Monday, September 15, 2014

My Fun Evolution Trip Part Nine: The Most Amazing Plant Fossils in the World, part one.

Ever since I read about the Idaho Miocene fossil beds, at a place called Fossil Bowl, decades ago in an essay by Stephen Jay Gould, I have wanted to visit them. This past summer I finally had the chance. I drove south of Coeur d’Alene in State Highway 3 for about fifty miles and drove through the little town of Clarkia, which has no services and which you could almost drive past without noticing. On the right (west) side of the road was a big open area that had been converted into a motocross track. Unless you have specific directions or just happen to see the hand-painted plywood sign set far back from the road, you will never recognize this as being a famous fossil deposit.

I drove in and looked for a sign telling me where to go. Because I had called the Kienbaum family (the owners) before coming, I knew to look for a house on the hill. So I started driving up what I thought was the driveway and found myself on the motocross track. I didn’t see it coming. Suddenly I was going up a steep slope and then my car (a little Scion) launched off into invisible space and came thumping down on the track. It didn’t make it up the next incline. Fortunately I found a way to exit the track. I found a van of young adult bikers who were taking an air conditioning break, and who had been immensely entertained by the sight of a little car on a motocross track, and they told me how to find the driveway. I had to knock on every door of the house with unfinished siding before Mrs. Kienbaum could tell me to look for her husband and sons in one of the many workshop buildings downhill. The younger son found me and led me through a crowded storehouse full of wooden furniture that Mr. Kenneth Kienbaum had made. I paid ten dollars for the privilege of digging fossils and taking them with me, perhaps the best ten dollars I ever spent. Kenneth told me of the interest that even major media such as PBS were showing in this site. I will be posting some YouTube videos [my channel] of my visit and will announce when I do. I make videos with no budget. If you want to see a video about Fossil Bowl that was actually produced with a budget, using support from Bucknell University, the University of Idaho, and the Botanical Society of America, see Plants Are Cool Too! Episode 2 produced by the very creative Dr. Chris Martine.

The younger Kienbaum son led me to a place I could park right beside the fossil deposit. You would never guess what it was. The outcrop is about the size of a three-car garage.

I set to work digging and photographing fossil leaves. (Others have found fossil fishes, but I did not. Leaves are always more abundant than fishes.) I found many good specimens that had already been excavated and were just lying around on the ground. One of my best specimens was one I found by stepping on it. I will provide some details and photos of these specimens in the next essay.

How did these fossils form? Fifteen million years ago, during the Miocene epoch, leaves of a lush forest fell into a lake and were preserved in sediments. Oxygen destroys organic matter, but the water and sediments kept these leaves away from oxygen. In fact, some of the leaves are not leaf fossils, but are actually still leaves, complete with tissue and DNA. I believe that these leaves have provided the oldest DNA specimens ever found, far older than the 30,000-year-old Neanderthal DNA in Europe. The organic molecules from the 70-million-year-old T. rex fossils were collagen, the protein that makes up cartilage, not DNA.

Once exposed to oxygen, these leaves quickly turn black. They are still beautiful fossils, but the organic matter is reduced to a residue. So to find “fresh” leaves, you have to split intact rocks open, which the older son, Riley Kienbaum, showed me how to do.

The leaves, mostly autumn deciduous leaves, are separated by layers of sediments. The leaves form a slightly weaker layer in the rock, so that you can carefully split open the rock and expose the leaves. Riley did this for me and I saw some leaves that still had the same red autumn colors that they had 15 million years ago!

I brought back some slabs of rock, which I kept moist, and which I split open in my laboratory and showed to my students. Unfortunately, in my specimens, the rocks layers crumbled and I was unable to recover any fresh-looking leaves.

How do we know the ages of these leaves? Radiometric dating provides the answer. Radiometric dating can be performed only on volcanic material. But 15 million years ago the Cascades were just rising up as a series of volcanoes, many of which remain active today. The volcanic dust layers interspersed with the leaves and sediments can be dated.

Meanwhile, motorcyclists did some amazing maneuvers just a few feet away from where I was digging. Some of them came over to see what I had found. They were genuinely interested in the fossils and were some of the nicest people I have met

Before planning your trip, it is good to contact the owners and make sure access is open when you plan to visit. They are really very nice people.

In the next essay, I will tell you about the fossils I found.

Friday, September 12, 2014

New video

I just posted a new video on StanEvolve. It has not shown up on the playlist yet but the link works. Rick Perry prayed for rain. Did God answer that prayer? How can you ever know? Falsifiability and science...

