Pharyngula

What? Only 50 myths?

Over at the Raving Atheist’s forum, contributors have compiled a list of 50 evolution myths. It’s actually at 51 right now—I could have told them there are a lot more than 50—but it’s entertaining. Now they just have to get cracking on 51 rebuttals to the myths. A lot of them are in the Index to Creationist Claims already.

1) Evolution gives you what you need

2) We popped out of monkeys one day

3) The theory of evolution is tied to the big bang theory

4) The theory of evolution says random chemicals mysteriously made the first cell

5) Darwin took back his theory of evolution on his death bed (that’s an urban myth created by Christians)

6) They eye accidentally formed itself somehow.

7.) That things evolve ‘magically’ without selection involved. It’s just some slow process…At least this is what I believed as a kid!8.) That evolution equals eugenics.

9.) That it has a GOAL.

10.) That it can happen to anything, even watches and pottery.

11.) That it’s a scientific conspiracy theory we believe in to battle Christianity.

12.) That evolution equals atheism.

13.) That there is an actual difference between micro and macro-evolution

14.) That it is a ‘Random’ process.

15.) That there are no transition fossils

16.) That humans evolved from the Apes that are around today.

17.) The second law of thermodynamics makes evolution impossible.

18) If evolution is true, how come there are still monkeys?

19) Evolution requires faith.

20) Survival of the fittest means organisms should go kill off weaker members of its species to make survival easier for the stronger members.

21) Physical changes that occur during the lifetime of an organism will be passed on the offspring.

22) Survival of the fittest is circular logic.

23) Only the fittest survive. (In actuality, if an organism can barely get by then it classified into the “fit” category).

24) Kent Hovind is an expert in the fields of evolution, biology, and other sciences.

25) Organisms evolve/mutate during their lifetime if a new selection pressure exerts itself.

26) Evolution caused slavery.

27) Many scientists are now casting doubt on Darwin’s theory.

28) Charles Darwin is Satan.

29) Evolution can’t exist because of irreducible complexity.

30) Evolution is JUST a theory.

31) God made evolution so he could trick as many scientists as he could into believing it, instead of him, just so he could light them on fire for all eternity. But he still loves them.

32) Man and dinosaurs existed at the same time. T-Rex used to be a vegetarian

33) ‘Darwinists’ claim that any criticism of the theory of evolution is unscientific

34) Evolution is effectively refuted by ‘the Cambrian Explosion’

35) Scientists “believe” in evolution.

36) There is great strife in the scientific community over evolution.

37) Kent Hovind is a brilliant man!

38) Evolution can’t explain love.

39) If evolution is true, why are there homosexuals?

40) There are no transitional forms: One species gives birth to another! Through magic!

41) If you believe in evolution, then that means you think it’s okay to kill, rape, and steal

42) Evolution is not testable or empirical, therefore it is not science.

43) No Darwin, then no Hitler

44) The perfect match between bees and flowers must be a designer because it can’t be evolution.Evolution has to do with survival from predators, not how well you can carry pollen.

45) Mutations are never beneficial

46) There is limits to biological change: new kinds never arise

47) Vertebrate embryos never resemble each other

48) Evolution must be wrong because gravity pulls things down right, but that clearly doesn’t happen because birds can stay up in the air.

49) Oh you evolutionists make me laugh, it was God who created the world. It says so in the bible and the bible says its true, so IT IS TRUE!!!

50) Evolution was responsible for the Columbine high school shooting

51. Evolution can never be proven because we didn’t see it occur.

By the way, #13 is not a myth. There is a recognized difference between micro- and macro-evolution. The myth creationists use is that macroevolutionary events are somehow less well supported than microevolution—they’re wrong.

Comments

  1. #1 flack
    August 21, 2006

    Seems to me that #30 is no myth either. Evolution _is_ just a theory, in the same way that Newton’s ideas about gravity and Einstein’s thoughts on relativity are just theories.

  2. #2 Larry Moran
    August 21, 2006

    PZ says,

    By the way, #13 is not a myth. There is a recognized difference between micro- and macro-evolution. The myth creationists use is that macroevolutionary events are somehow less well supported than microevolution–they’re wrong.

    I agree. Macroevolution and microevolution are decoupled in many ways so #13 is actually not a myth.
    I’ve posted a little note about this at Macroevolution.

    ————–

  3. #3 Corey Schlueter
    August 21, 2006

    The myth creationists use is that macroevolutionary events are somehow less well supported than microevolution.

    I do not understand why creationists do not recognize marcoevolution happened, yet they accept macroevolution. This tells me that they accept some part of evolution as fact.

  4. #4 Corey Schlueter
    August 21, 2006

    Whoops, that should be “yet they accept microevolution” (not marcoevolution).

  5. #5 Larry Moran
    August 21, 2006

    14.) That it is a ‘Random’ process.

    This one is also misleading. Much of evolution is effectively “random” for many meanings of the word “random.” What the author probably meant to say was that natural selection isn’t “random” but even that requires qualifications.
    For those who are interested in more information, I’ve put up a little essay on the topic at Evolution by Accident.
    —————

  6. #6 Lago
    August 21, 2006

    Micro and Macro can be seen as the same, or sharply different. It matters mostly on how one defines the two. I personally separate the two based on how I desire to define them, but in reality, no one has set up universally accepted definitions of these two concepts which do not allow for grey areas. This allows people, if they so choose, to view the two simply as different poles on a sliding scale from minor variations in size, shape, color, physiology…to speciation…and finally novel trait development that are used by people in an arbitrary manner to separate groups (For example, as reptiles from mammals).

  7. #7 TomS
    August 21, 2006

    25) Organisms evolve/mutate during their lifetime if a new selection pressure exerts itself.

    “Organisms evolve” is a myth, all by itself, and a persistent one. You don’t need to mention the rest of (25). Evolution is not about individuals.

  8. #8 flack
    August 21, 2006

    “Much of evolution is effectively ‘random’ for many meanings of the word ‘random.'”

    I’m not a scientist, so I could have this all wrong. But I struggle with the notion of randomness in this context. The mutations that occur within a species over generations have no regard for selection pressures — they would occur with or without them. I think this is what folks are thinking of when they describe the mutations as random. But random doesn’t really nail it for me as a descriptor. It implies haphazard and inconsistent. To me, these mutations look more like relentless and consistent attempts at diversification.

  9. #9 Steve LaBonne
    August 21, 2006

    flack- mutations aren’t “attempts” at anything, they’re mistakes in DNA replication or imperfect repairs of DNA damage. In other words, sh*t happens.

    Also, as you’ll find out if you read Larry’s essay (as I highly recommend you do), he is also speaking of the importance in evolution of genetic drift- a prototypical random process if ever there was one.

  10. #10 cserpent
    August 21, 2006

    PZ, could you explain what this difference is?

    There is a recognized difference between micro- and macro-evolution.

    The prefixes micro- and macro- imply a dichotomy of scale with no continuity between the two. Yet, it seems that most evolutionary biologists would agree that changes in gene frequencies in populations lead to speciation. Where does one draw the line? When two populations are sufficiently distinct to be called two species? When species have accumulated 1 million years worth of genetic differences? 10 million? Or at the other end – one generation’s change is micro- while two generations is macro-?

  11. #11 T_U_T
    August 21, 2006

    definitions of ‘microevolution’ and ‘macroevolution’, as I understand them :

    microevolution any evolution that a creacionist can not deny without perceiving himself foolishness of such denial
    macroevolution any evolution that a creacionist can deny without perceiving himself foolishness of such denial OR any evolution of homo genus.

    If there is something I got wrong, feel free to correct me here ๐Ÿ™‚

  12. #12 Tenspace
    August 21, 2006

    Wow, PZ. Thanks for the recognition. Keep checking back, I’m sure we will have more fun with that thread. With all the talk of macro vs micro, let me ask you this: Mayr’s definition of macroevolution is “evolution above the species-level.” Is there a technical difference between macroevolution and speciation?

  13. #13 flack
    August 21, 2006

    It looks like an excellent essay, very accessible to a curious non-scientist like myself. I’m going to have to go back for a more thorough read.

    This caught my eye:
    “We all know what we mean when we talk about chance events or accidents. We mean that such events are not predictable by any means at our disposal.”

    So here’s where I get hung up: we know that these mutations occur, and have done so for a very long time. Sh*t happens, as you say, and that same kind of sh*t has been happening since the begining of life on this planet (yes?). So that part of the whole system of evolution — the so-called random mutations that feed the Random Genetic Drift Larry describes in his essay — that doesn’t seem very random at all to me. If it happened only occasionally, sometimes, sometimes not, in this species but not that one, then it would look random to me. But instead it happens consistently, across all species all over the planet (I think — is that true?) So rather than being a “chance event” that is “not predictable by any means at our disposal” as Larry defines it, it seems to me that this process of diversification through genetic mutation is entirely predictable. It happens all the time and will continue to do so. The particular results of the process — what the specific mutations will be and which ones will turn out to be advantageous — may not be predictable, but as a whole, this process looks anything but random.

  14. #14 Philboid Studge
    August 21, 2006

    Thank you, PZ. Well done!

  15. #15 Larry Moran
    August 21, 2006

    cserpent asks,

    The prefixes micro- and macro- imply a dichotomy of scale with no continuity between the two. Yet, it seems that most evolutionary biologists would agree that changes in gene frequencies in populations lead to speciation. Where does one draw the line? When two populations are sufficiently distinct to be called two species? When species have accumulated 1 million years worth of genetic differences? 10 million? Or at the other end – one generation’s change is micro- while two generations is macro-?

    Imagine a primitive hominid population that spits into two distinct populations. One leads eventually to Australopithecus robustus and the other leads eventually to Homo sapiens.

    Explain, using microevolutionary concepts only, how this split occurred and why A. robustus is extinct while H. sapiens survived.

    Nobody denies that microevolution is part of macroevolutionary explanations–we just point out that they aren’t sufficient to explain the sorts of things that macroevolutionary biologists want to explain.

    You illustrate one of the problems with the sufficiency of microevolution argument. Your question focuses on the generation-by-generation changes in a lineage but ignores the important problems of explaining cladogenesis and extinction. It’s like not seeing the forest for the trees. You have to explain the pattern and not just the individual lines.
    —————

  16. #16 thwaite
    August 21, 2006

    “evolution by accident” is an accurate description of how evolution occurs. – from Moran’s essay.
    So, by analogy: is all the attention and analysis lavished on the stock markets justifiably motivated by only the stochastic processes which generate the great majority of each stock’s price (value) fluctuations?

  17. #17 dogscratcher
    August 21, 2006

    PZ,
    If possible, please do a full post on the difference between micro and macro evolution. I’m no biologist, but it seems to me that there is no difference: “changes in gene frequency” in a population are all “micro” changes, that may or may not be expressed on a “macro” scale. Isn’t it simply a matter of degree rather than difference of “kind?”

