02/23/2018

Why You Don’t See ‘Goosefoot’ On Your Thanksgiving Dinner Table

7:32 minutes

A green plant with tiny green spheres along the stem
Chenopodiaceae, part of the goosefoot family. Credit: Dinesh Valke/flickr/CC BY-SA 2.0

When we think of Native American agriculture, corn and maize come to mind. But before those blockbuster crops took over, indigenous peoples were farming things like “erect knotweed,” “goosefoot,” and “little barley.” So what happened to these domesticated plants, and why don’t they have a place on our Thanksgiving tables? Annalee Newitz, Tech Culture Editor at Ars Technica shares how one researcher is digging into the history of these “lost crops.” Plus, the Neolithic period probably smelled bad, but how do archaeologists measure 9,000 year-old smells?

[They say that seeing is believing—but soon, that old proverb could be out of date.]

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Segment Guests

Annalee Newitz

Annalee Newitz is a science journalist and author based in San Francisco, California.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow.

When we think of Native American agriculture, we think of corn– the stuff Europeans couldn’t get enough of once they got here. But before that crop became popular, indigenous people were farming things like erect knotweed, goosefoot, little barley. So what happened to these domesticated plants? And why don’t they have a place on our Thanksgiving tables?

Here to tell us about these lost crops, as well as other short subjects in science is, Annalee Newitz– Tech Culture Editor at Ars Technica. Annalee, welcome back to Science Friday.

ANNALEE NEWITZ: Hey, thanks for having me back.

IRA FLATOW: You’re welcome. So what are they? Where did they go? Things we’ve never heard of, like goosefoot, little barley. Give us the story on that.

ANNALEE NEWITZ: That’s right. So about 1,000 to 2000 years ago, indigenous people in the Americas had a very different set of meals than they would have had much later and that we have today. And there’s an archaeobotanist– which is somebody who studies ancient plants– named Natalie Mueller at Cornell University, who’s been studying these lost crops. And she focuses specifically, on erect knotweed, which, if you’re a gardener, you’ve probably heard of Asian knotweed which is an invasive plant.

This is not that. This is a local indigenous plant. Loves to live near the water in the South and the Midwest. And it has these really hard fruits that have starchy seeds inside that were quite delicious. And what’s interesting is that these crops which were so popular for so many centuries, really finally got pushed out over time, once maize arrived from Mexico– came up from the South– these crops became less popular.

And then, when Europeans arrived and started colonizing and killing off indigenous people, but also, more importantly, moving them around– basically, kicking them off the farms and kicking them out of areas where they had been farming these crops– the knowledge about these crops, the seeds for these crops, just disappeared. And so the examples we have of these domestic plants all come from very ancient sources. They’ve been found in ancient campfires and ancient camp sites that belong to indigenous people 1,000 years ago.

IRA FLATOW: So they’re still looking for these, wherever they can find–

ANNALEE NEWITZ: We’re still looking for them. Natalie’s work is great because she’s done a terrific job showing the difference between the domesticated erect knotweed and the modern wild version, and you wouldn’t be surprised to know, that when farmers farmed these crops, they looked for ones with bigger seeds and bigger fruits, and so the domestic version has bigger fruits. And they also germinate more quickly, which means when you plant them, you’re sure that they’re going to bear fruit that year.

And what’s really fascinating about this work is that this is a very rare example of a plant that we can study that was wild and then, domesticated and then, went wild again. And so Natalie is working with geneticists at the Smithsonian, trying to sequence the DNA of these ancient plants, as well as the modern ones– which, indeed, the modern ones are endangered so part of this is about trying to protect these contemporary wild plants, as well– but they’re trying to figure out, what happens when a plant, or anything, goes from being cultivated to being wild?

IRA FLATOW: Well speaking of plants, it turns out that they are 100,000 million years older– are they that old, than we thought?

ANNALEE NEWITZ: It turns out land plants are older than we thought. A new paper that just came out shows through DNA analysis that plants on land evolved about 100 million years earlier than we thought so they evolved about half a billion years ago, right around the time that multicellular life was evolving in the ocean.

And what’s cool about this story is– well, first of all, it just shows us what Earth was like when our ancestors– the multicellular animals– were hanging around in the ocean, there were indeed, things like mosses– very simple plants, like liver wart and such– on land.

But what’s really cool is that these were plants with root systems, and what root systems do is actually, kind of destroy the environment because at that time, free oxygen was still a relatively new thing on Earth and the process of putting down roots and shake up the dirt, make it into smaller pieces so when it rains and when there’s weathering from wind, that dirt runs off into the oceans much more quickly than it would if it hadn’t been messed up by these root systems.

And so that means that this jump-started a chemical process that drew carbon down out of the environment. That whole process of weathering pulls carbon down, and allows more free oxygen to hang around, which was great for those multicellular animals in the oceans. They love that oxygen. It helped them develop. It gave them enough energy.

So now we have a picture of how, basically, land plants helped our ancestors develop in the ocean, and so we have a much more complete view of how that time on Earth, during the Cambrian Explosion, what that time was like, basically. So plants were our heroes– is what I’m trying to say.

IRA FLATOW: They’re still my heroes.

Moving on. This is something really weird– researchers in Sweden found a group of 8,000 year old heads on spikes. Sounds like a Game of Thrones plot here. What was going on there?

ANNALEE NEWITZ: This is a story that is great because it reminds you that first impressions are not always correct. So this was a Stone Age site. It’s in central Sweden, and some construction workers were demolishing a bridge and found this ancient structure made of stone and wood, in the middle of a lake. And on it, they found human remains– skulls, which still had spikes in them so we know that they were mounted on spikes.

At first, your first impression would be well, this must have been some Game of Thrones stuff.

IRA FLATOW: King Joffrey at work doing something.

ANNALEE NEWITZ: Cut off their heads, stick it on a spike. But actually, when they examined the skulls, it turned out that these were the skulls of people who had been injured– possibly in battle– they had a lot of blunt force trauma on their head, but they’d recovered from the injuries. So it seems as if these were people who were the survivors– possibly of battle, possibly of some other very dangerous activity– and this may have been more like a war memorial or a place to honor them because they weren’t killed from these injuries.

And s– as I said– it’s a great example of how when we look at something through modern eyes and we imagine what it might mean, we really have to look at the evidence to see that there’s actually multiple interpretations here. This might really have been a place where people gathered for social events and ritual events to celebrate their culture, not just to do mean things to their enemies and chop them up and put them on stakes.

IRA FLATOW: It’s always good to present the evidence. Wait to make your conclusions after you analyze the evidence. Thank you very much.

ANNALEE NEWITZ: Exactly.

IRA FLATOW: Annalee, Thank you. Annalee Newitz– Tech Culture Editor at Ars Technica.

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