The Heresy Thread -- Where is Dawkins wrong?

[Mokele]

Nothing in science is 100% proven since every measurement has errors and/or assumptions inherent in them. I just felt that it was a bit of an absolute statement. 99.9% proven I would have been happy with, but maybe I am being pedantic.

 

True, though it's one of those cases of "how close to 100% is close enough?". We've had lots and lots of instances of evolution reported in journals, and all of those (at least in biology) must have a p of less than 0.05. Now, I'm not really clear on how that aspect of statistics works (haven't gotten around to that class yet), but I'd think the overall p of the phenomenon as a whole can be extracted from the individual measures somehow, and with each instance it gets smaller (at least I'd expect so). So basically, at this point we're around p< 1*10^-7568273 for evolution as a whole.

 

It is very clear that evolution (as in change in gene frequency) really happens and evolution by natural selection has been seen in the laboratory in organisms with short generations. But what is the real evidence of gene change by natural selection at very long time scales? Clearly it is the best mechanism we have, but is there more concrete evidence? How far back can they sample gene content? Could there be any other mechanisms at work, perhaps complementing or enhancing natural selection?

 

Well, on long time scales we can't directly observe it very well (what with our limited lifespans and such). However, we do have indirect evidence, mostly from genetic testing. An excellent example is the CCR-5 receptor gene, which codes for a cell surface protien on the CD4 immune cells. Previously, this receptor was the gateway into the cell for the bacteria Yersinia pestis, better known as the Black Death. Of course, mutations are common in any species (your average human as 4 mutations that affect the final form of a protien), including those that render protiens non-functional, so some people had fewer or none of this receptor, rendering them resistant or immune to the plague. Fast-forward a few hundred years to the days of genetic testing and HIV, which uses the same receptor (along with another one). We got curious about why some Europeans are resistant to HIV, and find out some are lacking a function CCR-5 receptor. Oddly, they all have the same mutation, a 25-base-pair deletion. We do widespread testing, and find that, for various part of europe, the gene frequency for that mutation (the one conferring resistance or immunity to black death or HIV) ranges from 0.05 all the way up to 0.25 (1 is 100% fixation, where it's the only gene in town).

 

So basically, our own DNA (especially if you're European) holds evidence of a massive bout of natural selection, even though it's been nearly 900 years since then (during which the gene frequency probably fluctuated randomly via genetic drift, since without either disease, it's neutral).

 

We have evidence from other species as well (fish and beetles are currently popular, along with fruit-flies), but for genetic evidence we're often restricted because of imcomplete knowledge of the past and having to recover the effects of selection from the current DNA code (though that's getting easier every year as sequencing advances occur).

 

The fossil record itself can also provide examples, if you have enough fossils and enough temporal resolution to get at microevolution rather than macroevolution. An excellent example is from a species I'm reading up on now, Deinosuchus, a collosal crocodylian from the Creataceous USA. Back then, there was an sea cutting across the US north-to-south, roughly covering the midwestern states. We find two populations of this reptile on the eastern and western sides of this seaway. The easterners are smaller (only about 30 feet long on average), and seem to have been opportunistic predators who ate a lot of fish (10 foot coelocanths) and marine turtles. The Westerners, who show up slightly later, are much larger, up to and possibly over 40 feet long, with 6 foot skulls. This is apparently an adaptation to the high availability of dinosaurs as a food source on the western coast of this interior seaway.

 

As for other mechanisms, yes, there's plenty. One is sexual selection, which is basically the quest to get laid, and explains why organisms my have traits clearly detrimental to survival (such as a peacock's tail). Another is genetic drift, which is basically randomness. If a gene isn't under any selective pressure, it's frequency will fluctuate randomly in a population because of random mating (with respect to this gene, though there may be selection on other genes). The smaller the population, the greater the genetic drift, and it can result in genes becoming 'fixed' (100% frequency) or gone without any selective pressure (which can affect evolution if the environment changes to put selective pressure on this gene).

 

Inbreeding also affects gene frequency, by reducing heterozygosity (organisms become more likely to have two identical copies of a gene, and the gene easily becomes fixed in spite of any negative effects).

 

Two of the champions for non-selective gene frequency alterations are founder effect and genetic bottleneck. They're both the same, except the former pertains to small colonizing populations while the latter pertains to small populations that survive disasters. Basically, imagine a big sack of beans (genes), with certain proportions of each type. If you take a small random sample, chances are it won't accurately reflect the composition of the sack as a whole. Infrequent beans/genes may be totally lost, and frequencies of more common ones might be altered. The smaller the sample, the worse the genetic bottleneck or founder effect. This is why things like cheetahs and Florida panthers and pretty much screwed: they've been through such a severe bottleneck that they've lost most of their genetic diversity, and damaging alleles have become the only ones around through this genetic sampling error (which is why many males of both cat species above have only one testicle).

 

Does that answer your questions? I'm a bit zonked at the moment; I leave for fieldwork in just under 36 hours, and I'm still packing.

