Now That's Really Weird

A major breakthrough in science is often heralded by these words. This time too? Perhaps.

18 comments:

douglas said...

Why would anyone expect to find the relationships different? Predator A's relationship to Prey B is exactly as Predator X's is to Prey Y- it's defined by the fact that one is prey to the other. That should almost automatically correct for all other variables, and create a consistency in the nature of their relationships.

Grim said...

I don't think that's obvious, though: a wolf eats mostly mice, which suggests a different mathematical distribution than (say) a predator that preys mostly on larger animals. It's also not clear why, as a general rule, predator prey would rise much more slowly than the population of food sources. That's the opposite of what we think is true with human food sources (only some of which are prey to us).

And the fact that the ratio lines up with the large/small animal ratios is very interesting. It's like there's something very important going on here about life in general that we haven't quite understood.

Ymar Sakar said...

Come on, mathematics can accurately predict physics and complex systems. That's what calculus was for. This isn't so much a breakthrough as using the same basic capabilities on different areas.

A breakthrough would be akin to a reactionless drive like the Chinese and NASA did experiments on using the claims of Roger Shawyer.

https://en.wikipedia.org/wiki/Reactionless_drive#Devices_that_do_not_generate_thrust
https://en.wikipedia.org/wiki/RF_resonant_cavity_thruster

Mathematical equations can predict a surprisingly large number of systems. The why of the matter remains unknown, which is why it isn't a breakthrough. It's merely an application, a new one though.

Tom said...

Well, no one's claiming a breakthrough yet, but this could lead to one.

Also, on the Wikipedia section for "Devices that do not generate thrust," is my old Pacer on the list? Man, that device did not generate thrust at a truly amazing rate.

Grim said...

Ymar,

I think you are missing the key point here.

That mathematics can predict a complex system isn't really the issue. The issue is that predatory relationships appear to follow a ratio even when the scale of the creatures is quite different, the environments different, etc.

Now, our understanding of how ecosystems -- including predator/prey relationships -- evolve is that it occurs through random mutation combined with natural selection for randomly evolved traits that are adaptive. If the mechanism is random, and the environments within which the ecosystems randomly evolve are diverse, it should be shocking to discover that the evolutionary patterns follow the same ratio.

The word "ratio" means 'rule' or 'measure' or 'proportion.' If evolution obeys such a rule or proportion, then evolution is in that sense of the term rational. And that would be a fundamental shift in our understanding of the world: one that would propel us, as it happens, backwards towards Aristotle. We would need to re-examine one of our fundamental views about how nature, and we, come to be.

Tom said...

Personally, in the physics vs. biology wars, I'm rooting for biology. Therefore I must look at this new, threatening development in the most skeptical manner. :-(

Grim said...

Good. But consider:

1) Teleology doesn't seem to exist at the level of organizations we consider physics, but you can't talk sensibly about biology without it.

2) Rationality must emerge at some level of biology, because we are at least somewhat rational.

3) There is evidence that it emerges at lower levels, because e.g. we can teach horses and dogs things they don't know by instinct. This isn 't merely programming: They seem to be able to reason out what we are trying to teach them to do, and to do it independently and creatively (my favorite example is cutting horses, who learn their job -- a predatory role in an animal that is by nature prey -- and do it without direction in spite of whatever the cow or steer may try to avoid them).

4) Thus, we know rationality emerges somewhere between physics and biology. The question is just where.

If it's somehow baked into evolution, which itself turns out to obey a kind of ratio, then this is a tectonic shift. But in another way, it shouldn't be surprising: it's what we always used to think was true, as Aristotle did from his careful observations of the same natural world.

Grim said...

To make the point a little clearer, the link between the two senses of "rationality" lies (I think) in a difference between how Aristotle understood learning about nature and how we do. What Aristotle thought you were doing was coming to know a form -- meaning a structure that served a purpose, a form of organization -- that was really out there. What we've come to believe we are doing is imposing a form on a nature that comes to be randomly, and just happens to work (or not).

In the latter case, and you can see the roots of this in that Kant song, we are the ones imposing the rule on nature. Rationality is a feature of our minds, but we can't say it's in the things as they exist before our minds get ahold of them and put them into an order we know how to think about.

If it's the former case, the forms we are describing are really in the things. It makes sense to talk about "predators" and "prey" as universals that apply to tigers and wolves and sharks and so forth, because there really is something in nature that's unifying these things and making them behave according to a measure or ratio. What that thing is remains mysterious, and how it comes to be is mysterious. But observations suggest that something is causing this to be true of things our prevailing understanding of evolution should represent as unrelated random developments, some of them quite far removed from each other in the evolutionary sense (e.g., predatory birds and mammals).

