Filed under: Real Science Content, Speculation, Uncategorized | Tags: electrofishing, plesiosaurs, Speculative paleontology, Tanystropheus
I’m venturing back into the land of speculative paleontology with a modest suggestion about the reason why two groups of aquatic Mesozoic animals had ridiculously long necks. Some of these animals are very familiar: plesiosaurs. Some Plesiosaurs, members of the Plesiosauroidea, had ridiculously long necks. This trait was shared with the lesser known Triassic Tanystropheids, such as Tanystropheus longobardicus. Their necks are typically relatively stiff and weakly muscled, which gives rise to real questions about how the animal used them. Plesiosaurs, for example, could not raise their necks out of the water in the classic Loch Ness Monster or “swan” pose, nor could they sinuously retract their necks as if they were snakes’ bodies. Tanystropheus’ neck was even more limited, being compared to the stiff tails of hadrosaurs.
How did they use these necks? Proposals include Elasmosaurus “conceal[ing] itself below the school of fish. It then would have moved its head slowly and approached its prey from below” (from Wikipedia) to Tanystropheus fishing from marine shores as some sort of dipsy-diver, dropping its head down into the water from above. More bizarrely, taphonomic evidence in the form of fossilized sea floor gouges suggests that Plesiosaurids with long stiff necks were benthic feeders like rays or grey whales, grabbing their prey out of the mud (from Tet Zoo 2.0). It is hard to image an animal less adapted to such a hunting mode.
This doesn’t even get into the exquisite vulnerability of this body shape. Long, thin, stiff necks are very vulnerable to aquatic predators. Indeed, multiple artists have illustrated elasmosaur necks as the chew toys of large pliosaurs, and it is hard to imagine Tanystropheus surf fishing without getting its neck dislocated.
I’d like to suggest a different hypothesis, that these long, stiff necks were perfectly functional, and that, indeed, there are animals today that have similarly constrained morphologies. They aren’t tetrapods though, they’re fish. Electric fish, to be precise. Electrogenic organs have evolved at least four separate times in fish (Gymnotiformes, Mormyridae, Malapteruridae, Torpediniformes), and occur in both salt and freshwater. The South American knifefish (Gymnotiformes) are a particularly good example. As a group they have linear, fairly stiff, poorly muscled bodies. The apparent explanation for their shapes relates to the complexity of interpreting information from electric fields, and simpler body shapes make for more unambiguous signals. It appears that most electrogenic animals (animals that actively generate an electrical field for sensory purposes) have stiffer bodies with simpler shapes than do their less shocking relatives. This is also true for manmade electrogenic sensors, as a simple shape makes for a simple, easily interpretable field.
If the long stiff necks of Plesiosaurids and Tanystropheids are electrogenic organs, the weaknesses of the necks become strengths. Their necks’ main job is to be held stiff and straight in the water, and they appear well-built for this task. Moreover, electrogenic organs are built from stacks of electrocytes, which were the inspiration for batteries. The longer the neck, the more “batteries” it can hold, the bigger a field it can create, and the higher a voltage it can generate. The advantages don’t stop there. Electrogenic organs have three potential functions: sensing, electrofishing, and defense, and I will explore each in turn.
Active Electrolocation
Many animals can detect electrical fields, with or without special organs. Humans can detect sufficiently strong electric fields, while everything from catfish to sharks and rays to platypuses and river dolphins have structures specialized in passively detecting weak electrical fields. Electrogenic animals all actively use their electrical organs to sense their environments, feeling differences in the field due to the presence of things that either are either more or less conductive than the surrounding water. They can also detect the electrical fields innately given off by all animals through things like muscular exertion, heartbeats, or (in fish) the gill area. All of this adds up to a sophisticated electrolocation sense.
This is particularly important for animals that hunt in waters where vision is limited, either through turbidity or at night. It is also quite useful for hunting animals buried in the sediment, which is an explanation for the Jurassic sea-floor gouges caused by Plesiosaurids.
In an attempt to illustrate this, I chose the small (30 cm long) tanystropheid Tanytrachelos. This species was found in the Triassic, in the Solite Quarry in Virginia. It was apparently amphibious, for it was found in the sediments of a highly seasonal lake, and its webbed footprints are found fossilized in lake mud. Its main prey were apparently insects, and it apparently co-occurred with the fish Turseodus, of approximately the same size. Given the description of the lake sediments (alternating layers of mud and decayed vegetation), I suspect that the water wasn’t terribly clear, as it has been illustrated. The lake water may have been stained tea-brown by tannins, or it may have been muddied by rain and animal activity. Either way, I would suggest that Tanytrachelos was something like a platypus, an aquatic insectivore that found its prey using their electrical fields instead of eyesight.
Cartoon of Tanytrachelos electrolocating a Turseodus in Solite Lake
I should note that all the long-necked species probably used electrolocation. It doesn’t take a large electric organ, and in turbid or dark environments it can be critical. It’s also possible that a majority of Plesiosaurids and Tanystropheids were electrolocators only. In modern electric fish, a majority are electrolocators, not active shockers, and there’s no reason to think this was different in the past. Certainly there is a tradeoff between carrying an electric organ and using a neck for something else, and there’s no reason to expect them all to be electrofishers. But some could have been.
Electrofishing
Here, I would like to compare the fish biologists’ standard sampling tool, electrofishing, with the biological versions. While it is not clear that electric eels hunt with their electric organs, marine torpedo rays certainly do. However, the best insight comes from human electrofishing. For those who are not familiar with it, electrofishing involves using a generator, a transformer, and at least two electrodes. When the system is properly tuned, fish are stunned and can be captured for population samples. Most electrofishing rigs work in freshwater, but several research groups practice marine electrofishing. Still, there are a number of complexities.
Human electrofishing works on a simple principle. Many fish, when caught in a pulsed DC field between a cathode and an anode, involuntarily swim towards the anode, a phenomenon called positive electrotaxis that is caused by involuntary muscle contractions in the fish. Fish biologists use this trick to draw fish into the anode area without killing them, so that they can count and measure them. Translating this to electrofishing animals, I propose that the animals used pulsed DC current, with the anode located immediately behind the head. If one looks at the field lines, this would cause fish to swim uncontrollably straight into the predator’s mouth. Additionally, electrofishing rigs are deliberately designed with the anodes as large as possible to avoid damaging the fish (reference). One could easily argue that the long, slender necks with small heads of animals like Elasmosaurus or Tanystropheus are the exact opposite, with small anodes evolved to stun, injure, or even kill the the prey before it reaches the predator’s mouth. I used Tanystropheus in the cartoon below to illustrate the principle, with the anode behind the animal’s head.