  18. #18 T_U_T
    August 21, 2006

    Explain, using microevolutionary concepts only, how this split occurred and why A. robustus is extinct while H. sapiens survived.

    Could you explain first, which concepts are microevolutionary only, and which ones are distinctly macroevolutionary ?

  19. #19 George Cauldron
    August 21, 2006

    If possible, please do a full post on the difference between micro and macro evolution.

    As a person with no biology credentials, my understanding is that the microevolution/macroevolution distinction is totally bogus, no?

  20. #20 Larry Moran
    August 21, 2006

    flack says,

    The particular results of the process — what the specific mutations will be and which ones will turn out to be advantageous — may not be predictable, but as a whole, this process looks anything but random.

    If you don’t like the word “random” then feel free to substitute any other word that conveys the essential meaning. I’ve decided to use “accident,” as in “evolution by accident,” precisely because I want to avoid semanitc quibbles about the exact meanings of “random” and “chance.”

    The point is that there’s a lot more chance and accident in evolution than most people admit. When you say that evolution isn’t random you are denying an essential, and well-documented, element of evolution at many levels.

    This is where Richard Dawkins should jump in–I know he’s reading this ….

    ————

  21. #21 Carlie
    August 21, 2006

    “Mayr’s definition of macroevolution is “evolution above the species-level.”

    Tenspace: Go into a roomful of systematists, ask what constitutes the species level, and then stand back with a body shield and a Taser for if the melee gets too close. I spend almost three lectures in my evolution class on species concepts, and I barely touch on the basics. A “species” is just a construct that people use to define a particular group of organisms. They can be based on relationships, characteristics, biochemistry, all kinds of things. One of the limitations of Mayr is that he’s an ornithologist, and used to creatures that tend to keep themselves separate, and tends to fixate on them. Try using his definition of species on grasses. Or bacteria. Even among people who define species in the same way, there’s always argument on how to divide genera and species, and when to collapse and when to split, and where this weirdo variant fits in, and so on. A species is not a magical entity with a wall around it (although most Creationists seem to think that it is). That definition of macroevolution is absurd, because there’s no way to define the “species level” in the first place. That’s basically my beef against the distinction between micro and macro in the first place – everyone would draw the line in a different spot.

  22. #22 Steve LaBonne
    August 21, 2006

    flack, what I think you’re not getting is that mutation rates are typically VERY small. We may, for all we know, be looking in many organisms at the minimum attainable rate of errors- there has undoubtedly been pretty intense selection in that direction, as the elaboration of DNA repair systems will attest. In that view genetic change of populations over time is simply an inevitable, biologically “unintended” (so to speak) consequence of the laws of chemistry and physics, so your “predictability” really is an empty concept. The alternative is the various group-selectionist arguments for “evolution of evolvability”, which seem dodgy to me though they certainly have been defended by people far smarter than I am.

  23. #23 Blader
    August 21, 2006

    I always assumed the micro vs macro false dichotomy is one springing from the the myth that something must be observed to be factual.

    For example, creationists can sometimes find it difficult to deny the evolution of bacterial resistance, and so the invention of microevolution helps them over that particular hurdle.

  24. #24 Gregory
    August 21, 2006

    I can’t believe they forgot PYGMIES AND DWARVES!

  25. #25 flack
    August 21, 2006

    Larry – thanks for responding. And please don’t mistake my curiosity for argumentativeness. If I’m quibbling it’s only an attempt to fill in gaps in my own non-expert understanding.

    I suppose you’re right that it really comes down to a semantic issue of what we mean by random. If we look at the level of individual genetic mutations, then yes, random, accidental, chance, these seem appropriate.

    But to look at the process as a whole, where we see all these species cranking out a steady flow of mutations, generation after generation, it starts to look less random and more like some kind of evolutionary constant. At that level, certainly there is an element of chance in play, but “random” falls short of describing the bigger picture. Sure there is a factor of randomness, even a very important factor as you write in your essay. But does that then mean that the whole process of evolution should be considered random?

  26. #26 Steve LaBonne
    August 21, 2006

    Again, flack, nothing is being “cranked out”; mutations are simply unavoidable (and to all intents and purposes random) noise in the transmission of genetic information. It’s not physically possible for organisms to stop “cranking out” mutations.

  27. #27 JakeB
    August 21, 2006

    Gregory–

    Sorry to nitpick, but it’s “PYGMIES + DWARVES!”

  28. #28 JS
    August 21, 2006

    […] the so-called random mutations that feed the Random Genetic Drift Larry describes in his essay — that doesn’t seem very random at all to me. If it happened only occasionally, sometimes, sometimes not, in this species but not that one, then it would look random to me. But instead it happens consistently, across all species all over the planet (I think — is that true?) So rather than being a “chance event” that is “not predictable by any means at our disposal” as Larry defines it, it seems to me that this process of diversification through genetic mutation is entirely predictable.

    Well, the concept ‘random’ is a pretty tricky one – and your confusion seems to be less about the biological specifics than randomness in general, so I’ll take a shot at an explaination.

    The answer to the question ‘is X random?’ depends entirely on scale. (Almost) all random phenomena behave at least quasi-deterministically if you look at a large enough population.

    Take, for example, a rigid container full of gas, with a moveable piston in one end.

    Such a container contains (no pun intended) something to the order of 10^23 molecules, if the pressure in the container is in the same region as the atmospheric pressure. We cannot – literally cannot, as in ‘can be shown to be impossible even in principle’ provide a deterministic description of the motion of a single molecule around the box. This motion is random in all reasonable interpretation of the word.

    This does not prevent us, however, from predicting which way the movable piston will go if the pressure inside the container is different from the pressure on the outside. This motion is not random in any reasonable sense of the term.

    So, is the motion of the gas random? Well, if you look at the molecular level, it is random. If you look at the macroscopic level, however, it is most definitely deterministic.

    The same kind of reasoning can be applied to the example of mutation.

    On the atomic level, mutation is indeed random. Taking any given piece of the reproduction process, it will be impossible to say whether or not it will contain an error or fail to rectify a previously introduced error.

    (Sure, for every known species there is a non-zero chance of a mutation in any cell during any given division, but that does not, in any reasonable sense of the term, make the process non-random.)

    But on the species level, we can say conclusively that mutations will occur. We can even come up with some ballpark figures for the frequency of such mutations. But this is simply an issue of dealing with sufficiently large numbers.

    There are 6.5*10^9 humans on this planet. There are manyfold more humans that have died already (probably by a couple of orders of magnitude, depending on your preferred definition of ‘human’).

    If you take 6.5*10^9 random events, you get something that’s at least quasi-deterministic most of the time, just as you get something deterministic from taking 10^23 random molecular motions in a container.

    OK, there’s quite some way from 6.5*10^9 to 10^23. But consider that each human has a number of bacteria in his gut that’s about comparable to the total number of humans in the world – and that these critters duplicate and die and duplicate every day, and you get a truely staggering number of birth events over the lifetime of a human.

    Easily above the 10^23 random motions it took to make a non-random, macroscale motion in the gas container.

    So, is mutation random? When talkning about a single individual, it most certainly is. When talking about an entire population, over an evolutionary timeline, it is more like quasi-random.

    Of course, selection pressures often behave as chaotic systems, but that’s a whole ‘nother kettle of fish, and this post is too long already.

    – JS

  29. #29 Lago
    August 21, 2006

    Carlie said:
    “That definition of macroevolution is absurd, because there’s no way to define the “species level” in the first place. That’s basically my beef against the distinction between micro and macro in the first place – everyone would draw the line in a different spot.”

    Yes, my point exactly. As I do use the terms as seperate myself, I do so for my own arbitrary reasons that are far from universal.

    I choose to draw the line based on what most creationists would view as “Kind-to-Kind”. When I debate a creationist, it is always best to find where they define the “kind” line, and then debate them at this point as to not waste time.

    I find most creationists are rather simple-minded (surprised?) and “Kind” is usually defined as, Cat, dog, horse, as well as Mammal, reptile, bird ect…

    This means “Macro” is what ever separates these groups, as oppossed to “Micro” which is whatever is within these groups…

  30. #30 Steve LaBonne
    August 21, 2006

    By the way, just for old times’ sake, I’ll opine that Larry and Dawkins don’t fundamentally disagree but are simply talking at cross purposes by way of their different rhetorical emphases. Dawkins does not deny the random element in evolution; if he did he’d have, for example, to reject the use of molecular clocks. Larry obviously does not deny that populations become better adapted to their environment via selection. Dawkins, understandably in his books addressed to non-scientists, feels the need to (over)emphasize the perfection of adaptation to counter creationist propaganda which aims to deny the existence of any non-random element in evolution, thereby rendering the appearance of design inexplicable execept by invoking Big Daddy in the sky. Larry, equally understandably (and especially because his professional focus is molecular evolution, where drift is highly visible), wants to promote scientific accuracy by countering the mistaken impression that Dawkins’s readers may well receive that there is no significant non-random component in evolution (beyond the occurrence of mutations). I can see where both are coming from, and the “war” seems a bit overblown to me.

  31. #31 Steve LaBonne
    August 21, 2006

    That should be “no significant random component”, not “non-random”. Sorry.

  32. #32 cserpent
    August 21, 2006

    Larry Moran wrote:

    It’s like not seeing the forest for the trees. You have to explain the pattern and not just the individual lines.

    This defines macroevolution as description of patterns and microevolution as mechanistic explanation. In that case, I would say the distinction isn’t particularly important. That is, macroevolutionary explanations aren’t really explanations so much as descriptions.

    Microevolutionary explanations (mutation, natural selection, sexual selection, genetic drift) seem to work pretty well as mechanisms explaining population-level changes that, in allopatry and over long timespans lead to cladogenesis. I don’t think that other explanations are necessary.

    I suppose one could argue that allopatry and long time spans add a context lacking from those explanations. In that case I would say that microevolution so defined is incomplete and that macroevolution completes that definition, rendering both terms unnecessary and easily handled by just one – evolution. (Before someone chimes in about sympatric speciation: yeah I know it requires different explanations from allopatric speciation but I don’t think it has any relevance to the macro-/micro- question.)

    Also, a pet peeve – extinction is not evolution nor even a part of it. It is a separate phenomenon.

  33. #33 thwaite
    August 21, 2006

    Thanks Steve, I think you’ve stated very well the minor ‘balance of forces’ differences between adaptationists and randomists (not a word – until now).
    Is evolution adaptive or accidental? The answer is: “yes”.

