In the Roger Scruton on altruism thread, some commenters have expressed confusion over the evolutionary explanation of altruism in ants. If workers and soldiers leave no offspring, then how does their altruistic behavior get selected for?
The answer is simple but somewhat counterintuitive. The genes for altruistic behavior are present in both the workers/soldiers and in their parents. Self-sacrificing behavior in the workers and soldiers is bad for their copies of these genes, but it promotes the survival and proliferation of the copies contained in the queen and in her store of sperm. As long as there is a net reproductive benefit to the genes, such altruistic behaviors can be maintained in the population.
Selfish genes, altruistic individuals.
Let’s dedicate this thread to a discussion of other counterintuitive evolutionary truths. Here are some of my favorites:
1. The classic example of sickle-cell trait in humans. Why is a disease-causing mutation maintained in a human population? Shouldn’t selection eliminate the mutants? Not in this case, because only the unfortunate folks who have two copies of the allele get the disease. People with one copy of the allele don’t get the disease, but they do receive a benefit: improved resistance to malaria. In effect, the people with the disease are paying for the improved health of the people with only one copy of the mutation.
(Kinda makes you wonder why the Designer did it that way, doesn’t it?)
2. In utero cannibalism in sharks:
Shark embryos cannibalize their littermates in the womb, with the largest embryo eating all but one of its siblings.
Now, researchers know why: It’s part of a struggle for paternity in utero, where babies of different fathers compete to be born.
The researchers, who detailed their findings today (April 30) in the journal Biology Letters, analyzed shark embryos found in sand tiger sharks (Carcharias taurus) at various stages of gestation and found that the later in pregnancy, the more likely the remaining shark embryos had just one father.
(Kinda makes you wonder why the Designer did it that way, doesn’t it?)
3. Genetic conflict between parents and offspring. Here’s a great example from a 1993 paper by David Haig:
Pregnancy has commonly been viewed as a cooperative interaction between a mother and her fetus. The effects of natural selection on genes expressed in fetuses, however, may be opposed by the effects of natural selection on genes expressed in mothers. In this sense, a genetic conflict can be said to exist between maternal and fetal genes. Fetal genes will be selected to increase the transfer of nutrients to their fetus, and maternal genes will be selected to limit transfers in excess of some maternal optimum. Thus a process of evolutionary escalation is predicted in which fetal actions are opposed by maternal countermeasures. The phenomenon of genomic imprinting means that a similar conflict exists within fetal cells between genes that are expressed when maternally derived, and genes that are expressed when paternally derived.
(Kinda makes you wonder why the Designer did it that way, doesn’t it?)
Can readers think of other counterintuitive evolutionary truths?
Addendum
4. Mutant organism loses its innate capacity to reproduce and becomes a great evolutionary success. Can anyone guess which organism(s) I’m thinking of?
petrushka,
But their death *does* maximize the prospects of having their genes passed on.
keiths:
DNA_Jock:
Good guess, but I’m thinking of something that flourishes on its own as a separate organism.
keiths,
Priests?
keiths,
Viruses (if one plays somewhat fast and loose with the term ‘organism’, and assumes they ever had the ‘innate’ capacity for self-replication).
Allan Miller,
Old people. They can no longwr reproduce, and yet we get more and more of them.
It’s something that is unambiguously a separate organism and no longer has an innate reproductive capacity, yet the population is flourishing.
Pitless grapes and dead dogs?
Gralgrathor:
Ding Ding Ding Ding Ding… We have a winner!
I was thinking of navel oranges, but seedless grapes work too.
They lost their innate capacity to reproduce, but they did it in an environment where there were human animals who valued the seedless fruit and were willing to take over the reproductive job.
In effect, humans are the reproductive organs of navel oranges and seedless grapes.
Sorry, I ran out of good answers. Really, “old people” was the best I could manage today. Still a bit fuzzy from last night, I guess.
I was scratching my head over “dead dogs” (not exactly an evolutionary success story!), but you got the right answer and that’s what matters.
keiths,
Dead dogs?
Wheat?
Some of them, at least! They are not clones.
keiths, to Gralgrathor:
Alan:
Too funny. UD is a gold mine, isn’t it?
But they cannot pass on any unique genes that may have contributed to their behavior. They are, by definition, not reproducing organisms.
I think I am in the mainstream by thinking of them as cells in a greater organism. their behavior contributes to the survival of the organism, but their behavior is selected at the organism level, not at the individual ant level.
Gralgrathor:
keiths:
Gralgrathor:
I didn’t say that he was being dismissive. Walto just made that up:
He even put quotes around “dismissive” as if I had used that word.
What I actually said was that walto “should hesitate before dismissing his [Joe’s] carefully-worded statement”:
walto:
keiths:
When dealing with walto, always, always remember to check the original sources.