Tanystropheus electrofishing, with the anode behind the head.
While this is simple in theory, it becomes complex in practice. For one, seawater conductivity varies depending on temperature and salinity. For another, fish catchability varies depending on the ratio of conductivity between the fish and the water, with a maximum efficiency where the fish has the same conductivity as the water. There are other factors, such as the frequency of the pulsed DC current used, which varies by fish targeted (usually determined empirically by biologists), and factors such as the thickness of the fish scales (thick-scaled fish are harder to catch this way) and the size of the fish (larger fish are more vulnerable than smaller fish) (reference). As an aside, it is not clear whether electrofishing works on squid or insects, apparently due more to lack of experimentation than anything else.
Thus, there is no one optimal design for electrofishing animals. Plesiosaurids could not broadly harvest every fish in the water, but would be constrained by how they could adjust to factors like salinity and the fish present, and I suspect that the substantial diversity they show represents adaptations to different electrofishing strategies. Most likely, the biggest plesiosaurids would have to migrate frequently to avoid fishing out local habitats and to take advantage of spawning clusters or feeding congregations, much as large sharks do today. Since a proportionally bigger electrofishing rig is required for oceanic uses, it suggests that freshwater electrofishers should have proportionally shorter necks. This appears to parallel the fossil record, where known estuarine or freshwater species have shorter necks than do marine animals.
As an aside, I get the impression that Mesozoic fish had thick scales compared to those of today. While this may be erroneous, it is possible the Plesiosaurid electrofishing caused adaptive pressure on Mesozoic fish to favor thicker scales than we find today.
Why are there so few electrofishing modern animals? I would suggest that the answer is aerobic capacity. Electric eels reportedly get 80% of their oxygen from the surface. They are air-breathers, more than some amphibians, but torpedo rays (the other electrofishers) are not. While I’m not aware of any physiological studies, large electrical organs have to be metabolically expensive, and being air-breathing does make it easier to power them However, electric eels are stuck morphologically, because they have to cram their all their organs into a shape optimized for electrogenesis, and they have heavily vascularized oral cavities rather than true lungs. Air-breathing reptiles are not so constrained. Better still, their electrical array is physically separated in their necks, away from their heart, lungs, and swimming fins, allowing each system to work separately with fewer morphological constraints. As a result, they could grow much larger than electric eels or any modern electric animal. As for how Plesiosaurids avoided electrocuting themselves with their own voltage, all I can say is that electric eels somehow get away with it, so presumably it’s quite possible. Some electrolocating fish have encephalization quotients close to those of humans, so it’s unlikely that electrogenesis would be a problem for Plesiosaurid nervous systems.
Electrical Defense
This is a normal outgrowth of electrofishing, although current characteristics probably differ. Indeed, more modern electrogenic animals use these organs for defense than for food gathering. This is the classic electric eel defense, and I suspect that any electrofishing animal could effectively defend its neck from larger predators. A pliosaur attempting to bite down on an electrogenic elasmosaur would be in for a nasty shock. I’ve attempted to illustrate that below, with my cartoon of what might happen when a Pliosaur attacks an Elasmosaurus.
An electrified Elasmosaurus teaching a Pliosaur that it is not a prey item (with apologies to Luis Rey and Robert Bakker)
In Conclusion
Of course this is all speculative, soft-organ paleontology. I haven’t been able to locate a picture of an electric eel skeleton, so I have no idea how electric organs affect bone shape, or whether it’s possible to determine the presence of an electric organ from any skeleton. Some Plesiosaurid neck vertebrae are described as “odd and asymmetric”, but I have no idea whether this could be due to the presence of an electric organ or anything else.
Still, the strength of this hypothesis is that it presents a good explanation of why both Plesiosaurids and Tanystropheids have long, weak, inflexible necks, and it also accounts for how such an animal could be an efficient aquatic or benthic hunter. As such, it is certainly no worse than the idea that they are stealthy hunters, with their bodies hidden by their long necks so that they appear smaller. In fact, it makes them seem rather formidable. Electric sea dragons, anyone?
Offline References
Bakker, Robert. 1986. The Dinosaur Heresies. Zebra Press.
Fraser, Nicholas. 2006. Dawn of the Dinosaurs: Life in the Triassic. Indiana University Press.
This post was inspired by a couple of Charlie Stross’ recent postings, about expectations for 2030, and the future of computing. Also, my Mom’s friend subscribes Chemical and Engineering News, passes them to my Mom, who passes them to me about six months later. I’ve gotten a bit of education about Big Pharma through that, and through friends in the industry. I’m not a pharmacist, but I do like wild speculation, and that’s what I’m writing here.
As of last year (I’m only now seeing 2012 C&EM issues), Big Pharma was having troubles. It costs somewhat north of a billion dollars to bring a new drug to market in the US, mostly due to the costs of testing to meet regulatory requirements. As I understand it, most of that cost (I heard 75%) is salaries. Partly as a result, there’s a phenomenon known as the “Valley of Death” in the process of creating new drugs. That valley lies between discovery of an interesting new potential drug, and when that chemical enters human testing. Big Pharma has been increasingly scrapping their discovery divisions, and focusing on human testing (which is done in places like India, less in the US, to keep costs down. This is a global industry), and far less than 1% of interesting chemicals make it across the Valley of Death to be tested on people. Drug discovery is currently being paid for by government-funded research, and non-profit groups like the Gates Foundation. Weird but true–capitalism seems to require charity to make new drugs.
Now, let’s look at a disruptive technology, the chemputer that prints out chemicals, including potentially drugs. If this gizmo works out (and there’s no reason to think it can’t), then it bids to do to Big Pharma what the internet did to the music, film, and publishing industries. There’s no point in blowing a billion dollars on drug development, if any hacker can print out the drug on demand, using reverse-engineered recipes from another country.
What will Big Pharma do? In the short run, obviously they’re going to send out the lawyers to defend their patents, and I suspect those legal battles will be finally settling down around 2030. I shouldn’t be too flip about this, because there’s a terrible human cost to dismantling the industry: most of that billion plus dollars goes to highly trained drug industry professionals and the people who watch over them, and that’s a lot of people to put out of work. Of course they’re going to fight, just like the American insurance industry fights against government health care. Still, I think the industry is ultimately going to lose, and it will have to adapt or die.
