Random Thought Depository

ftr I am forever going to be bitter that the post I wanted to be "let's talk about extinct ecosystems and how cool they are!" got derailed into yet another post just talking about a single taxon like the millions of other posts on palaeoblr

Please tell me more about these extinct ecosystems. Why did they go extinct? Could an ecosystem like that return?

When I say "extinct ecosystem", I mean those ecosystems that have existed in the past, with extinct animals and plants etc. inhabiting them

by their very definition, they are gone forever

there are ones that were truly unique, like Polar Tropical Forests and Fern Prairies, that we just could not have today

but there were ones that have equivalents to today, as well, like the first savannahs and steppes of the Miocene - they just have earlier versions of the plants and animals

there were so many because there are so many today, and each one had its own flora and fauna and was glorious

There's the wetlands and forests of Hell Creek in the Latest Cretaceous

the bizarre Volcanic Lake Forests of the Jehol Biota

whatever the hell the Ediacaran Reefs were

the Scale Tree Swamp Forests of the Carboniferous

"Mesozoic 2" aka pre-human Aotearoa

the Western Interior Seaway dominated by Mosasaurs

and so many other things, I couldn't possibly list them all. Every time period had its own biosphere and biomes, and they were all unique.

#i wanna see the Aurora Borealis over a tropical forest#BC Canada has a Boreal Rainforest so you can definitely get that

that isn't what I mean by "Polar Tropical Forest"

I mean a tropical forest

at the poles

ie, the ecosystems present during the Paleocene-Eocene Thermal Maximum

we have fossils of plants that showcase how different tropical plant lifestyles had to be up at the poles because of the light weirdness

the important part is "tropical", not "wet/rainforest". those are two different things

Temperate and Boreal Rainforests are wonderful and some of my favorite living biomes, but they aren't what I was talking about

May I ask about the fern prairies? That sounds really cool!

Grass is a relatively recent thing

it first evolved in the latest Cretaceous, but it didn't actually take over everywhere until the Miocene, when grasses that process light differently (look up C3 vs C4 photosynthesis) evolved and just took the fuck over the planet

before then, other plants formed the low ground cover over the earth, and in many places those plants were ferns - spread all over the ground and covering it, much like grass, but significantly less dense. Dirt would have been much more common everywhere.

This is why I am begging every single game developer to remember that grass is not a neutral ground cover

My favorite extinct ecosystem, if it counts while being as physically tiny as it was, is the floating logs that existed in the ocean between the first appearance of woody trees and the first appearance of organisms that could break down wood - floating reefs of a sort, trailing enormous filter-feeding crinoids below them. The baleen whales of their time

yeah that counts! And how bizarre those must have been!!!

Speaking of reefs, we're so used to rocky or coral reefs in the moderns world but there have been so many different reefs throughout prehistory that were made of things that straight up don't exist any more!

Like the reefs of the late Devonian, which were made of stromatoporoids, which may have resembled corals but were actually a highly diverse extinct group of sponges!

This is one of my own reconstructions of a stromatoporoid reef off the coast of Devonian Australia (plus anachronistic underwater baited camera):

The Cretaceous also had some wild extinct reefs which are known as carbonate reefs and were dominated by a group of bivalve molluscs called rudists!

Scale tree swamps are the only one of these I know anything about and they were SO WEIRD. There's definitely some controversy about how they functioned cause these things are hard to work out from fossils, but the current thinking is that these trees shot up to around 100 feet tall in 10-15 years, grew more tightly packed together than basically any modern forest, produced spores one time and then promptly keeled over and died. Forests just do not work like this anymore! It's not just different types of trees, it's a whole *different type of forest* that has gone extinct! Different nutrient cycling, different natural rhythms, different everything!

Even today there are all kinds of niche hyperlocal ecosystems that function in their own distinct ways - shale barrens, waxcap grasslands, cataract bogs. What else have we just never seen??

Anxiety over all the prehistoric organisms we’ll never know, meet your big sibling: anxiety over all the prehistoric ECOSYSTEMS we’ll never know

I've seen bracken fern meadows up north, where grass doesn't grow too well. I would imagine that fern prairies were vast versions of those.

That's actually something I've been wondering about for a while! Grasslands are actually a pretty new type of ecosystem (compared to how long land plants have been around), but the Earth of the Permian, Mesozoic, and early Tertiary must have had areas with the kind of climate that results in grasslands today, what did the vegetation there look like? Would it have looked grass-like cause convergent evolution, or...? I guess that kind of vegetation probably fossilizes a lot less often than woodier plants growing in wetter and muddier environments, so would we have any way of knowing?