We can maybe preserve the randomness of evolution if there's something about natural selection that does the work of enforcing the ratio. But what does that even mean? Natural selection just means that a randomly-evolved trait works or it doesn't. But this is meant to account for diversity more than similarity: in a different environment, a different trait is advantageous. It should be very surprising to discover that this ratio holds in many different environments, for very different species.

It's weird, because of course evolution and natural selection are well supported theories. It's one of those very interesting discoveries that may herald something of real moment.

douglas said...

"I don't think that's obvious, though: a wolf eats mostly mice, which suggests a different mathematical distribution than (say) a predator that preys mostly on larger animals."

But I think what I said is true- that the fact that the relationship is the same corrects for variables like size of prey or number needed for satiation. The discovered mathematical relationship is about the increase or decrease of populations relative to each other, not to number of feedings. That relationship holds true regardless if we're talking about Wolves eating mostly mice (and therefore quite a few of them quite frequently), or snakes that eat relatively larger prey once a week or three. The kind of prey that get hit the most, also tend to breed faster, and larger, less often preyed upon animals can get away with slower breeding cycles.

" It's also not clear why, as a general rule, predator prey would rise much more slowly than the population of food sources. That's the opposite of what we think is true with human food sources (only some of which are prey to us)."
Okay, I'm not sure what you mean in the second part of that sentence, but as to the first part, I agree, that's a less obvious aspect of this apparent discovery. I suspect it has more to do with breeding rate abilities and the lag a slower breeding cycle species would have in taking advantage of bountiful environs in supporting greater numbers of the species.

Grim said...

But I think what I said is true- that the fact that the relationship is the same corrects for variables like size of prey or number needed for satiation.

I think what bothers me about that is the question of the degree to which the relationship is "the same." It's true both feed on other forms of animal life. Nevertheless, a predator in an arctic environment has a meaningfully different set of needs than a predator in a jungle environment.

Okay, I'm not sure what you mean in the second part of that sentence...

"Predators" in the original context refer to animals who eat other animals. We also eat plants. It seems as if human population very closely correlates with food supply, which is more like prey animals than predators if this study is correct. Hunter-gatherer humans had small populations, whereas the invention of food-production and food-preservation technologies allowed populations to grow. East Asia has historically had a higher population than Europe because it's amenable to a kind of farming that produces more food (rice v. wheat). The vast boom in human population of the last two or three centuries comes from the results of the agricultural revolution and the industrial revolution's improvements in our capacity to feed ourselves.

That's what I meant by the second sentence. I suppose it's possible that humans also follow the ratio, and we're just not adequately accounting for plant populations -- maybe the populations of food-plants have grown in the same way that populations of food-animals would grow if we were more purely predatory in the sense intended by the article.

Tom said...

OK, but why would prey species with abundant food but no predators follow the function for predator species? They actually lower their reproductive rates when there are no predators around to what the predator rates would be.

And why would fish predators follow the same mathematical function as lions? It wouldn't surprise me if there were a general rule that prey animals have lower reproductive rates than prey animals, but the fact that fish and mammals in very different environments follow the same mathematical function in prey-predator ratios does surprise me.

By the way, this seems to kill Malthus's theory.

Tom said...

It's almost as if it were a "top of the food chain" function rather than a predator-prey function.

We know modernization has led to lower human rates of reproduction; I know technology is involved (birth control, etc.), but I wonder if we too follow the function, especially if we control for BC, abortion, etc.

douglas said...

"OK, but why would prey species with abundant food but no predators follow the function for predator species? They actually lower their reproductive rates when there are no predators around to what the predator rates would be."

Because existential pressures (lack of food, predator pressures, etc.) create increases in stress hormones which cause an increase in a desire to procreate (to counter the losses that are going to come from the pressures). Note the post 9/11 mini baby boom. This might also explain why predator rates of population increase don't keep up with prey growth- they too then feel less pressure and back off on reproduction a bit.

"And why would fish predators follow the same mathematical function as lions? It wouldn't surprise me if there were a general rule that prey animals have lower reproductive rates than prey animals, but the fact that fish and mammals in very different environments follow the same mathematical function in prey-predator ratios does surprise me."

Because the predatory fish are feeding on prey fish, and lions are feeding on prey mammals. Consistency of difference, and a maintenance of the predator-prey relationship. The mathematical function in question is, as a relationship between two growth rates, a ratio of sorts, and that can move scale, and conditions quite easily.

" The vast boom in human population of the last two or three centuries comes from the results of the agricultural revolution and the industrial revolution's improvements in our capacity to feed ourselves. "

Given that we now produce more food than the entire population of the planet needs to survive, it's hard to say we're any longer regulated by the relationship between food supply and reproduction. Also factor in that, quite unnaturally, we have large segments of the population that are not breeding by choice- much of Europe is essentially zero growth. Surely, the increased survival of many after the agricultural developments like those of Norman Borlaug could be seen to be proportionate to the ratios involved here, though I'm sure there is some affect from our omnivorous diet vs. the predator diet.