Fortunately, there’s an alternative. The brighter companies will get into the printer business.
Here’s the way it might work. Absent some interesting catastrophe like Peak Oil or a random apocalypse, middle and upper-class people in 2030 will probably have their genomes read as a normal part of their health regimen. They’ll probably even have their epigenomes read, and they might even get a periodic microbiome workup done. They will also likely have all sorts of cute portable monitors for all sorts of conditions, just the way diabetics have their meters now, and they will have all sorts of information on how drugs interact with their particular -omes.
Big Pharma 2.0 could get into this market. They can, for example, offer new parents a free genome and epigenome workup on their new kids, so long as they get to keep a copy of the data for research purposes. Companies may similarly offer free monitoring of a person’s health, so long as they get to keep copies of all the data they get while performing those diagnoses. They can sell the family a printer, and offer to print out the drugs they need (so long as the company can legally produce them), or tell the family when to go to a doctor for more sophisticated care.
What Big Pharma 2.0 is trying to do here is to get people caught up in their technical ecosystem, much as Apple does with their computers. Big Pharma 1.0 already specializes in running human trials, and this is, effectively, a way to recruit human guinea pigs. It doesn’t even particularly matter if the clients of such companies do things like abuse drugs or experiment on themselves. It’s more data for the companies at the other end of the monitor, after all.
As for discovery of new drugs, I suspect the discovery process will come to resemble Amazon’s commercialization of the slush pile even more than it already does. Right now, most drug discovery is done using government funded research, and there’s no reason to think that won’t continue. Certainly, some private individuals will get into the drug discovery game, and their products might even get popular enough that Big Pharma 2.0 picks up their chemicals, and starts offering the experimental drugs through their chemputers.
Wherever they get their experimental drugs, Big Pharma 2.0 can certainly let their clients volunteer to test out new drugs, especially if the clients get paid for it. Since the companies have a lifetime’s medical history for their clients, it’s more defensible medically and statistically to use these well-known volunteers than to recruit random people out of a Mumbai slum for testing. Big Pharma will simply be trading randomly recruited test subjects and an unknown market, for a captive audience of volunteers and patients. They will trade in data and care, not drugs.
I’m not sure what role doctors will play in 2030, assuming people start depending on home diagnostic units and chemical printers to dose themselves. Doctors will certainly continue to treat injuries, deliver babies, treat novel infections, and handle more complex problems. Still, being able to print drugs is going to wildly affect the whole huge medical system, in both good and bad ways. I can imagine people getting harmed by cheaply printed drugs and other such problems, but I can also see people getting better and cheaper care.
What do you think?
Filed under: livable future, Real Science Content, science fiction, Speculation, sustainability, Uncategorized | Tags: grim meathook future, science fiction
I’ve got to admit, starships are intriguing, as is the idea that someone can build a largish skyscraper with a fusion generator in the basement, and that building will contain a village-supporting ecosystem (powered entirely by the fusion generator) and also be missile-proof. On the bad side, this vision seems a bit, I don’t know, silly perhaps? The skyscraper, I mean. That’s effectively what a starship is, though, and existence of one implies the other.
On the other hand, we can assume the obvious answer for the Fermi Paradox, that the reason we haven’t heard from aliens is that starships are logistically impossible, even if they are possible under the laws of physics. This comes about simply because starships require so many breakthroughs in so many fields. A failure to achieve any of these breakthroughs–power plant, shielding, compact, human-supporting biospheres (or stasis, or computer upload systems that last for centuries), and keeping the crew together for the duration of the voyage–dooms the starship. All of them could be impossible.
At this point, some SF aficionados throw up their hands and scream “therefore we’re all doomed! The Earth won’t last forever, and humans have to.” This is foolish. Yes, of course we’re all doomed to die, one way or another (sorry if this is unwelcome news), but Earth has another billion or more years to run before it becomes uninhabitable, and it’s quite likely that humans on Earth have another few million years before we go extinct, no matter how stupid we are.
The basic point here is that humans will almost certainly survive a transition from our current, fossil-fuel based, economy to one that is not based on fossil fuels, and the only reason I say “almost certainly” is because I’m currently reading Legacy of Ashes: The History of the CIA, and cringing how many attempted suicides the US unknowingly avoided. Anyway, the point is that people will survive, whether we decide to end our dependence on fossil fuels by crashing civilization, or whether we get to innovating and finding ways to do more with less, just as we have for untold centuries.
What will that future look like? In some ways, it will look like the starship future, at least for the next few centuries. As we get nine billion people on the planet, we’re going to have to find ways to feed more people with less land and water. Given how much we currently waste, this may be possible, if not pleasant.
Other predictions:
–Oceanic fishing will largely disappear for centuries. There are so many anoxic zones already that it’s likely that most people will give up fishing, and ships will have to carry all their food with them. I’ve had fun imagining a future Pacific where big, ark-like windjammers travel among the islands, all the food grown or shipped with them and fresh water recycled aboard as much as possible. The islands that survive sea level rise may start to resemble the self-sufficient dome cities of the previous post, since they’ll be less able (or entirely unable) to draw on the sea for their livelihoods. This is a grim thought for those of us who admire the old Polynesian cultures, but fodder for any SF writer who wants to re-imagine the old idea of asteroid belt colonies out in the Pacific, with kite-sailers replacing singleships. Anyone want to mine lava for precious elements?
–Farming will change. We’ll probably start recycling sewage onto farmland (if only to recapture the phosphorus, since we’re running short of mineable sources for that essential element), and we’ll certainly eat less meat. We’re already getting a powerful taste of climate change, with those record-breaking heatwaves and storms, and it’s going to get worse. We’ll have to get used to the idea of crops failing, and we’ll have to get very good at storing food during the good years. Currently, big agribusiness has a lock on both the food economy and politics, but that may fail suddenly, if the few big companies that dominate the Ag industry fail to deal adequately with crop failures, changing climate zones, and other problems. Rural America has been “dumbed down” for most of a century, with the bright kids lured into the cities. We’re facing a time when we need really, really smart farmers. I suspect we’ll get them, and this will affect both agribusiness and politics. Personally, I hope that permaculture takes off in a big way, but that’s because I’m an ecologist and I think it’s cool.
