Units of Selection

Jeremy1952 · Posted: Thu Oct 31, 2002 9:14 pm Post subject: Units of Selection

Well, I've only just begun, but I feel the need to take exception already: on page six, Bloom says, "Individual survival is not the only mechanism of the evolutionary process. . ." The discussion shows a lack of understanding and his conclusion is wrong. Selection for the benefit of the group is physically impossible. The reason is this: if there is an organ, behaviour, any genetically determined aspect that benefits the group but detriments the individuals, genes of other individuals without that aspect will out-produce those with it. Because genes function within bodies and bodies function within social groups, the appearance of group selection frequently occurs. The reality, however, is that an individual who functions better as a "member of the team" prospers. The group is the environment in which individuals are selected.

I don't know the answer off hand to Bloom's question about stress, nor do I know off hand whether or not the answer is even know. I do know that "good for the group" is not a valid answer.

This is a difficult topic; some of the best minds struggle with these concepts. I've suggested The Extended Phenotype, and that is where a more extensive explanation can be found.

Chris OConnor · Posted: Thu Oct 31, 2002 9:44 pm Post subject: Re: Units of Selection

Jeremy:

I would refrain from passing judgement too early. I too was startled by his position, but he has compelling evidence as you will soon see in the next 50 pages.

What about the kamikaze pilots who gave their lives for their country? They could not be said to be acting in their own rational self-interest. They were excluding their own genetics from the equation by their actions, and were clearly not benefiting their families or offspring.

He has numerous examples that really build a strong case for his theory. Just keep reading and see if your views change at all...

Chris

Edited by: Chris OConnor at: 10/30/05 4:03 pm

Jeremy1952 · Posted: Fri Nov 01, 2002 8:34 am Post subject: Re: Units of Selection

I have no doubt that humans can work for the good of the group, to the detriment of their own progeny. If we can't, we might as well throw in the towel now. But this is based on thought and on culture.

AvatarofPower · Posted: Mon Nov 04, 2002 6:38 pm Post subject: Re: Units of Selection

There are lots of instances of beasties working for the interest of their genetic strain... I don't have any specific examples at the moment, but I recall reading about it in Shadows of Forgotten Ancestors by Sagan... I'll make a follow up post when I get a chance to dig through that.

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Jeremy1952 · Posted: Wed Nov 06, 2002 12:29 am Post subject: Re: Units of Selection

Bloom's insistence that cooperation means that biologists are wrong, and that there is some kind of mystical force directing species to work for the common good, reminds me of religionists insisting that the sunrise prooves there's a 'god'.

I counted four seperate attacks on mainstream biology on page 70 alone. "Contrary to contemporary theory, evolution is not built solely on competition between self interested loners." Bullshit. Richard Dawkins explains at some length how individual competition leads to group cooperation. I will dig out his analogy later but for now, the overview: genes are spread out through a population. A gene "for" something good for the survival of the group, that gets more copies of itself passed on (such as the warning behaviours Bloom mentions), will spread in the population . . . and that is the physical reality of evolution. At its base, evolution is the process of changing allele frequencies in a population.

Things that are good for the group cannot come about by themselves. There is no physical mechanism for attributes to get from the group back to the genome. Genes spread in a population; the individuals they live in live or die; and the act of spreading, they create the environment in which they live.

Chris OConnor · Posted: Wed Nov 06, 2002 1:46 am Post subject: Re: Units of Selection

Jeremy:

Couldn't the meme be the mechanism of change?

Chris

Edited by: Chris OConnor at: 10/30/05 4:04 pm

MichaelangeloGlossolalia · Posted: Wed Nov 06, 2002 6:36 am Post subject: Re: Units of Selection

I don't see Bloom's thesis as surprising at all. Naturally if a "weak link" in the tribe gets everyone killed off, there won't be any selective advantage. Humans are tribal, and warfare is one of the few serious events that can destroy a tribe, both by killing off the hunting males and by raping the womenfolk. This means any situation where a "weak link" is damaging to a war operation will be an event which affects not only that individual's genes but a large portion of the genetic viability of the tribe.

It's not impossible for an individual to sacrifice its life for the survival of the tribe. Bees do it. Stinging an invader means the death of the individual bee, but if enough bees do it, invaders are repelled and the queen's genes are perpetuated, along with the genes that produce self-sacrificing soldiers. The concept of dying for one's country at one's sexual peak is hardly questioned, because males past breeding age are less fit for battle (this may no longer be true, but habit dies hard) and the survival of the tribe is imperative.

