The Planetary News Radio – Episode 7: Preserving Biodiversity – Insects, Fungus, and Plastic

Hello. Welcome to the Planetary News Radio Episode 7 with Bryan White. The date is May 29th. It’s around four o’clock in the afternoon in Corvallis, Oregon. I’m outside again. So I apologize in advance for any strange sounds, although I’m in a quiet area, and that’s a good segue way to what I’m going to talk about today, which are insects. Now, the air temperature is finally warming up and I saw a Mayfly today, a little late in the season, although I haven’t been looking for them. But mayflies typically will emerge in May into adulthood. The order name for mayflies is Ephemeroptera, probably from the root ephemeral meaning temporary, which is strange because they’re actually quite long lived as larva, so Mayfly larva might spend two or three years eating in the stream and then swim up, moult, metamorphose into an adult, reproduce, and then die all in about a week. In fact, they’re so short lived as adults that their mouth parts are fused shut. They don’t eat anymore. So unlike a butterfly, that eats as a caterpillar and continues to eat as an adult, Mayflies are done once they pass through the larval form. And so that’s what’s going on now. Mayflies. They’re out and about, seasonal insects.

[Which brings me to the topic of this podcast,] “Why are insects special”? I mentioned in the previous talk about my idea for why we should preserve all biodiversity. Why should we value all biodiversity? It’s not physically possible to preserve every species, but we can certainly agree that there is a scientific value to preserving biodiversity, and insects are a great example. Insects or one of the most speciose as animal groups go. They might be the most speciose animal group, aside from maybe nematodes. Estimates of the total number of species for insects might range somewhere to 5 million, [up to 30 million including undiscovered species] with the total number of all animal species being [at least] 10 million. So that would mean insects make up maybe [at least] half of all animal species by count, maybe not by biomass, but that’s an incredible amount of diversity.

So what’s going on when that much diversity is happening [within a single taxonomic group]? A couple of things. One is that insects are different from vertebrates [in some key ways]. What allows them to adapt in terms of evolutionary time more quickly than vertebrates? [For one], they’re less constrained by their skeleton and by their body plan. So insects are more tolerant of maybe minor changes in their body structures: mouthparts, feeding structures, reproductive structures, and their flying/walking structures. So all of these things are much more flexible, whereas even a small change and the number of fingers that a human has could be could have a severe impact. Maybe not in modern times missing a finger isn’t too big of a deal. But maybe 1 million years ago, missing a finger was a big deal, and you might not have survived. So you see, chimpanzees have 10 fingers and humans have 10 fingers. We’re separated by 7 million years of evolution. [In the case of insects], within that same amount of time, [you’ll see them] duplicating appendages, losing appendages and things like that much more frequently, so insects are hyper adaptable. They’re out there filling all of these ecological niche spaces.

A good way to think about an ecological niche is that the environment is an N-dimensional hypervolume. There’s all these dimensions that could be occupied, [where each dimension represents a unique ecological environment], and an organism will go and occupy what it’s already adapted to, but then it might shift and adjust and fill various other dimensions in the ecological hyperspace. [After some more time] it might divide into more species, and those species might diverge and fill more of this space, until eventually the entire ecosystem space is filled by something. In a small ecosystem, this might be only one or two species. In a large ecosystem, it could be hundreds or thousands of species all the way up [through the trophic levels], from bacteria up to primary apex predators.

Insects are hyper adaptable, which means they can go into an ecosystem and fill all those little voids in the N-dimensional hypervolume that aren’t currently being occupied by an organism. You have primary producers, secondary producers, you have consumers, all within the insect world, so you have a full ecosystem just based on insects. That’s a lot of biodiversity. Every one of those ecological niches requires a genetic change in the organism, so every time a new species evolves, or diverges from an old species, one species splits for some reason, or even new variability within the species. Anytime a species gains in new adaptation, that’s a new piece in the genome. It’s a new genetic element that’s [translates into a] new physiological element. It’s a new piece of biological information, and my argument is that biological information is extremely important, but not just the genome. The genome isn’t enough. We need the phenotype, so we need to know how the genome builds itself. Builds the proteins in the organism. So we want to be able to see organism’s alive in their natural habitat in order to understand the genomic component to that diversity.

[To recap] what I’m just presenting here, is an argument that insects are very speciose, therefore, they have lots of biodiversity, and therefore they have lots of unique genetic elements. Now here’s a question someone might pose to me. Are any of those genetic elements useful? And the answer is, “I don’t know”. Maybe they might be. Some of them might be useful, and some of them might not. It depends on your definition of useful. For example, a fungus that grows on a tree might not be immediately useful, however, fungus growing on a tree [might be] breaking down wood lignin the molecule, and so this fungus is secreting a chemical that can break down lignin. Wood is a very strong material we know, because wood survive thousands and thousands of years intact. We use it to build houses, things like that. It’s kind of similar to plastic. Lignin is a polymer. Trees are building themselves as a polymer. So if we want to develop a chemical process for breaking down plastic [(a polymer)], we might look at something like a fungus that eats wood, [specifically] the wood rot class of fungus.

[Suppose someone did experiment to see if wood rot fungus could break down plastic, but it didn’t work. Then you might say,] “Well, lignin is too different from plastic. We can’t use this fungus to break down lignin because the molecule is too different from plastic”. And I might respond, “Well, okay, are there any organisms that do produce a molecule that do break down plastic”? [Which it just so happens that] there are. There are bacteria that will happily degrade petroleum based products like oil. However, these bacteria, they may be marine and have to be grown in [sea water], and so we want to do is create a genetically modified organism that has the structural properties of a fungus, [but the chemical properties of the bacteria]. We want to make a wood rot fungus that can degrade plastic, and so we could take the gene from the bacteria and [transfer it into the fungus so that the fungus can] produce the plastic degradation chemical. And now we have a fungus that can break down plastic.