–Politics: It’s amazing how much politics in the US is affected by air conditioners. If the amazingly complicated US power grid starts to fail, people are going to start migrating north, out of current red states and into the blue. Some people say this is what’s driving the current Republican party, and they may be right. America is getting less white, and throughout much of the world, we’re seeing smaller families. There will be a gerontocracy for the rest of our lives, I’m afraid, but after that, who knows? We’re so used to thinking of political economy as growth that it will take innovation to face a future where populations decline.
I could go on, because this is the kind of future that makes more sense to me. Perhaps it’s because I’m a pessimist? Or is it that the idea of human history having millions of years of one damn thing after another is actually more appealing than centuries of adolescent style, unlimited growth? For SF writers, there is good news here:
–there are plenty of Apocalypses to go around. If we really do live for millions of years, we’ll see the end of the fossil fuel age (in the geologic near term), the end of global warming (as I posted on a while back), at least one more ice age, multiple Carrington Events, asteroid strikes, devastating earthquakes and volcanoes, east Kilauea sliding into the sea and inundating the west coast, dogs and cats living together, and so forth. I was toying with the idea of starting an SF scenario called “after the 34th apocalypse” set waaaay far in the future, but I would have had to figure out what all 34 apocalypses would be. The point would be that the end of civilization as we know it might become old hat after a while, with coping strategies and everything.
–Many futures are possible. Given a combination of limited resources and humanity’s incredible capacity for ignorance, boredom, and self-delusion, I predict that people are going to try most options repeatedly. Everything from slaughterhouse dictatorships to drop-out wannabe utopias will appear again and again. Modern giant agribusiness isn’t the first time western civilization tried huge agriculture (see latifundias), and it’s certainly not going to be the last time, although I’m sure we’ll see periods of small farms in the near future. Dictatorships will come and go, and there will always be a new religion popping up somewhere, even if most of them don’t survive much past their creators’ lifespans.
–Science will always be around. It’s common knowledge that most of the world’s current great religions (Christianity, Buddhism, Taoism, Hinduism in its current incarnation, and Islam) were created during the so-called “Axial Age” of empires in Rome, India, and China. They and their descendents are still around, in massively altered form. We’re centuries in to another age of global empires, and I’ve been wondering what new form of religion will come about. The answer was so obvious that I almost missed it: science. History is accretionary, not cyclical. Although Christianity is monotheistic, it early on absorbed a whole body of saints and pagan holidays from the old religions it replaced. Islam and Buddhism did the same thing, and I think the trend is universal among missionary religions. Because of this, I’m pretty sure science won’t go away either, no matter how hard people try to suppress its inconvenient truths. It’s so embedded in all of our lives that, like the notion that God should be capitalized, it’s not going to go away. Science *will* change radically in coming centuries as it subsumes arising cultures, but people will keep doing it. When we go through future ages of upheaval and global empires in coming millennia, our descendents will likely come up with still other “religions” that fundamentally change the way we think. I wonder what they will be?
–Domestication will rule much of the world. As with ants and termites, the human species’ fundamental adaptation has been domestication, which I like to describe as a massive campaign of symbiotic adaptations. While we can live without agriculture, I don’t think we’re going to do so. It’s simply too useful. Rather, I think that evolution is going to continue to take advantage of our domesticated ecosystems, just as it is doing right now. We will see more pests, pathogens, and parasites (including social parasites), and they will only get more sophisticated through coming centuries. I’m quite sure our counter-measures will get more sophisticated too, in a coevolutionary arms race, and I suspect that agriculture in, say, 40,000 years, will look radically different than it looks today. Farm ecosystems will be much more complex, and much of that complexity will be outside human control. Fortunately, I don’t think wilderness will ever entirely vanish, either.
–Similarly, I don’t think machines are going away, and I think that the complexity of mechanized ecosystems will only increase over time. I also think it’s likely that domesticated and mechanical ecosystems will merge more thoroughly than they have already.
In other words, there will be grim meat-hook futures, but I suspect that for every grim meat-hook generation, the next generation will make the best of things, get on with life, and be relatively happy. Things could be worse.
Filed under: livable future, science fiction, Speculation, sustainability, Uncategorized, Worldbuilding | Tags: grim meathook future, science fiction
Okay, not quite in the original sense; However, I thought I’d play with a simple idea. In the future, we can build a starship, specifically a slower-than-light starship that obeys the laws of physics as we currently know them.
What will Earth look like in this case?
Let’s unpack this scenario a bit. For a starship to work, we will need to have developed a bunch of technologies and practices that we currently don’t have.
These include:
–small biospheres that can support people for long periods of time without breaking down. Remember what happened with Biosphere 2? That’s what I mean by break down.
–light-weight shielding that can deal with debris hitting it at absurdly high velocities.
–Either cheap, compact, very, very safe fusion that can burn continuously for decades (for a torch ship), antimatter that can be cheaply made and safely stored for centuries, rather enormous lasers that can fire for decades, and can be aimed with nanometer precision (for a laser sail), or some form of highly accurate, high-powered linear accelerator and “smart particles” that can be cheaply made, fly at relativistic velocities, and steer themselves with nanometer precision (for a beamrider).
–The social engineering to keep small groups working together for multiple generations, or the ability to store humans in some form of stasis for centuries. Remember what happened with Biosphere 2? We’ll have to do much better than that.
The thing about this is that the world will have these technologies, as do the starships. While the technology will be unevenly distributed, bits and pieces of it will be in use all over the planet. For example, if we have fusion, we likely won’t be using fossil fuels for much of anything, because most large metropolitan areas will have fusion plants. They likely will use these energy to power desalination/water purification plants, so that we can all live by the coast and not worry about continents drying up. As I noted in a previous post, we’re stuck with climate for millennia, regardless. I’m not sure where the waste heat goes or how one maintains one of these magic power plants, but based on current experimental plants, it looks like it requires precision engineering at a scale we can’t yet match. This, in turn, implies a stable infrastructure of some scary-good engineers.
In fact, all of these require a lot of really, really good engineers, which means there will be the infrastructure to educate those engineers, whether they are humans, computers, or both. What does that mean for, oh, consumer electronics, aside from having stuff that’s much more complex than what we have today? Who knows?
But let’s look at the other new technology. Small biospheres implies that arcologies are possible. People can build floating “sea castles,” live in domes in the Arctic, on the sea bottom, or in Saudi Arabia’s empty quarter, or anywhere, and live off whatever they can grow in the domes. If they have enough money, that is. Cities will likely use this technology to produce more food within bounds, while wealthy separatist groups flourish wherever they can set up their biosphere.