Looking it up on Google, apparently fern meadows look like this. So I guess the ground cover of the Mesozoic equivalent of the Serengeti might have looked a lot like that?

Also, this reminds me of this and my speculations here and here.

I don’t understand the difference between European and American nature.

Take wildfires, for instance. The story people tell is that Native Americans knew nature and allowed forest fires, and then Europeans came and didn’t know nature, and they made the mistake of trying to stop forest fires, resulting in even bigger fires. But Europe has forests! Did no one pass down their ancestral European knowledge about forest fires? Or were they shouted down by the people whose ancestors came from windswept moors or wherever?

I can gesture vaguely at a few possible factors (differences in historical population density, absence of grazing livestock in North America before the Columbian Exchange, English settlers not being familiar with Mediterranean climates, etc.), but I really don't know and now that you bring this up I'm curious about this too!

the mountain lions are unwittingly practicing witchcraft to improve their hunting chances and leaving patches of terra preta behind

Wonder how many other big predators do this.

Could totally see prehistoric Blindsight vampires having deliberately done this, both directly and indirectly through manipulating the behavior of other large predators. Would fit well with my idea of them having been beekeepers and ecosystem engineers.

I did some math on it real quick and the chestnuts produced by the American Chestnut trees killed by the blight could have fed 4.8 billion people

This assumes a diet of only chestnuts, but it also assumes that every chestnut produced by every tree is collected, so I feel like those assumptions cancel each other out and just show that chestnuts were an incredible staple food

Wait never mind I fucked up the math I think

*angrier calculating noises*

Okay so the american chestnut trees could have fed around 400 million people

That is still completely insane

Can you explain your math? Is this a 2000 calorie diet, day in and day out, for years, or do you break it out some other way?

Number of trees: 4 billion

Yield per year: 50-100 pounds of nuts

Days in a year: 365

Calories per pound: 755, I think

So yes it's assuming a 2,000 calorie Only Chestnut diet which is obviously dumb, but it's a good way to get a rough sense of how much food the trees can produce

@headspace-hotel is there a possibility for recovery for them? How much of the gene pool survived?

Efforts to restore them are well under way, it's very likely they will recover. A genetically modified version with immunity to the blight given by a gene from wheat is about to be released to the general public I think

Hmm, I think this runs into issues when you apply an important sanity check: even high count estimates put the pre-Columbian population of North America north of the Rio Grande at 12.5 million people. North American peoples in the period also extensively practiced agriculture; I would not expect people to spend considerable effort growing corn, beans, and squash if there was an easily exploitable vast surplus of food that did not require cultivation, or at the very least in the presence of such a surplus I'd expect the chestnuts to be the staple food, occupying roughly the niche that wheat and rice did in Old World society (IIRC, the actual staple food of most fifteenth century North American people was corn, beans, and squash).

For comparison, fourteenth century Europe before the Black Death had about 70-80 million people on a similar land area and seemed to have problems feeding itself, as this was also the time period of the Medieval great famine, and the entire world in the same era had something like half a billion people, heavily concentrated at the opposite ends of Eurasia. Estimates I've seen for the Pleistocene world population (the number that would probably roughly correspond to how many humans could actually be supported by uncultivated gathered food) are usually low millions.

Assuming your chestnut productivity number is accurate, I'm guessing:

I think a plausible basis for a sedentary society in a carnivore species is fishing, and also settlements in places where the terrain bottlenecks seasonally migrating herds. A big limitation on such societies is they would be very geographically limited. So the Centaur world might have a lot of fishing villages on sea coasts and on rivers that are migration corridors for anadromous fish (equivalents), and some more fixed settlements in hilly or mountainous regions where the terrain channels migrating herds into narrow bottlenecks, and otherwise be mostly inhabited by herder nomads.

Tangential vagueblogging (about somebody I generally respect, and I don't want to add to the pile-on they're getting), but I'm going to note that I really don't like when people present "predators control the population of prey species and kill off their sickest and weakest individuals" as if this is some kind of favor to the prey species, a merciful euthanasia of beings that are literally better off dead.

It's impossible to know how deer feel about the merits of slowly starving to death vs. being ripped up by wolves, but we can look at human emotions and behavior in comparable situations.

"Life, although it may only be an accumulation of anguish, is dear to me, and I will defend it." - Mary Shelley, Frankenstein.

