Episode 6: Mag Population

[0.6s] Saul: Hello, and welcome to Mag World, where we like to ask big questions, make wild guesstimates, and quantify literally everything on a magnitude scale. If you’re new here, you should know that on a magnitude scale, every mag 1 means times 10. To multiply mag numbers, you simply add them together. So 100 is mag 2 and 1,000 is mag 3, and multiplied together, that’s…

[21.8s] Mike: mag 5, or 100,000.

[23.9s] Saul: That’s right. That’s all the math you need to know to understand what’s going on in Mag World. Just remember that every order of magnitude is a big deal, because as we say in Mag World, quantity has a quality all of its own. If you wanna learn more about Mag World, come visit our website at magworld.pw. I’m Saul Pwanson, your guide to Mag World, and I’m here with my friend, Mike, who used to work with endangered populations. Today’s episode is Mag Population, where we’re talking about humans and animals and bacteria and how many there are of each.

[52.6s] Mike: I’m really excited about this episode, Saul, because we’re finally talking about something that’s in my background, not computers. It’s- [Saul: Uh-huh.] … right within my wheelhouse. So I am excited to get to use my brain.

[66.3s] Saul: That’s awesome. Well, you’ve been using your brain, maybe too much. Maybe that’s part of the problem. But now you get to test me and see if you can tell me some things about biology. So first of all, a population, we, I did some research for this episode, of course, and a population, in general, is a group, is not a group of individuals, but it is a statistical entity. Well, it’s basically when individuals stop being single things and start acting like a group, a flock of birds or a city or whatever. That’s a population, right? [Mike: Mm-hmm.] And so, that’s already kind of poking at the idea that as you climb the mag scale of population, you’re gonna have different kinds of populations, right? If you have just one or a couple, you have a single person or you have a family. A family is a very small population, right? If you have mag 1 people, that, let’s call that a party. You know, you have dozens of people in your house. Or if, actually there are some parties that are more than mag 1. There’s a mag 2 party.

[02:03.9] Mike: That’s a good party.

[02:04.7] Saul: It’s a good party. It’s a rager. It’s a rave, or it’s a wedding. And if you plan a wedding or plan a rave, you can, are very aware of how different it is to plan one of those versus a regular house party. [Mike: Mm-hmm.] And it’s largely because the number of people are, is an order of magnitude more.

[02:21.4] Mike: Did you know that there is a mag 4 party planned for tomorrow in Seattle?

[02:26.9] Saul: I have heard something like that, and it’s because, I think the Super Bowl just got played.

[02:33.5] Mike: Yeah. We are recording this the week after Super Bowl 60 with the Seahawks and the Patriots. And being from Seattle, the winning team- [Saul: Mm-hmm.] … there is going to be a party and a parade- [Saul: Mm-hmm.] … downtown tomorrow. And I think they’re expecting somewhere in the range of mag 4- [Saul: Mm-hmm.] … probably not quite to mag 5- [Saul: Mm-hmm.] … people downtown, up to mag 5 people just in that area. And did you know that in the history of the human, the human species- [Saul: Mm-hmm.] … that is two orders of magnitude more than the lowest the human population has ever been?

[03:16.9] Saul: Well, so I had heard about this. This is the Lake Toba catastrophe. [Mike: Mm-hmm.] Or Mount Toba, maybe they’re one and the same, in which the population got wi- volcano erupted, and, terrible things happened there. it was dark for a while. And, there were down to 10,000 adults, I heard. So that’s mag 4. That’s only one order of magnitude less that I’ve heard.

[03:40.8] Mike: We, about 900,000 years ago- [Saul: Uh-huh.] … the genetic and archaeological history was estimating that about 1,200 breeding adults.

[03:52.7] Saul: Oh. And so you’re saying they’re down to about 1,200 adults almost a million years ago?

[03:57.3] Mike: Mm-hmm. And so looking at the stadium full of people- [Saul: Mm.] … it’s well more than an order of magnitude more- [Saul: Yeah.] … than all humans on Earth-

[04:07.4] Saul: At that time.

[04:08.0] Mike: … at one point.

[04:08.4] Saul: Yeah. Wow.

[04:09.2] Mike: Or pre-humans.

[04:10.3] Saul: Now, of course, they weren’t all in one stadium at that point. [Mike: No.] So-

[04:12.9] Mike: They were not, but-

[04:14.4] Saul: And I’ve heard actually that, when you have that few, you can exist as hunters and gatherers, and it’s about 10 per square, mm, not sure if it’s square mile or square kilometer. But, it’s a very low density, right? [Mike: Mm-hmm.] But that’s not the case today. And so first of all, so we were talking about how we were down to mag 3- [Mike: Mm-hmm.] … almost a million years ago, and then we came back from that and got up to mag, I believe it’s mag 5. And then in, 70,000 years ago, we got down to mag 4 again, as I’m saying, 10,000 adults- … after the Mount Toba thing. And so there’s that cycle, and then, but since Mount Toba, we’ve only been on a mag rise of population. And so it’s gone from mag 4 70,000 years ago. How many humans are there on the planet today?

[05:06.0] Mike: Well, it’s not quite 10 billion, so that’s about mag 10.

[05:12.9] Saul: We are mag 9.9. We are destined for 10 billion around 2050 or so. And that’s-

[05:19.9] Mike: Which is not so far away.

[05:21.1] Saul: Not so far away. It’s, I mean, I-

[05:22.5] Mike: That’s my cross fingers, that’s my lifetime.

[05:25.9] Saul: Yeah. And we’re gonna see that, and like, barring absolute major catastrophe that’s already baked in, we’re going to see that. [Mike: Mm-hmm.] It’s just natural it’s going to happen. And so we’ve gone from mag 4 70,000 years ago to mag 10 in 70 to some thousand years. But if we look at the trajectory of that, it hasn’t all happened evenly, right? 70,000 years ago was mag 4. We climbed to mag 6. It’s only about a million or so individuals, by 5000 BC when civilization starts. The-Numbers that I look at, that I keep in my head, mag, because we don’t know exactly how many humans there were. We’re kind of extrapolating and doing it from the record. But we have more of a record of this when we have … when history starts. And, in fact, in around 500 BC, there were mag 8 people in the Roman Empire, about 100 million people on Earth.

