…and this is a 
It was a fine evening here in Chicago, with all these superstars of evolutionary biology in attendance. It was also an information-dense evening — I tried to keep up on my little laptop, but I know I missed a lot. Fortunately, I'm not alone: Rob Mitchum and Jeremy Manier were also covering the event, and have a play-by-play available. I'll just dump what I've got here tonight. I do have wi-fi passwords so I can get things up a little more promptly tomorrow and Saturday.
Richard Lewontin opened up with a few deprecatory comments about the religiosity of our surroundings (the talks were given in a chapel) and our purpose, the reverence given to Saint Darwin. He was there to talk about the importance and danger of metaphors, and addressed two of them. The New Testament metaphor of genes make organisms, and the Old Testament metaphor that organisms adapt to the environment.
It's not true that genes make organisms. Organisms are consequence of interactions between inside and outside, genes and molecules, and the phenotype is not predictable from the genotype. He discussed the classic example of norms of reaction in Achillea, showing growth of clones in different environments. Cloned plants taken from cuttings — so they're genetically identical — and grown in different environments show different patterns of growth, and, for instance, don't show a simple relationship between morphology and the elevation at which they're grown. Another example is bristle number in Drosophila which show similar unpredictable pattern of response to temperature. Another thing to think about: look at the fingerprints on your left and right index fingers. They're not identical, but they have the same genes and formed in the same environment at the same time. Living organisms are the outcome of developmental and physiological processes influenced four factors: genes, non-genic molecules in the embryo, environment, and random variation. Biologists have known this for years but have fallen prey to the metaphor of genetic determinism. (He also mentioned another bad metaphor as an aside: the cell as a machine.)
The other bad bad metaphor is the idea that organisms adapt to ecological niches. Organisms do not fit into preexisting niches. You can't look at "niches" in the environment…there are an infinity of them. The organism determines the niche. A better idea is the concept of niche construction, in which niches change as organisms evolve. Organisms take whats available and integrate it with their biology, and the life activities of organisms determine what is relevant. When did living in water become the niche of the ancestral seal?
Organisms seek out appropriate environments, the idea of microclimate. Put mesic (adapted to environments with a moderate amount of moisture) and xeric (dry or desert) flies in evironments with different zones of humidity, one surprising result is that the xeric flies move most quickly and determinedly to moist areas, more so than mesic flies. It's not that dry-adapted flies can handle dryness better…it's that they're better at finding damp microenvironments.
Lewontin gave several other examples of organisms that respond in sophisticated ways to confound simple interpretations of adaptation: that we all produce shells of altered microenvironments around us by our metabolic activity; that trees can count the number of days of a certain temperature to trigger flowering; that Daphnia measure the rate of environmental change to determine whether to reproduce sexually or asexually; that organisms modulate the statistical properties of their environment by storage.
He suggested that we need to set aside the bad metaphor of adaptation for a less bad metaphor of construction. Unfortunately, this creates a difficult situation for scientists interested in selection, because, for instance, frequency dependent selection means that the addition of new genotypes to the gene pool (which happens constantly) causes fitness to change in unpredictable ways. It's a game of rock-paper-scissors with a lot more than just three possibilities. He closed by saying that addressing this kind of problem should be the goal of the next generation of evolutionary biologists.
Life Science
Comments
Posted by: taranaki
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October 30, 2009 12:28 AM
Rockefeller Chapel has many uses - I got two degrees in there and heard some great music. This evening ranks right up there. I am looking forward to watching the tapes of this evening's talks to review what was said. I thought Richard Lewontin gave the most compelling and interesting talk. PZ's summary helped clarify some of the talk. I need to read Rob Mitchum's play by play. No more live conference for me - I will have to wait for the tapes to be posted.
Any chance for a meeting with your loyal Chicago Pharyngulites?