I think humans show a strong revealed preference along those lines. Suicide seems to be a minority choice even in the most miserable conditions in the historical record. Take, for instance, slavery in North America circa 1500-1850 or so; pretty awful. Some slaves did commit suicide. But most of them did not. This is just one many examples in the historical record of humans enduring appalling conditions and apparently mostly not choosing suicide (Irish potato famine, Nazi death camps, gulags, classical era Greco-Roman slavery, etc.). This is actually kind of remarkable if you stop taking it for granted. Of course, it makes perfect sense if you think about it in terms of evolutionary theory; for a species intelligent enough to imagine suicide, choosing to live is a selection pressure, potentially a quite powerful one. We're all descended from the people who chose survival, because those who chose death left no descendants. For a species intelligent enough for long-term planning and suicide, an attitude of "my life, though it may only be an accumulation of anguish, is dear to me, and I will defend it" is an adaptive trait, and it is no surprise that it seems to have approached fixation before the beginning of recorded history.

The predators alive now mostly do not attack humans because they follow mother's wisdom. The conservatism inherent in the mother's wisdom strategy may keep humans safe for a while, but big predators in most of the world have had tens of thousands to millions of years to eat a human (or proto-human), discover we are quite edible, and add us to the mother's wisdom food list that they transmit to their offspring. Why hasn't this happened? Well, what happens to a predator that kills and eats a human? Other humans follow the people-eater back to its den and kill it! The only predators that survived were the ones that did not habitually eat humans, either as a matter of blind luck or because they were smart enough to learn that we're more dangerous than we look. I suspect the saber-tooth cat, the marsupial lion, etc. are not around anymore because they were unable to make this adjustment. Point is, it sure looks like when humans got smart one of the first things they did was give themselves the same circumstances as deer that have no predators to control their numbers!

You'll often find references to early agriculture actually being a step down from hunting and gathering; primitive farmers are not well-nourished, have a lot of diseases, etc.. To me, preindustrial agricultural humans look a lot like those overpopulated deer; there aren't any predators left to control their numbers (a circumstance they arranged for themselves!), so now what caps their population is malnutrition and infectious disease (and the synergy between the two; malnourished animals and humans get sick and die more easily), so they mostly live on the edge of starvation, so they're hungry and sickly and riddled with diseases (and they are a great burden upon the wider ecology). Being an ancient or Medieval peasant sounds miserable in a similar way to how being a deer in an overpopulated park or a city pigeon sounds miserable. And yet, I think most people would agree that ancient Mesopotamia or Medieval Europe would not be improved by adding Blindsight vampires with the crucifix glitch fixed, even if the survivors the vampires don't eat might have better diets and fewer parasites as a result (because the vampires would kill a lot of the people they'd otherwise have to share their food and other resources with).

It's also pretty suggestive that an often repeated theme of human stories is "what if there was something that related to you in the way a wolf relates to a deer?" and the intended and default reaction to that idea is horror. From dragons, vampires, and Grendel to the "xenomorph" from Alien, the human imagination is persistently haunted by the fear that something may target us for predation; even the ostensibly human killers of e.g. slasher horror are in a sense just another kind of predator. Predation is also a favorite metaphor for human exploitation and abuse of other humans; we speak of rapacious rich people and manipulative abusers as "predatory" even though, of course, they (usually) don't literally eat us.

Humans were a prey species once and, gee, it sure looks like we hated it, like it was a trauma that still haunts us hundreds of thousands years later (probably burned into our genes; predator avoidance would have been a selection pressure), and like as soon as we got smart enough one of the first things we did was to give ourselves the circumstances of those overpopulated deer, choosing chronic food insecurity and high disease load as the lesser evil.

How would you feel about your grandma and your disabled son being dragged away and devoured by wolves? How would you feel about somebody who suggested that such predation was a sort of favor to your species?

How would you feel if you were hungry and sick and in pain and had a broken and infected leg and the wolves came for you? I think I would say, "my life, though it may be only an accumulation of anguish, is dear to me, and I will defend it!"

Like, my first articulated objection to "predators are actually good for prey species" thinking is "imagine how ghoulish it would be if somebody applied the same logic to humans!"

I'm not an expert on animal behavior, but it seems to me that the behavior of most animals suggests a similar revealed preference. When the wolves come for an injured deer, I would guess the deer will likely try to hobble away. The city pigeons that occasionally walk by my window are likely malnourished and riddled with parasites and some of them have pretty gruesome foot injuries (I remember reading a post about this once), but they continue to go about the business of survival and even reproduction (I occasionally see them doing what I think are courtship behaviors).

