Today you’ll learn about how rockets are preventing the ozone layer from healing properly, how researchers are figuring out the smells of the ancient world, and how mother orca whales take care of their sons to ensure the survival of their species.
Today you’ll learn about how rockets are preventing the ozone layer from healing properly, how researchers are figuring out the smells of the ancient world, and how mother orca whales take care of their sons to ensure the survival of their species.
Rockets Ruin Ozone
Neanderthal Smells
Orca Moms
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Find episode transcripts here: https://curiosity-daily-4e53644e.simplecast.com/episodes/rockets-ruin-ozone-neanderthal-smells-orca-moms
[SFX: INTRO MUSIC/WHOOSH
NATE: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from Discovery. Time flies when you’re learnin’ super cool stuff. I’m Nate.
CALLI: And I’m Calli. If you’re dropping in for the first time, welcome to Curiosity, where we aim to blow your mind by helping you to grow your mind. If you’re a loyal listener, welcome back!
NATE: Today you’ll learn about how rockets are preventing the ozone layer from healing properly, how researchers are figuring out the smells of the ancient world, and how mother orca whales take care of their sons to ensure the survival of their species!
CALLI: Without further ado, let’s satisfy some curiosity!
[SFX: WHOOSH]
CALLI: Good news, everyone. The ozone layer is repairing itself. Bad news? It won't if we don't stop launching rockets.
NATE: Oh, what a classic. Good news. Bad news combination there. Pleasantly hypothetical situation immediately undone by something completely outside of my control. So remind me why this would be bad.
CALLI: Okay. As I'm sure you know, the ozone layer is a layer in the Earth's stratosphere, about 9 to 18 miles above the earth’s surface and it absorbs most of the ultraviolet radiation reaching the earth from the sun. Now, back in 1985, reports of an ozone hole popping up over Antarctica made international news because the ultraviolet radiation that the ozone layer protects us against began seeping in increasing risks of skin cancer and other nasty diseases at a massive rate.
NATE: Oh, yeah. I definitely remember like talk about the ozone and how there is a hole in it and how we needed to do things to fix it. But it seems like most of that discussion has gone away and I really don't hear much about it anymore.
CALLI: That is because of a coordinated global effort known as the Montreal Protocol, which came into effect in 1987, leading to a ban on the type of chemicals that were directly contributing to ozone depletion called chlorofluorocarbons, or CFCs, which is going to be easier for me to say. These were so common they could be found in almost every aerosol can or refrigerator unit. And every time they were used, they contributed to massive ozone depletion. Now, thankfully, after the CFC ban, even more chemicals were banned that contributed to ozone depletion, which meant that by a whopping 99% of ozone depleted chemicals stopped being used, which meant that the ozone layer has been steadily rebuilding itself as a result of the Montreal Protocol and then some. Because of the protocol, we’ve mitigated some of the damage of climate change by fending off global warming to the tune of nearly 33 degrees Fahrenheit. By the year 2100 will have fought off another 33 degree temperature increase. The Montreal Protocol has done a lot of good for the planet, and what we're about to talk about in regards to rockets is more of an unintended side story to the story of the ozone layer. It's sort of a new challenger in the ring, if you will.
NATE: All right. So we're talking about rockets. What is the problem with rockets? Do they have CFCs? Is that like the one thing excluded from the Montreal Protocol or is a different issue?
CALLI: No, see, that's the thing. Rocket fuels don't have CFCs. There are just so many rockets launching around the planet that when they travel through the atmosphere, they’re leaving behind a trail of gasses that could slow down the recovery of the ozone. These gases are liquid kerosene and then cryogenic, hyperbolic and solid gasoline. When these fuels combust, they create a number of nasty exhaust chemicals, including carbon dioxide, water vapor, black carbon, alumina, reactive chloride and nitrogen oxides, all of which are known to destroy the ozone. Worse, none of these rocket fuel emission types are regulated, unlike CFCs.
NATE: Oh, okay. I see. So how much damage have we already been doing with these rockets?
CALLI: Thankfully, not enough to actually prevent the ozone layer from fully repairing itself. But that's going to change over the next decade as the space launch industry is expected to expand. Some financial estimates say the global space industry is about to grow by up to 3.7 trillion by 2040. Yeah, with the looming possibility of space tourism.
NATE: I mean, I really like the idea of going into space more. I think it’s cool, a lot of scientific advancements. I sure would like if we didn't have to ruin the earth to do that though. So is there anything we can do?
CALLI: Well, researchers who discovered this suggest that rocket launch providers, environmental regulators, atmospheric research scientists and government agencies all need to join forces and start talking about it.
NATE: What good might that do for us?