 

Mokele

[bascule]

I saw a very enlightening Penn & Teller's Bullshit last night on Intelligent Design. One scientist noted that the type of people who make an issue out of intelligent design are a certain breed of fundamentalist who feel that if one word of the Bible is shown to be wrong, then you have to throw the whole thing out. They apply this same ideology to evolutionary theories, nitpicking through scientific journals looking for one aspect that they believe to be wrong, then attempting to argue that if said aspect is wrong, you have to throw the whole theory out.

 

Apparently they don't understand that science operates with the idea that any scientific claim is potentially falsifiable given enough evidence, and when a part of a theory is falsified, you simply move on to other explanations...

[Mokele]

I saw that one. I actually have it, it's part of the first season which is out on DVD. I don't have the second season yet, but it's out too.

 

I was especially fond of how they pointed out that the Raelians (the loonies who claimed they cloned a baby) believe exactly the same thing, just with aliens rather than god.

 

Mokele

[Severian]

Thanks for the explanation.

[Bill Nye Guy]

Severian Quote:

Originally Posted by Bill Nye Guy

Microevolution is hard to disprove. If you look it up and learn about it i think you will find that it has been 100% proven.

 

 

 

 

That sort of statement does not enhance your case.

 

well no i didnt mean to say that it would enhance my case at all, all i was saying is that it is probably one of the most accepted parts of evolution, or at least the part of evolution that people less argue about.

 

And sorry about saying "100% proven" guys, that phrase was alittle to strong for what i really ment.

 

[ElijahJones]

Well, this is an active topic. Might as well throw in a few thoughts. I feel strongly that the existing arguments for an old earth (~4 billions years old) are in fact rational and sound. Also thinking old earth, Genesis 1-3 shows alot of insight if you read it right. I am also certain from studying mathematics and formal logic that you cannot prove or disprove the existence of God(omniscience, omnipresence, omnipotence). Since we somehow were "given" rational minds with which to find our way through the world, God cannot be in the business of sending people to hell based upon their sincere belief in rational arguments as tools for revealing truth.

 

Its a fallacy that has invaded modern American Christianity that not believing the Earth is 6,000 years old causes the whole Bible to be meaningless. Its just not true. The wisdom of Proverbs stands all by itself. The vision of the endtimes written of by the prophets are inspiring to read and await fulfillment, thus they cannot be proven wrong at this point anyways. The message of Christ centered upon the golden rule is however in direct conflict with some of the ideas that Dawkins is throwing around. I believe that it is scientifically, socially and ethically more valid to create communities that bridle extreme self interest with an ethic of cooperation.

 

We have lost that sense of really needing each other in America and the place is worse off because of it. People exist day to day in competition with each other, this is fine for producing pre-championship Michael Jordans. But even the great one had to learn how to empower his team to reach the pinnacle (those championships owed as much to Rodman, Pippen, Kerr, Paxon as they did to Jordan). Yes it is true that one can cooperate from selfish ambition. Personally I never get the warm fuzzies from using people like that. Of course I want to succeed, but I really want you to succeed too. Because when both of us are fulfilled we really have something to fight for, something to cooperate for.

 

Sadly we have created a world where too many prizes go to only one person. But don't you realize that the food you get at the supermarket is produced by the work of thousands of others just like you? The gas that you pump, thousands of human hours went into that. How can we only be in it for ourselves when we need each other so badly? No, in my opinion humans will never see their real potential as a species until they know how to love. And with the world going the way it is, that is getting harder and harder each day.

[zyncod]

Nobody that's not in a mental institution rejects parsimony as a philosophy even if they reject philisophical naturalism. If you put your hand on a stove ten times and you get burned ten times, the simplest possible explanation is that putting your hand on a stove causes you to get burned. You haven't ruled out supernatural causes; God could have picked those times randomly to burn you, but irregardless, you're not going to keep putting your hand on the stove.

 

The only valid counter to naturalism that I have ever seen is postmodernism and that is pretty incompatible with a faith-based lifestyle. And even the postmodern thinkers go and get the medical treatments based upon the admittedly discounted naturalism. Naturalism and parsimony might not truly explain the workings of the universe, but we all live as if they do and so far, our lifestyle has been more useful than the alternative. Just like intelligent design might actually be correct but it is not at all useful as a hypothesis, whereas evolution might be incorrect but is useful as it actually makes predictions that tend to be borne out (ie, dinosaurs are similar to birds; I predict a birdlike dinosaur; I find Archaeopteryx skeletons).

 

And the fact that fewer people of faith are found in the upper reaches of science is probably due to the fact that, as they become more educated, they find the workings of the universe inconsistent with its creation at the hands of an intelligent, let alone omnipotent, being. Of course, the lack of people of faith at the top [/b]could be due to a vast conspiracy, but really, which explanation is simpler? Oopsy me, I forgot, we only reject Occam's Razor when it's convenient for us. You're probably right: God exists, it's all just a conspiracy, and the reason people get fat is not eating too much, it's the Cupcake Elves blessing them with extra padding so they bounce right back up when they fall down.