Things get really interesting when you look at the shielding issue. I don’t know if the shields on a starship could withstand a nuclear explosion, but I do think they’d be impervious to almost all conventional arms. In other words, for the first time since the Middle Ages, defense becomes an option, and castles make sense. They make even more sense if you can live inside one indefinitely, treating it in effect like a starship without an engine. Of course, this radically changes the face of war. I don’t know whether the great powers will go in for castle-busting munitions (terawatt lasers, perhaps?), or more covert action, but basically, every evil genius with plans for world domination now gets his impregnable secret fortress, fully staffed with loyal minions.
Scary thought, isn’t it? We can also ponder the lives of the people who choose to live inside such fortresses. Presumably, it will be possible for them to live in there indefinitely, or to hold themselves in stasis “until the stars are right,” but I doubt it will be what we lazy, middle-class Americans consider to be a Good Time.
Does this sound like an appealing world? I’m not so sure. It’s likely more Neuromancer than Star Trek. That’s the thing I wanted to bring out: a star-faring culture would look very different than what we normally see in science fiction. It will have a technical infrastructure far beyond what we have today, but there’s no particular reason to think that it’s going to be a utopia where domestic robots attend to our every whim. It could just as easily be a weed-infested world dominated by the domed and armored cities of the wealthy and powerful. The only good news will be that people are willing to live that way.
So here’s the question: what did I miss? Any other easy extrapolations?
Filed under: Uncategorized
I’m having fun reading the New Yorker article referred to in BoingBoing, about how smart people are more vulnerable to common thinking errors than dumb people are–or at least, there is a positive correlation between SAT scores and bias errors.
I suspect that Terry Pratchett got there first, since I remember a quote about his character Leonard of Quirm, who (in Lord Vetinarii’s estimation), had, in scaling the heights of intelligence, found heretofore undiscovered new plateaus of stupidity. It’s not quite the same thing, but it’s a similar sentiment. Most geeks and nerds don’t end up doing better in life than their dumber peers, despite their measurably greater intelligence.
In a similar vein, I’ve been reading a history of Korea, the most Confucian kingdom in Asia. Even though they had a bureaucracy of demonstrably smart, exam-passing men, even though they invented movable metal type at least two centuries before Gutenberg, 1870s Korea was an agrarian backwater, where a few families owned most of the land and an unfortunate proportion of the population were slaves. For some reason, some of the most brilliant Confucian scholars in the world, steeped in a theory of government that’s certainly no more stupid than most, were quite vulnerable to regulatory capture by the land-owners, and the result was over a century of bad governance. Government by the smart didn’t work for them, and it doesn’t seem to work very well in its modern incarnation of technocracy.
I’m not going to say government by the stupid works any better. Effective government is hard, and all models tried so far have critical shortcomings. Instead, I’d like to stretch out to a rather cynical view of evolution.
Let’s say, for the sake of argument, that this research is correct. Above a certain basic level of intelligence, getting better scores on IQ, SAT, or similar test does not make you a better decision maker. Rather, it makes you more vulnerable to your own unconscious biases.
What does this mean in evolutionary terms? Apparently, there’s little selection pressure for greater intelligence, for the simple reason that it doesn’t lead (on average) to greater resources or to greater reproductive success. It *might* also mean that the New Agers and Aquarians were right. If we get lucky, we may see evolution favoring increasing consciousness, average people becoming more aware of their own biases. Enlightened, not smarter. Of course, Tibet provides a cautionary model of what government by the enlightened looks like…
Do I believe this proposition, that evolution won’t make us smarter? I’m not totally sold, but I fear it’s true.
Now, before you say “Obviously, we’ll be computer augmented cyborgs soon, and that will solve the problem,” let me point out that increased processing power (as measured by an SAT) may make you more vulnerable to your own unconscious biases, not less. Cyborging won’t help. Unless you can invent a computer that gives you a better unconscious and fewer biases, increasing your processing power isn’t going to save you from doing stupid things. It will just help you get there faster and with greater confidence in your own wrong answers.
What do you think?
Filed under: Uncategorized
I’ve been having a lot of fun reading Curt Stager’s book Deep Future: The Next 100,000 Years of Life on Earth, (Amazon Link), and I highly recommend it, especially for anyone interested in science fiction. I linked Dr. Stager’s webpage to his name up there, but for anyone who doesn’t want to follow the link, he’s a PhD paleoecologist, as well as a science writer. In other words, he knows what he’s talking about.
The reason for highlighting his book here is what he lays out for the future of atmospheric carbon on this planet. I think the people who glance at this blog get the idea that I’m not a typical science fiction geek. I’m getting increasingly less fond of the miracle fix, which in this case would be something like fusion (“safe,” “cheap” energy), plus a miraculous gadget to turn CO2 back into a coal that doesn’t involve burying a swamp under rock for a few dozen million years. Also, I’m a SFF maverick who doesn’t really believe that humans will a) go extinct in the near future, or b) transcend through some singularity to the point we are no longer human. That was me ten years ago. Now? Not so much.
The question is, what does the next 100,000 years hold in store for us? Oddly enough, it does depend on how much carbon we burn in the next century or so, whether we go for the conservative 1000 gigaton release of CO2, or the “use up all the coal and to hell with it” 5000 gigaton release of CO2. These are the “moderate” and “extreme” scenarios used by the International Panel on Climate Change, incidentally. To put it into perspective, we’ve released something like 300 gigtons of CO2 since the start of the Industrial Revolution, so the IPCC’s idea of moderation is pretty grimly realistic, compared with the 350 ppm goals of climate activists (the idea is that 1000 gigatons is what we get when we try for 350 ppm and miss).
The good news: If one follows the Milankovitch cycles, the next probable ice age would have been around 50,000 years from now, assuming atmospheric [CO2] was no higher than 250 ppm. Under both the moderate and extreme gas release scenarios, atmospheric CO2 will be above 250 ppm, so we can breathe easy, there won’t be an ice age in 50,000 years. Compared with global warming, an ice age is a serious problem.
The bad news: the carbon will take a very long time to leave our atmosphere. Most of it will go into acidifying our rocks and oceans, but fortunately we’ve got a lot of calcium bicarbonate lying around in the ocean (and in limestone on land) to help sequester about 750 gigatons of carbon. This will take a while, and since much of the soluble calcium occurs in things like coral reefs and mollusk shells, we’re going to mess up the oceans. A lot.