Posted by: Nerdette | October 30, 2009 12:36 AM
Rockefeller is a beautiful building that fits its many faces. The carillon went under maintenance my third year into my forth, and I feared I would never hear the bells again. They rang again the spring before I graduated. I got my bagpipes and my bells :)
Enjoy Chicago! Such is luck that you should visit the year after I left. Be sure to walk around Botany Pond - many hours of studying were spent around those benches, and many hours of counting gypsy moth NPV occlusion bodies were spent in the basement next door.
Posted by: Diane G. | October 30, 2009 12:44 AM
I sometimes think biology lends itself too much to semantic arguments, which are more or less insoluble, at least by scientific means...Much of this presentation sound like just another representation of the dynamic tension between needing to simplify variables to experiment/collect data, basically reductionism, vs. needing to keep in mind all the inherent messiness of multi-layer biological processes, i.e., complexity. Sometimes one's preferred metaphor can have a lot to do with one's preferred political philosophy...
Meaning no disrespect to the great lights of science...Just an observation from following similar discussions since the late 60's.
Definitely food for thought, but too much worrying about metaphors can lead to something like lumper vs. splitter dithering.
As an erstwhile botanist, it's always refreshing when evolutionary theorists remember to include examples from that other significant branch, where organismal strategies can appear quite different. And how would a microbial-centric evolution fit the various metaphors?
I'm all for a big-tent evolutionary synthesis & suspect that some metaphors are truer for some spp/groups, others for other ones...
Thanks, PZ, for the timely & generous summary. Was there any interesting discussion after the talk?
Posted by: Janine The Ineffable, OM | October 30, 2009 12:45 AM
Watch for the parrots. There are a couple of huge parrot colonies in that area.
Posted by: Douglas Watts | October 30, 2009 2:49 AM
The other bad bad metaphor is the idea that organisms adapt to ecological niches. Organisms do not fit into preexisting niches. You can't look at "niches" in the environment…there are an infinity of them. The organism determines the niche.
This is a very good point. Sea-run fish like Atlantic salmon cannot be said to adapt to an ecological niche. Their habitat extends from tiny headwater streams in the mountains of Maine all the way the East Greenland, and back. And each salmon covers every bit of this enormous, pan-global "niche" in the first 4 years of his or her life.
Posted by: Mintman | October 30, 2009 2:55 AM
Oh dear. Despite the Achillea example, this shows a very zoology-centred view of things.
You can't look at "niches" in the environment…there are an infinity of them. The organism determines the niche. A better idea is the concept of niche construction, in which niches change as organisms evolve.
That is true to a certain degree, but for plants, the options are fairly limited. There is a small number of parameters - such as minimum and average temperature, acidity of the soil, moisture, seasonality - that define the habitat for a plant, and as such can be used to think in terms of niches. The fundamental niche is where a plant could survive in a multidimensional space that has these parameters as axes.
Organisms seek out appropriate environments, the idea of microclimate.
And this is where it completely breaks down. Plants do not seek out. They get dispersed somewhere, and if they cannot grow there (either because it is not in their fundamental niche space or because competitors or herbivores kill them -> realized niche), they die.
So as a botanist, I will probably stay with the adaptation metaphor, thank you.
Posted by: Thanny
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October 30, 2009 4:03 AM
It's not true that genes make organisms, because genetic expression varies with environmental factors?
That's like saying range burners don't boil water, because it happens at different temperatures depending on altitude.
Or that ink doesn't stain clothing, because the result looks different on a blue shirt versus a red shirt.
Posted by: Douglas Watts | October 30, 2009 4:10 AM
Thank you, Mintman. I have a tiny tulip tree growing in my yard in Maine which i planted. The species does not grow in Maine and never has but if you plant it, it might grow for awhile. But aside from me planting one, there will never be tulip trees in Maine (they will not reproduce and live to adulthood by spread seeds up here).
The same with American Holly. It grows naturally near Cape Cod, Massachusetts and to the south but no farther north. I can actually see the line in Middleborough, Mass. on Route 28 where it stops growing naturally. Yet, if you plant one, in the right spot, the plant will grow, but the seeds will not disperse and naturally reproduce and take hold.