And sure, that's dubious reasoning from analogy. Notably, humans are probably pretty unusual in being intelligent enough to imagine suicide (and also having hands and being smart enough to make weapons, which makes suicide much easier), and therefore present humans are probably the product of a very unusually strong selection pressure for wanting to live. Probably most animals lack the cognitive capacity for suicide, even the passive suicide of suicide by starvation or suicide by predator. I wonder if the point where humans became intelligent enough to imagine suicide is marked by a genetic bottleneck... Deer likely don't have the cognitive capacity to imagine their own death, and if they did they might be more at peace with the idea than we are, because they've experienced no selection pressure for conscious avoidance of death qua death; the injured deer likely tries to hobble away from the wolves because of some combination of pre-programmed reflexive instinct and fear of the pain of the bite, or something like that. If you magically gave a deer human intelligence, it might be much more at peace with the reality of its eventual death than we are.

I guess my truest objection to "the wolves are really good for the deer" thinking is that it feels like another manifestation of Just World thinking and therefore deeply conservative - not in the sense of conventional political conservatism, but I think it's a manifestation of a sort of thinking that's one of the wellsprings of political conservatism; I talked about it here. @aksemmi, I'm wondering if maybe you meant something like that.

You seem to be assigning moral value to the actions of animals that have no concept of right and wrong the way humans do, and I find that deeply unsettling. You can acknowledge that deer feel fear and pain when they die without vilifying wolves for doing what they have to to survive.

Predators are necessary for the health and long term survival of prey species because they coevolved together. Without predation certain plants and areas get severely overgrazed, which in turn has detrimental impacts on other animals and insects that are dependent on those plant species. All ecosystems evolved as complex interconnected webs, and eliminating even one species from that can have catastrophic consequences. Humans using controlled hunting to keep the deer population in check in certain areas is necessary only because we drove out all of their natural predators. It is righting a wrong that we caused that is having a negative impact on every plant and animal species in those areas. Reintroduction of predators is a better long term solution, but it takes time and money and is much harder to get people on board with.

And as a chronically ill/disabled person, please stop comparing us to animals. It's insulting and dehumanizing.

If you read my post carefully, you'll notice I never say that wolves are, like, evil or something. My point is not to suggest that predators deserve some kind of moral blame, my point is that being a prey species probably sucks. When we consider wolves we should be able to see them as organisms instead of villains, but we should be able to do that without sugar-coating what it means to be part of their food supply.

I don't think deer overpopulate in the absence of wolves because they co-evolved with wolves; I think even if wolves and other predators were never around, deer would still tend to breed up to the limit of their food supply in the absence of predators, because deer that do that would produce more offspring than deer that limited their reproduction to maintain a "good" deer population size. Natural selection promotes genes that are good at getting more copies of themselves into the next generation, it does not promote genes that make the species happier or healthier except insofar as that is congruent with making more offspring. The population size of a species is inevitably constrained by something, that constraint is often predation, but this doesn't mean that predators are necessarily good for a prey species, it just means there's trophic space for a predator species to occupy and some animal has evolved to follow that life strategy. I think a not bad analogy for how this works is viruses and parasites; it's probably pretty common for a species and its parasites to co-evolve, and parasites are another constraint on population size, but this doesn't mean the parasites are good for the host, it just means there is trophic space for parasites and something that has evolved to inhabit that niche. Again, this is not a moral judgment on predators, it's just how nature works; a lion isn't evil, but then a malaria-causing plasmodium parasite isn't evil either. Removing predator species may have undesirable consequences, but I think it's important to remember that nature fundamentally does not care about things like the well-being of organisms or harmonious ecosystems.

I don't see how it's insulting to disabled and chronically ill people to point out that "wolves really do deer a favor by weeding out the sick and weak," if you apply it to humans, is fascist/eugenicist logic. People seem to take offense to such comparisons because they see drawing parallels between human and animal experiences as implicitly lowering the moral status of the human, but I raise the comparison in the exact opposite spirit: the question I ask when I raise those comparisons is "what conclusions might we draw if we viewed animals more like the way we view humans?"

And, like... Not to play the standpoint epistemology card, but I'm not exactly super-healthy myself, and one of the reasons I don't like the "wolves are really good for the deer" argument is that one of the possible implications I read in it is that, actually, it was great that a million years ago somebody like me would likely have been dragged away and ripped up by lions, my life isn't really worth living anyway and it would have freed up ecological space for my healthier, more genetically fit fellows to thrive. I am probably only alive today because I have the incredible species privilege to belong to a species where most individuals live to old age, and I am very conscious of how incredibly lucky this makes me compared to what's normal for animals (or even what was normal for humans before 1900 or so), and I'm very much coming from that perspective here.