[06:20.2] Mike: In the Roman Empire.

[06:21.8] Saul: Yes. But the Roman Empire was vast and-

[06:24.1] Mike: So vast.

[06:24.9] Saul: … and everyone else, it … The thing is, it doesn’t matter. Like, it, there are plenty of other peoples on the planet. But all those peoples on the, on the order of a million, or even if they are 10 million, it doesn’t matter because 100 million people in the Roman Empire is gonna dwarf all of that. [Mike: Mm-hmm.] So there are about 100 million people on the Earth in 500 BC. And then human population grows and grows and grows. But when does it reach mag 9, a billion people? Do you know?

[06:54.0] Mike: I don’t know, but I’m going to guess around the Industrial Revolution?

[06:59.8] Saul: Yeah. That’s actually totally right. [Mike: Great.] Nice job. So I link these two things together. So it is 1800 AD- [Mike: Mm-hmm.] … that we hit mag 9, or one billion people. And also what happened in 1800 was Malthus famously came around and said, “We’re all doomed. There’s not enough food to feed everybody. We were growing so exponentially here, we’re all gonna run out of food and starve.”

[07:23.6] Mike: So this is the guy behind Malthusian.

[07:27.5] Saul: Yes. A Malthusian pros- prophecy or Malthusian … I mean, I think even though he didn’t make it, make it up, he’s the one that recognized it. And yeah, Malthus. And it was exactly the time we hit a billion people, and I think that’s very interesting because it does represent a state change. I mean, he felt it. He wasn’t saying it because the number hit, rolled over and now it’s a longer number. But he was saying, “Hey, wait a second, guys. This is actually … We, we can’t just keep doing this, right?”

[07:55.9] Mike: Well, about then, was there a rate of change?

[07:59.7] Saul: Yes. We started with 100 million people in 500 BC. Started with. We actually got there, right? And then by 1 AD, we had 200 million people, and by 500 AD, we had 300 million people. So every 500 years, we were adding another 100 million people, and that was pretty steady state until about … Or steady state. It was quite … growing quite rapidly when you think about it. Like, 500 million people by 1500 AD.

[08:19.7] Mike: Mm-hmm. But that’s a pretty straight line.

[08:22.5] Saul: That’s a pretty straight line, yes. But that’s until 1500 AD. And then once 1500 AD happens, and of course that’s right around the time the New World is discovered by the Europeans, and, um- [Mike: Colonized.] And colonized, and then every 100 years after that, we hit 100 million more. So basically, it does ramp up significantly at the … It’s not the Industrial Revolution. It’s like the, Renaissance era. And then it picks up again at 1800 or so. So we’ve got, we basically are going every 500 years there’s 100 million, then every 100 years there’s 100 million. By the time 1920 rolls around, we’re at two billion, so it only took 120 years to hit a whole other billion people. And since 1920, we have gotten almost to 10 billion people, so five times the population since 1920. That’s 100 years ago. So that’s eight billion people in 100 years.

[09:15.3] Mike: So the doubling rate has gone up. [Saul: Yes.] Dramatically.

[09:21.6] Saul: Yes. And it has gone up dramatically since 1970. That’s the big inflection point. [Mike: Hmm.] Right.

[09:28.3] Mike: Thank you, modern medicine.

[09:29.8] Saul: Right. Well, actually, what … Malthus, why was he so wrong? That was one of the questions that I had here. Right? So Malthus is actually correct for his time. [Mike: Mm-hmm.] He was right that if things continued as they were, we would totally run out of food. And what happened was, do you know?

[09:46.8] Mike: I don’t, but I have three good guesses.

[09:50.1] Saul: Okay. What are they?

[09:51.4] Mike: one is increased food production. [Saul: Okay.] One is germ theory. [Saul: Okay.] And the other is related, but, municipal water.

[10:03.7] Saul: Interesting. Okay.

[10:05.6] Mike: Are there more that I should consider?

[10:07.3] Saul: No, no, it’s, it’s, it turns out the answer is your first one, in total.

[10:11.4] Mike: In total? Oh great.

[10:13.4] Saul: Yeah. No, the actual reason why we could ramp up food production kind of an order of magnitude is the Haber-Bosch process. Energy that produces nitrogen-based fertilizer is the answer.

[10:26.0] Mike: Mm-hmm. The Bosch-Haber process was in 1910.

[10:30.3] Saul: Oh, okay.

[10:30.5] Mike: Only 10 years after the first synthetic nitrogen fertilizer.

[10:34.9] Saul: Look at that, okay.

[10:35.6] Mike: And this was 50 years after the first, phosphorus- [Saul: Okay.] … fertilizer production.

[10:42.7] Saul: So yes, population has exploded because we’re able to feed everybody because of these technological advancements that allow for an, order of magnitude more food production than we’ve had in the past. [Mike: Mm-hmm.] Okay. So I wanted to get back to the human population over time.

[11:00.6] Mike: Right on.

[11:01.1] Saul: We were talking about the population bottlenecks that we’ve had- [Mike: Mm-hmm.] … over time, and there’s two things. One thing is I wanted to know, do you know how many humans there have ever been? If there are mag 10, almost mag 10 humans now- [Mike: Mm-hmm.] … how many humans have there ever been on the planet?

[11:19.6] Mike: I’m gonna say fewer than mag 11.