 

BTW - revprez, you are the worst example of an agnostic ever.

[ElijahJones]

Parsimony is basically the same as Occam's Razor, which says: all things remaining equal the simplest solution is usually correct.

 

It is sort of like saying that every system takes the shortest path to equilibrium. In classical physics this principle explains pretty much everything you see but it does not explain how anything could exist in the first place. Notice though that the lowest energy state is only one of many that a system can be in and there can be many paths of equal energy between two points (conservative systems). So when I read about evolution and they just casually use parsimony I say "ok what the hell it seems reasonable." Math modelers use parsimony all the time. But it does not prove that the tree of life is as easily explained as we want it to be. More realistically it gives us a starting point, namely simplicity.

[FreeThinker]

Dawkins is a great writer. I believe that his view of natural selection is not only interesting, but very credible. Genes are most likely the unit of selection, not species. Can anyone provide any arguments otherwise?

 

His views on religion are extreme, but well justified. I suggest reading his essays , not just his books, to get a clearer picture of his views.

[Mokele]

Genes are most likely the unit of selection, not species. Can anyone provide any arguments otherwise?

 

How can genes for longer teeth in a lion spread *without* growing a full lion and witnessing the selective effect on the organism?

 

Genes don't die or find mates, organisms do, as *collections* of genes. If selection occured at the genetic level, each gene would be acted on separately. The occurence of linkage groups alone disproves this, not to mention developmental genes.

 

Let's try sickle-cell. Is that allele good or bad? The answer is, you don't and *can't* know. Not until you have an organism and an environment (with or without malaria) for it to interact with.

 

Lions don't just kill the genes for poor running in the unfortunate mutant gazelle they catch, they kill and eat the whole animal, all it's genes, good and bad.

 

There *are* instances of gene-level selection (transposons would be one), but for the vast majority of the time, it's the organism which is acted upon by selection.

 

(Aside: Oh, thank f-ing god, a real evolution discussion, noT just squabbling with creationists!)

 

Mokele

[LucidDreamer]

Genes are most likely the unit of selection' date=' not species. Can anyone provide any arguments otherwise?

[/quote']

While I agree that natural selection can act on individual genes, I can see problems with this view, and see how other units, such as individuals could be just as viable. Having a great rack of horns can be great if you’re a stag, but only if you can support the weight. So in other words, a gene that codes for a larger rack of horns can be an advantage, but only if you have genes that code for strong neck muscles and other genes to support it. Since the advantage of each gene isn't always mutually exclusive from the other genes, there are problems with this view. Also, even if you view it on the individual level, some humans are very fit for certain societies, but not for others. So since there are interrelationships between the potential units of selection there are again problems with claiming individuals as the units of selection.

 

In fact, whatever level you choose you will find interelationships because the world is one large intrarelated ecology. I believe that the genes are a good study for the effects of selection, but you have to be willing to acknowledge that other factors besides the "fitness" of a particular gene could affect it's frequency in a population. I think you have to be willing to accept a certain level of ambiguity to study evolution. I think you have to have a great deal fluidity in your thought processes to uncover its mysteries.

[FreeThinker]

How can genes for longer teeth in a lion spread *without* growing a full lion and witnessing the selective effect on the organism?

 

The organism itself would be influenced by *genes* for their own selfish needs. Once the genes are passed on, each gene would react differently in different organisms. By abandoning the previous body, the genes will be judged on the ability to interact with other genes, and this is where genes come into play as units of selection. The important thing to remember is that the genes will not always be of benefit to the organism, which, if it was the case, could be mistaken for a overall genetic improvement of a species by constant weeding out of *bad* genes.

 

Genes don't die or find mates, organisms do, as *collections* of genes. If selection occured at the genetic level, each gene would be acted on separately. The occurence of linkage groups alone disproves this, not to mention developmental genes.

 

The genes will only work together a period of time, the lifespan of a organism. The genes that are best capable in working as a *team* with other genes will be passed on. This can be misleading, so it is important to remember that working well with other genes is a crucial requirement of a particular gene.

 

A soccer team might have eleven players. They all appear to be working as a team, but actually each player started of trying to make a career, for himself. Why do you think they change clubs when a bigger money offer is on the table?

 

 

Let's try sickle-cell. Is that allele good or bad? The answer is, you don't and *can't* know. Not until you have an organism and an environment (with or without malaria) for it to interact with.

 

Organism can not be the unit of selection. The life of a organism is too short to have any kind of selective power. The sickle-cell works exactly as would be expected if genes were the unit of selection. It is not necessarily a beneficiary to a particular organism, but yet it manages to be passed on. Its multi-abilities, if you like, have enabled it to be a very successful replicator.

 

Lions don't just kill the genes for poor running in the unfortunate mutant gazelle they catch, they kill and eat the whole animal, all it's genes, good and bad.

 

There *are* instances of gene-level selection (transposons would be one), but for the vast majority of the time, it's the organism which is acted upon by selection.