Under the moderate scenario, mean temperatures peak a few degrees higher than they are now, and average sea levels 6 to 7 meters higher than they are now, and these maxima will occur perhaps a century after we reach peak carbon concentrations. The reason for the lag is that the oceans will take a long time to respond, because they are so very large.
As we’re finding out, though, the averages don’t tell the story. Some climate scientists prefer “global weirding” to “global warming,” and class the unusual weather we’re having under climate change. And we’ve only experienced about a degree of average temperature increase so far. I’m not sure what saying that global weather will get four times weirder means in real terms, but it probably won’t be pleasant for most people.
The interesting part is how the carbon leaves the atmosphere. Under the moderate scenario, the limestone scrubbers will take about 7000 years to get their 750 gigatons of carbon out. At that point, silicate minerals (granite, basalt, etc) take over. Over the next 50,000 years, they will get [CO2] down to where it is today, and it will probably take them another 100,000 years to get it down to baseline. There’s another Milankovitch-induced ice age lurking out around 130,000 years in the future, and it’s possible that one will happen, if we stick to our moderate carbon release scenario (or rather, if do everything we can to get off fossil fuels now, and fail).
Then there’s the extreme scenario, 5000 gigatons of carbon, all of our oil and coal up in smoke. Temperatures would peak somewhere between 2500 and 3500 AD, at 5 to 9 degrees C above today’s mean temperatures (read weather 5 to 10 times more weird than we have today). Sea level rises up around 80 meters over the next few millennia, with most of that (not all of it) in the first thousand years (that’s right, continual sea level rise for centuries). Ultimately, it takes over 100,000 years for the rocks to sequester carbon to today’s level (and for the sea to drop back 80 meters), and 400,000-500,000 years for a full recovery.
In the moderate scenario, most of the changes take place in the first 1000 years, followed by a long, slow rebound, while in the extreme scenario, the heat and water keep rising for thousands of years, followed by an enormous, even slower rebound.
In both cases, though, the Earth will eventually equilibrate, the carbon will get scrubbed out of the air, and humans will face another ice age. If people are smart today and don’t use up all the coal, our distant descendents may decide to burp another gigaton of CO2 into the air 130,000 years from now, to prevent the next ice age. If we’ve burned through it all, too bad, they’re screwed, and all the polar high civilizations they’ve developed will be ground into forgotten dust by the resurgent glaciers. Since the Earth will have gone through an Eocene-style global hothouse, there won’t, of course, be any polar species left to take advantage of the advancing ice, so the next ice age might be a rather barren place, unlike the last one. But heck, when have any extremists worried about the distant future?
The other fun part of this scenario is how we’re going to live during the coming hot times, which is the ultimate reason I’m blogging here. One technology I’d like to focus on is biodiesel, Craig Venter style. In a recent Wired interview, Dr. Venter talked about the great idea of using algae to make diesel or gasoline. The algae would make diesel precursors, rather than the starches or oils they store now. Nothing too farfetched here, there are companies working on the same idea now, using unicellular marine algae. In the future, it’s quite likely we’ll see huge algae farms springing up in deserts and along desert seascoasts all over the world, where they make diesel using algae and saltwater. It uses non-potable water and barren land. What’s not to like?
The fun part that Dr. Venter didn’t talk about is the carbon cycle. The algae scheme only works if there’s a lot of CO2 in the air. The CO2 will get fixed into fuel by the algae, then burned off to power motors. This isn’t as stupid as it sounds, because diesel and gasoline really are great energy sources. The only limitation will be the amount of sun each algae farm gets. In general, the future gas industry will be solar powered, and there will be rich investors who want to keep a lot of carbon in the air. They may not want to deal with continually increasing sea levels and progressively radically unpredictable weather, but we’ll have to wait and see whether such predictions make them wiser, or not. Regardless, this will be a limited solar age, using gas as a storage medium, not the cheap, plentiful fossil gas we have even now.
Ultimately though, unless people do something drastic about limiting weathering, all that atmospheric carbon will disappear, and the hydrocarbon age will end. This end might happen even faster, if farmers try to sequester carbon into their trees or into their soil (soil carbon helps soils hold nutrients). Personally, I foresee a continual conflict between the fuel industry, on the one hand, who wants to keep CO2 in the air for recycling as long as possible, and nature and farmers on the other hand, who want to sequester carbon in the soil and the rock. A war between air and darkness, as it were? In the end, the world will sequester all the surplus atmospheric CO2 into forms we can’t burn, and if we haven’t weaned ourselves off gas by then, we will be ultimately screwed. Of course, if we have gone post hydrocarbon, humans will be dealing with another ice age.
This gives SFF writers a lot of future to play in, does it not? Anyone want to try playing with it?
Filed under: Real Science Content, Speculation, sustainability, Uncategorized | Tags: climate change, noosphere
To use the high school tactic, if you haven’t heard of a noosphere before, here is Google’s definition: “A postulated sphere or stage of evolutionary development dominated by consciousness, the mind, and interpersonal relationships (frequently with reference to the writings of Teilhard de Chardin)”
This idea crops up a lot in, well, collegiate dorm thinking, and it generally expounds the idea that the world is evolving in stages from inanimate matter towards some grand future where all thinking beings are connected, there’s universal consciousness, the Singularity has happened, or similar versions on the Christian rapture dressed in scientific terminology (Mssr. de Chardin was a Jesuit Priest, so there is a distinct Christian undertone in this whole idea).
I’m going to argue something very different: the noosphere is already here, it’s been growing for over 500 years, and rather than being a rapture of the nerds, it’s becoming quite a pain in the ass, mostly because the sciences it has fostered resolutely refuse to acknowledge its importance.
This whole train of thought was inspired by a quote from William deBuys’ A Great Aridness (Amazon link). In talking about what we learned from Biosphere II, Mr. DeBuys said, “In this respect, Biosphere II proved a true microcosm of Biosphere I, where venality, ideology, self-interest, and other elements of the globe’s political ecology, much more than the workings of the nonhuman world, have generated the greatest obstacles to solving environmental problems, climate change foremost among them.”
There’s that thumbprint of the noosphere: political ecology. Since I’m not a global climate change denier, I see nothing controversial in de Buys’ statement. The “problem” with it is that it lets slip the dirty laundry. Politics matters. Global politics, a signpost of the noosphere of human thought, is now a major factor in the biosphere. Most biologists and ecologists hate this conception, but most would agree that it is nonetheless true. The ecology of politics is another factor to consider, along with the physical world.
