak (Quercus macrocarpa)
·         Eastern cottonwood (Populus deltoides)

This makes sense because bur oak can survive in prairies and is the most likely oak of all eastern species to have migrated westward across the prairie, and cottonwoods migrated from the east along creeks and rivers.

Other species migrated in from the north:

·         White spruce (Picea glauca)
·         Paperbark birch (Betula papyrifera)
·         Quaking aspen (Populus tremuloides)
·         Twinflower (Linnaea borealis)

I can scarcely refrain from posting all of the dozens of birch bark photos I took.

Some tree species can be found in virtually every state, such as boxelder (Acer negundo).

Some of these species are mere remnants of larger populations in other areas. For example, other mountain goat populations are not found within about a hundred kilometers of the Black Hills.

Not only have species migrated to the Black Hills, but some of them can only be understood as remnants from the last ice age. Thousands of white spruces persist in the Black Hills, but mostly in creek bottoms and on north-facing slopes in the higher, northern part of the Hills. As the weather became warmer and drier after the last ice age, the spruces retreated uphill while the ponderosa pines moved in. The limber pines are found in only a tiny population near Harney Peak, the highest point in the Hills, also retreating from the warming, drying climate.

The Black Hills is also a good place to observe microclimates. The wet birch forests along the creeks have lots of ferns and violets. Immediately upslope, you can find ponderosa pines on the dry rocky slopes. In thin soil on top of the rocks you can find cactus, while in the moist cracks of the very same rocks you can find small ferns. Perhaps best of all, in the bogs near Black Fox campground, as in many other acidic bogs in coniferous forests of northern North America, you can find a little birch shrub with small leaves, the bog birch Betula glandulosa.

You can also notice geographic patterns within species in the Black Hills. I am accustomed to seeing three to five leaflets on Oklahoma box elders, but in the Black Hills they mostly have five to seven leaflets.

Biogeography is like a mystery novel in which you try to figure out where everything came from over evolutionary time. I recommend the Black Hills for a biogeography adventure.

Tuesday, August 19, 2014

My Fun Evolution Trip Part Three: The Great Unconformity of the Black Hills

One of the greatest new insights into the history of the Earth was when James Hutton realized that the Earth had to be very old and that geological deposits were recycled over and over again—an idea called uniformitarianism. Hutton was not the first person to think of this but he was the first to pursue the idea in an organized fashion. His complex thoughts were later summarized by John Playfair and extended by Charles Lyell. As the modern paleontologist Michael Benton has explained, uniformitarianism can mean lots of things, some of which (such as uniformity of process) is still accepted by modern scientists, but others of which (such as uniformity of rate) are not. The former means that you can understand the past by studying the processes of the present, rather than invoking random miracles. The latter means that those processes have operated as slowly in the past as they are at present, which is clearly not the case.

Hutton, loving near Edinburgh, Scotland, in the late eighteenth century, looked at the local geological deposits and thought about them. At Siccar Point is an unconformity with nearly vertical Silurian sedimentary layers on the bottom and gently sloping Devonian and Carboniferous sedimentary layers on top, with millions of years of missing history in between. He realized that such sedimentary deposits could not have formed all at once during a global flood. And here’s why.

When the older, lower sedimentary layers formed, they had to be horizontal, due to the law of gravity. But these layers had been turned on their sides. If they were still mud when turned sideways, they would have gone PHHHHHHT! and squished into a big pile. The fact that they retained their layers meant that they had become rock before being turned on their sides. Then other sedimentary layers formed on top of them. This simply could not have happened during a single global Flood of Noah. Of course, creationists then as now could simply invoke miracles. They could say that God squished the lower layers into rock and turned them on their sides in the middle of the Flood. Does the Bible say this? No, they just make it up.

You can go to Scotland and see it for yourself. Sounds to me like a great excuse to go to Scotland. But there are other formations called The Great Unconformity, including the one John Wesley Powell discovered in the Grand Canyon. An unconformity is a geological formation in which a large chunk of time is missing. But there is a really good one (which didn’t make it into the Wikipedia entry) in the Black Hills of South Dakota, which has Precambrian sediments raised at a 70 degree angle on the bottom, and horizontal Cambrian strata on top, with almost two billion years of missing strata.