The same with white birch. It can be planted in southeastern Mass. but will not grow there naturally. Its true range begins in southern New Hampshire and southern Maine and only in northern Maine does it truly become a dominant tree species.
There are no "infinities" of ecological niches for a pink ladyslipper or an Atlantic white cedar. There are actually very few of them and they are highly specialized and finite.
Especially when you have trees which develop highly specialized symbiotic relationships with fungi in their root systems.
Posted by: Douglas Watts | October 30, 2009 4:23 AM
Pitcher plants did not "move" to acidic swamps just to use their unique, carnivorous, insect-catching and eating leaf structure. They developed it because acidic swamps have such low nutrient levels that supplementation of insects in the boles of leaves filled with rainwater is worth the effort to make these oddly shaped leaves. Which is why you don't see pitcher plants anywhere except acidic bogs and swamps. It's an adaptation to a very difficult environment in which to live, if you are a plant.
cf:
http://tispaquin.blogspot.com/2009/07/poquanticut-cedar-swamp-at-borderland.html
Posted by: Diane G. | October 30, 2009 4:25 AM
Mintman,
It's possible you have more of a semantic than a biological disagreement, which gets back to my distaste for semantics. I suggest that "the organism seeks out appropriate environments" is shorthand for "somehow ends up in" the environment that best suits it, be it intentionally or due to physiological or random factors...
And of course, plants "evolve" (teleological shorthand, again) dispersal mechanisms to help out the process.
And as you know there's plenty of botany that shows how plants modify their environments...
I could be wrong about Lewontin's intentions, though!
I, too, see nothing wrong with traditional adaptational language, and wonder what exactly Lewontin wants to replace it with? Organisms & environments co-evolve? Sure--but what does that gain us in understanding?
And it doesn't really seem that the Achillea example refutes the role of genes, as Thanny points out above.
Nice to hear from another plant person!
Posted by: MadScientist
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October 30, 2009 4:36 AM
That's excellent - I'm forever trying to correct people on blatantly incorrect notions such as "organisms adapt to their environment" and the degree to which genes determine what an organism will be like. I don't understand why people can't understand the "genes don't determine the organism"; Mark Twain clearly understood that difference when he wrote Puddin' Head Wilson (monozygotic twins have different fingerprints). Now I know an expert to point people to. :) It's also good to be reminded that cloning is nothing new - plants have been cloned for well over a century and for at least 50 years grafts have been used to ensure the quality of fruit borne by plants in orchards.
Posted by: Douglas Watts | October 30, 2009 4:38 AM
I suggest that "the organism seeks out appropriate environments" is shorthand for "somehow ends up in" the environment that best suits it, be it intentionally or due to physiological or random factors...
Diane G: I think your redefinition is so broad as to no longer have meaning and also ignores the clear intentionality of adaptations seen in a sundew or a pitcher plant (for example). Think about it this way. Carnivorous, insect-eating plants are only found in highly restricted, nutrient poor environments like acidic wetlands. Presumably a plant which could eat insects would be successful wherever there are insects, which is everywhere. Why aren't there carnivorous plants in all types of habitats, from fields to woods to beaches? Why only in acidic wetlands and bogs? To me this clearly points to the development of a carnivorous plant as a directed adaptation to a very specific environment where nutrients except as gathered by insects are very hard to come by. If not, we should find carnivorous plants everywhere insects are found near plants, which is not the case.
Posted by: Xenithrys
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October 30, 2009 5:24 AM
Thanny @ #7.
Yes! That's why my three children are all Homo sapiens and look (a bit) like me.
Posted by: Mintman | October 30, 2009 5:40 AM
Well, if we are going to be worried about metaphors that could lead to misunderstandings, then teleological shorthands are the most dangerous, aren't they?