[11:22.1] Saul: Okay. The actual answer is mag 11. [Mike: Hmm.] It’s about 100 billion people that ever existed on the, on the planet. [Mike: Mm-hmm.] Before we move off of human population, which we’re gonna get off and talk about a lot of other things here, I wanted to mention that the, my general scale was, mag 7 for a state. That’s tens of millions of people for a state. There are some cities that have tens of millions of people- [Mike: Mm-hmm.] … but they’re the huge, mega-cities. You know, New York or Tokyo, for instance. [Mike: Mm-hmm.] And then mag 8 is a count- actually mag 7 also, could be a country. it’s a mega-city, a state, or a small country. mag 8 is a really, actually a pretty big country, ones that have hundreds of hundreds of millions of people- [Mike: Mm-hmm.] Brazil and the US and Japan and Russia. mag 9 are the huge countries. There’s only two of them. There’s India and there’s China, right? [Mike: Mm-hmm.] And-

[12:12.3] Mike: Or otherwise just-… an entire continent.

[12:15.2] Saul: Entire continent, right. Africa’s got more than a billion people, Europe has more than a billion people, the North and South America combined have about a billion people, and then there’s, like, the rest, right? There are actually three billion people, more than three billion people in Asia aside from China. So anyway, it’s a lot of people and they’re, we’re measuring these people in billions when in 1800 there was only one billion people in the entire world. Okay, so besides humans, what are the largest number of big animals? Like I, I know that there’s lots of insects and things, and we’ll get to that in a little bit. But I wanna talk about the other megafauna. What is as populous or around as populous as humans? Vertebrates. [Mike: Vertebrates?] Yeah.

[13:06.4] Mike: So, when I’m driving around- [Saul: Yeah.] … going through the countryside- [Saul: Mm-hmm.] … I was mooing at cattle.

[13:13.5] Saul: You were mooing at cattle?

[13:14.3] Mike: I’m mooing at cattle. Yeah, I think what would be equivalent to the number of humans is gonna be the humans’ animals. [Saul: Yeah.] Like cats and dogs, there’s a lot of those. Even if not everyone has them, it’s gonna be within order of magnitude.

[13:28.5] Saul: It’s true.

[13:29.0] Mike: We eat a lot of beef, pork, and chicken. [Saul: Mm-hmm.] I think each of those, sheep, they’ve gotta be up there.

[13:36.4] Saul: Yeah, so in fact, the mag 9 animals are pigs, sheep, goats, cattle, and you are… So that’s mag 9, those are billions of those each. [Mike: Mm-hmm.] And of course, you’re right, our pets, cats and dogs, and, you’re right that the best thing that an animal can do for its long-term species survival is cozy up to humans- [Mike: Mm-hmm.] … and become indispensable to us, and then we’ll make sure they’re surviving. Nothing else will survive, but they’ll survive anyway. So there’s one thing though I wanted to mention. So you mentioned chickens. [Mike: Mm-hmm.] There are more than mag 9 chickens in the world.

[14:10.6] Mike: Are there mag 10 chickens? Are there mag 11 chickens?

[14:13.7] Saul: There are mag 10 and a half chickens, but because chickens take only six weeks to a few, couple months to actually mature and become edible- [Mike: Mm-hmm.] … we have about four generations of chickens every year, and so close to mag 11 chickens are slaughtered every year. [Mike: Wow.] Yeah.

[14:33.5] Mike: So we have more dead chickens in a year than alive chickens at any point?

[14:39.0] Saul: Absolutely. There are more dead chickens in one year than there have ever been humans. In fact-

[14:46.9] Mike: Damn, there’s enough of them to take over.

[14:49.1] Saul: The dead chickens? Zombie chickens? A zombie chicken takeover? Well, the thing is that, this is actually a pretty recent development. Like, you’re right that our livestock and pets have kind of tracked our population over time, but this explosive growth of the chicken industry has really only happened since World War II. The broiler chicken industry since World War II is what caused this- [Mike: Mm-hmm.] … and that’s, this has only been in the last, what, 70, 70 or so years, 80 years that this has completely taken off. And in fact, it’s a proposed marker of the Anthropocene era.

[15:25.5] Mike: Oh, what’s that?

[15:26.3] Saul: Chickens, that- [Mike: Just-] … the chickens.

[15:28.8] Mike: … the fact of chickens.

[15:29.7] Saul: Yeah, they’re gonna look back in 1,000 or 10,000 years and go, “Look at all these chicken bones and chicken DNA at this point in the, in the record.” Yeah.

[15:40.5] Mike: Wow, so the same way that current archeologists will unearth middens and piles of- [Saul: Mm-hmm.] … shellfish, in the future, they’re gonna find my old KFC bucket.

[15:54.1] Saul: So anyways, that’s our little, that’s a, that’s a little bit of, an anchor point here. mag 11 chickens slaughtered every year. [Mike: Hmm.] There are some other vertebrates that are up there. [Mike: Fishes.] Fishes, if you’re thinking of all fishes, yes, there’s about mag 12 and a half of all fish, of the, and there, and there’s like 18,000 species, so it’s- [Mike: Mm-hmm.] … tuna and it’s the tiny guys and it’s everything. And then, birds, there’s about mag 11 birds, so chickens, there’s, there’s more chickens-

[16:24.4] Mike: Than all other birds?

[16:25.6] Saul: … all other birds. [Mike: Wow.] So that’s something. Anyway, and then the other one is rats. How many rats are there in the world? Think there’s more rats or more humans?

[16:35.2] Mike: I feel like rats and humans are concomitant, like they- [Saul: Mm-hmm.] … fill, the rats fill an ecological niche that humans have provided.

[16:47.2] Saul: I think you’re right.

[16:48.2] Mike: And so there’s going to be, gosh, I’d say fewer.

[16:56.4] Saul: Fewer rats than humans, yeah?

[16:58.1] Mike: Well, I’m trying to think about-

[17:01.1] Saul: There’s so much smaller, though, you know?

[17:02.4] Mike: There’s so much smaller, but how many… I don’t want to think that there’s at least one rat per person in my household.

[17:10.4] Saul: Mm, mm-hmm. So the actual answer, you’re right, the actual answer is about mag 9 rats. There are fewer rats than humans. Most of them, the lions, the rats’ share of rats-

[17:23.2] Mike: The humans’ share of rats.