 

The best genes might not always survive. If a lion kills a gazelle and it had a poor gene for running , it is obvious that other genes didn’t interact well with the poor - running gene. Those same genes probably go on surviving in other gazzeles where they are better suited to interact with other genes.

[Mokele]

I like the analogy of genes working in "teams", but doesn't that reinforce my point? They're stuck in their team, and whether they get to the next round (reproduce) depends on the *whole* team. If one team member screws everything up, they all go down.

 

As for sickle-cell, I'm not sure that really does bolster your point, either? How does gene-selection theory account for heterozygote advantage? Seems to me, it would predict a total take-over by one or the other (in a 'selfsih' manner), rather than a stabilizing effect.

 

Genes are what is affected by selection, and are the best currency to measure evolution in, but the act of selection itself mostly occurs at the organismal level, at the level of the "teams of genes".

 

Or, to abuse the team analogy a bit, even if the players are cooperating but still looking out for number 1, it's the team as a whole who wins or loses the game.

 

Mokele

[FreeThinker]

I like the analogy of genes working in "teams", but doesn't that reinforce my point? They're stuck in their team, and whether they get to the next round (reproduce) depends on the *whole* team. If one team member screws everything up, they all go down.

 

Each player plays for better recognition. We get an illusion of a *team* when infact it is eleven (soccer) individuals playing for their own selfish gains(career!

 

As for sickle-cell, I'm not sure that really does bolster your point, either? How does gene-selection theory account for heterozygote advantage? Seems to me, it would predict a total take-over by one or the other (in a 'selfsih' manner), rather than a stabilizing effect.

 

Good point. The simple explanation is that it is the strength/weakness of the gene. By evolving a dual-ability it is its way of survival. Given enough time, a gene with different effects on different bodies would probably go extinct.

 

Genes are what is affected by selection, and are the best currency to measure evolution in, but the act of selection itself mostly occurs at the organism level, at the level of the "teams of genes".

 

When a organism is eaten, genes who were particularly bad at working in a *team* would be the cause. After, lets say,genes that were the most capable of adapting to different bodies/genes would have survived. Individual lives of organisms are too short to have any significant impact.

 

What happens when a organism with good genes is killed by some freak accident (falling of rocks, drowning..)? If you look at it from a organism as unit of selection view, its a failure to reproduce and pass the genes forward. From a selfish gene view, it was just a unfortunate accident, those same good genes will go living in other organisms.

 

Or, to abuse the team analogy a bit, even if the players are cooperating but still looking out for number 1, it's the team as a whole who wins or loses the game.

 

Remember that each member is "Number 1". Everyone looks after themselves. Usually when a player is not getting enough time on the field, he will move clubs. If it was truly a *team* commitment, he would stay, having him on the bench is better for the team than not having him at all! Genes are selfish in the same way, they just don’t have a choice but to stay in the body!

 

I have no doubts that organism play a part in natural selection. But it is a limited part, a lot smaller than the role played by the genes!

 

On a slightly different note, I am starting University next year, studying Bachelor of Science. Most of the science I learn is from self learning (books, magazines, peers…). I feel that this forum can help me expend my knowledge of the field. I am not really familiar with the more sophisticated side to science/biology. So if you could reference some books, websites, it would be greatly appreciated. My special area of interest is evolution.

 

Cheers!

 

Freethinker

 

 

FreeThinker

[Mokele]

Each player plays for better recognition. We get an illusion of a *team* when infact it is eleven (soccer) individuals playing for their own selfish gains(career!

 

But what about learning, for instance? This can clearly affect survival in important ways (ex:"don't eat that plant/snake, it's poisonous/venomous) and occurs at the organismal level based on experiences. While the ability to learn is coded for by genes, the actual content is not.

 

Good point. The simple explanation is that it is the strength/weakness of the gene. By evolving a dual-ability it is its way of survival. Given enough time, a gene with different effects on different bodies would probably go extinct.

 

I'm confused. While we've been saying "gene", shouldn't we properly be saying "allele", in that alleles are competing for representation in their locus/gene? If so, shouldn't the sickle-cell and non-sickle-cell alleles be in direct competition?

 

Or am I missing something? I'm more on the organismal level (as you've probably guessed), so this is sort of at the edge of my purview.

 

Individual lives of organisms are too short to have any significant impact.

 

I'm not sure about this statement. I'd think that short, fast lives (like insects) would be beneficial, in that the genes would have shorter times between replications.

 

So far as I know, selection works equally well on elephants and dung beetles.

 

What happens when a organism with good genes is killed by some freak accident (falling of rocks, drowning..)? If you look at it from a organism as unit of selection view, its a failure to reproduce and pass the genes forward. From a selfish gene view, it was just a unfortunate accident, those same good genes will go living in other organisms.

 

It's an accident all around.

 

I have no doubts that organism play a part in natural selection. But it is a limited part, a lot smaller than the role played by the genes!

 

My position is that the genes are the currency of evolution, and that they *do* act in a manner like you describe, but that it's what happens to the organism that is selective. The genes put together the best organism they can, then selection happens to that organism, and then the genes either profit or lose as a result. Just like the team works together to play the best game they can, and the whole team wins or loses, and that affects everyone's careers.