(Walto has an uncomfortable relationship with the truth. I think they should spend more time together.)
Walto,
Joe’s words are unambiguous and they support my claim (against Alan’s) that the behavior of the sterile castes requires a genetic explanation.
Instead of trying to invent mistakes in what I’ve said, why not learn something about the biology of altruism?
P.S. What’s with the deliberate misspellings of my name? Are you a fourth grader?
petrushka,
I’m not sure why you keep focusing on unique mutations arising in sterile caste members. Those aren’t the important ones, as I explained to Neil:
petrushka:
‘Superorganism’ is the term generally used for things like ant colonies. Using ‘organism’ would cause confusion.
Also, biological altruism isn’t incompatible with the idea of a superorganism. It isn’t an either-or situation.
I didn’t “dismiss” anything Joe said either, dipshit. (I’m still not entirely sure you know what that term means.) He said the quote you like and some other stuff that is also relevant to the question asked of him that you don’t like to mention, because it’s construable in a manner that suggests that we do not have a good evolutionary explanation of altruism in soldier ants. His remarks on the subject are only unambiguous in your deranged head. You really should refrain from paraphrasing anybody. You’re too….uh….to put it nicely….result oriented.
I think everybody here recognizes this, already however, so it’s probably not necessary for me to keep bringing it to their attention.
How you doing on my (really very simple) questions btw?
Keiths, I don’t see that you have contradicted my posts or added anything to them, other than the term superorganism, which is somewhat useful.
I don’t understand whether there is a real debate going on, or just people raising their voices. I am certainly not debating. I’m just trying to clarify things, primarily in my own mind.
For what it’s worth, behavioral tendencies are certainly inherited, included those that result in hive or tunnel or nest or web building. I think one of the cool discoveries in the past few decades is understanding how simple and how minimal are the set of behaviors required to build complex structures, and how simple are the feedback mechanisms controlling the specifics.
petrushka, with keit, there’s always a debate going on. He’s not happy otherwise.
keiths,
Am I misspelling your name? What IS your name, anyhow? I shortened “keiths” (which doesn’t sound like any name I know, actually) to “keit” which I assume is your nickname. You wouldn’t do that?
petrushka,
No, there are substantive disagreements between us. Here’s how I expressed it to Neil, in a nutshell:
See? If there are no disagreements between you two, Mr. Cheerful Acknowledgement can’t WIN, petrushka. And that’s what this is about. Did you forget that?
This is just so wrong it is ludicrous. Nothing I have said could possibly be construed by a sane person to support the notion that unique mutations in sterile individuals contribute to evolution. I have explicitly said just the opposite.
In fact, I pointed this out as my reasons for characterizing them as “appendages” to a superorganism , rather than as individuals exhibiting altruism. Their behavior cannot promote or repress any unique characteristics they may possess, and their death cannot affect the continuation of anything unique to their genome.
All he’s asking for is for you to take responsibility for your own comments as construed by him. Is that too much to ask?
petrushka,
Yes, and yet Alan objects to the term “genetic explanation” for some odd reason.
Keiths, I am not aware of any single, global, undisputed definition of altruism. I have labeled my own use of the term as personal.
Totally irrelevant. Read what I wrote, not what you think I wrote. If an actor is sterile, then self-sacrifice has no effect on their copies of these genes, their progeny. Zero, nada, zilch. Helps their half-sibs’ genes, though.
Say what? Semantics is the study of meaning. I have not seen any confusion caused by people who grok alternative meanings for ‘prime’.
“Altruism” seems to be causing a debate here.
Sez you. Hence the SEMANTIC debate.
Yawn.
Communication would have been clearer if you had retained my statement
“As others have noted, the “soma vs germline” analogy is more apt. ”
The daily sacrifice of my skin cells has zero effect on the evolutionary prospects of their copies of my genes, even if they happen to save my daughters’ lives.
Some behavioral tendencies are “certainly inherited.” Others are not.
I’m guessing you are not temperamentally capable of understanding other people’s point of view, or of trying to clarify a point as opposed to winning.
keiths:
petrushka:
Well if you understand his objection, then let us know what it is. He’s never clarified it, and the term ‘genetic explanation’ as biologists use it is certainly applicable to the fact that an ant’s behavioral repertoire is encoded in its genes.
Hence my admittedly private objection to the term altruistic when applied to individuals that cannot pass on their unique genome. The analogy to skin cells or to immune system cells seems apt. They are part of a system or part of a superorganism, and not reproducing individuals.
Keiths, I’m sure you meet the minimal standards for sincerity on this site, but at least half a dozen people who would normally be your allies in the science vs ID and creationism debate, are so turned off by your single-minded obsession with fault-finding that they simply don’t give a damn what you think on any issue.
