Why do some creatures forgo their own reproduction to help their relatives survive and reproduce? While we all might like to believe that naked mole rats really do care and are thus willing to sacrifice their creepy little lives for the good of the colony, the true answer probably has more to do with gene frequency across generations and evolution.
A scene from the 2003 ant remake of "Saving Private Ryan". Needless to say, it did not fare well at the box office.
Since the late 1950's, the idea of 'kin selection' has been the most widely accepted explanation for such bizarre behavior in species. The basic premise of kin selection (before you all attack my summary, please note that I work in tech sales, not a genetics lab) is this: Natural selection tends to...
...weed out genes that put individuals at a reproductive disadvantage. When the gene, however, causes the individual to have a lessened chance of reproducing, but also increases the chance of the individual's relatives in reproducing, that gene may actually increase in frequency over time. Why? Because the individual's relatives also carry that gene. In these cases, the benefits that the gene causes to the relatives outweighs the losses that it causes for the individual and thus the gene continues to be passed along through generations.
What was her true motivation? The heavenly Father? Or a dominant gene?
The idea behind kin selection was originally proposed by JBS Haldane in 1955 and, though sometimes controversial, has been more or less widely accepted by the scientific community for the last 30-40 years. The idea even helped make Richard Dawkins a star, as a central idea in his 1976 bombshell The Selfish Gene.
Now, however, the whole idea of kin selection is being called into question by one of the most influential biologists of our time, E.O. Wilson of Harvard. Wilson has a new hypothesis that he is releasing in his upcoming book, Suck It! Just kidding the book is called The Superorganism.
"You're stupid," he seems to be saying.
According to Wilson, such behavior is not a result of kin selection, but of the fact that personal sacrifice by individuals increases the chances of overall colonies in surviving, and thus has been selected for over time.
Hmmm...sounds like we're in the verge of a good old fashioned bio-smack down!
Where do you weigh in on the issue?
Life Science
Brain & Behavior
Comments
Sounds like this is about group selection vs gene selection (rather than kin selection), which I think Dawkins has made very compelling arguments against. A group full of altruists working for the good of the collective would be too easily cheated on by a few scoundrels.
Besides, saying that "personal sacrifice by individuals increases the chances of overall colonies in surviving" is really a statement in support of kin selection - if you're talking about for instance ants. Which E.O. Wilson is fairly likely to be doing, considering.
Posted by: Felicia Gilljam | January 9, 2008 4:40 PM
I'd be interested to read this. Like Felicia said, it sounds like he's touting group selection, which I have yet to read a compelling argument for. I'd like to see how he's laying this out.
Posted by: Stevie | January 9, 2008 5:04 PM
The idea behind kin selection was originally proposed by JBS Haldane in 1955 and, though sometimes controversial, has been more or less widely accepted by the scientific community for the last 30-40 years.
haldane offered a rough verbal description. but the formal theory of kin selection/inclusive fitness was presented by w.d. hamilton in the mid-1960s.
hamilton's original ideas were formulated before genetic testing allowed researchers to calculate precisely coefficients of relatedness. they had to make assumptions. it turns out that the coefficients of relatedness are sometimes lower than necessary for kin selection to be the only or sufficient principle maintaining group cohesion.
in any case, re: wilson, he is promoting group selection, i think specific interdemic selection and the super-organism analogy. but he isn't repudiating kin selection, only arguing it isn't necessary as an explanation for all cooperation that we see among eusocial insects. many group selectionists would argue that kin selection is a subset of group selection.
Posted by: razib | January 9, 2008 5:21 PM
I agree with the first comment. A colony of social insects is a large family group with only one reproductive member and regarding it as a "superorganism" isn't exactly a new idea. Doing so for non-family groups seems suspect to me, but then I've not read this book and I have read The Selfish Gene.
I think colonies are selected on, but I can't see any way for them to pass on their characteristics -- if a few members sacrifice for the group and fail to reproduce, their genes will be underrepresented in the next generation. That means they're selected against within the colony.
There'd have to be some indirect way these genes were being preserved within the colony: it all has to boil down to gene selection eventually, just like cosmology has to boil down to the basic physical laws eventually.
Posted by: Andrew | January 9, 2008 5:26 PM
A colony of social insects is a large family group with only one reproductive member
not always.
Posted by: razib | January 9, 2008 6:16 PM
I'm with E.O. Wilson on this one, and in fact have held the "group selection is valid" position for a while. As Wilson points out in one of his summaries, competition within a group favours selfish actors, or those who favour close kin over distant kin. However, when interactions between rather than within groups are factored in, then groups which have a higher percentage of true altruists and cooperators survive better.
Think about it in terms of human game theory, for a minute. If there exists only a single group of people, then most everyone's time is taken up with competing with each other for status in the group. The minute another group shows up on the horizon, possibly carrying spears, then the group which immediately shoves aside all internal rivalries in order to concentrate on the external threat is much more likely to survive as a cohesive unit and pass on its culture to children. If they are too busy fighting each other for resources to deal with an outside threat -- through self-sacrifice of heroic individuals if necessary -- then the entire group is far more likely to get stomped.
Also -- the potential for true altruism to be passed on genetically even if there is only a single reproducing individual in a colony is certainly feasible, if you think about it. All such traits have to arise spontaneously in a single mutant breeding individual at some point; what then becomes important is the differential survival of those who carry that genetic potential as opposed to the originals. If those offspring which carry the mutant trait are able to better foster the next breeding offspring, the trait has an advantage over other, non-mutant-breeder groups.
Posted by: Luna_the_cat | January 9, 2008 6:29 PM
It may help to go back to basic thinking about fitness. There is simple Darwinian fitness which is a measure of how well you do in producing sexually mature offspring. Inclusive fitness is a measure of how many copies of your genes get passed on to the next generation, and is the basis for the idea of kin selection.
Posted by: Jim Thomerson | January 9, 2008 8:22 PM
It's 'fare' well. Not 'did not fair well at the box office'.
Posted by: Joshua Marker | January 10, 2008 12:51 AM
I was just reading the other day on Wikipedia about Kropotkin the Anarchist (wait, hear me out!). His theory was cooperation of the entire species against others for the good of all rather than competition within a single species for the good of an individual. I like that theory, since it really does seem humanity faces innumerable challenges when it comes to survival--take us out of our cities and without training and weapons we're just soft and delicious. Of course it doesn't work-- it's basically communism and that's just something that hasn't worked for anyone well. Maybe small groups, I remember my high school history teacher saying that really the Plains Indian tribes were one of the few civilizations that actually practiced what you could call communism.
There's also a German film by Herzog about the mystery of Kasper Hauser entitled 'Every man for himself and God against all.'
And that's my day's worth of hyperbole and intellectual dillettantism all rolled up into one comment!
Posted by: Jenbug | January 10, 2008 10:35 AM
Joshua Marker, what do you mean? That's what I had written the whole time.
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