Again, there’s nothing new with this idea. The problem is that most scientists want to keep their science somehow pure. Politics happens, certainly, but arguing that politics is integral to a biological study can cause all sorts of problems in fields where nature is considered to exist separately from human thought.
Of course, the noosphere not new. Once Columbus got back from the Indies, human political ecology has been stitching the world together in radical ways (“reknitting the seams of Pangaea” in Charles Manns’ wonderful formulation in 1493). There are whole ethnicities, such as Hispanics, who are the direct result of political ecology. My ancestors have been living in the US since the 17th Century, and my ancestors come from what are now a dozen European countries. National borders (such as the idiotic Border Wall along the Mexican border) now extirpate species (such as the few Baja rose growing in the US), and the most rapidly evolving plants and animals on the planet arguably are pests and crop plants, both of which depend intimately on rapidly changing, human-maintained ecosystems. Political ecology is important.
More subtly and pervasively, the non-human biosphere is dominated by human politics and thought, whether its our effluents causing climate change (“Global Wierding” in deBuys aptformulation), fishing and hunting radically changing ecosystems throughout the world, park boundaries (which turn what used to be huge gradients across which organisms spread into discrete island patches), even concepts of nature which ignore nature outside those park boundaries and guide our actions to favor some species and harm others.
I could go on, and in fact I think it might make a nice book at some point. The problem is that this is a dirty, unromantic conception of the noosphere, one that brings along all the destructive baggage that most of us got into ecology to avoid. It also conflicts with de Chardin’s arguably romantic conception of progress from inanimate nature to a God of pure consciousness. Consciousness (in its human incarnation) is a part of the biosphere now, but the biggest factors right now aren’t our lofty, enlightened thoughts, but rather our worst impulses: “venality, ideology, self-interest, and other elements…”
This is in line with real evolution. While mass extinctions happen (one has been happening for the last 50,000 years or so) major lineages seldom go completely extinct. We add on, rather than proceeding from stage to stage. We’ve still got theropod dinosaurs around (birds), and they’re arguably more common than they used to be. Mammals are an ancient lineage that predates the dinosaurs, and we’re here. So are reptiles and amphibians, along with insects, fish, and so forth. And as Stephen Jay Gould once noted, rather than living in an Age of Mammals, we’re living in an Age of Bacteria, as we have for the last 4.5 billion years. They keep the critical recycling bits of the biosphere working, just as they always have.
What’s wrong is de Chardin’s concept. He saw evolution as progress in stages, from inanimate rock through bacteria, plants, invertebrates, reptiles, mammals, man, then the Noosphere (with celestial, uplifting music, no less). Evolution is more like a compost pile, with new stuff added, often by chance, at irregular intervals, and a pile that continues to churn nonetheless.
So yes, welcome to the noosphere. We were all born here, but we never realized it, did we?
Filed under: livable future, Real Science Content, science fiction, Speculation, sustainability, Uncategorized | Tags: future, green, sustainability
This one’s inspired by this NPR story, about sustainability.
What does sustainability look like? In The Ghosts of Deep Time, I have one character say that civilization is cool, quiet, and green, and that’s still my thumbnail for a sustainable city. To unpack that a bit:
Cool. Forests are cooler than grasslands, not because they get less sunshine, but because they catch more of that sunlight and do things with it. Scientists can actually determine how stressed a forest is by measuring how hot it is. Efficiency translates into less energy loss, which means less heating.
In cities, we tend to waste a lot of energy, which is why they are hot. Most of the sunshine gets reflected, or absorbed into surfaces that it heats up. Most of our equipment runs hot, which means we have to get rid of that heat too. A sustainable civilization doesn’t waste much energy, so it’s going to be cool.
Quiet goes with cool. Much of the noise of modern civilization is wasted energy, gone to making sound waves instead of useful work. An efficient civilization is going to be quiet as well as cool.
Green. This is both in philosophy and color. Plants can perform a large number of functions, from cleaning water to providing shade and cooling air. Moreover, we humans aren’t so far from our evolutionary roots that we don’ enjoy having plants around, even if our thumbs are scummy black rather than green. Obviously, a sustainable city will be ethically green as well, but from a simple design standpoint, I think it’s difficult to have a sustainable city without having a lot of functional plants around.
Anything else? Or can we do without one of these?
Filed under: livable future, science fiction, Uncategorized, Worldbuilding, writing
Simple topic. A few months ago, I self-published a SF novel called Scion of the Zodiac. I just dropped the price and made the first half free. Check it out.
I posted about it on Antipope, where John Meaney guest-blogged about world building. Since I spoke up about it, I figured I’d better provide a venue, in case anyone wants to comment on it.
Criticism is fine, and constructive feedback is much appreciated. Note that “It’s okay,” “I liked it,” and “it sucks,” don’t really qualify as constructive feedback. I’m trying to make the next one better, after all.
Darren Naish wasted a lot of my time in the last two weeks, not that it was his fault. It was fun, actually. I was looking for a distraction, and I found it in his discussion of protobats. I didn’t (and don’t) believe the model he put up there, because it doesn’t make sense. At one end, there’s a nice, tree shrewish gliding animal, and at the other end is a bat, and in the middle is a flying insectivore with big hands. What happens in between?
• It goes from rear-wheel drive to front-wheel drive, which is another way of saying that the antebat (bat ancestor with no aerial modifications) has the strong hindlimbs, flexible spine, and barely rotating shoulders common in mammalian quadrupeds, while bats have enormously strong and flexible shoulders, highly reduced pelvises, and hip joints that have rotated substantially, such that their knees tend to point outwards or even backwards. The protobat (something with a patagium and presumably some aerial ability) would be a mosaic in the middle.
• It goes from a rigid glider to a powered flapper. I think I saw this problem first mentioned in Grzimek’s Encyclopedia, but I’m probably wrong, and it was a decades ago. The problem that someone pointed out is that a flapping flying squirrel doesn’t glide farther, it falls out of the sky, for two different reasons.
–First, there’s the question of how a flailing patagium generates lift, especially when the trailing edge is being held semi-rigid by the hind legs. It will lose lift because the aerofoil is disrupted, and it is unlikely that the forelimb movement will get air under the patagium any faster.