So if you sincerely want to convince anyone of anything, you will have to assume that other people are not retarded; you will have to assume that that they might have a point to make; and you will have to wrench your brain into whatever uncomfortable position is required to find that point of view. there are more dimensions to reality than keiths and wrong.
keiths, to Neil:
petrushka:
You’re right. I phrased that badly. I should have said this instead:
I think you should stick to quoting. You don’t seem able to paraphrase without saying something I did not intend.
Some said (upthread a bit) that my previous comments were not responsive to the question. That is quite possible, as there doesn’t seem to be a consensus on what the question is.
But let me just add one more point, in case it is relevant:
Natural selection on genetic variation can explain evolution of sterile castes in social insects. Genetic variants that increase the probability of (say) soldier ants acting like soldier ants could be selected, and Hamilton’s kin selection formula will show when.
However note that this does not imply that differences between queens, workers, and soldiers would be genetic, in the sense that they would tend to have particular different genotypes. Once a new allele satisfied the kin selection conditions, it would often rise to fixation and be found in every caste. Then the genotypes would be the same, and they would be ones that enabled soldiers to respond to the appropriate signals and have worker morphology and behavior, and also enabled soldiers and queens to respond appropriately..
The explanation would be genetic (and also environmental) but the differences between castes would not be genetic.
I have no idea whether this is an issue in this discussion, but there it is if needed.
🙂
petrushka,
I am not interested in an “us vs. them” tribalism. I think that everyone’s views, including my own, can be legitimately criticized here at TSZ. We can even criticize the views of those on our own side of the ID debate, and as skeptics, we absolutely should. No double standards, please.
That’s why I listen to the arguments that people make and respond to them. The current topic of ant altruism is a good example. I am not assuming that you are “retarded” or that you don’t have a point to make. I’m responding to what you write!
You need to accept the fact that you make mistakes, petrushka, and that people are not forbidden from pointing them out (especially not at TSZ!) Nor are they attacking your soul or threatening your life by doing so.
You dislike making mistakes, and that’s fine. Most of us would rather not make them either, if we had a choice. But we don’t, and part of growing up is learning to acknowledge our mistakes. Give it a try.
The mistakes I’ve pointed out here are not mere quibbles. The “unique mutations” part of your argument, in particular, is causing you a lot of confusion.
Take a calm look at it. Do you understand why unique mutations are unimportant, and that the relevant mutations for altruistic behavior are the ones that occur in queens and drones and are passed down to their offspring, including the sterile castes?
Thank you, Joe.
Yes, your comment answers the question, though it remains to be seen whether Alan and Walto will accept that.
Joe. I am quite a bit less than expert on this, and i write primarily to test my understanding. Into the crucible, so to speak.
You seem to have said that all individuals — sterile and otherwise — will have the genes responsible for the self-sacrificing behavior. They will be fixed in the population, however the population is described.
DNA_jock suggested an analogy with skin cells sacrificing themselves for the good of the organism. This specialized behavior in individual cells is the result of a developmental program, rather than a differentiated genome. All individuals in the colony would share the genes responsible for the program, but only some would develop along the altruistic line.
petrushka, DNA_Jock,
Regarding the word ‘altruism’, of course it has multiple meanings. So does the word ‘prime’.
In a biological discussion, the sensible thing is to use the biological definition of ‘altruism’. In a mathematical discussion, the sensible thing is to use the mathematical definition of ‘prime’.
Can we at least agree on that?
petrushka,
As I said, the idea that an ant colony is a superorganism does not clash with the idea that workers and soldiers are altruistic.
The analogy can be extended in the opposite direction: Immune cells can be loosely characterized as altruistic, because they sacrifice themselves in the service of the body.
However, biologists typically use the word ‘altruistic’ to apply to organisms, not cells, which is where the analogy breaks down.
Go on. What is the singular, universally accepted, uncontroversial definition of altruism in biology? The one TRVE definition that covers all cases and expresses unambiguously the true meaning.
Indeed, thanks Joe.
LOL
You are the outlier Keith. I don’t see any difference from what Joe is saying to what I have been saying. Of course I know what I intended to say; Others can only read my words.
Where did this start?
I said:
You said:
I asked;
You replied:
which I found uninformative to say the least; I don’t think there is anyone else commenting here who disagrees with the germ-line/soma distinction, unless you do. I think many words have been wasted subsequently and I apologise for being drawn into such a pointless semantic meander.
You’re not the only one to feel that! 😉
This!
Some of them is good enough for purposes of selection.
petrushka,
There are multiple overlapping definitions of biological altruism, but none of them include your strange notion:
The biologists are right. It does make sense to describe sterile individuals in an ant colony as altruistic, because the biologists are talking about biological altruism. There is nothing nonsensical about their notion of altruism, and they have correctly identified it in the sterile castes.
I know you’re unhappy about that, but them’s the breaks.
It seems a good analogy to me.