  34. #34 Kagehi
    August 21, 2006

    Lets put it this way, Flack.. Statistical predictability isn’t the same as “actual” predictability. While its unlikely, its not impossible, for the single member of a species to suffer “no” noticable mutations in some arbitrary period of time. Its also possible, even without some external condition causing it, for a member of a species to have double the normal mutations. On average we can say that X number happen, sans external forces like radiation, in a Y period of time. The individual events are not predictable, even if, like a coin toss, the average, over time, is X at Y rate. This is why its a semantic issue. It “is” random, but it is also, to some extent, “predictable”, just not in any sense that makes one bit of difference to the guy trying to guess when, how or what the mutation is likely to be.

    Of course, some regions of DNA are more susceptible to others, to you can bet on which one “might” change, for much the same reason that someone was able to build a device to predict Roulette. If the odds of certain results can be skewed, but you know enough about the physics, you can predict which segment of three slots the ball will land in. With DNA, if you know which regions are prone to mutation, you can guess which “region” might show a change. You could also be dead wrong, just as the Roulette predictor failed because it couldn’t account for the ball hitting one of the raised diamonds on the outer edge, if the ball hit it.

    There are serious problems trying to use “random” *or* “predictable” when talking about mutation. The meaning of them is entirely contextual, dependent on what scale or time frame you refer to and have vastly different meanings, depending one what scale and time frame you are referencing. But in no case does the former mean, “100% impossible to predict”, or in the later case, “100% certain.” It would be like me predicting not just how many cars will pass by my house today (and not being allowed to cheat by predicting them individually), but the precise color each of them will be and what order they arrive. Knowing what cars my neighbors drive and their work schedules would only net me “maybe” 70%, but only because I knew what “usually” passed by my house. If I was living next to a freeway, that would get a whole heck of a lot less certain. lol

  35. #35 flack
    August 21, 2006

    Thanks JS — your molecules/piston metaphor seems very apt. Looked at from a planetary scale, the whole process tends to appear more deterministic. Zoom in to the level of individual organisms, or molecules, and the randomness is more apparent.

    Steve — Evolution of evolvability, huh? I’m going to have to ponder that one for a while. The notion of a “minimum attainable rate of errors” is fascinating though. It conjures up an image of two competing forces at work: on one hand, the greater the diversity of mutations a species produces, the better the odds that one of those mutations will prove advantageous. On the other hand, too high a rate of mutation could be a problem for the species’ survival. I guess it’s not surprizing to hear that the equilibrium lies somewhere near the “minimum attainable rate of errors”.

    Anyway, my grasp of all this is pretty basic, and probably a little exasperating to the specialists in the house. Thanks for some enlightening Monday conversation.

  36. #36 Edward Braun
    August 21, 2006

    Nobody denies that microevolution is part of macroevolutionary explanations–we just point out that they aren’t sufficient to explain the sorts of things that macroevolutionary biologists want to explain.

    I would have to take cserpent’s side on this one – although I would stress that there are respectable opinions on both sides of this genuine debate in evolutionary biology. In fact, the most recent issue of Science that crossed my desk (which I have regrettably not had time to read) had a comment on this topic by Jerry Coyne in the form of a reply to Davidson and Erwin, Science 311, 796 (2006). Davidson and Erwin took a position more similar to Larry Moran’s.

    The big question to me is whether something fundamentally different has to change to generate a “macroevolutionary” change. The big point is that I think it is perfectly respectable to take either opinion at this point in time.

    Explain, using microevolutionary concepts only, how this split occurred and why A. robustus is extinct while H. sapiens survived.

    I think this is a bit unfair – you have to admit that the question is moving toward the Hovindesque “if you can’t explain the whole universe using your hypothesis it must be wrong!” We may never be able to explain all of the details of A. robustus extinction and H. sapiens survival. But it may be possible to establish some pathways of that type. I’m not sure how many examples we would have to find to push the notion that microevolution can explain macroevolution into the “most plausible hypothesis” category.

    My favorite example of a charater that would appear “macroevolutionary” in nature that potentially could be explained through microevolutionary concepts is oviparity/viviparity. Many squamates lay eggs that are about halfway through development – earlier laying reinforces oviparity, longer retention leads to viviparity. It is not unreasonable to expect the period of egg retention in the female to be heritable, and mutations would be expected to alter it. On the extreme, failure to develop a shell coupled with transport of gasses and nutrients across the chorioallantoic membrane would yield a placenta.

    Within the squamates, all modes of reproduction are evident, as are many intermediates. So something that would seem highly discontinuous in mammals (ovoviviparity with a yolky placenta in marsupials vs a complex placenta in eutherians) can be seen as continuous in another group of organisms.

    I hope Larry doesn’t take umbrage at the statement about his question – I think this debate is interesting and about a much more “real” issue than anything out of the creationist/ID camp. Some of it is philosophical – for example, would a change in ASPM that leads to a large brain size increase be within the realm of microevolution? What about a regulatory gene like teosinte branched in maize? I would say that they are, but I suppose there are ways in which they could be conceptually separated from standard microevolution. It is too bad that folks like PZ and others have to fight the good fight against the creationist/ID folk – talking about the genuinely open aspects of evolutionary theory would be more fun.

  37. #37 Larry Moran
    August 21, 2006

    Steve LaBonne says,

    I can see where both are coming from, and the “war” seems a bit overblown to me.

    I agree. I don’t understand why some evolutionists make such a big deal about evolution being non-random when it’s clearly untrue. Perhaps it’s because these same evolutionists want you to think that organisms look “designed” instead of a mixture of sloppiness, maladaptiveness, Rube Goldberg construction, accident, and “design.”

    By harping on the (false) fact that organisms are designed they play right into the hands of the Intelligent Design Creationists. We need more emphasis on the fact that much of evolution doesn’t look designed at all.
    —————-

  38. #38 Larry Moran
    August 21, 2006

    flack asks,

    Sure there is a factor of randomness, even a very important factor as you write in your essay. But does that then mean that the whole process of evolution should be considered random?

    No, not all of evolution is accidental or random. Natural selection is a non-random process although it’s effect is often exaggerated. How many people know that there’s an important stochastic component to natural selection? Most beneficial alleles are lost before they ever become fixed in the populations.
    The other point about natural selection that’s often ignored is how the direction is determined not only by the accidental fixation of certain alleles but also by whether the mutations ever arose in the first place. This is why modern mutationism is much more important than most people realize.
    Here’s one of my favorite quotes from Doulgas Futuyma,

    … random processes are involved in the evolutionary process. For example, the origin of new mutations: a lot of evolution is dependent on particular mutational changes in genes that were very, very rare or unlikely, but that just happened at the right time, in the right species, in the right environment, but it need not happen that way. So, there’s this unpredictability.

    ————-

  39. #39 Steve LaBonne
    August 21, 2006

    By harping on the (false) fact that organisms are designed they play right into the hands of the Intelligent Design Creationists. We need more emphasis on the fact that much of evolution doesn’t look designed at all.

    I agree with that, since the “sloppiness” is one of the things that makes ID obviously untenable. However, it would also be idle to deny that under some regimes of very strong selection pressure- often involving arms races- evolution can come up with very good designs, and demonstrably has done so. I don’t see the need for extreme one-sided statements on either side of this question.

  40. #40 Larry Moran
    August 21, 2006

    Edward Braun wrote,

    I think this is a bit unfair – you have to admit that the question is moving toward the Hovindesque “if you can’t explain the whole universe using your hypothesis it must be wrong!” We may never be able to explain all of the details of A. robustus extinction and H. sapiens survival. But it may be possible to establish some pathways of that type. I’m not sure how many examples we would have to find to push the notion that microevolution can explain macroevolution into the “most plausible hypothesis” category.

    I think you missed the point. In order to explain the formation of new populations and the death of old ones you have to go beyond population genetics. You need to look at various mechanisms of speciation and extinction and you need to consider the environment and what was going on when the event occurred. It’s not something that you can just casually dismiss as “microevolution.”
    That’s what people need to understand about macroevolution. It’s the field of study that deals with common descent and the unique history of life. You can pick out any known trait and say that a mutation occurred and the allele became fixed in population X. But that’s not sufficient for macroevolutionary biologists. They also want to know why that mutation occurred and not some other. They want to know why it became fixed when it did and not five million years earlier. They want to know why that particular species was affected and not others. None of these questions can be answered by appealing only to population genetics.
    There are dozens of interesting questions that have been used to illustrate the importance of macroevolutionary biology. One of my favorites is why there were no large placental mammals in Australia. Do you think this question can be answered by population geneticists? How about a population genetics explanation of mass extinctions or the origin of mitochondria? Is that possible?
    Of course it’s not. Your explanations will involve microevolution at some point – how could they not? – but it won’t be sufficient. You’ll also have to mention plate tectonics, asteroid impacts, and endosymbiosis, no?
    And we haven’t even begun to talk about species sorting … ๐Ÿ™‚

    ——————-

  41. #41 cserpent
    August 21, 2006

    I agree. Macroevolution and microevolution are decoupled in many ways so #13 is actually not a myth.

    The use of the word decoupled here puzzles me.

    Your explanations will involve microevolution at some point – how could they not? – but it won’t be sufficient. You’ll also have to mention plate tectonics, asteroid impacts, and endosymbiosis, no?

    If microevolutionary explanations (NS, SS, GD) are part of macroevolutionary explanations, how are the two decoupled? If they aren’t, then what is a macroevolutionary explanation and what does it explain?

    I don’t disagree that to explain the grand diversity of life, one has to invoke the enormity of geological time and geological events on vast scales, including catastrophic ones. But evolution occurs by little steps. Those steps may be really fast or very slow depending upon mutation rates, generation times, population sizes, and selective regimes, and there are occassional, but very rare, big jumps (whole genome duplication anyone?), but even whole genome duplication is just one big mutation that is immediately subject to selection and drift – the realm of microevolution. The prefixes macro- and micro- are unnecessary. It is all one process of changes in the heritable characteristics within and among populations of living things across generations leading to a branching pattern of ancestor-descendant relationships. One word, evolution, encompasses those changes, from the simple generation to generation shift in gene frequencies to the substantial mega-generational differences between phyla. I don’t think one can separate the large timescale patterns from the small timescale processes. Where do you draw the line?

  42. #42 cserpent
    August 21, 2006

    Explain, using microevolutionary concepts only, how this split occurred and why A. robustus is extinct while H. sapiens survived.

    I’m not sure what you were asking here. The AustralopithecusHomo split may be explained by standard evolutionary mechanisms (NS, SS, GD) and allopatry or one of the sympatric speciation hypotheses if it occured in sympatry. Because the most recent A.r. fossil predates the earliest H.s. fossil by over 1 million years, the survival of H.s. is an entirely separate phenomenon from the extinction of A.r.. They require two separate explanations.

    But how about a much more dramatic example, such as the diapsid-synapsid split and subsequent radiations? The fossil record provided a beautiful series of transitional forms for the evolution of synapsids from a common ancestor shared with diapsids and similar transitional forms for modern diapsids. Which part is macroevolution – the earliest detectable split between the clades or every branch point along the way in each clade? All of the above? Or would you argue that the diapsid synapsid differences don’t represent macroevolutionary differences? That would be a hard argument to make while simultaneously claiming that the AustralopithecusHomo split represented macroevolution. This why I see the macro-/micro- dichotomy as a false one. It is simply evolution.