CALLI: Well, we can begin by discussing the need for a sustainable way to grow the space industry without hurting the earth. And that can begin with everybody collecting and sharing that data. For example, anybody who builds and launches rockets should estimate what rocket emissions are going to be like during their design work and then measure actual emissions for their launch vehicles. Since we don't have these emission estimates now, we're limiting our own estimates on how powerfully the atmosphere will resist a launch. So it's a win win for everybody. Everybody here kind of holds their own piece of the puzzle, and it's up to us to put that puzzle together now.
[SFX: WHOOSH]
NATE: There's a phrase about stopping to smell the roses in life. But it turns out that might be a pretty modern thing because ancient humans wouldn't really get anything out of that. They couldn't smell flowers.
CALLI: Wait, what? That's sad. Okay. Why?
NATE: So humans, much like our ancestors, the Neanderthals and the Denisovans, all adapted over time to our geographic locations and the different food odors available to us. And it's no secret that this is part of why dietary niches are important to us evolutionarily. But it's the dietary shifts in humans that have taken over the course of industrialization that have changed how our odor receptors function. Now, we can only actually speculate on how Neanderthals and Denisovans smell things. Both have been extinct for centuries. But at Duke University, a recent study has come closer than anyone ever has to figuring out what did the world used to smell like.
CALLI: Okay, well, I can answer that one for you. A world where you can't smell flowers just smells like sadness. But I am very curious now, how. How do they do this?
NATE: So they use a very complex laboratory technique that allowed them to test smell sensitivity on odor receptors grown in a lab dish. And to simplify it, they used DNA from Neanderthals and Denisovans to recreate the inner smelling mechanisms of the nose. And I'll be honest, I don't I don't quite understand how all of it works, but for sure, what they did was gather amino acid sequences for the samples of the odor receptors and created a cladogram which visualizes relationships across samples of different odors.
CALLI: Smell a vision.
NATE: Exactly.
CALLI: Sorry. Sorry. Okay. So it's a sort of simulation of how the nose would have smelled. That's actually really cool.
NATE: It is. And it's also one of the more complex things I've ever tried to explain. So bear with me. Once they created this technique, they used 30 different sets of odor receptors from all three types of human to basically sniff a number of fragrances. And all 30 odor receptors were successful in detecting the fragrances. But to varying degrees, for example, the Denisovans, who existed 30 to 50000 years ago, couldn't really smell flowers, but they were four times better at sensing sulfur than modern humans and three times better at picking up a balsamic scent. Interestingly, they were also better than us at sensing honey.
CALLI: Okay. That's actually really weird because, well, I mean, honey is sort of derived from flowers, but also they both smell really sweet.
NATE: It's true. But one of the issues that has prevented us from expanding this study further is that we don't really know what Denisovans ate. All we have is context clues based on similar civilizations. For example, the Hadza of people of Tanzania are modern hunter gatherers, and a major part of their diet is honey, because it's high calorie and nutritious. So we can make the deduction that older hunter gatherers, like the Denisovans may have also sought out honey for similar reasons.
CALLI: Okay, so that makes more sense. So they're they're searching out or they they developed the ability to smell something that they needed. Okay. What about the Neanderthals?
NATE: Their sense of smell was a little bit similar to ours. They were three times less likely to smell flowers, but also three times less likely to smell other plant-based smells, including spices. Which is interesting because it's believed that their odor receptors are virtually identical to human receptors in every way except for sensitivity. And this led the researchers to the conclusion that every species, human, mammal or otherwise evolves odor receptors to maximize a sort of fitness for finding food. And this is made super complicated because of humans, because we eat so many things to stay alive. And it's even more complicated when you consider how our ancestors diets may have evolved.
CALLI: This is actually really fascinating, but what's the conclusion here? What does all this mean?
NATE: Well, the cell based fragrance model can also be used to observe genetic diversity among modern humans. And it hasn't been tested yet. But the idea revolves around how certain people smell things that other people can't. A famous example would be how the spice, cilantro smells and tastes like soap to some people like myself, but to others has a much more citrusy parsley like taste.
CALLI: Wait, it tastes like soap to you.
NATE: Absolutely.
CALLI: It tastes like poison to me.
NATE: It's disgusting to me. The taco ruiner of spices.
CALLI: The bane of our existence.
[SFX: WHOOSH]
CALLI: Hey, mama's boy.
NATE: Where is this coming from?
CALLI: Listen, I'm not necessarily judging you and your relationship with your mom. I was just trying to see how much you relate to the recent revelation that adult men being babied by their mothers isn't a uniquely human phenomenon. It's something we've actually discovered happens with killer whales, too.
NATE: Are you calling my mother a killer whale?