 

On a slightly different note, I am starting University next year, studying Bachelor of Science. Most of the science I learn is from self learning (books, magazines, peers…).

 

You're kidding me, right? Hell, you already know more than (and can discuss better than) most of the people I graduated with.

 

In all seriousness, your extracuricular reading has and will serve you well; it certainly helped me. An additional tip: ask the teachers about undergrad research. While classes are great, if you can get in with a lab doing what you want, it can be a major boost and generally give you a really good idea of just what you want to do and how to do it. Hell, I only did it for 1.5 years, and, since I stayed at the same place for my (current) masters work (not always recommended, I had special circumstances), I'm already 3/5 done with the first chapter of my thesis, before I even start.

 

I feel that this forum can help me expend my knowledge of the field. I am not really familiar with the more sophisticated side to science/biology. So if you could reference some books, websites, it would be greatly appreciated. My special area of interest is evolution.

 

Well, stick around here, of course, but http://www.talkorigins.org also has a lot of information (and I mean a *lot*), as well as, oddly enough, wikipedia.

 

Irony of the day: I did most of my extra-curricular reading in Gould. ;-)

 

Mokele

[Skye]

The strange thing is that gene was chosen when nucleotides are the obvious most basic unit of selection. Genes are also only a part of the genome, and certainly the other parts are under selection as well. I suppose The Selfish Nucleotide doesn't sound as good. Then again, The Extended Phenotype is no better. It is probably just due to the virulent popularity of the gene meme.

 

Anyway, at every level there's some influence from other players at that level. Nucleotides rely on there being the nucleotides of rest of the genome for replication. The genome relies on the phenotype created, includes perhaps somatic genotypes, to replicate itself at the organism level. Organisms themselves rely on other organisms within their species, especially in sexual and social creatures (man o' war ). And species often, not always I guess but at least for most species, rely on other species to survive. Web of life and all that.

[FreeThinker]

But what about learning, for instance? This can clearly affect survival in important ways (ex:"don't eat that plant/snake, it's poisonous/venomous) and occurs at the organismal level based on experiences. While the ability to learn is coded for by genes, the actual content is not.

 

As far as I understand, experience doesn't get passed on. Genes just act as a template for a new organism and don’t pass on any "learning" done by parents. I do see a fault in this however. The fear of snakes must have been passed on, because we don’t encounter snakes in modern times. Can you offer any references regarding the inheritance of “learning experiences”? I would be interested in further reading.

 

I'm confused. While we've been saying "gene", shouldn't we properly be saying "allele", in that alleles are competing for representation in their locus/gene? If so, shouldn't the sickle-cell and non-sickle-cell alleles be in direct competition?

 

Aren't the sickle-cell and non-sickle-cell allele identical. I though the genes the sickle-cell interacts with decided the effect it has on the body.

 

I'm not sure about this statement. I'd think that short' date=' fast lives (like insects) would be beneficial, in that the genes would have shorter times between replications.

So far as I know, selection works equally well on elephants and dung beetles.[/quote']

 

Genes move through generations of replicators. They mix with different genes and have different effects on organism’s throughout their existence. It doesn’t matter whether an organism lives for a day or a century; these are all small fractions of time compared to the "long reach" of the gene. I look at it as if a "sub-evolution" is happening within organisms. Genes interact with other genes, just as animals interact with other animals. The genes are judged for the abilities to have the best effect on the bodies and how well they interact with other genes. Individual roles a minor, compared to the roles played by genes.

 

If I am a good driver, the car I am driving will not have a huge influence on the amount of accidents I have. It might contribute slightly (brakes, air bags...) but on the end it will be the driver (genes) who is responsible for any accidents.

 

 

It's an accident all around.

 

Not really. From the individual as the unit of selection view, if the individual dies, that’s it. Evolution stops the selection process right there. The unfortunate organism will not have offspring.

 

From the genes point of view it doesn’t really matter. Those same genes, in different bodies, will continue striving and having an influence in the long run.

 

 

Thanks for the compliments, and for the link. I have completed some studies in a different field (IT) but the big questions about life have always been in my head. When I think about it, why would anyone study anything else? People always comment that Atheists can not have morals or purpose. My motivation comes from being an Atheist and from having the opportunity to explore such a mysterious and beautiful world.

 

 

FreeThinker

[Mokele]

As far as I understand, experience doesn't get passed on. Genes just act as a template for a new organism and don’t pass on any "learning" done by parents.

 

Correct, and that's part of my point: learned behavior can affect fitness/selection, and yet it's not encoded by the genes. This supports my view that selection acts primarily at the organismal level, and that genes are like members of the team who're stuck for the long haul, no switching.

 

The fear of snakes must have been passed on, because we don’t encounter snakes in modern times. Can you offer any references regarding the inheritance of “learning experiences”? I would be interested in further reading.

 

I certainly do encounter them, lots and lots of them. But they're what I work on (as well as 2 of my pets), so I'm not typical in that regard.

