16 November 2015

“Making North America,” episode 3: Human

Posted by Callan Bentley

The PBS series NOVA has a new three-part series called “Making North America” that premiered two weeks ago. Hosted by the director of the Smithsonian Institution’s National Museum of Natural History, Kirk Johnson, the series explores the tectonic assembly of terranes that resulted in the bedrock of the continent, the panoply of diverse creatures that have dwelled here in the past, and the human prehistory of our continent. I was given press access to review the episodes in advance. I have been covering them one by one. Today, we’ll take a look at the final offering, “Human.”

It begins with the Ice Age of the Pleistocene, since that’s apparently when North America was first inoculated with humans. They came from Siberia, but did they (a) climb over the Laurentide Ice Sheet, (b) wait in the great Alaskan vestibule until an ice-free corridor opened up, or (c) use boats to travel down the west coast? Kirk goes ice climbing and finds it difficult, and uses that as a visually striking rhetorical device that option “a” isn’t so likely. Option “b” is presented as the standard academic party line, but that’s a lead in to an emphasis on the preferred hypothesis, “c,” which leads us to the Channel Islands of California, where a 13,000 year old femur is explored as evidence for boat technology existing early on in the human history of North America.

So people somehow got to places like coastal California, and then they moved inland. One thing they found was critters, and part of the episode visits the La Brea tar pits in Los Angeles, and we get a taste of some fun paleontology as well as a hint of the overkill hypothesis for the extirpation/extinction of the Pleistocene megafauna. That leads us to hunting, and to Clovis points, our oldest uncontroversial archaeological evidence of humanity’s presence in North America’s interior. There’s a cool scene where Kirk makes a spearhead and then tests it against hide-covered ballistics gel.

Agriculture and soil are the next topic, presented starting at Mesa Verde, but then it goes off in a “but then the Europeans showed up” kind of way. I was delighted to see David Montgomery, MacArthur fellow and author of Dirt: the Erosion of Civilizations, show up alongside Kirk in a North Carolina tobacco field. They engage in a fun examination of the soil, and I thought it was pretty clever that they put on aprons for a faux cooking show set up, combining ingredients from jars to make soil: sand, silt, clay, organic matter, living critters, and -this caused both of them to laugh- “time” in a bottle.

The depletion of east coast soils was a matter of national security in the early days of the United States of America, and this offered a way to segue into discussing westward expansion, railroads, and the California gold rush. Kirk and a local expert travel into a mine and examine auriferous hydrothermal quartz veins there. They interpret these as the healed scars from earthquakes, which is stretching the point but probably a good approach for the show’s audience, and it’s accompanied by a lovely animation – showing a vein crystallize from the inside, with quartz nucleating on the walls and grow inward, trapping gold flakes along the way. Another cool visualization was of the old school variety: simply comparing “then” and “now” photos of Los Angeles, showing the profusion of oil wells that used to occupy that town. Even today, there are 3000 active wells in L.A. County.

Burning oil makes CO2, and global warming gets a brief mention, but it’s not dwelled on for more than 30 seconds or so. But a more palpable disaster lies waiting in the Pacific Northwest, so it’s off to Washington to examine a ghost forest and tsunami sand deposit. I appreciated the decision to say “a Pacific Ocean plate” instead of “the Juan de Fuca plate,” for the sake of simplicity. It’s an elegant choice that’s technically correct and also intuitive for the nontechnical audience. But matching this good word choice is a bad word choice – I shudder to report that “fault line” gets used at least once.

The episode concludes with a visual recap of the whole series, and a good message that geologists are useful: learning about the past helps us prepare for the future. As we look back in time, or predict what comes next, we can see that no landscape is permanent. I endorse both of those messages wholeheartedly. They encapsulate the sense of participating in the grand sweep of epic events, and this series did a good job of expressing those events.

I’ve been keeping tally with each episode of the gender ratio of the experts interviewed, and this final episode has a ratio of 6 named male experts to 2 named female experts, one of whom also appeared in episode 1. That makes “Human” the most male-skewed episode of the series (previous episodes were 5:2 and 2:2).

The episode airs in two days: on Wednesday, November 18, on your local PBS station. Check it out.