[Using this method we end up with something] a little more useful than the bacteria, because now you could do is you could take a landfill and create an environment that will grow this fungus and plastic mashed in together, and we can erode the plastic. While you could do this directly with the bacteria [that can decay plastic], then you would have to do an active process because you have to keep the bacteria alive. You have to culture the bacteria, and so you need energy. And so my suggestion is to use the fungus because it doesn’t require extra input energy. All you do is you put it outside and you let it go, but it has [to have] that chemical [acquired from bacteria] to break down plastic, otherwise, it’ll just sit there. And maybe we can tweak the fungus a few other ways so it can grow in soil and we might have to modify its habitat a little bit. We want to keep the soil moist so the fungus has water to conduct its chemical reactions when it add some nutrients. But for the most part, [with] fungus, you just put it out and it grows. And if this fungus has a chemical that breaks down bacteria, we could create landfills that can destroy plastic. And that will help solve our plastic problem.

What about with insects? Well, maybe we could do the same thing. We can make a caterpillar that can break down plastic. Maybe there’s a parasite that lives inside of caterpillar that digests compounds similar to plastic, and so maybe there already is a caterpillar out there that can break down plastic. [The point is, if we have the available biodiversity, we can create as many different types of “plastic degrading organisms as feasible]. We could just have the fungus. Or we could have the fungus and the caterpillars, and so we could create an entire ecosystem where the fungus and the caterpillar are growing and living together. The caterpillars eat, deposit, nitrogen and things like that into the soil. The fungus grows, and it’s a whole little life cycle, all based on the degradation of plastic without any added energy input. We don’t need to run an expensive, dirty, fire based bioreactor that burns trash puts out chemicals. It’s all passive.

So how does that link back to my original statement? Well, if we lose that species of caterpillar, then we lose [the ability to create] that entire system. So if a caterpillar that could break down plastic goes extinct before we’ve figured out how to cultivate it in the lab, then we lose this entire opportunity to degrade plastic and this really efficient, really cool way. And we don’t know what’s out there, [there might be other organisms and biochemicals out there that we haven’t even imagined possible yet]. So every time we lose a species, we don’t know what we lost. Maybe we’re losing plastic degraders. And maybe it doesn’t matter most of the time, and probably 90% of the time it didn’t matter, [in terms of biochemical diversity when a species was lost]. Maybe the special biochemical adaptations that the organism had were already duplicated [in another species], and other members of the genus, or the order, [or some other] higher taxonomic level. Maybe that animal wasn’t that unique and so we didn’t really lose that much information. [But again,] we don’t know what’s out there, [so we don’t know what we’re losing in terms of physiological biodiversity]. We don’t [really have] anything cataloged [in a meaningful way to address this problem].

If we really wanted to answer the questions, “What are we losing [in terms of genetic engineering potential]?” and “Are we losing an important species?”, we have to catalog the species [in a meaningful way]. Now, how could we do that? Well, we have to find them and sequence their DNA. Sequencing DNA is really good for cataloging [and understanding diversity]. But if we want to actually create real biological systems, we need to have the animals or the organism’s alive. And so that’s why biodiversity [itself] is so important and why preserving [as much] biodiversity [as possible] is so important. If we think of [living organisms as being filled with] these as tiny molecular machines that are jam packed full of information that we can learn from for how to create our own systems, our own molecular machinery, then biodiversity becomes really important.

And sure, maybe someday in the future of humanity, there will be a time where we don’t need animals anymore. And maybe that’s a question for future humans to answer. [In a future where] biodiversity no longer serves a function in the human economy. [In other words, when even the knowledge we could gain from the genetics of animals is no longer relevant], will we still keep animals? Will our descendants 500 years from now have zoos just for fun, just to look at animals and remember where we originated from? Remember that we are animals. Maybe we’ll have zoos. Maybe we’ll make new animals. Maybe humans will merge and split and divide into 10 new different species. We don’t know what’s going to happen [in 500 years], but when we lose the species, we lose the option.

So that is more insight into my thinking and the reason I think this way is because again, as I mentioned previously, my goal is not to just be a animal rights activist. My goal is to be pragmatic. I’m saying there is a real pragmatic reason to keep animal diversity life, [and all] biodiversity alive. And so this argument should work across the entire political spectrum. I should be able to convince a fiscal conservative or liberal that preserving biodiversity is important because it’s an investment in humanity. It’s not just to feel good, although it might make us feel good. Feeling good about animals is just an added benefit. And trees, we are, after all, apes. We were born in the trees. We left them, but we still need them. It’s okay to like trees. We should enjoy wildlife and the outdoors and nature, and we should be able to have a good reason for keeping it around. So that’s what I’m offering, [a reason to preserve biodiversity that can appeal to all humans].

I’m sure I’ll talk more about this as I formalize the idea more, but I think this was a really good example. Insects and fungus. Interestingly, both organisms that use chitin as there primary structural bio-protein. There’s something special about chitin. It’s an interesting molecule for evolutionary genetics, but I won’t say more in this episode. I’ll let everyone think about this topic. This is Bryan White signing off with The Planetary News Radio. Have a good day.

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