It is difficult to get directions to find it. So remember this. Find Nemo Road west of Rapid City. There are several ways to get there. Just as soon as this road, as you go west, crosses over the line from Pennington County into Meade County, you will see a bridge over Boxelder Creek. Immediately to your left is the Great Unconformity.

This is what it looks like from Nemo Road:

Even though it is in Black Hills National Forest, there are private landholdings all around, so you need to stay away from people’s yards. You will probably find, as I did, a path worn through the grass by generations of geology students from the South Dakota School of Mines and Wheaton College Science Station. There are other places to see the unconformity, but this is the only place where you can walk right up to it and put your finger on almost two billion years of missing history.

How could this unconformity have formed all at once during a flood? But maybe creationists have another explanation. Maybe the lower Precambrian layers were pre-Flood, which would have given ample time (almost two thousand years) to form the sediments into rock and then push them to their current 70 degree angle, and then the upper sediments were of Flood origin. This approach is not much help, however, because two thousand years is not enough time to have turned all the Precambrian sediments into rock and pushed them over, unless God did a miracle which the Bible conveniently does not mention.

So when you are in the Black Hills, forget about Deadwood and even Mt. Rushmore. The only really interesting thing, to me, about Mt. Rushmore, is the remnant populations of the rare fern Asplenium septentrionale that someone showed me in 1993 but which have apparently died. Go see the Great Unconformity, a hidden treasure—there is not even a road sign to mark the Nemo Road location.

Thursday, August 14, 2014

My Fun Evolution Trip Part 2: Carhenge, the Other Interesting Thing in Nebraska

I continue my series of posts about a very interesting trip I took this summer. Part of the trip took me through Nebraska. I will simply note that there is, in fact, a Nebraska National Forest, in the western part of the state, with scattered ponderosa pines (not, as you might suspect, giant cornstalks).

Carhenge is exactly what its name suggests: a smaller (but not miniature) model of Stonehenge built out of big old hoopdie cars. A farmer with more money than he knew what to do with (something unlikely to happen today) decided this would be a sufficiently outlandish artistic expression. Why would anyone do this? And why am I writing about it in a science blog?

In addition to the menhirs and dolmens of cars, there are models of fishes, insects, and even dinosaurs made out of car parts.

One car has even been made to look like a covered wagon.

I use Carhenge—which you just have to see, otherwise you will not believe it—as an example of memetic variation. Just as biological natural selection is based on genetic variation, so cultural evolution is based on memetic variation. And there is no telling where these new memes can come from. The idea for Carhenge did not come out of nowhere—in Neolithic times there were many astrological henges, mainly in Europe, and Carhenge is not the only modern imitation. Carhenge, once it was created, became part of the pool of memetic variation.

But it never really caught on. Apparently nobody saw it and said, “I’d like to build me one of these.” There are lots of imitation Stonehenges in America, including one in Missouri built out of old refrigerators, but no other carhenges. So, in this sense, Carhenge was a failure of cultural evolution. And in another sense: I would have expected local people to form neo-pagan skyclad groups that would celebrate the summer solstice there. Carhenge has had one or two solstice celebrations, but not enough to take on a life of its own, certainly not with skyclad pagans (this is, after all, Nebraska). There is graffiti everywhere, mostly people’s names, and some of it Christian.

There is a time capsule there. When the time capsule is exhumed, more people might remember Carhenge than would remember you, or me.

Friday, August 8, 2014

My Fun Evolution Trip Part 1: Ashfall Beds, Nebraska

Today I begin a series of essays about a long trip I recently completed, which took me from Oklahoma to Idaho and back, stopping at lots of places of ecological and evolutionary interest. The second day of the trip, July 20, I visited Ashfall Beds in Nebraska, which is one of the most amazing fossil deposits in the world.

Ashfall Beds State Park is in rural Nebraska. It is not on the way to anything, but it was my principal reason for going to Nebraska. But it is well worth a trip to Nebraska even if for no other reason.

About twelve million years ago, life was abundant in the savannas of what is now Nebraska. There was certainly an abundance of animal life. Reptiles included the giant Hesperotestudo tortoise, now extinct. Among the now extinct mammals were horned rodents of the family Mylagauidae, the “raccoon dog” Cynarctus, saber-toothed deer (I am not making this up), and three-horned deer. There was a kind of dog that specialized on eating fruit. There were three kinds of small camels. The most abundant mammal in this fossil deposit was the now extinct rhinoceros Teleoceras.