[17:24.1] Saul: The humans’ share of rats are in India and China. mag 9.2 in India and mag 9.1 in China.

[17:29.7] Mike: So remember how you were talking about how one sure way to survive as a species is- [Saul: Mm-hmm.] … to become useful- [Saul: Mm-hmm.] … to humans in some way? [Saul: Mm-hmm.] The other way is to find yourself a niche- [Saul: Uh-huh.] … living off the humans. [Saul: Uh-huh.] ’Cause rats have been a scourge that have traveled everywhere as humans have colonized.

[17:54.5] Saul: Yes, I guess you can call them a scourge. They’re very sweet animals, really, but I guess one rat is a very sweet animal. 10 rats is a problem.

[18:02.9] Mike: In small quantities. [Saul: Mm-hmm.] Kept and fed and not in my food supply.

[18:08.9] Saul: Okay, so let’s talk about some other megafauna. There are still some animals that have, there are millions of a particular species. So one thing that I learned is that there are Mag… Well, first of all, there’s mag 6, caribou…. and reindeer up north, still. And even though the populations have dropped in recent years, but there’s still millions of those, there are mag 7 kangaroos in Australia.

[18:35.3] Mike: Bully for them.

[18:36.7] Saul: Well, tha- that’s why they are considered a pest and are hunted for, and, well, culled, and, culled for their meat. Tens of millions of kangaroos is a lot. That’s like, basically there’s as many kangaroos in Australia as there are people. Actually, I think there’s a few more people at this point but, yeah. The other one that there were tens of millions of but no longer are is the American bison.

[19:01.6] Mike: That’s right. Pre-1800 there were 60 million.

[19:07.3] Saul: 60 million, okay.

[19:08.2] Mike: Your estimate, this is-

[19:10.0] Saul: Yeah, estimates of course, we don’t know.

[19:11.7] Mike: Mm-hmm. Yeah, but s- 60 million, so, um-

[19:14.2] Saul: So mag 7.8 or so. [Mike: Mm-hmm.] Yep.

[19:16.8] Mike: And mag 7.8 bison, that biomass, is-

[19:21.4] Saul: Oh, yeah.

[19:21.9] Mike: … mag 10.7. [Saul: Yeah.] ’Cause they are-

[19:25.3] Saul: Big animals.

[19:26.0] Mike: … massive.

[19:26.3] Saul: Are there, there, are they a ton actually? [Mike: Uh-] I mean, I’m doing the math here in my head, right?

[19:30.4] Mike: They, they average a little under, like- [Saul: Uh-huh.] … under a ton but-

[19:33.6] Saul: But not that much.

[19:34.2] Mike: … well more than humans.

[19:35.7] Saul: Yeah. Of course. [Mike: Yeah.] Yeah. So that’s a huge amount of biomass.

[19:39.7] Mike: So, do you know the biomass of ants in the world right now?

[19:44.7] Saul: You know, okay, not off the top of my head, but I do have some numbers here because I did my research too. [Mike: Oh.] And so there are mag 16 ants, I read, in the w- the world over, of all different kinds of species. [Mike: Mm-hmm.] Right? And so let me do some quick math here. So if there are mag 16 ants, I think every ant could weigh a gram? Probably, oh, I think close, closer to a gram than a milligram for sure.

[20:07.5] Mike: Oh my god. Do you know how much a gram is?

[20:11.0] Saul: It’s like a paperclip.

[20:13.2] Mike: What sort of crazy ants you got?

[20:15.3] Saul: Okay, so you’re saying that an ant is actually a tenth of the mass of a paperclip?

[20:18.5] Mike: I feel like yeah, or less.

[20:20.8] Saul: Okay. Well, I know, well I’m saying it’s definitely more than a milligram. [Mike: Mm-hmm.] So I’m say- okay, so I think you’re right. Probably ten ants per paperclip. That seems about right. You’re right. A metal is a lot heavier than an ant. So yeah, let’s go for, 10,000 ants per kilogram seems about right. Mag, mag 4 ants per kilogram. So if that’s mag 16 ants times mag 4, oh, I’m sorry, divided by mag 4, that would be mag 12 kilograms of ant material. Is that right?

[20:52.7] Mike: You’re off by an order of magnitude.

[20:55.2] Saul: Because I, they’re actually-

[20:56.9] Mike: They’re, I think they’re much lighter than that.

[20:58.9] Saul: They’re even lighter than a- [Mike: Mm-hmm.] Okay, so more like, 10 milligrams for ant, okay.

[21:04.9] Mike: Mm-hmm. 10.7, mag 10.7- [Saul: Okay.] … kilograms.

[21:10.3] Saul: Of all ants?

[21:11.3] Mike: Of all ants, which is equivalent to the biomass of all bison at their peak.

[21:17.5] Saul: Wow, okay. [Mike: And-] And a lot less than the m- biomass of humans.

[21:21.8] Mike: That is one-tenth. [Saul: Yeah.] That is an entire order of magnitude less than the biomass of all humans.

[21:29.4] Saul: Because all humans, that’s a mag, it’s about, it’s about mag 10 humans- [Mike: Mm-hmm.] … times mag 2 kilograms per human, actually less because- [Mike: Mm-hmm.] … that’d be 200 pounds per human. So that’d be mag 12 for all humans, maybe mag 11.5 for all humans, yeah. [Mike: 11.6.] 11.6. [Mike: Exactly.] There you go.

[21:45.1] Mike: Yeah. Well, that’s a great job. [Saul: Yeah.] And do you know how many ants there are per human?

[21:52.8] Saul: Well, oh, that’s a, huh, that’s an easy one. [Mike: Mm-hmm.] In mag world. so if there are mag 10 humans and mag 16 ants, then that would mean that there are mag 6 ants per human, so it’s about a million ants per person.