 

I recall someone here saying something a process by which learned behaviors become genetic, but I'm not super clear on that (nor do I recall the name, sorry).

 

Aren't the sickle-cell and non-sickle-cell allele identical. I though the genes the sickle-cell interacts with decided the effect it has on the body.

 

Nope, it's a single point mutation that alters the last amino acid of the beta-hemoglobin chain. No interactions with other genes, just nice straight Mendelian stuff. It does interact with environment (high altitude can cause heterozygotes to developed the same symptoms as homozygotes, at least temporarily), but it's just a simple system otherwise, and often used in teaching for just that reason.

 

Genes move through generations of replicators. They mix with different genes and have different effects on organism’s throughout their existence. It doesn’t matter whether an organism lives for a day or a century; these are all small fractions of time compared to the "long reach" of the gene. I look at it as if a "sub-evolution" is happening within organisms. Genes interact with other genes, just as animals interact with other animals. The genes are judged for the abilities to have the best effect on the bodies and how well they interact with other genes. Individual roles a minor, compared to the roles played by genes.

 

But my question is why should the timescale have anything to do with it? You said that the lives of organisms were too short to be meaningful to selection. Wouldn't short lives be good, though. A team can get more wins if it plays more often.

 

Not really. From the individual as the unit of selection view, if the individual dies, that’s it. Evolution stops the selection process right there. The unfortunate organism will not have offspring.

 

From the genes point of view it doesn’t really matter. Those same genes, in different bodies, will continue striving and having an influence in the long run.

 

True, but it comes down to what level selection acts on versus what level is affected. Genes, I agree, are the currency of evolution, the most affect, the best measure, etc. However, I hold that it's selection on the organism level that affects the genes. The genes are what we're counting and watching, but it's not the genes dying or screwing, but rather the organism. Essentially, I think a gene-based view of evolution does not necessarily have to be gene-only, and that selection occurs at the organism level, while pretty much everything else is at the gene level. Even if I take an organism-level view of selection, genetic drift is still just an accident because I'm counting the genes.

 

To abuse the team analogy some more, I say the games are where the winning and losing occur, but the player's careers are the best measure and eventual result of the game series.

 

Mokele

[FreeThinker]

Mokele,

 

To help you understand my point of view I will introduce another analogy. I have used the car metaphor before, but now I will take it one step further. I will use the engine to represent the genes and the rest of the car to represent the individual. The car appears as though it is the driving force of motor vehicle evolution, because it is successful models that a replicated in the future. But the most important units of selection in the car industry are the individual parts of the engine. Most of these parts don’t get changed, but are simply passed down to new models (individuals). Sometimes an engineer will find a way to improve a part, and this can be compared to the random mutations of genes. The engineer takes the role of nature, by constantly weeding out and improving the performance of the engine (genes). However, the car does play a part in motor vehicle evolution, even though it is a relatively small one. The paint, seats and the sounds system all have an influence upon future models, but all would be utterly useless without the engine.

 

I do agree that learned behavior does work on the individual level; I am just reluctant to accept that it plays a major role in the overall picture. When writing a computer program you allow the program the versatility to make some basic decisions based on previous experience. I believe this is what genes do to the individual bodies. So what happens when an individual doesn’t learn, and gets eaten? It genes didn’t make very successful programmers. In the future, genes that are capable of better programming will be favored. Better programming might represent a single citron which will enable the dear to remember past events better than its peers. The questions that are raised from this are: how important are the casualties along the way? When dealing with millions of year of evolution, how important are a few individuals? I admit that I am not too familiar with the topic of learned behavior and how it is passed on. Is there anyone who can offer an explanation or provide link on the topic in the forum?

 

Same genes seem to pass through different species, adapting towards different conditions. Those same genes started at point A at some time in the distant past and they will move towards the future by adapting to different organisms. All the casualties, failed mutations and failures to learn along the way, are just small bumps on the road.

 

Genes alter the organism to help them selves get passed on to the next generation. I can not help use the Dawkins cliché “we are all gene machines”. Genes program us to be faster, stronger and smarter and it is genes that get the reward, by being passed on to future generation. Every mistake along the way is weeded out, every good creation observed. We are nothing by experiments, constantly changed for the good of the genes.

 

I think we are both agreeing up to a point where I think that the individual is really a collection of genes and you interpret it as something else. When you say “but it's not the genes dying or screwing, but rather the organism” what do you think drives the organism to “screw up”. It is the genes, the architects of the body. They are to blame for every success and failure of the organism. They are the true units of natural selection.

 

FreeThinking

[Mokele]

I would reply point by point, but I agree with so much of it that it'd be pointless. I think we both agree with the gene-centered model of evolution, and about organisms being put togehter by a collection of genes, as well as about evolution being most interpretable and measurable from a genetic standpoint. I even agree that natural selection acts on the genes (though not exclusively). Let me see if I can try to make my position more clear.