Posted by: Drosera
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October 30, 2009 6:35 AM
Douglas Watts @12,
This is not the whole story, since many plants growing in nutrient-poor environments are not carnivorous (orchids and Ericaceae, for example). And I doubt that insect-eating plants would be successful everywhere. For carnivory to evolve a number of things are required:
1. The benefits of carnivory should outweigh the costs of growing traps. This is probably not the case in habitats that are not extremely nutrient-poor, because there are no obligate carnivorous plants in nutrient-rich habitats (except perhaps the West African rainforest liana Triphyophyllum).
2. The steps towards developing carnivory should improve fitness. Again, this is probably not the case in nutrient-rich environments.
3. There should be pre-adaptations that can be modified step by step into an insect-catching and digesting mechanism (for example, sticky glandular hairs initially used as a defense mechanism, or cup-like vegetative structures initially evolved to collect water).
4. The plant should not already have an efficient mechanism to obtain nutrients, for example through mycorrhiza.
In short, carnivorous plants are very nice subjects for teaching the principles of evolution, and in particular to show the pitfalls of thinking in terms of purpose.
It is also interesting to point out that carnivory probably evolved at least seven times independently, and that some carnivorous plants with very different trapping mechanisms are closely related (Pinguicula and Utricularia for example).
Posted by: Stumpy | October 30, 2009 6:48 AM
"To me this clearly points to the development of a carnivorous plant as a directed adaptation to a very specific environment where nutrients except as gathered by insects are very hard to come by. If not, we should find carnivorous plants everywhere insects are found near plants, which is not the case."
Unless the digestive system of carnivorous plants is very costly, which compared to not having to build a digestive system, almost certainly is.
By the same logic, because conifers can make a living everywhere they do and could also make it where deciduous trees do, the planet should be covered with only pines. Except where deciduous trees can make a living, they do so far more efficiently than pines and starve their thin-leaved cousins of resources.
Posted by: Aratina Cage
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October 30, 2009 7:38 AM
This:
reminded me of this:Life, for all its complexity, is delicate. As I see it, the second notion, that life constructs its niches, is negated by the first (that genes do not make organisms). The fragility of life seems essential to natural selection, and the second notion seems to give life too great a sense of stability.Posted by: jeremyn | October 30, 2009 8:01 AM
Yes, it is blatantly obviously true that genetic determinism isn't true - no reputable biologist has thought this for generations.
Of course, this is totally irrelevant when it comes to debating gene selectionism (the well-supported theoretical idea that genes are the unit of [replicator] selection, evolutionarily-speaking). One is a developmental point, the other an evolutionary one.
Posted by: windy | October 30, 2009 8:05 AM
I predict that all of the (surviving) clones produced a phenotype resembling an Achillea plant and not, for example, the phenotype of a pine tree or a potato plant. What might I be basing this prediction on?
Posted by: taranaki
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October 30, 2009 10:08 AM
#2 - Is this Nerdette of "Cthulhu Hates Chordates" fame? Did you leave your sign for PZ to hold up and wave?
Posted by: taranaki
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October 30, 2009 10:22 AM
Nerdette - meant to link to PZ's post about you.
Posted by: Antiochus Epiphanes | October 30, 2009 10:32 AM
At Mintman and Diane G: Embryophytes in da hizzy!
I think because plants are so evolutionarily labile, plant evolutionary biologists tend to be circumspect about bold statements. One of my own pet peeves is the continual finger-pointing at selection as a hypothesis of change, and the neglect of other evolutionary mechanisms. I think that this often goes hand in hand with Darwin worship (sorry, but even biologists forget that the role of natural selection in evolution was clipped somewhat during the modern synthesis). There are many traits that appear to be adaptive in extant populations, but a disticntion between adaptation (describing a trait rather than a process) and adaptation (describing a process rather than a trait) should always be kept in mind when putting forward hypotheses. The roles of drift and draft are likely important, yet underestimated because they are somehow less exciting explanations than selection. I'm kind of with Lewontin on this one.