[22:05.5] Mike: You got it. Anyway, well, so w- we’re talking about biomass of various- [Saul: Mm-hmm.] … classes- [Saul: Mm-hmm.] … various populations. do you know the difference in biomass between mammals? We’ve talked about domesticated anim- animals and humans.

[22:24.5] Saul: Now I assume when you say biomass, you’re talking about the entire population, not just an individual, right?

[22:28.7] Mike: Yeah. Mm-hmm.

[22:29.6] Saul: Mm-hmm. Yeah.

[22:30.1] Mike: So of the entirety of mammals- [Saul: Mm-hmm.] … all mammals in the world weigh about, mag 12 kilograms.

[22:39.1] Saul: All mammals in the world weigh mag 12 kilograms. We just got through here in saying that all humans in the world weighed mag 11.6.

[22:47.5] Mike: That’s right.

[22:48.5] Saul: So humans are about half of all biomass?

[22:53.1] Mike: About 36%.

[22:54.4] Saul: 36% of all- [Mike: Mammalian.] … mammalian biomass- [Mike: Mm-hmm.] … in the world.

[22:58.4] Mike: Is human.

[22:59.0] Saul: Is human. Wow.

[23:00.2] Mike: And do you know what domestic livestock are?

[23:03.1] Saul: I mean, that must be the other half. Or like if, if it’s 30, if it’s 38% of that, I’m guessing that like some huge amount because livestock, if there’s billions of those, billions of cats, dogs, cattle, sheep, goats, et cetera, I’m guessing that that’s basically another 40% of the, of the total.

[23:19.1] Mike: Almost 60%, yeah.

[23:20.5] Saul: So actually it’s-

[23:20.8] Mike: What does that leave for wild animals?

[23:22.5] Saul: That’s like 2%.

[23:24.0] Mike: It’s 5%. It’s, so- [Saul: Wow.] … the biomass of wild mammals- [Saul: Mm-hmm.] … so this is all your, your koalas, your bears- [Saul: Yeah.] … your kangaroos, your-

[23:35.1] Saul: All these charac-

[23:35.5] Mike: … blue whales.

[23:36.7] Saul: All these, charismatic megafauna. [Mike: Mm-hmm.] Save the dolphins, right?

[23:40.5] Mike: Yeah, are the weight of humans and the- [Saul: Uh-huh.] … human animals-

[23:47.0] Saul: All our chickens.

[23:48.0] Mike: … is more than an order of magnitude larger than all wild mammals combined.

[23:54.8] Saul: Combined, wow.

[23:55.3] Mike: And it’s not always been so.

[23:56.8] Saul: No, it hasn’t.

[23:58.3] Mike: So do you know back in the past, there was only a biomass of 11.6. So about the same weight of humans now.

[24:08.7] Saul: like 200 years ago?

[24:09.6] Mike: Well, I want you to guess. [Saul: Okay.] Because at this point- [Saul: Mm-hmm.] … when all mammals weighed as much as humans weigh now-

[24:16.3] Saul: Mm-hmm. Mm-hmm.

[24:17.1] Mike: … the mass of wild mammals was 50%. [Saul: Okay.] But it is around a different number we’ve talked about.

[24:26.4] Saul: Are you saying that it is… Okay, yes. Well, when is it, then? [Mike: 1860.] Oh.

[24:33.3] Mike: And that is a couple decades after the introduction of the first synthetic fertilizer. [Saul: Oh.] And then it was a slow rise after that. But do you know what led to the more rapid rise?

[24:46.5] Saul: Well, hold on a second. I want to talk about something else here. I want to, I want to veer, I want to take advantage of-

[24:50.4] Mike: We’ve got overlapping subjects here. [Saul: Yes.] This is tremendous.

[24:53.5] Saul: This is great. Okay, so there’s also something else that happened in 1860, which is kind of tremendous, tremendous and terrible. We talked about the American bison of which there were 60 million of them on the continent. [Mike: Mm-hmm.] In… Before 1800. By the time 1860 rolls around, there are fewer, some ten- but still some tens of millions. By the time 1870 rolls around, there are mag 6.7, there are about five million only 10 years later. And by the time 1880 rolls around, there are only s- mag 5 and a half. There are about 400,000. So over the course of 20 or 30 years, the population of bison was, let’s call it culled, but basically was all but exterminated. [Mike: Mm-hmm.] And they, they fell down over the next several decades to the point that there were actually only about 50 bison total in the world that survived around 1900. So over the course of 50 years, we killed 60 million bison whose total biomass was around mag 10. And so those two factors are what make the proportion be, shift as, as it has.

[26:07.1] Mike: Mm-hmm. And Malthus didn’t know that there was going to be artificial fertilizer. [Saul: Right.] And that we would be growing so many plants with this artificial fertilizer, not just to feed humans, but to feed the animals that feed the humans.

[26:20.3] Saul: Uh-huh. Mm-hmm.

[26:20.9] Mike: And have you heard of trophic levels?

[26:23.8] Saul: No. What’s that?

[26:24.7] Mike: Well, this is, in, in conservation biology, population biology- [Saul: Mm-hmm.] … you talk about the energy that gets transferred between different layers in an ecosystem. [Saul: Uh-huh.] And so where does all energy on earth come from? So 100% of the sun that’s hitting the earth, plants can’t use all of it. [Saul: Right.] About 1%, mag negative two- [Saul: Mm-hmm.] … of the energy of the sun can get converted into life. [Saul: Okay.] And when we’re talking about these levels, we’re talking about energy. Biomass can be, a rough way to talk about it. [Saul: Mm-hmm.] But 1% of that energy- [Saul: Mm-hmm.] … goes into your producers, your, your plants- [Saul: Mm-hmm.] … your, the original photosynthesis.

[27:09.1] Saul: The OG.