 

"Selection" is really just a composite of individual "selective events" (my word, just pulled out of my cloaca), such as dying, getting laid, etc. Now, we have a zygote, containing a set of genes. These genes work together to make the best organism they can (as you describe), but they're stuck. They're stuck in the organism, and stuck together with their fellows. Nothing can happen, no selective event can work on just one gene; it's all or none (yes, technically only half, but that's random, so it all balances out in the end). It's the animal (and the genes trapped inside) that lives or dies, gets lucky or winds up playing D&D (j/k).

 

In essence, the genes build the animal, but it's the animal that things happen to. That's what I mean by selection occuring at the organism level. Of course the affects the genes, as you describe, but it's an all or none deal for whoever is in that body.

 

For analogy, imagine several groups of people driving through Miami, several to a car. While they each go their separate ways after they get out, and either profit or lose by the car being blown up in a gang war, it's all or none: either the whole car get's blown up and kills everyone, or they all escape.

 

The way I see it, selection occurs at *many* levels. Sometimes you do have selective events at the genetic level, like transposons. Mostly, you have selective events at the organism level, namely sex and death. Sometimes you even have selection occuring at the species level (though not often). In the end, the output is in genes, but there are multiple levels on which selection can occur, the most prevalent being the organism.

 

Mokele

 

PS. I'd just like to add that I am greatly enjoying this debate, and it's really making me think hard.

[FreeThinker]

Mokele,

 

I agree with you that evolution occurs on three different levels: the species, the individual and the genes. The question is: what is the primary unit of natural selection (PUNS)? The individuals of the species compete against each other (for food, mates, territory…). Each individual organism will do what is best for himself, and his genes (siblings, children and to some extent cousins). The individual organisms obviously have more impact on natural selection than the whole species and seem like a good candidate for being the PUNS. However, the individual can also be subdivided, into genes. A particular gene doesn’t just inhabit one organism; it is spread throughout the whole planet, depending on how successful it is at building individuals. So are genes the PUNS? If we discount the citron, which rarely changes anyways, we can comfortably say yes.

 

If several people are driving down through Miami, and are blown up in a gang war the question should be: did the people inside the car have any influence on whether they survive? The ability of the people in the car to retaliate, will decide whether they stay alive or not. The car really doesn’t have any significant say on the situation; it’s the people inside (the genes) that decide what happens! However, I believe this is a somewhat false analogy. The people in the car don’t have copies of themselves driving around in other cars. If they did, as genes do, the outcome of the incident wouldn’t really matter.

 

Yes, it is the individual that things happen to, but the individual is the result of gene programming. Do we blame, or commend, a car for breaking down, or the people who designed it? The genes are really being put through a series (a very long series) of tests. Their creations are being thoroughly examined, and if they weren’t efficient architects, their machine (individual) will die! But will the genes die as well? Not necessarily. The same genes that were responsible for the death of the particular organism go on living in other organisms, working in different conditions, doing different experiments.

 

“It's the animal (and the genes trapped inside) that lives or dies, gets lucky or winds up playing D&D (j/k).” Even when species go extinct, the genes don’t necessarily die off, they continue with their journey within other species (recently the genes responsible for the development of the mouse eye was implanted into a fly, it grew a perfectly good FLY eye). So when an individual dies, the genes don’t die with it, they go on living in other organisms (This is the reason why bee’s sacrifice their own life for the sake of the hive, because the sacrifice of a few genes is irrelevant, compared to the amount that will be saved). Genes for saving copies of them selves would have been favored by natural selection.

 

Finally, I will agree with you, this is really making me think. As you commented before, in an earlier post, it is good to have a discussion about real science, than non stop arguing with the creationists. It just makes you realize how annoying, boring and ignorant their arguments are. Gould and Dawkins agreed that debating them is pointless and that we should stick to debating each other. I couldn’t agree more.

 

Free Thinking

[LucidDreamer]

The way I see it, selection occurs at *many* levels. Sometimes you do have selective events at the genetic level, like transposons. Mostly, you have selective events at the organism level, namely sex and death. Sometimes you even have selection occuring at the species level (though not often). In the end, the output is in genes, but there are multiple levels on which selection can occur, the most prevalent being the organism.

I agree with you that evolution occurs on three different levels: the species, the individual and the genes.

Doesn't selection act on even "higher" levels? Wouldn't dinosaurs dying out because they all had similar physical characteristics be an example?

[FreeThinker]

Doesn't selection act on even "higher" levels? Wouldn't dinosaurs dying out because they all had similar physical characteristics be an example?

 

What is the cause of the similar physical characteristics? It is the genes, the architects, that are put through the test. This reinforces my point: the genes that were unable to cope with the change of conditions faced the same outcome, in this case extinction. If the dinosaurs were better designed (by the genes) to cope with the conditions (like the mammals and other surviving species) they would not have died out.

[Mokele]

However, the individual can also be subdivided, into genes. A particular gene doesn’t just inhabit one organism; it is spread throughout the whole planet, depending on how successful it is at building individuals. So are genes the PUNS?