  43. #43 Rhampton
    August 21, 2006

    ‘Evolution’ Study Implies U.S. Science Education Lagging Behind Europe — But Creationist Ken Ham Says Opposite Is True
    AgapePress, August 21, 2006

    …A researcher from Michigan State University studied beliefs about evolution in 34 countries, including the United States. The study found that in most European countries, at least 80% of adults believe in evolution. However, in the U.S. only about 40% were whole-hearted believers in Darwin’s theory — and 39% called it “absolutely false.”

    …The team conducting the study indicates that overall, this is a bad sign for American science education, suggesting it indicates current science instruction is not “effective.” But Ken Ham of Answers in Genesis sees it differently. Ham says it is really a sign of good things in the U.S.
    “[Americans are] actually ahead of the curve because they’re really taking real observational science into account and understanding that the science of genetics does not confirm that man evolved from ape-like creatures,” explains the Christian apologist.

    I think Mr. Ham has confused genetics with genesis. Afterall, it’s only off by a few letters — not much of a mutation.

  44. #44 Larry Moran
    August 21, 2006

    cserpent says,

    I’m not sure what you were asking here. The Australopithecus-Homo split may be explained by standard evolutionary mechanisms (NS, SS, GD) and allopatry or one of the sympatric speciation hypotheses if it occured in sympatry.

    Microevolution is evolution within a population (i.e., change in the frequency of alleles). In order to explain cladogenesis you need to add something else to describe how the two nascent populations became physically separated and how they became genetically isolated.

    Because the most recent A.r. fossil predates the earliest H.s. fossil by over 1 million years, the survival of H.s. is an entirely separate phenomenon from the extinction of A.r.. They require two separate explanations.

    Did the extinction of one species have anything to do with the survival of the other? If so, that would be one example of a higher level phenomenon that can’t be explained by the changes of allele frequency within a population. Even if the extinction and survival were completely independent, the extinction of one hominid lineage is an interesting historical event that calls out for an explanation. That explanation isn’t likely to be completely covered by standard microevolution theory alone.
    ————-

  45. #45 Larry Moran
    August 21, 2006

    Steve LaBonne says,

    I agree with that, since the “sloppiness” is one of the things that makes ID obviously untenable. However, it would also be idle to deny that under some regimes of very strong selection pressure- often involving arms races- evolution can come up with very good designs, and demonstrably has done so. I don’t see the need for extreme one-sided statements on either side of this question.

    It’s clear that something needs to be done. All you have to do is look at the comments posted above to see the extent of the misinformation that’s been spread by Dawkins and his fellow ultra-Darwinians.
    In my opinion, the best way to counter the extreme one-sideness of their books and articles is to present a strong case for the other point of view. That may require a few extreme statements in order to get everyone’s attention. I realize that for people like you that’s not necessary.
    ———————-

  46. #46 Larry Moran
    August 21, 2006

    cserpent says,

    The use of the word decoupled here puzzles me.

    It’s the standard terminology. Don’t try to parse it any more than you have to. It simply means that microevolution is not sufficient to explain all macroevolutionary phenomena.
    ————

  47. #47 Carlie
    August 21, 2006

    “Microevolution is evolution within a population (i.e., change in the frequency of alleles). In order to explain cladogenesis you need to add something else to describe how the two nascent populations became physically separated and how they became genetically isolated.”

    But why should they be separated? I consider evolution to encompass all of that – change in allele frequencies, vicariance events, hybrid swarms, introgression, extinctions, it’s all part and parcel of the same story, all related to how populations change. Claiming that micro and macro are different things entirely creates a nasty semantic problem that something is radically different about the way macroevolution works, and plays right into the hands of Creationists. Just because some people have decided to narrowly focus on the allele frequency part doesn’t mean they should claim a “different” type of evolution than the people who look at how that interacts with other events on a large time scale. It’s like claiming that being a saucier is fundamentally different than being a line cook. The main difference is that one does specifics while the other coordinates several areas at once, but they both need to know what the other is doing, they use mostly the same tools and techniques, and the same product comes out at the end.

  48. #48 Edward Braun
    August 21, 2006

    One of my favorites is why there were no large placental mammals in Australia. Do you think this question can be answered by population geneticists? How about a population genetics explanation of mass extinctions or the origin of mitochondria? Is that possible?

    Larry – I did misunderstand your point, although I would argue that the distinction you are making is still somewhat artificial. Asked in the way you have stated above, the answer to the question regarding the basis for the absence of large placental mammals in Australia cannot be answered using population genetics alone.

    However, the problem here is separating the idiographic aspects of evolutionary theory from the nomothetic aspects. I would argue that population genetics and mutation are the nomothetic aspects – they can be applied in a unified manner. The idiographic aspects are certainly important, but I would argue that all evolution is ultimately the embedding of universal principles of mutagenesis and population genetics in a set of unique environmental conditions.

    In the case of Australia, it is the timing of the breakup of Gondwana combined with the fact that mammals neither fly (with the obvious exception of bats) nor raft successfully across bodies of water. So I agree – understanding both the set of unique individual events and aspects of natural history (vicariance events, physiological limits to dispersal, etc.) are critically important.

    Although important at the deep-level in phylogeny, the unique events can also establish subspecific differences while subsequent changes can reverse the separation of populations. A major component of phylogeography is understanding the impact of these historical events upon gene frequencies – so I would argue that the sharp distinction you are drawing is more reflective of fields of study than of biology.

    However, the debate in the literature has largely focused on the question of whether there are aspects of macroevolution that are fundamentally distinct from those that characterize microevolution. I would say “no”, although I do not count the simple fact that microevolutionary processes are embedded in a larger “parameter space” that reflects the physical environment and species interactions as a reason to assert that there is something “beyond” microevolution. I would argue that the situation is comparable to populations in a genetic algorithm with an enormous and complex parameter space (with multiple and shifting optima) – it should not be surprising that populations can’t get anywhere in parameter space (e.g., that placental mammals can’t cross to isolated land masses).

    Whew.. I would add that the origin of mitochondria can be explained in microevolutionary terms. If a consortium of microbes (e.g., Bill Martin’s hydrogen hypothesis or the related syntrophic hypothesis of Moiera) has an advantage of the individual species both members of would experience selection to maintain the consortium. If genetic exchange between the species of microbe was neutral (or advantageous) it could be fixed, despite the fact that it could render the individual species dependent upon the consortium. Once the consortium transitions to a genuine endosymbiotic situation there are well characterized reasons for gene transfer to the nucleus.

    This is not to say that there aren’t mysteries associated with eukaryotic origins – there certainly are. But I don’t think there is anything for which it is obviously impossible to explain in microevolutionary terms.

  49. #49 Pete K
    August 21, 2006

    The micro/macro distinction only works if one believes in biblical “kinds”, which are essentialist illusions. As someone else once said, believing in microevolution and not macroevolution is like believing in inches and not in miles.

  50. #50 G. Tingey
    August 22, 2006

    “Species” – an organism that can breed with its’ own memebers, but not others…..

    BUT, as Dawlins, and others have pointed out, this definition, whilst generally useful, falls down sometiomes.
    There ia/are the gulls, which live around the N. palearctic region….
    Here in England we have the lesser black-backe gull – which can cross-breed with the Siberian lesser bb gull – which can breed with the Heuglins gull – which can breed with the Birula’s gull – which can breed with the Vega gull (BTW we’ve been goin round the Arctic Ocean in ab Easterly direction, and are now at the Bering strait – which can breed with the American Herring gull – which can breed with the (European) Herring gull – which is completely different from, and genetically incompatible with the lesser blackback …

    Dawkins also gives an example in “The Ancestors’ Tale” of Salamnders in the USA

  51. #51 Ichthyic
    August 22, 2006

    I’d love to see PZ further explain his initial comment rejecting the “myth” of macro vs. micro evolution, as from my viewpoint, I tend to agree with Carlie.

    All of us in the zoo. dept. at UC Berkeley never found reason to make the distinction, and NOTHING even in the itarweb has a definitive reason to make the distinction.

    both “macro” AND “micro” evolution have refered to chaning allele frequencies within a population, depending on who published a given paper. However, they do essentially refer to the same thing.

    I’ve only ever seen the term used by any biologist to temporarily make a distinction for arguments sake, but I’ve personally never seen a real distinction made in the literature.

    Aside from the creobot usage, that is, which is of course of their own design.

    It’s definetly worthwhile to hash this out, since, as I mentioned, there isn’t really any definitive authority on the subject.

    which of course bring up an obvious question:

    what would one accept as an authority on the validity of seperating the terms from the more parsimonius “evolution” by itself?

    Would any recent well accepted and used college level text on evolution be authoritative to most here?

    My version of Futuyma is pretty old at this point. Could somebody check and see what a new version of Futuyma has to say on this issue?

    if it says nothing, I’d say that’s a definitive answer by itself.

  52. #52 windy
    August 22, 2006

    I think you missed the point. In order to explain the formation of new populations and the death of old ones you have to go beyond population genetics. You need to look at various mechanisms of speciation and extinction and you need to consider the environment and what was going on when the event occurred.

    The recent burst of evolution in beak size in a Galapagos finch would be microevolution, I guess? But we can’t explain that solely with population genetics either, we have to include the change in environment and the competition with another species.

    That’s what people need to understand about macroevolution. It’s the field of study that deals with common descent and the unique history of life. You can pick out any known trait and say that a mutation occurred and the allele became fixed in population X. But that’s not sufficient for macroevolutionary biologists. They also want to know why that mutation occurred and not some other. They want to know why it became fixed when it did and not five million years earlier.

    And people (like me) studying microevolutionary events want to know those things, too. Or whatever the equivalent questions are for their system.

  53. #53 thwaite
    August 22, 2006

    Tingey,
    “Ring species” like your UK gulls are a pertinent dataset for micro/macro-evolution. The gull data have turned out to be even more complex so their status as a ring species is disputed – see the Liebers citation provided by the wikipedia on ring species. But Wake’s salamander study and Irwin’s greenish warblers are canonical, and Irwin’s site has a .pdf of his 2001 Genetica article discussing the micro/macroevolution issues explicitly from his perspective.

  54. #54 Edward Braun
    August 22, 2006

    The micro/macro distinction only works if one believes in biblical “kinds”, which are essentialist illusions. As someone else once said, believing in microevolution and not macroevolution is like believing in inches and not in miles.

    And people (like me) studying microevolutionary events want to know those things, too. Or whatever the equivalent questions are for their system.

    windy and Pete – I obviously agree with you regarding the big picture: macroevolution does not involve any fundamentally distinct processes from microevolution.