Posted by: bcoppola
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October 30, 2009 10:42 AM
See? SEE?? Darwinism IZ a religion!!!!!
Now that that's out of the way: Being a liberal-artsy guy, I like it when scientists talk about metaphors, because I can understand them for a change. :)
Posted by: Nerdette | October 30, 2009 10:42 AM
#20 - Tis. If PZ is so adventurous, the sign is in the basement of Broadview hall - about a mile east of campus. I left it for future Scav Hunts. You never now...
Posted by: Nerdette | October 30, 2009 10:44 AM
*never know... stupid n's...
Posted by: InfuriatedSciTeacher | October 30, 2009 10:50 AM
The multi-level inheritance discussion is important here... while one can reduce (in theory at least) the idea of epigenetics to an environmental effect on the expression of genes, and thus still genetically inherited, we can't make predictions about developmental plasticity solely from looking at the genes.
Posted by: Sven DiMilo | October 30, 2009 11:03 AM
Lewontin's been saying this exact same shit for decades. Yes, there is phenotypic plasticity. Yes, it can be difficult to define "the environment" to which an organism adapts. Yes, organisms that can behave can behave in ways that buffer environmental changes.
So what? Phenotypes still depend mostly on genotypes, and organisms do adapt to various aspects of their environments, and do so genetically/evolutionarily; and what's more, both phenotypic plasticity and behavior are at least partly genetically based/evolvable, i.e. can be adaptations.
Posted by: Sven DiMilo | October 30, 2009 11:06 AM
...where, of course, by "organisms" I mostly mean populations thereof.
Posted by: David Marjanović, OM | October 30, 2009 12:32 PM
Ehem…
As explained in comment 6, an ecological niche is not a habitat. It's what a species does (realized niche) and what it can do (fundamental niche).
It follows that salmon go through several ecological niches in their lifetime, and show adaptations to all of them.
Posted by: Antiochus Epiphanes | October 30, 2009 3:36 PM
@Sven DeMilo: "Phenotypes still depend mostly on genotypes, and organisms do adapt to various aspects of their environments"
1. Phenotypes may depend in part on genotypes. This is something that can be quantified, and MUST be quantified to determine the role that selection could play in altering phenotypes. Phenotypic variance can be split into components; of these, only additive genetic variance is important in determining the ability of selection to affect phenotypic frequencies in populations. Further, it is necessary to characterize the epistatic interactions underlying phenotypic expression, to understand genotypic variance. So for the sake of actually testing hypotheses of selection, "mostly" is not precise enough.
2. Natural selection is one of many ways that allele frequencies (and hence phenotypic frequencies) in a population can change. There are lots of other mechanisms, and there is no rational reason to default to natural selection.
If Lewontin harps on these issues, it can only spur scientists to find better ways of evaluating variance components. This would be an improvement to adaptationist storytelling (which doesn't really fly much anymore, anyway)
Posted by: Thanny
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October 30, 2009 5:00 PM
Put more starkly, without genes, we'd all be big piles of goo.
Differences in gene expression based on environmental factors do not support the crazy notion that genes don't construct organisms.
Furthermore, there are no adaptationists, as criticized. No one thinks all change is adaptive, but all sane people do think that all adaptive change is a product of natural selection.
Posted by: Sven DiMilo | October 30, 2009 5:09 PM
I think "may depend in part" is an absurdly weak statement, but I have no argument with your general point.
Certainly there can be roles for both nature and nurture in any specific case, but as windy noted above, phenotypic plasticity can only operate within the limits set by genotypes.
Debatable, of course, but not really my point. Drift happens, but outside of a tightly controlled experimental situation, attributing any specific case of phenotypic variation to drift alone is probably impossible. On the other hand, the annals of comparative physiology alone prove beyond doubt that adaptation occurs, and in a few specific cases we know enough about phylogenies and environments to demonstrate it conclusively. Selection (the process, as oposed to adaptation, the result) is easy to demonstrate in field populations these days, though the genotypic response to selection is tougher (in part because of plasticity).
