Yet how is a lichen 'more than the sum of fungus and alga'?
I don't know anything about lichen, but the below is what I assume "more than the sum of" in this context means:
"The symbiosis between the mycobiont and the photobiont creates an organism that is more than the sum of its parts, in other words, a lichen is an emergent property. Lets take a step back to examine this statement. On the one hand, neither the photobiont nor the mycobiont can withstand intense UV radiation, dessication, or extreme temperatures. But on the other hand, when the photobiont and mycobiont work together within the context of the lichen symbiosis, they create an organism that can withstand living in outer space – thats more extreme temperature and radiation (not to mention vacuum exposure) than is experienced on Earth! Lichen can even grow within rocks (endolithic lichen)! These are conditions that would kill a fungus or algae."
So that means that the complex of f&a acquires different properties, occurs in different conditions, and might - might - have an overall wider 'ecological amplitude'. Which is plausible, but hardly ever proven (I don't recall any direct comparison of rates of reproduction, dissemination, biomass allocation or any other objective measure of population success, not 'body type success', but I have not looked into it.)
This is apples vs. non-apples.
I understand synergy as when Effect(A) + Effect(B) < Effect (A & B). Basically, when you get nonlinearity in response.
This would not only be if you try to use it as medicine as you say, but also in their own capabilities.
So in this case, if you consider the algal component of lichen, take them alone, and see where they can live and what they can do, and if you consider the fungal component of lichen, take them alone and see where they can live and what they can do, your results will be (if the claim is correct) that these will not be half as widespread or capable as the two together are.
It seems pretty clear to me that this is what is meant. Does it make sense? Is this also an incorrect statement of biology?
But what effect? You can determine, for example, how much CO2 do the fungi and algae produce when taken together not as lichen, but they won't occupy the same habitats (and so their CO2 emissions will cause different effects in the environment, and totalling them would not be correct). I mean that yes, obviously you will obtain some values, and they even might be lower than for the lichen containing the exact same amounts of both. It just won't have any practical sense.
The effect here is just being able to survive and thrive in a place. Their range and coverage and so forth grow a lot.
Prove what? That that interpretation is what "they" meant or that it is biologically accurate?
The parent says in his final paragraph that he does not know whether it is biologically accurate or not.
The question is not is it whether this is accurate, but rather whether this is meaningful at all. I think it isn't. I do not expect, therefore, that it can be proved, and any other defence seems to me to be circular, but I might be wrong.
Whether 'the range and coverage and total population' is meaningful at all? I can't even understand how this being meaningful could be in question.
No. Sorry. I meant 'whether a comparison between the parameters for the f&a and for the lichen is meaningful at all, given different methods of [sampling, cultivation, quantification] 'searching' for all three, different ways of reproduction for all three, and different dissemination strategies for all three'.
It is sometimes difficult to compare two populations of the same species, for example for orchids. Suppose there are twenty adult-to-senescing plants in the location A, and no young plants visible at all, and ten struggling adult plants plus three possibly young ones in location B. What population has better prospects? The three young plants might actually be underdeveloped adults; the dust-like seeds, however uncommonly maturing, might germinate considerably far away; and both young and old plants can just sit under the ground eating their mycorrhiza for years and be, therefore, uncountable.
Now compare the difficulty of this estimation with the difficulty of the f&a vs. lichen one. The second boggles the mind.
Measuring it would be a ridiculously exhaustive task, but it seems like evolution has already performed the measurement for us.
No, it does not. The less faith people put into the 'evolutionary explanation', the more water it holds. Everything that is not forbidden is allowed; as long as the two versions both exist, there is no better one.
Everything that is not forbidden is allowed; as long as the two versions both exist, there is no better one.
This reads as trying to sound wise. Population and diversity of habitats are a big deal for evolutionary fitness.
The reason the measurement 'boggled the mind' a few posts back is because YOU would have to go out and perform the experiment - you would have to collect the data, you would have to categorize the situations, etc. It's too much. Also, the orchid example was a toy example. The question is too specific to even admit a statistical answer. But Lichen vs Fungus and Algae? Just take a bunch of samples and stick them down together and separately, over a wide range of locations and situations. Since you'd actually be sampling the overall space of interest instead of hyper-focusing in narrowly on orchid batch A vs orchid batch B, you can get an actual answer, like "In environments A, B, C, D, E, the algae thrive alone and the fungus die alone, but lichen thrive. In environments F, G, H, I, J, The algae and fungus die alone but lichen thrive. In environments K and L the algae alone survive but both fungus and lichen die. ..."
The only thing mind-boggling about this is the work involved in making the measurement, not trying to figure out whether the question makes sense.
Also, this rather resembles what has been done - without proper monitoring, to be sure, and insufficient separation of the lichen components when it expands into new territories, and when either component expands into a new territory without the other no effort is made to bring the other along... but aside from those weaknesses, this is more or less what evolution has been doing. Trying everything and seeing what works best, as you say.
IF lichen dominates the performance of either component in any environment at all, then the statement that 'the sum is greater than the parts' is to some extent justifiable. The more such environments there are, the more it applies. If the two components do really badly except together, then it's very reasonable!