[27:10.1] Mike: Yeah. And then you have your first level consumers. [Saul: Mm-hmm.] Your herbivores. [Saul: Mm-hmm.] The things that will consume the plants. [Saul: Mm-hmm.] And about 10% of the energy from the plants. So this is a rule of thumb. [Saul: Mm-hmm.] 10% gets passed on each trophic level. [Saul: Okay.] And so the next level of consumers, which are consuming the first consumers- [Saul: Uh-huh.] … will be 10% of that. [Saul: Mm-hmm.] The, the amount of biomass below them on these trophic levels. And you can see that since you’re losing an order of magnitude of energy each time- [Saul: Uh-huh.] … the range of each level going up your trophic levels has got to be bigger and bigger and bigger in order to ha- contain that much energy. There is, there does have to be some conservation of energy when you’re talking about wild- [Saul: Mm-hmm.] … animals, domesticated animals. In order to have enough food to feed a growing population, you need to take space from the wild population because-

[28:14.5] Saul: Because we are taking over their niche.

[28:16.1] Mike: Yeah. To go back to what you were saying about the bison, they got down to 50 individuals.

[28:22.5] Saul: Yeah. So this is a mag from mag 7, high sevens, down to mag 2 in about, in less than 100 years. I mean, 50 years basically, right? [Mike: Mm-hmm.] The sad thing about this whole thing is that the whole point, they didn’t even kill them for food. If they killed them for food, it’d be one thing. They killed them to keep the, indigenous population from having their food supply. It was inconceivable to the indigenous population that there wouldn’t be bison. It is just like, they’re just, huh, they’re everywhere. There’s tens of millions of them. They don’t, they couldn’t even count them. They were just everywhere, right? [Mike: Mm-hmm.] Anyway, down to mag 2 by 1900.

[28:54.4] Mike: And did you know that 50 individuals is about the theoretical minimum that a species can get to and still survive?

[29:03.0] Saul: That makes sense to me. But how, why, why can’t you survive with just an Adam and Eve?

[29:07.8] Mike: well w- with what’s called, um-

[29:11.4] Saul: Sorry, with a, what was your, what was, what was your rat’s names? Choco, Pony, and, uh- … and Moose?

[29:17.3] Mike: Chocolate Moose and Fudge Ripple.

[29:19.3] Saul: Fudge Ripple.

[29:19.6] Mike: Of course.

[29:20.2] Saul: So why can’t you have this Chocolate Moose and Fudge Ripple being the first two, the Adam and the Eve of the rats population?

[29:25.2] Mike: something called inbreeding depression. [Saul: Okay.] So as… You’ve heard of inbreeding. That’s when- [Saul: Mm-hmm.] … closely related individuals mate. [Saul: Mm-hmm.] And that means that recessive genes, genes that don’t get expressed unless you get one from each parent. [Saul: Uh-huh.] So oftentimes, recessive genes will be harmful to survival- [Saul: Uh-huh.] … and reproduction of the next generation. [Saul: Mm-hmm.] So if you have more closely related individuals mating- [Saul: Mm-hmm.] … you get inbreeding depression as those-

[29:56.3] Saul: ’Cause those recessive genes-

[29:57.3] Mike: … so many recessive genes- [Saul: Yeah.] … think about…

[30:00.0] Mike: … Habsburg chin.

[30:00.9] Saul: And there’s no way to get rid of them once they’re in there because that’s all you’ve got. [Mike: Mm-hmm.] Right? [Mike: Yeah.] Yeah.

[30:05.9] Mike: That’s why having a large mating population is really important for conservation. [Saul: Mm-hmm.] because there’s strength with genetic diversity. And 50 individuals in a managed population- [Saul: Hmm.] … is enough-

[30:22.5] Saul: Just enough.

[30:23.2] Mike: … just enough. So they’re … Back when I was in school, it was called the, 50:500 rule. [Saul: Okay.] So 50 would be the bare minimum. [Saul: Okay.] And 500 would be a long-term survival. Like 50 will survive for maybe 100 years. So when we’re talking about, ugh, mag 2 or mag 3 individuals in a population- [Saul: Mm-hmm.] … for actual survival- [Saul: Mm-hmm.] … we’re talking about what’s called an effective population. [Saul: Okay.] So in conservation, you’re gonna want mag 4, 10,000- [Saul: Mm-hmm.] … individuals to make sure that you have, a species with evolutionary potential.

[31:07.9] Saul: Evolutionary potential.

[31:08.7] Mike: Evolutionary potential, meaning enough diversity that you cannot just get the next 100 years-

[31:13.9] Saul: Mm-hmm. But-

[31:14.4] Mike: … before inbreeding depression leads to another crisis, but- [Saul: Yeah.] … a million years. Species last, on the whole- [Saul: Mm-hmm.] … a million to 10 million years per species.

[31:23.8] Saul: Takes them a million years to come around, so that would make sense. Thank you for all of that. That was actually really great. I learned some things. So a couple of other numbers. We talked about ants, and those are mag 16 ants. There’s mag 19 insects on the planet in total. Antarctic krill are famously one of the most populous, sea creatures. [Mike: Mm.] There’s mag 15 of those. Yeah, well, we’re all gonna be eating them pretty soon. So I’m using those as just anchor points, mag 19, mag 15, like, we’re in this zone. Let’s go to the very, very small end of the spectrum here. Bacteria, right? How many bacteria, individual dudes- [Mike: Individual?] … individual dudes-

[32:07.0] Mike: They’re so small.

[32:08.1] Saul: They are so small, right?

[32:08.5] Mike: There’s gotta be more than ants.

[32:09.9] Saul: There’s, there’s gotta be more than ants. And in fact, you’re right, there are. So how many bacteria are there on the planet?

[32:15.2] Mike: Jiminy Christmas. Bacteria live everywhere, Saul. I don’t know how they’re-

[32:19.7] Saul: I know. But they’re so small. They’re so, so tiny.

[32:21.7] Mike: But they’re, they’re in my gut. [Saul: Yeah.] They’re in your gut. They’re in everyone’s gut.

[32:25.2] Saul: That’s true.