    But I think there is a way to reconcile this position with the position advanced by Larry. The analogy I would use is chess. There is a limited set of moves that are straightforward to learn. So, if you wanted to study chess at a “micro” level all you might need to understand is the simple set of rules. But understanding a whole game would require understanding more than the rules – you would need to know the history of how that specific game unfolded.

    When does understanding the history of a specific game become vital to understanding what is going on? I suppose it would depend on exactly what you wish to learn and what is going on.

    I would argue that studying microevolution allows the use of certain simplifying models. For example, you don’t need to know when New Zealand separated from Antarctica to study the distribution of genotypes in a North American bird species. But when do you need to start understanding the idiosyncratic historical details of the environment? There is no clean answer – you might have to consider Plio-Pleistocene climatic fluctuations to understand the present day distribution of genotypes in that North American bird species.

    The point being that for certain questions focusing only on allele frequencies is sufficient, and those questions tend to involve a relatively shallow history. But that is – in my mind – simply a question of what we need to know to study a problem. The idiosyncratic historical details always matter – but we sometimes look at questions where those idiosyncratic details do not contribute significantly to variation in the character being measured.

    I would argue that everything I described is consistent with macroevolution being the accumulation microevolutionary changes (in the context of all of the detailed issues discussed). The danger in my mind of saying that macroevolution cannot be explained by microevolution is that it may imply that something we haven’t seen yet (e.g., the hand of the designer) is needed to allow evolution to proceed past a cetain point. I don’t think any of us believe that! (well, the trolls don’t, but this discussion probably isn’t interesting for trolls)

  55. #55 cserpent
    August 22, 2006

    Okay, since someone asked, I perused some evolution textbooks for definitions of micro- and macroevolution. Unfortunately, I’ve misplaced my copy of the most recent Futyuma, so my sources are older but all were essentially the same: Microevolution refers to changes in gene frequencies or heritable traits within populations and species, while macroevolution represents changes among populations or species that may lead to classification into higher-level taxa.

  56. #56 cserpent
    August 22, 2006

    In order to explain the formation of new populations and the death of old ones you have to go beyond population genetics.

    I agree that you have to go beyond population genetics to explain the origin of new populations from older ones, and to explain the extinction of populations. But I would add that characterizing microevolution as just population genetics is a strawman argument. Population genetics is a set of tools that can be used to infer evolution, but shouldn’t be confused with the evolutionary processes it infers.

    You need to look at various mechanisms of speciation and extinction and you need to consider the environment and what was going on when the event occurred.

    Speciation usually (polyploidy being an obvious exception) is not a singular event. It occurs as many small events over time and space. Natural selection and allopatry together can explain some, perhaps most speciation events. Higher order diversification is just a continuation of the lower order events across a broader sample. Just because large numbers of species are affected by large-scale events doesn’t mean that you can’t reduce the picture to individual populations consisting of individual organisms coping with local consequences of those global events.

  57. #57 thwaite
    August 22, 2006

    Whoops, my bad: Irwin doesn’t discuss micro/macroevolution as such, only microevolution and speciation. Though from his perspective of a few years studying subspeciation, full speciation may look pretty macro…

  58. #58 Steve LaBonne
    August 22, 2006

    But when do you need to start understanding the idiosyncratic historical details of the environment?

    Seems to me that if selection is operating at all in a population, you need to know a lot about the environment it inhabits even to understand the most “microevolutionary” incremental changes in allele frequencies in that population. Thus, the argument that “macroevolution” is something distinct because you need “more than population genetics” to understand it doesn’t seem to work, since you always need more than population genetics to study any evolutionary trend be it ever so “micro”, except maybe those that are pure drift (which admittedly may be true of a lot of such trends but decidely not all.)

    I would like to see Larry address this. I think it is now pretty well established that his first attempt to draw a fundamental conceptual distinction between micro- and macroevolution didn’t fly. Can he do better if he has another crack at it?

  59. #59 Pete K
    August 22, 2006

    Yes and every chess game is unique, just like every biosphere’s evolutionary history must be unique. As chess can can be played with strategically, we can ask whether there are discernable “strategies” in macroevolution, whereby evolution exploits possibilities in ever more interesting ways (e.g. the so-called major macroevoltionary transitions such as eusociality, multicellularity, intelligence, impetus towards overall increased complexity)?

  60. #60 Larry Moran
    August 22, 2006

    Steve LaBonne says,

    I think it is now pretty well established that his first attempt to draw a fundamental conceptual distinction between micro- and macroevolution didn’t fly. Can he do better if he has another crack at it?

    I’m sorry that my little essay didn’t do a very good job of summarizing the opinions of many evolutionary biologists. However, I did include lots of references so you can read the primary works if you want.
    I’m not going to take another crack at it. I’m happy to let the following scientists have their turn …
    Francisco J. Ayala
    R.I. Carrol
    Niles Eldredge
    Douglas H. Erwin
    Eugenie C. Scott
    George C. Williams
    Steven M. Stanley
    Stephen J. Gould
    Philip Kitcher
    Ernst Mayr
    Jeffrey S. Levinton
    Mark Ridley
    Bruce S. Lieberman
    Elisabeth S. Vrba

    If I had to recommend just one book it would be “The Structure of Evolutionary Theory” by Stephen Jay Gould. Perhaps you could re-open this thread when you have read the papers and books by the experts who want to decouple macroevolution and microevolution? I’ll be happy to discuss their views when you’re done.
    It looks like most people aren’t even aware of the fact that there’s a controversy. That’s quite sad, actually.
    ————-

  61. #61 cserpent
    August 22, 2006

    Pete K wrote:

    e.g. the so-called major macroevoltionary transitions… impetus towards overall increased complexity

    Except that this is an artifact of the starting point. The earliest lifeforms were extremely simple, so those populatons had no where to go but to evolve greater complexity. Yet there are endless examples of simple organisms derived from more complex ones, nearly all parasites for example, as well as solitary hymenoptera derived from social ancestors.

    The success of the neocon movement would indicate that some human populations may be evolving from higher to lower intelligence ๐Ÿ™‚

  62. #62 Steve LaBonne
    August 22, 2006

    Well, I hope Gould does better than “macroevolution involves more than population genetics”, since as we’ve already discussed, that does nothing to distinguish it from microevolution. If he has better arguments, why don’t you take five minutes to summarize them and educate us ignorant folks? It’s really too bad that you just go away in a huff trailing the argumentum ad verecundiam behind you when your pronunciamentos don’t meet with universal assent. Is that the example you want to set for the non-scientists around here on how scientists react when their assertions are questioned?

  63. #63 Steve LaBonne
    August 22, 2006

    By the way, I think this is an excellent common-sense comment on micro “versus” macro, one with which I can fully agree:

    The distinction between microevolution and macroevolution is often exaggerated, especially by the anti-science crowd. Creationists have gleefully exploited the distinction in order to legitimate their position in the light of clear and obvious examples of evolution that they can’t ignore. They claim they can accept microevolution, but they reject macroevolution.

    In the real world–the one inhabited by rational human beings–the difference between macroevolution and microevolution is basically a difference in emphasis and level. Some evolutionary biologists are interested in species, trends, and the big picture of evolution, while others are more interested in the mechanics of the underlying mechanisms.

    Wonder who wrote that?
    http://bioinfo.med.utoronto.ca/Evolution_by_Accident/Macroevolution.html

  64. #64 windy
    August 22, 2006

    Indeed Steve, I would have expected better from him. I’m not saying there can’t be a valid distinction between micro- and macroevolution, just that “microevolution can be explained by using population genetics alone” misrepresents the views of the people studying *micro*evolution.

    Unfortunately I don’t have time to take on Larry’s list of luminaries right now, because as a lowly grad student I have to go do some actual research ๐Ÿ˜‰

  65. #65 Ichthyic
    August 22, 2006

    It looks like most people aren’t even aware of the fact that there’s a controversy. That’s quite sad, actually.

    actually i think you’re wrong there, Larry. It seems to me that most here ARE aware of the controversy, but still see no definitive reason to seperate evolutionary theory into the two terms under discussion.

    We did, in fact, have this argument many times when I was a grad student at Berkeley, and every time concluded that the division was artificial and applicable mostly only in theoretical contexts, at best.

    You may not wish to take a crack at it again, but many of the individuals you list in support would have to be looked at in context. Without that specific context, like that of Gould’s contentions, the division doesn’t make sense at all.

    perhaps if you were to expound upon a modern bit of research that pragmatically utilized the distinction to good effect?

    I must admit, I haven’t seen any such papers in the literature recently, but it’s a big world out there.

    Bottom line, I still see no overall pragmatic value to the seperation of terms, but I’m willing to be convinced if someone can show a recent cogent argument, utilizing experimental work, that demonstrates a particular value to the seperation.

    I was hoping that those who examined their texts would actually cite relevant articles along those lines?

  66. #66 Steve LaBonne
    August 22, 2006

    I really think the “hierarchical levels of selection” mavens- who, like Gould, tend to be paleontologists- just don’t always take time to think about how much physiology and ecology go into understanding microevolution, and therefore exaggerate the extent to which new and supposedly revolutionary priniciples are needed to tackle macroevolution. Just as understanding evolutionary trends on the macro level demands a knowledge of environmental change over geological time and of evidence from the fossil record of how different lineages have reacted to those changes, and in many cases also an understanding of the developmental constraints that may help explain Gould / Eldredge’s “equilibria”, so too does understanding microevolution demand an understanding of the environment and its interactions with organismal physiology on a shorter time scale. To take a very common type of example, let’s say you have evidence, perhaps from comparing closely related species, that a particular allele has been fixed due to strong selection pressure during the history of a species.
    To fully understand this microevolutionary event you’re going to need to explore the nature of the gene product, its role in the organism’s physiology, and the interaction of the relevant bits of that physiology with the environment in which that species has evolved. There’s a lot more than population genetics involved there.

    In my (strictly amateur) opinion of course.

  67. #67 Ichthyic
    August 22, 2006

    so too does understanding microevolution demand an understanding of the environment and its interactions with organismal physiology on a shorter time scale.

    again, we could just substitute “evolution” for the micro and macro terms and your statement would be just as accurate, imo.

    Your analysis seems to me to be pretty good, though, regardless of whether I support the particular usage of terms.

    The point is, it seems irrelevant to create two terms for something that essentially overlaps to such a large degree when you do.

  68. #68 PZ Myers
    August 22, 2006

    Here are some recent papers with macroevolution in the title or abstract:
    1: Allen AP, Gillooly JF. Assessing latitudinal gradients in speciation rates and biodiversity at the global scale.
    Ecol Lett. 2006 Aug;9(8):947-54.

    2: Gayon J. Chance, explanation, and causation in evolutionary theory.
    Hist Philos Life Sci. 2005;27(3-4):395-405.