The REAL question is, what happens when individual or tribal competition threatens not only the tribe but the species? It's a unique situation for humans. The worst thing that could happen in ancient times was the genocide of a tribe. The worst thing that could happen now would be a nuclear and biological war. Theoretically, a handful of individuals, acting in the name of a nation or deity, could destroy millions or billions of human beings, or set of a chain of events having the same effect. Will our selfish genes destroy the human species and the ecosystem? I doubt it, but they can sure give us a scary ride.

Ani Osiris · Posted: Wed Nov 06, 2002 4:15 pm Post subject: Re: Units of Selection

Quote:
"Contrary to contemporary theory, evolution is not built solely on competition between self interested loners."

I have to agree with Dr. Bloom here, and I don't think it necessarily appeals to or evokes mysticism. Ontogeny, for example, is a powerful factor in evolution which sets up a sort of top-down influence. In terms of individual behavior in the context of a group (with the group as a unit of selection), swarm behavior provides an interesting case.

Army ants, for example, display different raiding patterns (group level behavior) when foraging. Studies (I'm to lazy to dig up references, but will if you want) have shown that this is not the result of differences in individual behavior - a significant amount of variation between the individuals' behavior can be present without changing the overall pattern in the least; rather it is the spatial distribution of the food source(s) which is critical, i.e. if the distibution is the same, then the same raiding pattern will emerge as an optimal pattern in terms of total food collected. Similarly, using the same basic rule of individual behavior will generate different patterns at the group level, and which pattern emerges depends on the spatial distribution of the food instead of the particulars of the rule followed. This suggests that selection (or similar mechanism) is in some sense operating at the level of the raiding pattern itself with, again, a top-down influence on individual behavior or genotype.

Also, obviously in the case of ants, the individual's success isn't going to do a thing towards directly changing the frequency of its alleles in the population; and if the particular genes of an individual somehow or indirectly became ubiquitous, the success/fitness of the group as a whole deteriorates. Social insects are admittedly something of a special case - though that simply argues in favor of Bloom's assertion that evolution is not solely a matter of competition between individuals.

Quote:
Couldn't the meme be the mechanism of change?

I don't think so. I mean, assuming the meme is an actual object, there still needs to be a mechanism which brings it into existence or which drives its change (suggesting the process runs from the genome up to the meme, not the reverse). More problematically, there needs to be some mechansism which transmits (transforms really) whatever trait the meme represents to its genetic analogue.

[quote}The concept of dying for one's country at one's sexual peak is hardly questioned[/quote]

Well, Gen. Patton sure as heck challenged that idea. I'm not sure if these were his exact words, but he said, "It is not a soldier's duty to die in battle. A soldier's duty is to survive and kill the enemy."

Chris OConnor · Posted: Thu Nov 07, 2002 1:07 am Post subject: Re: Units of Selection

Jeremy:

I do see your logic as it meshes with everything I've read by Darwin, Gould, Dawkins and Zimmer on evolutionary theory. I'm trying to keep an open mind though and hear Dr. Bloom out entirely. Steve Painter once said (Hi Steve!) that "I have seen the enemy, and the enemy is certainty." I don't want to ever be so certain of something that I close my mind to different perspectives.

As we all know, in the world of science, theories are always tentative. We need scientists and educators like Dr. Bloom to push the envelope and challenge us to think of accepted theories and facts in new and varied ways. It is this process that eventually leads to the toppling of established facts.

His ideas about memes have been what I've found the most intriguing. As I move deeper into the text I anticipate learning more of his meme theory...if I can call it that. I feel he is onto something here and its keeping me on the edge of my seat. Never before had I ever considered the meme as such a powerful mechanism for change.

But I want you to know I see your point and I don't necessarily agree with Dr. Bloom. I'll be the first person to admit that I'm a layperson when it comes to biological evolution and science in general. But damn I love to think. And that is what BookTalk is all about to me.

Chris

Edited by: Chris OConnor at: 10/30/05 4:04 pm

Jeremy1952 · Posted: Sat Nov 09, 2002 12:58 am Post subject: Re: Units of Selection

Here is how Richard Dawkins explains the process of cooperation between selfish genes.