Yes, of course, it is reasonable; I have just not read any report on this, whether positive or negative. Will have to repair that gap.
I thought the point of this post was the meta-level of whether such phrases ever make sense, not the more object-level of whether they make sense in this case.
The point was that using such phrases in front of the kids nurtures in them the habit of making highly incontestable statements requiring lots of disclaimers the kids can't think of, because they don't know enough stuff, and that's OK for them. The point was that I, personally, learned names for some (biological) concepts long after I was presented with the 'meat' of them, and I don't know if it is a good thing. But whatever, lichens are very interesting, too.
I think it's not so much a sum of properties as a union of property sets. If a system has a property that's not a part of a union then it's "more than the sum of its components". On the other hand I find the notion of something being "more than the sum of its parts" about as annoying as the frequent ads with "1 + 1 = 3 Buy two and get one for free!" equation. That is, very annoying.
It strikes me that you are taking what is supposed to be metaphorical as literally true. As in would you take a saying such as "an apple doesn't fall far from the apple tree" to be dysfuncitonal if "falling" is inadequately defined and "far" doesn't have any metric applied to it?
While "sum" has a technical meaning here it is used more of a standin for more loose category. For example in the same sense that "man + woman = man + woman + baby, ie 1+1=3". In a way even a childless family has pretty different properties than two singles considered as a group. But we don't need to go into concrete some kind of single defined "people sum" to appriciate this fact.
A funny thing is that my sister and I seem to have a sporadic third twin people keep insisting they know. We get to hear about how she's doing: married, smoking, had her hair cut just shorter than 'you' do, cheats on exams... I swear she has a more interesting life!
So I guess 1+1 can at times equal 3...
But the 1+1=3 situation has, thankfully, no continuation in the math course; the notion of synergism becomes itself a matter to understand afterwards.
There is an algebraic analogy that might be useful (or confusing, if you don't know the math involved). In a tensor space, there are elements called pure tensors that can be described by a simple term (rank 1 tensors), while others cannot be described by a such item. In a similar fashion, entangled systems in quantum mechanics cannot be described considering the simple sub-costituents in isolation.
Another, perhaps simpler, analogy is a probability distribution of two dependent variables.
Whenever I read "more than the sum of its parts", I do not imagine the literal sum, but rather that some variables or observables in the system are tensorial in nature.
...I will look up tensors:) I have already tried to understand the piece before, but could not.
Actually, I would appreciate it if you could write a post and expand your analogy to other matters within your interests; it would be great if people grew used to sharing their heuristics without thinking them biases from the outset.
From reading Wikipedia it seems that the definition is wrong in another way: Lichen don't always have algae in them but sometimes only cyanobacteria.
Even without cyanobacteria, 'algae' are paraphyletic, so people are willing to forgive such usage.
I agree. Not all Wittgenstein's ladders are necessary, and they can serve to confuse readers. It's just so hard to tell what's necessary from the inside. And what's necessary can vary with the student.
But the words just don't make sense! And I am somewhat afraid (a little bit) that some of my foundations are just as shaky.
...and since there is apparently such a thing as algicolous fungi, leaving on and in (maybe only marine) algae, and not always causing detectable disease;
we now have a situation where A&B (lichen) is more than A&B (algicolous fungi living on algae) in most cases, and the reverse is true for some special cases (like water content).
I get that A&B can be more than A+B, but I don't think we can get away with having the same thing be A&B or A+B whenever we feel like it and still be doing science.
Related to: 37 ways that words can be wrong.
Consider the following sentence (from Internet; but I have heard it before): 'Lichens consist of fungi and algae, but they are more than the sum of their constituents.'
It is supposed to say something like 'the fungus and the alga don't just live very close to each other, they influence each other's habitat(s) and can be considered, for most purposes, to form a physiologically integrated body'. It never actually says that, although people gradually come to this conclusion if they look at illustrations or read long enough. And I don't think the phrase is sufficiently catchy to explain its popularity; rather, that it is a tenuous introduction to the much-later-explained term 'synergism'. A noble (in principle) preparation of the mind.
Yet how is a lichen 'more than the sum of fungus and alga'? I suppose one could speak of a 'sum' if the lichen was pulverized and consumed as medicine, and then its effect on the patient was compared to that of the mixture of similarly treated fungus (grown how exactly?) and alga (same here). It doesn't exist in the wild. It shouldn't exist in the literature.
A child is not bothered by its lack of sense. When she encounters 'synergism', she'll remember having been told of something like it, and be reassured by the unity of science. It flies under the radar of 'established biological myths', because it doesn't have enough meaning to be one.
I picked a dictionary of zoological terms and tried to recall how the notions were put before me for the first time, but of course I failed. (I guess it should be high-level things, like 'variability', or colloquial expressions - 'bold as a lion', etc., that distort and get distorted the most.) They seem to 'have always been there'. Then, I looked at the definitions and tried to imagine them misapplied (intuitively, a simpler task). No luck. Yet someday, something other truly unknown to me will appear familiar and simple.
We can weed out improper concepts from textbooks, but there are too many sources which are written far more engagingly and 'clearly', and which propagate not even wrong ideas. Explained like I'm five.
And never named.