"Nevertheless, a predator in an arctic environment has a meaningfully different set of needs than a predator in a jungle environment. " Yes, but so too does it's prey, and I'll still posit that the essential relationship between predator and prey remains consistent regardless of differences in environment or scale of creatures involved. That's what I meant when I originally said that to me it seemed self-correcting for those factors.

Grim said...

...I'll still posit that the essential relationship between predator and prey remains consistent regardless of differences in environment...

Well, right, that's the argument you're making. The relationship must somehow do all the work of holding totally different species, randomly evolved, in totally different environments, in the same mathematical order. So how would it do that?

It seems really tricky to me. "Fish predators," for example, are also often prey: the ocean is much more diverse than land-based life, but you see it here too. It looks to me like the ratio ought not to exist according to what we'd expect, because if it did middle-predators should vanish: if they obey the ratio, they'll not produce enough of themselves to survive predation by apex predators. Do the apex predators obey this "relationship" only with the highest-level predator on which they prey?

Much more needs to be done, but something like that would have to hold for your argument to hold true. And how surprising that would be, wouldn't it?

Given that we now produce more food than the entire population of the planet needs to survive, it's hard to say we're any longer regulated by the relationship between food supply and reproduction.

Yes, that's right, it's a historical phenomenon. We don't know what's going on right now. I've seen answers for the lull in population growth ranging from hormonal changes brought on by pollution, to loss of social will to live, to dropping in sperm counts (cause or effect?), to pure speculation. I don't think anyone understands what's happening yet.

Tom said...

douglas, you haven't answered my mathematical question:

Tom: OK, but why would prey species with abundant food but no predators follow the function for predator species?

douglas: Because existential pressures (lack of food, predator pressures, etc.) create increases in stress hormones which cause an increase in a desire to procreate (to counter the losses that are going to come from the pressures). Note the post 9/11 mini baby boom. This might also explain why predator rates of population increase don't keep up with prey growth- they too then feel less pressure and back off on reproduction a bit.

No, why is the same function? Here, there is no predator-prey relationship, which was your claim earlier:

douglas: ... the fact that the relationship is the same corrects for variables like size of prey or number needed for satiation. The discovered mathematical relationship is about the increase or decrease of populations relative to each other ...

Not here it isn't; there are no predators, but the function holds. Why?

Tom said...

Grim, back to your four considerations above. I think that makes a lot of sense, and is probably the way it works. The argument between biology and physics I was thinking of when I joked above was between free will and determinism; biology seems to leave more room for free will, just because of the randomness. Of course, now there's quantum physics.

Also, I wonder if it's possible that Aristotle and Kant could both be right about forms. Are you familiar with Chomsky's idea of Universal Grammar? He posits that humans are born with an innate understanding of how language can be, and that as we learn our particular mother tongue, we reinforce the innate understandings we actually find, and forget the innate understanding of things that don't exist in our mother tongue. His UG turns out to be pretty primitive, but seems to have some validity. I wonder if nature might work the same way; if we are born with some kind of innate, primitive knowledge of forms, and as we come across things in nature our minds work with those forms to order what we experience.

Or something like that. I'm pretty tired. Evening, all.

douglas said...

Tom, because they become pseudo-predators- having no top down pressures, they are dealing only with bottom up pressures, as predators do. If there is adequate or better food supply, populations increase, but the increase is tempered by the lack of negative pressures that normally spur procreation. I think that is consistent with what I've been saying thus far.

" "Fish predators," for example, are also often prey: the ocean is much more diverse than land-based life, but you see it here too. ..."

Yeah, I thought about that too. I think there the math holds because you have to calculate their predator factor, and their prey factor and see if that matches their reproductive rate. If so, the theory holds. I assume if you're doing a study like this, you have to account for middle chain predators by doing the math both ways or it's not valid. So they might see an increase in population as a result of an abundant food chain, and also be pressured from above and as a result still be procreating at a higher clip than if the top pressures weren't there. Makes sense to me anyway.

" And how surprising that would be, wouldn't it?"

I guess that's just it- to me it isn't necessarily 'surprising', though it is quite interesting for all the implications that it holds. On the other hand, it could just be that survival leaves a rather narrow window open, and so those that make it through that window are going to show alignments in the nature of their success, regardless of how they got there- it's a self selecting sample of consistancy perhaps.

Tom said...

douglas, you present a coherent explanation. I am skeptical that it accounts for all of the variables, but I am all out of nits today. It'll be interesting to see what research shows us about this.