Wednesday, September 10, 2014

My Fun Evolution Trip Part Eight: Tundra and Meadow

I was driving from Bozeman, Montana toward Coeur d’Alene, Idaho, which should have been a relatively short drive. But I looked toward the south of I-90 and saw snowy peaks. And I wanted to hike to the tundra. So I took a highway south from Bozeman to the resort town of Big Sky. I kept driving past all the resorts where people spent a lot of money to do things I consider boring. At the end of the road there was a crowded parking lot for a trail leading to the Lee Metcalf Wilderness and Spanish Peaks. I took a little water, and my camera, and started walking. During the next four and a half hours of vigorous hiking, sometimes running, my body burned about 1500 calories.

For a long ways, I walked through rocky subalpine meadows. Meadows are not the same as tundra, though they intergrade into one another. Meadows are open areas, associated with creeks, surrounded by forests of more or less full sized conifers, while tundra is an open area underlain by permafrost, interspersed with small krummholz trees. They are not the same, but it is understandable to confuse them. (What is not understandable is for Garrison Keillor to describe the tallgrass prairie of Minnesota as tundra.) One of the things tundra and subalpine meadows have in common is that they have a short growing season, and if the wildflowers are to bloom, they have to do it all at once, which just happened to be late July when I and hundreds of others were visiting.

For most of the trail, I was surrounded by meadows, characterized by some of the following plants. If you don’t like lists of plants, just skip ahead, but I include them for search engines to find.

Geraniums (both red G. viscosissimum and white G. richardsoni)
Mertensia bluebells
Balsamroot (Balsamorhiza), with inflorescences like huge sunflowers
Arnica, with smaller inflorescences
Cow parsnip of the genus Heracleum, probably H. sphondylium, introduced from Europe
Yellow columbines (Aquilegia)
Larkspurs (Delphinium)
Bright red Indian paintbrushes (Castilleja)
Prairie smoke (Geum), in fruit
Forget-me-nots (Myosotis)
Bistort (Persicaria bistorta)

Elderberry (Sambucus)
Just try to imagine all the colors riotously thrown together! These photos will not do full justice.

Meadow flowers, with red geranium in the foreground.

Meadow flowers, with cow parsnip in the foreground.

Indian paintbrush from a subalpine meadow.

Columbine from a subalpine meadow.

Geranium viscosissimum from a subalpine meadow.

Not far from the trail, my fellow hikers and I saw a moose. It was the only moose I have ever seen and may be the only one I ever see.

There were also nutcrackers flying around, and I was delighted to tell the people who were watching them about how nutcrackers plant white pine seeds amidst the rocks.

And then, around one last bend, just before I was about to give up and turn around, I found a flat tundra with an utterly blue lake and patches of July snow. There was almost no overlap in plant species with those in the meadow. There were buttercups, a different species of lupine, lilies, and sedges. They were only about 15 centimeters tall, in contrast to the half meter height of the meadow plants.

Everyone on the trail seemed to be cheerful, and I had wonderful conversations with a large number of them. When I headed back down, I encouraged those who were still headed up that, when they reached the blue lake at the true tundra, they would feel like they were in heaven, if heaven was windy and chilly even in July. “May the forest be with you!” I told them, a phrase also on my T-shirt. I was as happy cheering on my fellow hikers as with the hiking itself.

Friday, September 5, 2014

My Fun Evolution Trip Part Seven: What is Devil’s Tower?

Announcement: I am starting to post YouTube videos from my summer evolution trip. I just posted the first one, “Darwin falls off a cliff,” about the adventure of science! I will be posting other videos, including ones about Devil’s Tower and about my six earlier blog entries, in upcoming weeks. My thanks to videographer Sonya Ross.

Now, about Devil’s Tower.

Devil’s Tower, in southeastern Wyoming, formed from a massive volcanic intrusion through sedimentary layers. In subsequent millions of years, the sediments eroded away, leaving the hard igneous rock. The crystalline structure of the material produced lava tubes that were roughly square in cross section.

It would seem that no other explanation is possible. Creationists such as the folks at Answers in Genesis give a very vague explanation that does not account for the details. They basically say that all kinds of squishy, explosive, and creepy things were happening as the Flood waters receded, so you shouldn’t be surprised at anything that you might see of a geological nature. And of course God could have always done a miracle, even without mentioning it in the Bible.