One oarsman on his own cannot win the Oxford and Cambridge boat race. He needs eight colleagues. Each one is a specialist who always sits in a particular part of the boat--bow or stroke or cox etc. Rowing the boat is a cooperative venture, but some men are nevertheless better at it than others. Suppose a coach has to choose his ideal crew from a pool of candidates, some specializing in the bow position, others specializing as cox, and so on. Suppose that he makes his selection as follows. Every day he puts together three new trial crews, by random shuffling of the candidates for each position, and he makes the three crews race against each other. After some weeks of this it will start to emerge that the winning boat often tends to contain the same individual men. These are marked up as good oarsmen. Other individuals seem consistently to be found in slower crews, and these are eventually rejected. But even an outstandingly good oarsman might sometimes be a member of a slow crew, either because of the inferiority of the other members, or because of bad luck--say a strong adverse wind. It is only on average that the best men tend to be in the winning boat.

The oarsmen are genes. The rivals for each seat in the boat are alleles potentially capable of occupying the same slot along the length of a chromosome. Rowing fast corresponds to building a body which is successful at surviving. The wind is the external environment. The pool of alternative candidates is the gene pool. As far as the survival of any one body is concerned, all its genes are in the same boat. Many a good gene gets into bad company, and finds itself sharing a body with a lethal gene, which kills the body off in childhood. Then the good gene is destroyed along with the rest. But this is only one body, and replicas of the same good gene live on in other bodies which lack the lethal gene. Many copies of good genes are dragged under because they happen to share a body with band genes, and many perish through other forms of ill luck, say when their body is stuck by lightning. But by definition luck, good and bad, strikes and random, and a gene that is consistently on the loosing side is not unlucky; it is a bad gene.

One of the qualities of a good oarsman is teamwork, the ability to fit in and cooperate with the rest of the crew. This may be just as important as strong muscles. . . .natural selection may unconsciously 'edit' a gene complex by means of inversions and other gross movements of bits of chromosome, thereby bringing genes that cooperate well together into closely linked groups. But there is also a sense in which genes which are in no way linked to each other physically can be selected for their mutual compatibility. A gene that cooperates well with most of the other genes that it is likely to meet in successive bodies, i.e. the genes in the whole rest of the gene pool, will tend to have an advantage.

Ani Osiris · Posted: Thu Nov 14, 2002 5:12 pm Post subject: Re: Units of Selection

Not to be lost in this analogy is that fact that the whole idea is to win the race, not to pick out all the individually best oarsmen.

Let's suppose you were able to determine which oarsman was the best at each position. Does placing those best of the best in the same boat guarantee that you'll have the fastest boat possible? No. Joe's stroke, say, is very powerful so on average he is in a winning boat. But Joe's stroke is long and fouls the oars of those in front of and behind him when theirs is not equally long. Similarly with Sue, who tends to be in a winning boat because her stroke is short and rapid. Put them together and you have a crew that is unable to move, much less win a race. So, you put in a coxswain who can regulate the timing and length of the strokes (note the lack of any significant role of regulatory genes in Dawkins' model, so it already has a serious flaw); but when you shorten Joe's stroke and slow Sue's stroke, they lose what, individually, made them good strong oarsmen and you end up with a slow boat.

Ok, so you assign a much higher fitness value to the oarsmen with the teamwork quality, but how do you do that when, as with Dawkins' model, all you have are particulate genes? Dawkins gets terribly vague at this point because it doesn't really work. Chemistry is nothing if not strict in its reactions, so there is no generic 'cooperative' gene in the sense that one particular sequence can work with a large variety of others to yield the same effect - it has a specific and different effect with each. In other words, because they are all specific effects, the apparent cooperative trait is really an illusion - remember, there was supposed to be a 'teamwork quality' that made all this work, but the floor just dropped out from under the argument since there's no longer any trait or gene for selection to actually work with. So you're back in the boat with Joe and Sue, and cooperation remains totally unexplained.

However, if you toss the notion of the selfish gene, I think you're in much better shape. Then you can include factors of process and organization in a real sense instead as a product of population genetics. Instead, say, Sue is in love with Bill and when she's in his boat her efforts are doubled (i.e. Bill is the equivalent of a chemical catalyst). Now, there's something that will not only give your boat an advantage, it's likely to blow the other boats completely out the water. The advantage is only with the boat as a whole, not for the oarsman invidually; and it arises from the specific chemistry between Bill and Sue. You do not necessarily need natural selection to explain cooperation in the sense of constituents working together either selfishly or altruistically, and perhaps it's an inappropriate explanation - all you need is basic chemistry. More generally, you have systemic properties which set basic patterns and influence the evolution of the constituents. As a shaping factor, something like autocatalysis is at a more fundamental level than selection - meaning 'cooperation' is built into the very structure of life from the get-go, it does not result from an amplification of or a dependency on the properties of the individual constituents.


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