–Second, gliders tend to have fairly long bodies, with the center of mass in the center. Increasing strength in the arms pulls the center of mass forwards. You can replicate the problem by making a wide-winged paper airplane and adding paperclip or staple weights, and seeing what this does to the plane’s flight characteristics.
Worst, the hypothetical protobat does makes all these structural changes while needing to glide. If I was feeling snarky, I’d point out that this is akin to evolving a helicopter from a glider, and it’s certainly evolving an ornithopter from a glider.
The real problem with these ideas is that the intermediate stages look less able than their predecessors. This seems to violate evolutionary theory, which posits that evolution proceeds blindly, favoring traits that increase (or at least maintain) fitness, traits which will spread through a polymorphic population and eventually take over, possibly through isolation. A flapping, mid-weighted flying tree shrew seems to embody the worst of both worlds, since it doesn’t have the advantages of flight, nor does it have the simple stability of a glider.
So I started thinking. If bats didn’t evolve from something that looked like a tree shrew, how did they evolve? I assume that there are two limits:
1. There are no extant protobats. This supports two ideas. It implies that evolutionary theory is correct. If bats were at a selective disadvantage, there would be lots of non-flying chiropterans around. It probably also implies that protobats had an advantage over antebats as well.
2. We’re pretty sure that bats evolved in the Palaeocene, simply because their fossils show up in the early Eocene. That tells us a bit about the environment in which they evolved. For simplicity, I’m going to say that it looks something like modern Papua New Guinea (there’s a bit of research behind this statement, but it’s not germane. Take it on faith for now).
Designing an antebat
It’s probably instinctive for biologists to think of gliders as the antecedents to powered flyers, but this may be problematic. There are quite a few extant gliders, for example, but how many of them launch with their front limbs? The only group I could find are the freshwater hatchetfish, and as noted in the comments on Naish’s blog, they are jumpers, not properly gliders. However, all flying animals use their forward limbs to propel themselves through the air. To me, this suggests that we may mislead ourselves by assuming that the ancestor of a flying animal looked like a flying squirrel.
What other way is there? Let’s look at bats and bat development. I don’t for a second buy that bat ontogeny exactly recapitulates bat phylogeny, for the simple reason that it doesn’t in humans. Enormous wings need to develop first and fastest, just to function. That said, the developing bat fetus does suggest a few possibilities.
First, their wings are very different than the hind feet. This seems obvious, but one possibility is that protobats looked like the so-called flying frog ( such as Rhacophorus nigropalmatus) where all for feet are enlarged. There’s no evidence for this in bats: their hind feet are much more similar among species than their wings are, and I assume that this has always been true. Antebat hind feet probably look like those of extant bats. Perhaps their front feet looked like those hindfeet as well.
Second, it appears that the bat’s pelvis is splayed even in the embryo. People seem to assume that the bat pelvis splayed to accommodate the growing wing, but there’s no particular reason to think that.
Third, modern bats have a massive amount of morphological diversity in their heads, but that has as much to do with echolocation as anything else. Still, I think it’s reasonable to assume that antebats had a reasonable amount of head diversity, to the extent that different species or morphs may have consumed arthropods, nectar, fruits, and tree gums, much as modern bats do.
So what did I come up with?
Arachnosorex dubius: a hypothetical antebat
Yes, that’s the dubious spider-shrew, and I’ll be amazed if they ever find it. The name describes both how I think it moved and the niche it held. The images above are my crude sketches of the critter.
In constructing this antebat, I started backwards. What if, rather than the patagium coming first, the hip and shoulder alterations came first?
Are there any animals that have powerful front shoulders and outward pointing knees, and second, are there any advantages to this configuration? Bats have these characteristics, (as do spiders and other non-mammalian animals). Many bats are quite good on vertical surfaces, even ceilings, and they cling well. Something like a vampire (Desmodus rotundus) moves well on the ground, on walls, even on rough roofs, and can launch itself into the air using the power of its forelimbs. The advantage of those backwards pointing hind feet is that they make excellent grappling hooks. An antebat with strong forelimbs and backwards pointed hindlimbs would be quite agile on a variety of surfaces, whether face up, face down, or sideways. However, it gives up some speed for this maneuverability (since it gives up that characteristic mammalian gait, the gallop), so the antebat would be limited to areas like tree-trunks (on the bark or inside a hollow tree), on thin branches (especially the underside of branches) and in caves—in other words, places we find bats now.
This satisfies the first criterion, that bats outcompeted their predecessors. Here I’m suggesting that antebats exploited the same types of food sources as bats do now. Since bats are faster (through flying) than antebats, bats also have a comparative advantage. Additionally, these types of habitats were available in the Paleocene, so it satisfies the second criterion
From nose to tail: the spider-shrew’s head is based on a primitive fruitbat, with a smaller braincase but still well-developed eyes. The forelimbs are well developed, but there is little enlargement of the hand. The hindlimbs are splayed, and the spider shrew overall has a semi-sprawling posture. However, it can move effectively on the ground. The tail is thin and fairly stiff. Its primary function is to act as a support when the antebat is climbing.
Instillator hypotheticus: the dropper, a hypothetical protobat
This “hypothetical dropper” was inspired by a fruitbat photo I found on Flickr. In this case, the patagium is developed, but I see no reason why it should have a hairless patagium.
Here I suggest that antebats became protobats by developing long-distance jumping and falling as an efficient defense and as a way of covering long distances. This lifestyle change hinged on developing more powerful forelimbs and better vision (echolocation evolved after bats flew, according to the fossils). While yes, I’m suggesting a gliding intermediate, in this case, I think it’s likely that protobats powered their takeoff jumps with their forelimbs, not their hindlimbs. They saved on weight by making their bodies more compact and their limbs longer, as seen in modern bats. Probably finger elongation started initially as a way of increasing patagium area (as here, with the dropper), and protobats early on developed the folded wrist we see in modern bats, effectively climbing on the backs of their wrists, with their thumb claws providing the support of the five claws of the antebats. It’s also possible that the uropatagium developed with the arm membrane, giving a “three-winged” form to glide with before ultimately developing into the bats we know today. The advantage of the three-winged form is that there is a separate wing structure that, combined with the highly developed shoulders the protobat inherited from its antebat ancestors, can lead to ultimately to powered flight. The more Instillator develops its forelimbs, the better it does.
Diet wise, I suggest no change from antebats to protobats. The protobats ate the same food as their ancestors did and their descendents will. As with the spider shrew, this satisfies both limiting criteria.