[32:25.7] Mike: They’re in soil. [Saul: Mm-hmm.] They’re in water. They’re in- [Saul: Mm-hmm.] So mag 16 ants, mag 10 people, mag-

[32:34.7] Saul: Let’s do a … I might want, I want to give you something, to help you out here. So, there’s mag 24 human cells on the planet. There are mag 23 ant cells on the planet. So that’s just to give you a general anchor point there, and that’s in just individual one, type of creature. Of course, there’s everything else too.

[32:53.5] Mike: If you can derive this- [Saul: Yeah.] … write in and let us know how you would solve this.

[32:58.7] Saul: I would love to know how you actually could, could figure this out. And you can even … We can work backward from the number if you want, as long as you could then work forward from other things to figure out what the actual answers are. [Mike: Mm-hmm.] So there’s actually mag 30 bacteria on the planet. [Mike: Hmm.] I have one little factoid here that blew my mind anyway. A third of them are a single species-

[33:20.0] Mike: Of bacteria?

[33:20.8] Saul: A third of all bacteria are one species, Pelagibacter communis. It is … They occupy, the upper 200 meters, the ph- the photo, the photopic zone in the ocean. And they-

[33:34.5] Mike: Oh, yeah.

[33:35.2] Saul: … and they do it in the middle of nowhere. Basically, it’s, in the open ocean away from shore in that photopic region and in a low nutrient zone. So they’ve found a niche that nobody else is sitting in. They’re just consuming. And they’ve made themselves so unattractive to anybody else who’s eating anything ’cause they’re so small and they have no … there’s no meat on their bones at all, that even the ones who filter through seawater to get things aren’t even paying attention to those. They’re kind of almost below the level that peop- can con- that things are gonna consume them in terms of their size. They are the, kind of the minimal creature. They’ve evolved for this space.

[34:07.1] Mike: The minimum viable creature.

[34:08.5] Saul: Minimum viable creature, and they dominate. They are a third of all prokaryotes on the planet are in those ocean zones. [Mike: Amazing.] Yeah. Now, I learned about this, this niche here. It is the largest uniform habitat on Earth, the particular niche that they occupy.

[34:24.4] Mike: That makes sense.

[34:25.9] Saul: There’s another class of, not animal. Animal? Can you call it a nematode, an am- animal?

[34:32.0] Mike: Yeah, it’s an animal, absolutely.

[34:33.0] Saul: Yeah, because it moves around, right? And so nematodes-

[34:35.3] Mike: Well, it’s a class Animalia.

[34:37.3] Saul: Well, look at you, Mr. Biology. Biolology. So yeah, so nematodes are like worms and things, right? [Mike: Mm-hmm.] And, there are mag 20 nematodes on the planet, so that’s-

[34:48.0] Mike: They’re everywhere.

[34:48.6] Saul: They’re everywhere, and there’s some, I mean, there’s some, some big ones, there’s some small ones, but that’s like 10,000 more than the number of ants on the planet, right? So-

[34:56.4] Mike: I mean, they live in ants.

[34:58.9] Saul: So I want to talk about one particular-

[35:01.0] Mike: Oh, no, let’s not talk about parasites.

[35:02.9] Saul: Let me ta-

[35:02.9] Mike: I love parasites.

[35:03.4] Saul: We are gonna talk about one parasite in particular here.

[35:05.8] Mike: Oh, my.

[35:06.2] Saul: So wha- as I was doing this research, I ran across the Guinea worm, which causes drucunculiasis. I think I’m pronouncing that right. And so it’s a roundworm that can get up to a meter in length, so it’s really, really … And actually, this is actually interesting too. There is some serious dimorphism in the species, so the female can get up to 80 centimeters in length, but the male only gets up to about four centimeters in length. So basically, it’s an order of magnitude difference between the male and the female size of this particular roundworm. [Mike: Ooh.] Well, anyway, we’re not talking about the males here because the females are the ones that if you ingest them, they happen to be in a copepod, hanging out, and then you ingest a copepod, and your stomach acids digest the copepod, but then this actual roundworm guy gets into your-

[35:50.5] Mike: Just, just the head.

[35:51.4] Saul: … gets into your thing. After about a year, he s- she starts coming out your, an open wound. They create a little sore and start popping out, and they can’t …… there are, first of all, there’s no cure for this. Once you’re infected, you’ve got to see the process through. And they start coming out and you can’t even yank them out. You have to let them come out a little bit at a time. I think you were mentioning that you had heard about this before.

[36:15.8] Mike: Yes. Well, because if you try and pull it, it’ll break this.

[36:18.7] Saul: Yeah. And that’s bad news.

[36:20.1] Mike: Real bad. [Saul: Yeah.] So you twist around- [Saul: Mm-hmm.] … a little stick- [Saul: Mm-hmm.] … a little more each day-

[36:26.2] Saul: About a centimeter a day?

[36:27.3] Mike: … and just keep doing it- [Saul: Yep.] … until it’s all the way out. [Saul: Yep.] And-

[36:31.0] Saul: And this could be 80 centimeters long, so it could be like months. But in 1900, there were some 50 million cases of this a year and there has been a concerted effort to extinctify this particular thing because it is so nasty. [Mike: Mm-hmm.] And in fact, by 1986, they had been down an order of magnitude. Now that, so that was mag 7 in 1900 cases, human cases a year, and in 1986, we got down to three and a half million cases, so mag 6. And in 1986, they made a concerted effort to try to eradicate this thing. And over the, by, a decade later, it was down to mag 4, under 100,000 cases. A decade after that, it was mag 3. And then, in 2012, it got down to mag 2. Now, since 2021, there are about a dozen cases a year and they are in Sudan and the Congo, basically places that they just can’t do what they need to do. Filtering water basically-

[37:23.0] Mike: Mm-hmm. Mm-hmm.

