 Good morning, Hickets Tuesday. You recently made a video about the overall biomass of humans, and how humans and their livestock together comprise over 90% of the total biomass of mammals. And that got me to wondering how our biomass compares to non-mammals, and it turns out that, at least in terms of weight, we are sort of a rounding error. Okay, so biomass is one way we use to understand the prevalence of different life forms on Earth. Like, there are obviously way more bacteria on Earth than there are humans, but we are larger, and also not to brag, a little bit more complex. And so biomass can be a helpful way of thinking about, like, of all the carbon in all the living things on Earth, how much of it is, say, human, and how much of it is, say, microbial. Humans amount to about 2.5% of total animal biomass. Wild mammals, everything from squirrels to mice to elephants comprise another 0.3%. Our livestock, cows, pigs, etc., make up about 4%. Another 4% is aquatic invertebrates from coral to jellyfish. Fish make up 29% of animal biomass, their total weight is more than 10 times that of humans. And arthropods are around 42% of animal biomass, so at least by biomass, most animal life is either fish or arthropod. But in a biomass sense, animals are a tiny, tiny part of the story, like animals make up much less than 1% of Earth's biomass. Like, we are down here, we weigh less than viruses, a lot less. 12% of Earth's biomass is bacteria, all the bacteria combined weigh about 200 times more than humans do. And we are also dramatically outweighed by fungi and protists, and especially by plants, which comprise over 80% of Earth's total biomass. Like, from a biomass perspective, this is a plant planet with a scattering of other life forms. And I think this is important to understand, because one thing about humans is that we're a little self-aggrandizing. Like, we tend to place ourselves right at the center of the story of Earth, and I guess in some ways that's justified, we are different from other life forms, not least because through writing and video and other communication technologies, we can efficiently share knowledge across space and time. And we do currently have outsized power, our behavior is causing extinctions and reshaping the climate and our habitats. Like, I live in Indiana, which people tend to think of as an endless conglomeration of cornfields, but 400 years ago, this was all hardwood forest. Indiana is not a corn land, it is a forest land that we terraformed for corn. So yeah, we are very powerful, and we are causing big changes to our biosphere, but we also shouldn't exaggerate our power, like, we are just a form of life. The world is very big, and we are a very small part of it, not just in terms of biomass, but also like in terms of time. This ginkgo tree looks very much like the ginkgo trees from the Jurassic age, over 150 million years ago. We, meanwhile, have been around for about 300,000 years, or 0.2% of the ginkgo's history. Earth, and indeed life on Earth, will be okay without us. Earth has recovered from far greater shocks than humans. The thing is, I want us to stay around. Like, I realize this is a somewhat counter-cultural opinion at the moment, but I'm broadly in favor of humans. Like, I think viruses are interesting and everything, but I just think we're more interesting. I tend to think we should conceive of the situation less egotistically and more realistically. Not that we are in danger of destroying life on Earth, but that we are in danger if we don't make better choices of making Earth less habitable for us and other complex life forms. Because ultimately, to me, what's most valuable and important about Earth is not that it's a planet, but that it is a habitat, which currently hosts a huge array of life that contains altogether around 550 gigatons of carbon, of which we are about 0.1%. Hank, I'll see you on Friday.