    3: Ding G, Kang J, Liu Q, Shi T, Pei G, Li Y. Insights into the coupling of duplication events and macroevolution from an age profile of animal transmembrane gene families.
    PLoS Comput Biol. 2006 Aug 11;2(8):e102. Epub 2006 Jun 26.

    4: Oakley TH, Ostman B, Wilson AC. Repression and loss of gene expression outpaces activation and gain in recently duplicated fly genes.
    Proc Natl Acad Sci U S A. 2006 Aug 1;103(31):11637-41. Epub 2006 Jul 24.

    5: Moczek AP. Integrating micro- and macroevolution of development through the study of horned beetles.
    Heredity. 2006 Jul 12; [Epub ahead of print]

    6: Macfadden BJ. Extinct mammalian biodiversity of the ancient New World tropics.
    Trends Ecol Evol. 2006 Mar;21(3):157-65. Epub 2006 Jan 10. Review.

    Here are some books from Amazon with “macroevolution” in the title:

    Macroevolution: Diversity, Disparity, Contingency: Essays in Honor of Stephen Jay Gould by Elisabeth S. Vrba and Niles Eldredge
    Macroevolution: Pattern and Process by Steven M. Stanley
    Genetics, Paleontology and Macroevolution by Jeffrey S. Levinton
    Phanerozoic Diversity Patterns: Profiles in Macroevolution (Princeton Series in Geology and Paleontology) by James Valentine
    At the Water’s Edge : Macroevolution and the Transformation of Life by Carl Zimmer
    Morphological Evolution, Aptations, Homoplasies, Constraints, And Evolutionary Trends: Catfishes As A Case Study On General Phylogeny And Macroevolution by Rui Diogo
    Population structure in relation to macroevolution by Verne Grant
    Geography of Macroevolution in Higher Plants (Soviet Scientific Reviews/Section G, Vol 1, Pt 2) by Sergei V. Meyen
    Macroevolution: An important change in evolutionary thinking by Bert Thompson
    Systematics, Functional Morphology and Macroevolution of the Extinct Mammalian Order Taeniodonta (Yale Univ. Peabody Mus of Natl Hist) by Robert Milton Schoch
    Macroevolutionary Theory on Macroecological Patterns by Peter W. Price

    These are distinct concepts. Don’t buy into the creationists’ misuse of the terms: there is good, valid stuff here.

    I will try to write up something on the subject in the next few weeks. Unfortunately, classes start next week and I just got handed a couple of major deadlines for some other work…so I don’t have time for any long posts right now. Patience!

  69. #69 Steve LaBonne
    August 22, 2006

    PZ, I also wouldn’t by any means go so far as to deny the usefulness of having two terms, provided the distinction isn’t exaggerated or abused. (By the way, it may be sexy to put the word “macroevolution” in the title of a paper about a gene duplication event, but after all that’s just a mutation on sort of a grand scale. Much of the rest of that list is the familiar Gould / Eldredge / Stanley stuff, which I think it’s fair to say is a respected but distinctly minority viewpoint in the overall universe of evolutionary biology.) Which is why I quoted Larry’s own very sensible assessment from his online article. In this discussion he seemed to trying to go significantly beyond what he wrote in that article, in some way that he didn’t succeed in making very clear.

  70. #70 Ichthyic
    August 22, 2006

    thanks PZ. I won’t make further comment until i re-read some of these articles with this specific argument in mind.

    It is worth doing a specific thread on, if you ever get the time.

  71. #71 Larry Moran
    August 22, 2006

    Ichthyic says,

    We did, in fact, have this argument many times when I was a grad student at Berkeley, and every time concluded that the division was artificial and applicable mostly only in theoretical contexts, at best.

    I used to think that way up until a few years ago. Then I started to be bothered by the fact that some very, very smart people, who knew a lot more about macroevolution than I did, disagreed.
    It took me about two years to digest all the information and begin to understand where they were coming from. During that time I realized that many of the people who argued that macroevolution was just lots of microevolution had an agenda. I also began to realize that most of them (e.g., Dawkins, Dennett) didn’t really understand macroevolution.
    I decided to write a little essay to explain what I have learned and why these smart people think the way they do. I guess I wasn’t very successful.
    I recently read Eugenie Scott’s explanation in her latest book. She uses the analogy of macroeconomics and microeconomics. I may try and incorporate that into my essay since Levinton’s astronomy/physics distinction didn’t seem to make much of an impression.
    ——————

  72. #72 Ichthyic
    August 22, 2006

    During that time I realized that many of the people who argued that macroevolution was just lots of microevolution had an agenda.

    funny, I never had any inkling it was all a conspiracy…

    what agenda do you speak of?

  73. #73 Larry Moran
    August 22, 2006

    Steve Labonne asks,

    Wonder who wrote that?

    I did. And here’s the next two paragraphs ….

    The Creationists would have us believe there is some magical barrier separating selection and drift within a species from the evolution of new species and new characteristics. Not only is this imagined barrier invisible to most scientists but, in addition, there is abundant evidence that no such barrier exists. We have numerous examples that show how diverse species are connected by a long series of genetic changes. This is why many scientists claim that macroevoluton is just lots of microevolution over a long period of time.

    But wait a minute. I just said that many scientists think of macroevolution as simply a scaled-up version of microevolution, but a few paragraphs ago I said there’s more to the theory of evolution than just changes in the frequency of alleles within a population. Don’t these statements conflict? Yes, they do … and therein lies a problem.

    I’m doing my best, Steve. This is a complicated subject and it’s made even more complicated because most people don’t like being told that they need to rethink their point of view. Open your mind and meet me half way.

    —————–

  74. #74 Steve LaBonne
    August 22, 2006

    I believe I’ve done that, Larry. And I’m glad you came back.

  75. #75 Larry Moran
    August 22, 2006

    Ichthyic asks,

    funny, I never had any inkling it was all a conspiracy…

    what agenda do you speak of?

    Are you really as naive as this, or do you just play one on TV? ๐Ÿ™‚
    The scientists who work in the field of macroevolution tend to think like Levinton, Gould, Mayr, Eldredge, Vrba, and Stanley – although there are exceptions. Most of them are paleontologists. Their agenda is to legitimate paleontology and bring it to the high table.
    The ones who are pushing the idea that macroevolution is just lots of microevolution tend to be mostly interested in living species and population level events. They tend to be ultra-Darwinians. Very few of them understand punctuated equilibria or species sorting. Their adaptationist worldview is threatened by hierarchical theory and that’s probably why they oppose it so vehemently.
    It’s not a conspiracy, it’s just normal scientific infighting. It took me a while to recognize what was motivating the opponents in this controversy. The fact that they have an agenda doesn’t make them wrong but it means you have to be careful when you try and figure out what’s right and what’s wrong. Be skeptical when you read Dawkins and be skeptical when you read Gould.
    ———————

  76. #76 Steve LaBonne
    August 22, 2006

    Very few of them understand punctuated equilibria or species sorting.

    That is, let us say, a highly tendentious remark. I could be equally tendentious and say that the paleontologists assert these things but really don’t understand them either.The libray catalog of serious theoretical attempts to make real demonatrative mathematical sense of multiple levels of selection basically contains two author entries: Sober, E.; Wilson. D.S. And it’s a very fair statement to say that they have left an awful lot of biologists unpersuaded.

  77. #77 windy
    August 22, 2006

    Very few of them understand punctuated equilibria or species sorting.

    I don’t understand why these processes are claimed to be so different from microevolution. Do those researchers studying the evolution of beak size in Galapagos finches (which looks like microevolution to me) not understand punctuated equilibria? Are they trying to explain everything by population genetics? What if one species of finch were to go extinct due to the competition, would they be unable to explain it?

  78. #78 Ichthyic
    August 22, 2006

    Are you really as naive as this, or do you just play one on TV? ๐Ÿ™‚

    not at all, but whenever i hear “agenda”, i immediately think to post something that causes the person making the claim to spell it out for us.

    which you did.

    IMO, you’re dramatically overinflating the role “agendas” play in this area.

    but then, that’s what I expected, so maybe I’m just biased and have an agenda of my own, yes?

    (psst: I’m one o dem der “ultra-Darwinians.”)

    *snicker*

  79. #79 Ichthyic
    August 22, 2006

    BTW, earlier I asked what the latest version of Futuyma had to say on the issue and Allen MacNeil had just posted this in response to a similar query over at the ‘Thumb:

    From Futuyma, D. (2005) Evolution Sinauer Associates, Sunderland, MA, Ch. 21 “Macroevolution: Evolution Above the Species Level”, pp. 501-521:

    “Much of the modern study of macroevolution stems from themes and principles developed by the paleontologist George Gaylord Simpson…, who focused on rates and directions of evolution perceived in the fossil record, and Bernhard Rensch…, a zoologist who inferred patterns of evolution form comparative morphology. Contemporary macroevolutionary studies draw on the fossil record, on phylogenetic patterns of evolutionary change, on evolutionary developmental biology, and on our understanding of genetic and ecological processes.”

    this still leaves open for debate the specific efficacy of the separation, but pretty much solidifies in my mind that I’ve fallen behind in what the latest arguments are.

    However, it does hearken back to the endless arguments between the paleos and the zoologists that i recall from my graduate school days.

    I’m going to spend some time re-reading a lot of these references and get a better handle on the issue and see if I change my mind over my stance from 20 years ago.

    Oh, drat, that’s right, I’m an ultra-darwinist and so my personal agenda will likely override my ability to rationally decide the issue for myself.

    oh well.

    ๐Ÿ˜‰

  80. #80 Steve LaBonne
    August 22, 2006

    And by the way, in their original punctuated equilibrium papers the main mechanism postulated by Gould and Elddredge was- wait for it- the good old allopatric speciation model of Mr. Modern Synthesis himself, Ernst Mayr (of which there are in turn clear anticipations in Darwin). So I don’t think punk eek is actually very relevant to the “Dawkinsist vs. Gouldist” cage matches Larry is so fond of detecting; it really doesn’t require novel mechanisms beyond those routinely invoked in the study of “microevolution”. The real differences in worldview are more in the area of the relative importance of different levels of selection. Further discussion of that topic might be interesting and Larry’s views on it would be most welcome.

  81. #81 Ichthyic
    August 22, 2006

    Further discussion of that topic might be interesting and Larry’s views on it would be most welcome.

    agreed, but I’ve got some catching up to do before I jump in again.

    Hopefully PZ will have some time to get involved in a new thread discussing the issue.

    cheers

  82. #82 Larry Moran
    August 22, 2006

    Ichthyic says,

    IMO, you’re dramatically overinflating the role “agendas” play in this area.

    The evolution wars are all about perspectives, worldviews, and agendas. Facts aren’t that important. But don’t get me wrong, worldviews are important. It makes a big difference on how you interpret data.

    but then, that’s what I expected, so maybe I’m just biased and have an agenda of my own, yes?