 

Even when species go extinct, the genes don’t necessarily die off, they continue with their journey within other species

 

Ok, perhaps a re-phrase: Each organism gets a set of copies of genes, which build the body and such. All of these copies are stuck together in the organism, which is the part that dies or reproduces, which in turn affects the genes.

 

Basically, I agree that the genes are the currency and driving force, but, because the organism is the bit that lives or dies, mates or winds up alone, that's the level where selection (the events that kill or sterilize organisms, preventing geneflow) occurs.

 

Let's go back to the team analogy. Selection occuring at the gene level would be like the individual players winning the game, regardless of team, based on some criterion. Selection occuring at the organism level is analagous to the team winning or losing.

 

Basically, I'm saying that what defines the sucess of a gene, what makes or breaks it, is how many organisms carrying it survive and/or reproduce, and that the events that lead to that, while governed by genes, are occuring at the team/organism level, and either the whole team wins or loses.

 

Of course, the team analogy breaks down for kin selection and such unless you postulate cloned players (hey, give it 30 years and we might see just that). But my point is that the events that determine how many copies of genes are made are at the organism level: sex and death.

 

Doesn't selection act on even "higher" levels? Wouldn't dinosaurs dying out because they all had similar physical characteristics be an example?

 

Eh, maybe. On one hand, Raup's paper in the early 80s showed that a *lot* of extinction was purely stochastic (random), because things don't adapt to circumstances that only occur rarely, and the future is more or less random.

 

If a population splits into two species, and one becomes adapted to arid, desolate environments while the other becomes adapted to a semi-aquatic life, which goes extinct depends on whether the next big disaster is a flood or a drought. On a larger scale, species of a certain large order or class might all share common traits that just happen to be exploited by one particular extinction event. If this is so (and Raup argues fairly convicingly for most cases that it is), then extinctions are technically non-selective, as species cannot adapt to them to become better are surviving them.

 

However, there are some cases (competetive replacement) where there *does* seem to be a selective element, though these cases are rarer than once thought. So it's not *always* random and non-selective, just mostly so.

 

If the dinosaurs were better designed (by the genes) to cope with the conditions (like the mammals and other surviving species) they would not have died out.

 

Except, as I point out above, genes cannot design on such a long timescale, because evolution is a fundamentally short-term, unanticipatory, local process: the animal adapts to here and now, not the possible future. Which lineages go extinct is pretty much random on a long timescale, and depends on the nature of the environmental change or particular cataclysm.

 

This, I feel, underscores my assertion that selection occurs mostly at the level of the short lived organism compared to the long-lived gene. Any allele that would allow great success in surviving asteroid strikes, faced with an allele that would not allow such sucess but would allow a doubling of the number of offspring, would quickly be outcompeted and vanish, in spite of this being to the long term detriment of the species and all associated genes. Because genes/alleles persist for so long (your example from eye development, for instance), such a short-sightedness in evolution can only be explained by selection at the level of short-lived units, namely organisms.

 

Mokele

[FreeThinker]

Mokele,

 

 

the organism is the bit that lives or dies, mates or winds up alone, that's the level where selection (the events that kill or sterilize organisms, preventing geneflow) occurs.”

 

How do you explain the fact that mothers are willing to die for their offspring? If it was really down to the organism, it would value its own life more than anyone else’s. Sure the organism lives and dies, but only by what the genes programmed it to do. If a gazelle is eaten by a lion, it is the genes that are responsible. I think we both agree with that. The reason is that genes in that particular gazelle weren’t as good at cooperating with each other, as they are in other gazelles. Just say in the population of gazelles a gene exists that will give them better hearing than other gazelles. Now when the lion approaches this gazelle escapes, it lives! Did the gene for better hearing save the gazelles life?

 

 

Let's go back to the team analogy. Selection occuring at the gene level would be like the individual players winning the game, regardless of team, based on some criterion. Selection occuring at the organism level is analagous to the team winning or losing.

 

This happen often. Often a player will play a great game, and lead the team through. Marradons goal against England in the 1966 World Cup is a great example. He single handedly got them through that game. These days that Argentinean team is hardly remembered, but Maradonna is treated like a god. This analogy could represent the organisms (Argentina) who died off in the past, and the good surviving genes ( Maradonna). I should note Maradonna has retired in 94, but that doesn’t metter for the sake of this discussion.

 

 

This, I feel, underscores my assertion that selection occurs mostly at the level of the short lived organism compared to the long-lived gene. Any allele that would allow great success in surviving asteroid strikes, faced with an allele that would not allow such sucess but would allow a doubling of the number of offspring, would quickly be outcompeted and vanish, in spite of this being to the long term detriment of the species and all associated genes. Because genes/alleles persist for so long (your example from eye development, for instance), such a short-sightedness in evolution can only be explained by selection at the level of short-lived units, namely organisms.”

 

But even organisms that were better at reproducing, would spread over organisms that were capable of surviving the asteroid strike. We can not judge neither the organisms nor the genes with future environmental conditions. Genes, and organisms, are best suited “ right here , right now” and if there was a sudden change in environment, the organisms that carry the best genes for surviving in that environment would benefit.

 

FreeThinker