Posted by: Antiochus Epiphanes | October 30, 2009 5:30 PM
My statement is weak, but not absurdly so. It is imprecise, but accurate, because variance contributions will vary wildly from one population to another, even in regard to the same phenotype. Stating that phenotypic variation is mostly a result of genotypic variation is both imprecise and innaccurate.
Also:
Drift and selection act simultaneously and each contribute to changes in allele frequency. They are not competing causes. Of the two, drift is easier to falsify and in my opinion this makes for a better null.
Posted by: John Scanlon, FCD | October 31, 2009 9:11 AM
Sure they're metaphors, but the significant point is that these things don't occur by magic (calling something 'development' or 'adaptation' doesn't actually specify a mechanism) but by matter doing computation. And that is a real process that happens in parallel at all places and times, not a metaphor at all.
Hasn't Lewontin usually just been attacking a strawman with an obvious ideological agenda? Or is there really no substantive difference between what I just said about matter processing information, and 'Dialectical Biology'? I don't know, but I find him about as unreadable as Steven Rose (or Ernst Mayr, just to show I'm not an ideology-snob).
Wrote that before reading the first 33 comments. Thumbs up for Thanny #7, jeremyn #18, Sven #27.
Posted by: windy | November 1, 2009 1:21 PM
But that's a different thing from what Sven was saying. If you're asking how much phenotypes depend on genotypes in general, it's not enough to just look at within-population variation. Otherwise you come to the weird conclusion that once an adaptive mutation gets fixed in a population, it no longer counts as a genetic contribution to the phenotype.
Posted by: Dov Henis | November 5, 2009 11:43 AM
Evolution, With Compliments Of
"Breathtaking View, Offered With The Compliments Of XXX Company" - was a signboard I once saw next to a bench at an off-a-climbing-road mountain-top look-out.
Quotes from "Genetic Steps To Adaptation"
http://www.the-scientist.com/blog/display/56136/
1) "Genetic mutations -- occurring over just a few generations -- that allow bacteria to respond to environmental changes"
* No no no. Definitely not genetic mutations occurring over just a few generations that allow bacteria to respond to environmental changes. Genes expressions are modified per cultural feedback of the organism. It is culture that drives genetic changes, definitely not genetic changes that drive culture. Thus it is a Pavlovian process that drives an onset of genes', which are organisms, addiction. The addiction is NOT due to an accidental genes' mutation.
2) "We showed how evolution happens in real time"
* This time we are offered, with compliments of biologists, a view of evolution, the evolution each and every one of us sees all around us every second of our life, with the compliments of a biologist from Leiden University plus fellow scientists. How thrilling.
3) "bacteria and other organisms can switch back and forth between phenotypes to better survive in new environments", "The results thus suggest that phenotypic switching is a strategy that can readily evolve, and may capture the earliest evolutionary solutions to life in fluctuating environments"
* With sad exasperation I suggest that this is NOT A RARE, BUT A FREQUENT, demonstration of scientists observing and recording data properly yet coming to a pre-experiment-upsidedown-ideefixe factually wrong conclusion. It is not that the evolution they observe is upside-down. It is their concept of evolution that is upside-down.
Sadly suggesting,
Dov Henis
(Comments From The 22nd Century)
Posted by: Sven DiMilo | November 5, 2009 11:49 AM
Let me be the first to ask:
WTF?
Posted by: Antiochus Epiphanes | November 5, 2009 11:59 AM
@Sven--someone had to ask.
@Windy: When an allele becomes fixed in a population, genotype no longer contributes to phenotype in a meaningful way...that is, natural selection cannot happen because such a population has zero additive genotypic variance for that trait.
Posted by: PZ Myers
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November 5, 2009 12:26 PM
Apparently, in the 22nd century, the web will no longer be bounded by time.
People will also be speaking some language other than English.