    Yes. Everyone approaches these problems with biases. Mine happen to be a molecular bias with a fondness for Gould and pluralism. I tend to see evolution as a sloppy, complex phenomena with many causes. If you’re an ultra-Darwinian you will have a very different bias. Part of that bias is to downplay and trivialize all challenges to classic Darwinism.
    It’s good to recognize our own biases and try to compensate whenever possible. But you knew that already, right?

    ———————-

  83. #83 Larry Moran
    August 22, 2006

    Steve LaBonne says,

    And by the way, in their original punctuated equilibrium papers the main mechanism postulated by Gould and Elddredge was- wait for it- the good old allopatric speciation model of Mr. Modern Synthesis himself, Ernst Mayr (of which there are in turn clear anticipations in Darwin). So I don’t think punk eek is actually very relevant to the “Dawkinsist vs. Gouldist” cage matches Larry is so fond of detecting; it really doesn’t require novel mechanisms beyond those routinely invoked in the study of “microevolution”.

    Spoken like a true ultra-Darwinian! Dawkins would be so proud of you! ๐Ÿ™‚
    Like I said, lots of people don’t understand punctuated equilibria. ๐Ÿ™‚

    Have you read The Structure of Evolutionary Theory yet?

    ————————-

  84. #84 windy
    August 22, 2006

    It seems that anyone who disagrees with Larry on this is an ultra-Darwinian by definition ๐Ÿ™‚

    Ok, perhaps we don’t understand punk eek. Are you referring to PE strictly in the sense of speciation happening mostly in isolated peripheral populations, or a more general picture of stasis vs. rapid change?

  85. #85 ulyssesdraco
    August 22, 2006

    49) Oh you evolutionists make me laugh, it was God who created the world. It says so in the bible and the bible says its true, so IT IS TRUE!!!

    Meh, I’m a Christian and evolution (Micro or Macro) does not bother me at all. It all depends on how you choose to interpret(Which is what the whole Bible is about, interpretation) the whole God made the earth in six days thing. Whether you take it as 6 earth days or 6 “God days”(which are like eons each) is up to you. Either way, you’re all like “Wow, 6 earth days is freak’n fast mang, He’s one powerfull dude,” or “Man our concept of time is nowhere near as grand as His;” You still end up all praise-y and humbled and whatnot.

  86. #86 windy
    August 23, 2006

    Everyone approaches these problems with biases. Mine happen to be a molecular bias with a fondness for Gould and pluralism. I tend to see evolution as a sloppy, complex phenomena with many causes. If you’re an ultra-Darwinian you will have a very different bias. Part of that bias is to downplay and trivialize all challenges to classic Darwinism.

    Oh, and one more thing – Since microevolutionary and gene-level events are clearly sloppy, complex phenomena with many causes as well, your insistence to take macroevolution seriously would be more impressive if you stopped misrepresenting microevolution and those studying it.

    I, for one, can’t think of a good example of microevolution that *isn’t* a sloppy process with many causes. Anyone?

  87. #87 Steve LaBonne
    August 23, 2006

    Have you read Gould and Eldredge’s original papers, Larry? Try it, as an exercise. You’ll find that my statement is accurate. THEY said it, not me.
    Here, I’ll make it very easy for you:
    http://www.blackwellpublishing.com/ridley/classictexts/eldredge.pdf

    (Their only novel wrinkle, aside from elaborately constructing their strawman version of “phyletic gradualism”, was the vague handwaving about “mutations causing breakdown of developmental homeostasis”, but that’s a check that certainly can’t be cashed against the fossil record. Stasis by the way is also easily explained by standard genetic mechanisms- a species already very well adapted to its environment won’t show much morphological change as long as the environment doesn’t change, since most mutations that affect the kinds of things you’d be able see in the fossil record will decrease fitness and be eliminated by purifyings election. That’s exactly why G & E had to stress the importance of the allopatric model. You’ll find an explicit recognition of something like this in Darwin, by the way.) Apparently you’re one of those people who don’t understand punk eek. You reinforce that impression every time you snark instead of posting something substantive.

    Gould’s posthumous magnum opus appears to a disorganized baggy monster, and it received decidedly mixed reviews. Why don’t you summarize the novel insights to be found there- you might tempt me to read it. Don’t you care about proselytizing for these ideas that you find so gripping?

  88. #88 PZ Myers
    August 23, 2006

    I think Gould’s Structure is an excellent book for the ideas (but also represents the flaws in Gould’s writing style at their peak), but is more than a little daunting. I recommend Stanley’s Macroevolution: Pattern and Process as a better starting point. That’s the book that made PE clear to me, anyway.

    Saying that “Stasis by the way is also easily explained by standard genetic mechanisms” misses the point. Eldredge and Gould were not proposing any new genetic mechanisms. It’s like dismissing Mendel because he failed to advance any new chemistry.

  89. #89 Steve LaBonne
    August 23, 2006

    That’s exactly my point, PZ. They weren’t really proposing anything new, at all. Their strenuous efforts to appear more novel than they really were, depended heavily on comparing their ideas to their own strawman version of “phyletic gradualism”. The hated “ultra-darwinists” of the modern synthesis were perfectly well aware- to put it in modern terminology they wouldn’t have had available to them when their ideas were first formulated- that a large proportion of evolutionary change is associated with cladogenesis.

    To put it somewhat crudely, what Eldredge and Gould essentially did was simply to bring Mayr’s ideas to the attention of paleontologists.

  90. #90 Steve LaBonne
    August 23, 2006

    P.S. you might find this essay by Mayr to be of interest: http://www.stephenjaygould.org/library/mayr_punctuated.html

  91. #91 PZ Myers
    August 23, 2006

    No, it was something new — it was just something new at a different level than you are looking for. Seriously, my comment about Mendel was intended to illustrate that…to a chemist, Mendel said nothing new, there were no novel properties of the biochemistry of pea plants proposed, it was nothing but the same ol’ reactions shuffling and sorting about. Big deal.

    Meanwhile, the physicists are bored with the chemists because they keep playing with atoms. And the mathematicians are all scratching their heads and wondering why any of us are wasting our time with specific instantiations of matter and energy.

  92. #92 Steve LaBonne
    August 23, 2006

    Well, as you can see from my link Mayr was certainly unconvinced that it was all that new. Can you articulate what you think was so novel about it?

  93. #93 Rada
    August 23, 2006

    This is all a load of bunk anyways, the flying spaghetti monster says so!

  94. #94 duncan
    August 23, 2006

    New study links being religious to being an idiot. Surprise!

  95. #95 Larry Moran
    August 23, 2006

    Steve LaBonne says,

    Have you read Gould and Eldredge’s original papers, Larry? Try it, as an exercise. You’ll find that my statement is accurate. THEY said it, not me.

    … Apparently you’re one of those people who don’t understand punk eek. You reinforce that impression every time you snark instead of posting something substantive.

    I read the papers 25 years ago. The classic Eldredge & Gould paper was published 34 years ago. Unlike you, I’m aware of the fact that ideas change and I make an effort to find out about the modern views before I launch into an attack on out-of-date ideas. I think I understand the modern theory. Do you?
    (BTW, here’s the complete list of Ridley’s classic papers. Why do you suppose Eldredge & Gould (1972) is on that list?)
    The modern view of punctuated equilibria is covered in “Structure.” That’s why I asked if you had read it. You might want to take a look at Chapter 9: “Punctuated Equilibria and the Validation of Macroevolutonary Theory.” It’s 279 pages long and, no, I will not post a 10 page summary so that you can avoid doing your homework.
    Here are some teasers ….

    We took Mayr’s allopatric theory … and tried to elucidate its implied expression when scaled into geological time. We did not select this theory to fit a paleontological pattern that we wished to validate. We choose Mayr’s formulation because his allopatric theory represented the most orthodox and conventional view of speciation then available in neontological literature–and we had been given the task of applying standard evolutionary views to the fossil record. I recognize, with 30 years of hindsight, that our original assessment both of Mayr’s theory and professional consensus may have been both naive and overly dichotomous, but we could not have stated our intent more clearly–the reform of paleontological practice by the paradoxical route of applying a fully conventional apparatus of neontological theory. (emphasis in orginal) p. 779

    Most people don’t realize how much punctuated equilibria has evolved in the past three decades. They also don’t realize that Eldredge & Gould have changed their views and admitted mistakes. This may come as a big surprise to those (Steve LaBonne?) who think that scientists never change their minds and never admit they were wrong. Here’s another little snippit from “Structure” …

    Of course we made mistakes–serious ones in at least two cases–and the theory has changed and improved by correcting these errors. In particular … we were terribly muddled for several years about the proper way to treat, and even define, selection at the level of species–the most important of all theoretical spinoffs from punctuated equilibrium. We confused sorting with selection. We also did not properly formulate the concept of emergence at first; and we remained confused for a long time about emergence of characters vs. emergence of fitness as criteria for species selection. In retrospect, I am chagrined by the long duration of our confusion, and its expression in many of our papers. But I think we have now resolved these difficult issues.

    So, to answer your question once again: yes, I have read the original 34 year old papers on punctuated equilibria. What’s your point? ๐Ÿ™‚
    ———————–

  96. #96 Steve LaBonne
    August 23, 2006

    My point is as stated above- of course E & G’s paper was a classic, of course it was deservedly influential, but it was not nearly as novel as advertised. In particular, it was quite heavily based on Mayr’s work. I substantiated that (familiar) point and you’ve neither contradicted it nor added anything to it. So I wonder what your point is and why you bothered with that last comment.

    I’m also well aware that they later modified their views. How clearly aware are you that the modifications were generally in the direction of softening some of the exaggerated claims in their original paper?

  97. #97 Steve LaBonne
    August 23, 2006

    P.S. Here’s a nice quote from Levinton that I stumbled across: “Mayr’s hypothesis of peripheral isolates and genetic revolution must of necessity be a centerpiece of the punctuated equilibria theory; it is the theory, for all practical purposes.”

  98. #98 Microbiologist
    August 23, 2006

    I think an easy way to deal with the difference between macro and microevolution is to look at it in terms of microorganisms. There are many different species of bacteria and these are classified as species using a number of different criteria. If a species say for example E. coli manages to break into two new species this is termed macroevolution. This type of change occurs less frequently than microevolution and has huge implications. Microevolution on the other hand is frequent and occurs at the level of individual bacteria. Generlly this does not give rise to a new species just new “types”. Evolution is a continual process that results from the accumulation of mutations (which do occur randomly) which may give rise to individuals which can be successful despite environmental pressures. Does this help?

  99. #99 privy
    August 23, 2006

    Why do u say that “it is only a theory” is a myth?
    Sorry if it is too dumb

  100. #100 carol
    August 23, 2006

    The scientist have known for sometime that it was Spencer’s theory of natural selection that explains much better the way we have come to this state in our long process of civilization and that the theory is also applied to the animals,how they survived the conditions of the earth’s changes over these millions of years.