[37:23.7] Saul: … in order to destroy this thing. And so we’ve all but eradicated this particular nematode, sorry, this particular this particular roundworm that causes dracunculiasis. That is- [Mike: Amazing.] We are on target. This is the second disease to be eradicated after smallpox.

[37:41.5] Mike: Whew, I, that’s great, but here I thought we could get there with measles.

[37:46.0] Saul: Yeah. Well, nope, not, not yet.

[37:50.1] Mike: But congratulations to whoever’s nematode fighters.

[37:54.5] Saul: Yeah. Congratulations to those guys. They-

[37:56.7] Mike: If you ever want to do a full episode on parasites- [Saul: Yeah.] … would love that. My degree project was on- [Saul: Yeah.] … nematode worms. [Saul: Yeah.] It was fascinating stuff.

[38:05.7] Saul: mag parasite. Okay. I’ll add that to the list. One other thing I wanted to talk about just sheer numbers here. We’re almost out of time, but I wanted to talk about how many … So we’ve talked about these big numbers, right? mag 20 nematodes, mag 30 bacteria. How many stars are there in the universe for comparison? More or less? Sorry.

[38:28.2] Mike: Than bacteria?

[38:28.9] Saul: More or fewer than bacteria? 100 billion stars-

[38:32.4] Mike: mag 11 stars.

[38:33.3] Saul: … is mag 11 stars. Yep.

[38:34.2] Mike: In our universe.

[38:35.2] Saul: In our galaxy.

[38:35.8] Mike: I mean in our galaxy. [Saul: Yep.] And if there are as many galaxies as there are stars in our galaxy… [Saul: Mm-hmm.] So that means we have mag 11 times mag 11 is mag 22 stars.

[38:52.5] Saul: Mm-hmm. Yeah. That’s, remarkably close. There, there are, well, what I read anyway, there’s mag 24 stars in the universe. And so by comparison there are more bacteria on this planet than there are stars in the universe by about a million. There’s a million bacteria on this planet for every star in the universe. [Mike: Oof.] That’s a lot of bacteria.

[39:14.0] Mike: Grody. Man, that five-second rule I’m going to have to rethink.

[39:18.4] Saul: More like a 0.5 second rule, am I right?

[39:22.5] Mike: Well, before we sign off- [Saul: Uh-huh.] … I want to maybe transition from talking about biomass for a little bit. [Saul: Okay.] We’ve talked about numbers of populat- numbers of animals, numbers of organisms- [Saul: Mm-hmm.] … weight of organisms.

[39:36.4] Saul: Mm-hmm. Mass of organisms.

[39:37.6] Mike: Mass of organisms, biomass. [Saul: Mm-hmm.] Have you ever heard the term technomass?

[39:44.6] Saul: No, I haven’t.

[39:46.5] Mike: Oh. Would you venture a guess what technomass would be?

[39:49.0] Saul: I’m guessing it’s the mass of stuff that humans have produced, produce.

[39:54.1] Mike: Absolutely, yeah. That’s-

[39:55.5] Saul: Unnaturally, right?

[39:56.6] Mike: Un- Yeah. So things that the studio we’re in, the clothes we’re wearing. [Saul: Mm-hmm.] The food we eat is biomass, but everything else in our life- [Saul: Mm-hmm.] … is technomass. [Saul: Okay.] And we recently surpassed, the technomass of the world- [Saul: Okay.] … has recently surpassed global biomass. [Saul: Surpassed?] Surpassed.

[40:22.1] Saul: Wow. So you’re saying more than mag 15 kilograms of technomass?

[40:27.7] Mike: Yeah. Technomass surpassed extant global biomass in 2020.

[40:33.6] Saul: Wow. Wow.

[40:35.7] Mike: Yeah. And it doubled since 2000.

[40:41.7] Saul: Wow. Wait, I’m sorry. So that, the production of it doubled. The actual quantity of it, the real- [Mike: Quantity.] … amount- [Mike: Doubled.] … has doubled. Yeah. Wow.

[40:50.4] Mike: Which means the rate of production of human stuff- [Saul: Yeah.] … has more than doubled. [Saul: Yeah.] So-

[40:59.4] Saul: And there’s more, there’s more humans making more stuff- [Mike: Mm-hmm.] … faster. [Mike: Yeah.] Yeah.

[41:04.0] Mike: So I think this could- [Saul: Wow.] … lead us nicely into talking about our next episode.

[41:08.9] Saul: Yeah. Well maybe we should talk about, what, mag trash? mag recycling? Next episode?

[41:13.2] Mike: Something like that. Yeah. mag stuff, mag waste.

[41:16.1] Saul: mag stuff. I, I can see mag manufacturing and-

[41:20.8] Mike: Because if we’re creating- [Saul: Uh-huh.] … the entirety of human mass and stuff, we’re making roads, we’re making plastic- [Saul: Yeah.] … we’re making houses. [Saul: Uh-huh.] It’s every week- [Saul: Mm-hmm.] … the entire human biomass is being made in our stuff.

[41:40.3] Saul: And unfortunately, that stuff does not get consumed by other things that make just nice biomass- [Mike: Yeah.] … out of it, right? We’re just, we’re consuming it, just letting it sit there.

[41:47.5] Mike: Well, we’re extracting it from somewhere too. [Saul: Yeah.] Where is this stuff coming from? Where is it going? [Saul: Yep.] So I think those are some big numbers I’d like to talk about.

[41:56.9] Saul: That’d be great. I would, I would love to talk about that with you, Mike. That sounds like a good idea. [Mike: Amazing.] Thank you so much for talking with me about this today.

[42:03.2] Mike: Yeah. Thank you for letting me talk about my things too.

[42:06.4] Saul: Absolutely. I, I-

[42:07.4] Mike: I like learning.

[42:08.2] Saul: I had fun doing math this time.

[42:11.0] Mike: I have fun doing math every time.

[42:13.4] Saul: Well, I will see you next time, Mike. Let’s do some more math.

[42:16.0] Mike: Yeah. Let’s do some trash math.