CALLI: Moving on. It was discovered recently. Listen, listen. It was discovered recently that there is a population of killer whales near the Pacific coast of North America. And the mothers catch fish and share them with their sons, but not their daughters. What's even more interesting is that this kind of pampering lasts for decades and has been observed anecdotally until recently, when a study finally came out about mama's boy whales in the journal Current Biology.
NATE: The entire study about the arrested development of the whale population. Tell me more.
CALLI: Okay. Not the entire whale population. This is off the coast between Washington State and British Columbia in Canada, where a population of Orcinus Orcas live. Unlike many whales, these whales don't migrate, instead feeding year round on the areas fish. When the moms catch a fish, they do this sort of interesting head jerk motion where one half of the fish stays in their mouth while the other half of the fish floats behind them while they swim away. If their son is swimming with them, the son will grab the other half and just eat it.
NATE: All right. But is this like extra pampering or is this like, maybe the sons are just freeloaders, you know?
CALLI: Okay. I mean, that's a fair point. But the researchers witnessing this said the company of the son looks consensual and the behavior checks out when stacked against the other observed behavior. For instance, mother whales and their sons spend a lot of time floating on the surface of the water together, almost as if they're just hanging out and relaxing. And I've said it before, and I will say it again we need to be careful when comparing animal behavior as the same as human behavior. Animals don't have the same emotions as us, but in this case, it really does seem like the mother and son orcas have a special bond. But the researchers strongly believe that in every aspect of a mother whale and a son whale’s relationship, it truly seems to be one born from nurturing.
NATE: Okay. You're talking about people anthropomorphizing an animal, which is the act of applying human traits or characteristics to other creatures. But I wonder, do you think that the mother orcas prioritizing their sons over their daughters explains lower birth rates in whales? Because this is something that we've seen over the past decades, like are the daughters suffering because the men are getting all the food and better treatment?
CALLI: The team leading the study don't think so, at least not directly. It might actually be something the mom is doing for her own interests, not the sons. See, the way the whale mating works is that a mother alone will raise her children. All the male has to do is mate with a female whale and then move on with their lives. One of the genetics tests the team did suggested that the two oldest males in the group they studied were fathering more than half of the new orca calves in the region.
NATE: Okay. So how does this benefit mom?
CALLI: Because by keeping her son healthy, she's ensuring that she's going to be a grandma. There's a very good chance that this is all an evolutionary way for whales to actually stay alive.
NATE: Okay. But what about the mother's daughters? Wouldn't she want her daughters to have a fighting chance to give birth to some grandchildren, too?
CALLI: I mean, yes, but female killer whales have way more issues facing them than male whales, unfortunately, see their pregnancies last on average 18 months. To put it bluntly, in the time, it would take one female killer whale to birth one baby, a male killer whale could impregnate dozens, if not hundreds of other killer whales. For the killer whales to survive, mom, whales need to make sure their sons are happy.
NATE: Well, hang on. Female killer whales are one of the only non-human species that experience menopause. And even though they stop reproducing in their thirties or forties, they live on average to be 80 something years old. So if we're talking about evolution as a reason for mama's boy whales and what does that all mean?
CALLI: It all comes back to nurturing. After a female whale stops mating. She devotes her life to taking care of the group, which includes her son or even sons. A lot of this is theoretical and based on exactly one region of whales. So this isn't an explanation for all killer whales. Not a single other killer Whale population's records match what this study is proposing. So whether this is the result of a strange evolutionary deviation happening to Washington state whales or a sign of things to come in the science of food based bonding, one thing is for sure Mama's boys exist, at least in one other part of the animal kingdom. So you're not alone.
[SFX: WHOOSH]
NATE: Let’s recap what we learned today to wrap up.
CALLI: Due to the power of the Montreal Protocol, the ozone layer is finally on its way back to what it looked like before a hole was developed in it back in 1980… unless we don’t stop launching rockets. Turns out that through a nasty combination of chemicals in rocket fuel, we’re actually risking opening ANOTHER hole in the ozone layer. With the looming threat of “space tourism,” experts agree it’s time we finally discuss a way forward to save the planet yet again!
NATE: What did the world used to smell like? Science says it smelled a lot less fresh and a lot more like burning eggs. Ancient humans were four times less likely to smell flowers, but three times more likely to smell sulfur than modern humans, a fact that likely has to do with the difference in humans’ diets then versus now. The method used to do this could actually help us figure out the phenomenon of why some people can smell things that others can’t, like how cilantro smells like soap to some people and like citrus to others!
CALLI: Researchers have observed orca whale mothers in the Pacific Northwest share their food with their sons, letting the daughters fend for themselves. The working theory is that mothers are trying to ensure the survival of their species by keeping their sons healthy so they can mate with as many female orcas as possible.