But creationists are not the only ones who have alternative explanations for how Devil’s Tower formed. There are also Native American legends about how it formed. Here is one. Seven sisters and a brother were out in the woods, and the brother turned into a bear and chased the sisters. The sisters found a massive tree that spoke to them and invited them to take refuge in its branches. The bear climbed after them, creating the vertical scratch marks in the massive trunk. I guess the bear wandered off somewhere, but what happened to the seven sisters? They became the Big Dipper.

This reminds me of a story from a California native tribe. There were seven husbands and seven wives. The wives were out digging wild onions, and ate them. The husbands hated the smell on their wives’ breath and drove them from the village. The wives found a rope hanging from the sky and climbed up. They became the Little Dipper. The husbands got lonely and went out looking for the wives. They found another rope hanging from the sky, climbed it, and became the Big Dipper. Ever since then, the Big Dipper has been chasing the Little Dipper around the North Star.

Did the native tribes actually believe any of these stories? Maybe they were just stories for children. There remains today a vibrant and humorous Native American storytelling tradition. Or maybe they actually believed them. Or maybe they started out as stories but became religious beliefs. I don’t know. But I do know that native tribes did not burn each other at the stake for the heresy of not believing one of these stories. They would burn each other at the stake for other reasons, but not for religion. (My sixth great grandmother Nanyehi, or Nancy Ward, rescued a white woman from being burned at the stake by her fellow Cherokees.)

Fictional and religious stories serve a purpose: they enhance tribal and community identity. Whether they actually “literally” happened is largely irrelevant. Scientific stories also serve this function. Scientific meetings, such as the Botanical Society of America meeting toward which I was heading, are a great time of friendship. But in addition, scientific stories are designed to be “literally” true. Creationists are religious people who are not satisfied with the community-identity function of stories, and will stop at no stretch of the imagination to try to make their stories sound like science—and will then send you to hell for not believing them “literally.”

Tuesday, September 2, 2014

My Fun Evolution Trip Part Six: Adaptations and Stories

We saw a couple of really interesting plant adaptations in the Black Hills. The first is the white buttercup, which filled some of the shallow ponds of Little Spearfish Creek.

The underwater leaves were finely dissected, which increases their surface area for absorbing dissolved carbon dioxide. Terrestrial leaves could also absorb more carbon dioxide this way but would lose too much water, which is not a problem for an aquatic plant. The flowers, however, float on top of the water where insects can find and pollinate them.

Another set of adaptations is represented by the quaking aspen, Populus tremuloides. When you see a whole clump of aspens, perhaps covering several acres, it may be a single genetic individual that has spread by underground stems. All of the aboveground stems are the same height. The resulting genetic uniformity has its risks: diseases can spread rapidly not only because of the genetic monoculture but because of whichever underground connections may remain intact. But the connections help to stabilize the massive clone: the stems (ramets) growing in favorable locations can help to support the ramets growing in unfavorable locations, very much like the phalanx of an army. Many plants have this adaptation, but aspens are famous because they have such massive clonal growth.

Other aspen adaptations sound more like just-so stories. The first is the ability of their leaves (as well as those of cottonwoods, which are in the same genus) to quake in the slightest breath of wind. They do this because of their flat petioles. The standard explanation is that this allows the leaves to absorb more carbon dioxide. I am confident that this is true, but I can only ask why, if quaking is such a wonderful adaptation, that more plants do not employ it?

The second is a nearly unique bark adaptation. The bark looks greenish and is capable of carrying out photosynthesis. Underneath a tight white layer of tissue, there is an intensely green layer, at least in the Black Hills populations. Apparently the photosynthesis in this layer is less inhibited by cold temperatures than in leaves and might benefit the tree in early spring or late autumn. I could not readily find references about what aspens might do with the sugar their bark produces; perhaps they load it directly into the adjacent phloem and send it down to the roots and underground stems. Apparently this layer was actively producing sugar, for an ant quickly found the shallow wound that I made in the bark.

I do not doubt the value of the adaptation, but once again I ask, if it is such a great adaptation, why don’t other trees have it? Of course, many young stems do have it. We cut down a mulberry tree in our yard, which was inconveniently disturbing the foundation of our house, and hundreds of thick green stems immediately sprouted back. Even older mulberry stems have a green layer—but not, to my knowledge, the trunks, as in aspen.

I would think that green trunks, like quaking leaves, would be easy to evolve, and should be more common, if our facile adaptive just-so stories were entirely correct. It appears to me that a few plants have evolved great adaptations within evolutionary constraints.

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.