The nearest relatives of some of these mammals live today in Eurasia and South America. Mammals such as these and many others were thriving in North America until about twelve thousand years ago (not twelve million), when they died in the Pleistocene Extinction. This extinction event probably resulted from the interaction of climate change and overhunting by newly-arrived humans, neither one of which by itself would have been sufficient. It was an interaction, with the effects of climate change amplifying the effects of overhunting, and not a simple additive effect.

What was perhaps most interesting about these mammals is that they represented earlier stages of evolution. The best example is probably the horses. Some of them, such as Protohippus and Hypohippus, had three toes, while others, like Pliohippus and Hipparion, had a hoof and two small stubby toes. Some horses grazed (ate grass), while others browsed (ate broad leaves). The specimen numbered "2" is one of the horses.

What happened? One day a volcano over the Yellowstone Hot Spot erupted and sent ash into the air. The finest ash traveled to what is now Nebraska, where it covered the leaves and grass. The mammals breathed and ate the ash. Tubercles on their bones showed that they survived for weeks (but not years) after eating the ash. One of the symptoms was that they got very thirsty and converged on a water hole. But drinking water did not save them, and they died, piled up on top of one another at the water hole. That’s where we find the mass of bones today, entombed in volcanic ash. It was not like one day in Pompeii; it took a few weeks, but with the same effect.

Creationists have a nearly impossible time explaining such a fossil deposit. They make no attempt at all to explain how Noah’s Flood could have produced this deposit. Instead, they claim that this deposit was formed after the flood in pretty much the way scientists have discovered. They just claim that it all happened in the last four thousand years rather than the twelve million years indicated by radiometric dating of the ash. Processes such as the formation of the sedimentary cap over the volcanic ash occur slowly today, but the creationists simply invoke a more rapid pace, perhaps of miraculous origin. The Bible indicates no such miracles, but creationists love to just make up miracles whenever they want to. In one creationist article about Ashfall beds, the authors do not address why the mammals are similar to but not the same as modern mammals—for example, the three-toed horses. There were no modern horses of the genus Equus. And no modern camels (even the South American ones) or dogs or cats or… Are we to suppose that God scooched the primitive-looking mammals over to North America, and kept the modern ones out, just to trick us into accepting evolutionary science?

Ashfall Beds is an amazing place to see fossils which fit in perfectly with evolutionary processes and the evolutionary timeline.

Tuesday, August 5, 2014

Frugality and the Market

I just returned from a long and wonderful journey through ten states. I saw a lot of ecology and evolution and I want to tell you all about it in upcoming essays. Meanwhile I will post this general essay until I can get the new ones written. On this long journey, I ate out a lot. I was more frugal than most travelers but less frugal than I am when at home. Which leads to the topic of this essay.

I am almost off the charts for being frugal in my use of energy and my consumption of processed materials. I am not a Scrooge; I actually enjoy frugality—I greatly enjoy the few things I spend money on, as well as the free things like taking a walk with my wife.

For example, I just do not eat out very often. Sometimes, as I noted in a recent blog essay, my frugality has made me a target for people who, perhaps with religious motivations, want to disrespect me for the carefulness with which I treat what they consider to be God’s creation.

But when I do eat out, I like having variety to choose from. I will admit that I have a hard time telling Cheesecake Factory apart from Applebee’s, but I wouldn’t want my only choice to be sushi—even though I love the new sushi restaurant in Tulsa (Sushi House, on Lewis near 71st) very much.

If everyone lived like me, however, the bottom would drop out of the restaurant business. Tulsa would have a couple of sushi places, a Japanese steakhouse, Marley’s Pizzeria, India Palace, and that’s about it. The very diversity of market experiences that I enjoy depends on people living the way I think they shouldn’t.

I’m not too worried. If America goes frugal (which is about as likely as the sun going supernova next year), the loss of market diversity would be a small price to pay for the promotion of a healthy local economy full of farmer’s markets, ecological sustainability, and personal financial responsibility. I find fast food establishments to be useful on rare occasions, but if they all closed up I wouldn’t be too upset. Meanwhile I will continue to enjoy, on rare but memorable occasions, the diversity of restaurant food that is made possible by people who are too busy eating out to read this blog.