  101. #101 carol
    August 23, 2006

    The scientist have known for sometime that it was Spencer’s theory of natural selection that explains much better the way we have come to this state in our long process of civilization and that the theory is also applied to the animals,how they survived the conditions of the earth’s changes over these millions of years.

  102. #102 windy
    August 23, 2006

    The Futuyma textbook, for example, makes the point that extinction of lineages is not covered by microevolutionary theory, although speciation can be included in it. But what about metapopulation biology, conservation biology and the like? Haven’t they done a lot of research on what factors can lead to the extinction of populations? Is the extinction of species an entirely separate question?

  103. #103 jose
    August 23, 2006

    For Christians, I believe numbers 9 and 12 are contradictory. In my experience, many Christians who understand evolution and believe it’s true, also believe that it has a goal. And that goal is to ultimately create humans. I suppose you don’t have to be an atheist to believe evolution, but I don’t think you can be a Christian AND believe evolution AND believe it has no goal.

    I think this idea of directed evolution is implicit in some of the comments in this thread. I get the impression, for example, that people are implicitly giving “purpose” to the process of evolution. There seems to be a belief that evolution produces a constant and steady stream of mutations in hopes of getting “advantageous” mutations so that species can evolve, presumably into the ultimate goal of the process–humans.

    I don’t think you can ever convince creationists that 12 is a myth. It’s clear to me that this is their ultimate problem with evolution.

  104. #104 Matt
    August 23, 2006

    Evolution is common sense know to all ancients. Natural selection is JUST a theory.

    Things obviously evolve (read: change) over time. Humans have changed even over the last generation – and this is obviously caused by the environment.

    Now, this idea about nature “selecting” and all is pure speculation. No one really knows but all of the ancients believe in evolution AND a direction for it – just not the “natural selection” part.

  105. #105 Larry Moran
    August 23, 2006

    Steve LaBonne says,

    P.S. Here’s a nice quote from Levinton that I stumbled across: “Mayr’s hypothesis of peripheral isolates and genetic revolution must of necessity be a centerpiece of the punctuated equilibria theory; it is the theory, for all practical purposes.”

    Eldredge & Gould invoked Mayr’s concept of genetic revolution in small isolates when they wrote their original paper. It was fairly standard orthodoxy at the time and it seemed to be an excellent way of explaining the pattern of punctuated equilibria.
    Note that the pattern of punctuated equilibria is an observation (fact) and the “theory” is an attempt to explain the fact. The theory can change without altering the fact, just as the theory of evolution has changed without altering the fact of evolution. That’s how science works. Anyone who would attack evolution by criticizing Darwin’s acceptance of acquired characteristics would be thought a fool.

    Mayr’s ideas fell out of favor in the late 1970’s and that’s why Gould writes in “Structure”,

    I can claim no expertise in this aspect of neontological theory, but I certainly acknowledge, and therefore must provisionally accept, the revised consensus of the past twenty years that has challenged this body of thought, and rejected any general rationale for equating the bulk of evolutionary change with events of speciation in small populations, or with small populations in any sense. (p. 797)

    This is why the modern version of punctuated equilibria relies mostly on Futuyma’s (1987) theory about the coupling of morphological change to speciation events (“Structure” p.798-802, Gould & Eldredge, 1993). Levinton doesn’t seem to have kept up with the shift that occurred over the past twenty years as Mayr’s ideas were abandoned. This form of myopia seems to be quite common among opponents of punctuated equilibria.
    —————-

  106. #106 Steve LaBonne
    August 23, 2006

    I’m aware of that shift. It’s completely beside the point I was making, which concerned the intellectual origins of punk eek (not its current status) and that point, once more, is that punk eek was never the conceptual revolution that it was sold as. (The Levinton quote was from 1983, by the way.)

    Another thing that needs to be understood is that punk eek is not logically needed at all for postulating a possible role of species (or higher taxon) selection in macroevolution (despite the strong association of these topics in Gould’s mind), and that includes the theory of Futuyma to which you refer. This works in your favor, by the way- it would be entirely possible for punk eek to prove largely false and yet evolutionary change to be largely associated with cladogensis and higher-level selection to be important in macroevolution. See for example
    http://www.biology.duke.edu/mcshealab/McSheaLabPage/revised%20darwinism.pdf

    That’s why a few comments ago I tried to shift the discussion away from punk eek and towards species selection etc. which is more interesting and more relevant ground when discussing the distinctness of macroevolution. I’m still interested to hear what you have to say in that general area.

  107. #107 Steve LaBonne
    August 23, 2006

    P.S. The decreased emphasis on small populations and “genetic revolutions” since Mayr’s original proposal is really a matter of nuance rather than the fundamental logic of speciation. Mayr’s most fundamental insight was the predominance of allopatric over symapatric speciation, an insight of which Futuyma is as strong a chamion as you’ll find anywhere.

  108. #108 Anthony
    August 23, 2006

    You know, this is a pretty interesting conversation to have. One thing that people on both sides (creationists v. evolutionists) have is the “need to be right”
    It reminds me of a Physial Anthropology class I took years ago where the Professor asked aloud if diversity wasn’t simply a normal occurance in all species.
    He went on to name all of the different characterictics of modern man today: short, tall heavy, slight, dark, medium and pale skinned. Different color eyes, different kinds and colors of hair. Epicanthic eye folds and Y-5 molars. Some are Eskimos and some are politicians.
    It’s to bad we all haven’t upgraded our 4 year old conversation of having to be right.
    Have you ever seen a 4 year old that can have a tantrum when he or she doesn’t get his own way? And he blames everyone else for his misery?
    Of course you have, every time you look in the mirror.
    You get mad because YOU want to be right, and want me to be wrong. And I want to be right so I take a poke at you, or worse, I gossip about you behind your back.
    And we blame people from other countries?
    We are horrible to each other, especially people we know.

    What would a 15 year old say? What would an adult say?
    Something along the lines of “all is well”
    Then maybe we’d stop fussing and killing, and get down to having fun.
    Good luck people.

  109. #109 Steve LaBonne
    August 23, 2006

    That’s “sympatric” and “champion”, sorry for the poor tying and proofreading.

  110. #110 Steviepinhead
    August 23, 2006

    Ah, and along trundles Matt with the shopworn “JUST a theory” canard. Clue in, Matt: gravitation is “just” a theory, but you would not be well-advised to emulate Wiley Coyote. Weather forecasting is “just” a theory, but I’ll leave you to judge whether to evacuate the next time a force-four hurricane is predicted to landfall on your hovel.

    And what’s this hang-up with what the “ancients” thought about a subject of current scientific scrutiny? Are you going to maintain solidarity with the “ancients” on, um, the efficacy of alchemy, on the geocentric view of the world, on the “vitality” of gross matter, on the demon-possession theory of disease…

    One could, of course, go on and on but, with any luck, we won’t hear further foolishness from you, and won’t need to.

  111. #111 Larry Moran
    August 23, 2006

    Steve LaBonne says,

    I’m aware of that shift. It’s completely beside the point I was making, which concerned the intellectual origins of punk eek (not its current status)…

    Who cares? That’s ancient history.

    … and that point, once more, is that punk eek was never the conceptual revolution that it was sold as. (The Levinton quote was from 1983, by the way.)

    Well, it may not have been a “conceptual revolution” but I’d sure like to have produced a little insignificant contribution like that. The Eldredge & Gould (1972) paper is considered a classic and punctuated equilibria get serious mention in every textbook.
    If it wasn’t a conceptual revolution or some sort, then why are we still talking about it 34 years later and why do so many people feel threatened by punctuated equilibria? For three decades people have been whining that punctuated equilibria aren’t important. Are they going to continue for another three decades?
    You may not like punctuated equilibria. The pattern and theory may even be wrong. But if it’s correct, it’s certainly significant. Isn’t it kind of silly to pretend otherwise after all this time?
    ——————–

  112. #112 Steve LaBonne
    August 23, 2006

    Yes, of course it’s significant as an observation about the tempo and mode of evolution (though again, the extent to which people other than Gould and Eldredge were really “phylogenetic gradualists” before they came along has been exaggerated, not least by them). However as I pointed out above, it’s not central, or even necessarily connected at all, to a discussion about whether macroevolution is in some sense “more” than microevolution writ large.

    Here, I’ll get that discussion started off. I pretty well agree with this statement that I found in a recent entry on John Wilkins’s blog: “Macroevolution (evolution above the species level) really is just the effect of microevolution (evolution at the population level). But it is skewed in ways we can’t predict from populational evolution because we can’t predict the topography and parameters of the environment of species over time.”

    Let’s consider species sorting (I like Gould’s use of “sorting” by the way, to emphasize that selection is not necessarily involved) and let’s consider a drastic case of it, mass extinctions and their aftermaths. Here is the nub of the question as I see it. What Wilkins is basically saying in that statement is that the component of this sorting that is not understandable from the principles by which we understand population-level evolution is mostly a matter of randomness: on a geological time scale, shit happens, so to speak. The alternative- the kind of thing that Gould, or in a more theoretically well-worked-out way, Sober and Wilson, are trying to do- is to show that if not exactly predictable, a major component of this sorting can be subsumed under some kind of theoretical regularities, involving principles genuinely not reducible to those used to understand population-level evolution.

    We know which side of this question you’re on. But what are the arguments and models you find most convincing on your side?

  113. #113 Tiak
    August 24, 2006

    50) Evolution was responsible for the Columbine high school shooting

    Technically speaking, it IS responsible… Had evolution somehow not happened (say, no genetic variation ever occured in any life form ever) it wouldnt’ve happened, now would it?

  114. #114 Michael Allen
    August 24, 2006

    In reference to #51.. This is actually not entirely true. There are human beings currently being born without an appendix. We all know it’s useless to us and apparently evolution agrees now. The next several generations are going to see a steady decline and ultimate elimination of an organ we don’t actually need.

  115. #115 Thomas
    August 24, 2006

    The Big Bang and evolution consits of a lot of bullshit,theories and more theories,just yeterday it said in a scientific discovery that scientists are not sure about how it happens,scientists replaced God,with their CREATOR SCIENCE

  116. #116 Millimeter Wave
    August 24, 2006

    just my humble opinion, of course, but I really think that #18 should be #1…

  117. #117 Lamont B Dumont
    August 24, 2006

    The problem with #30 isn’t the use of the term “theory”. The problem I’ve always had with it is the use of the term “just”. To say something is “just a theory” indicates not a weakness within the theoretical idea, but instead a weakness in the individual’s understanding of a theory. Too many people use the term theory when they mean hypothesis (or even something weaker, like a hunch.)
    Yes, evolution is just a theory; so is gravity. When a scientific concept has been rigorously vetted to the point where it reaches the exalted status of theory, it means essentially “we know for certain that this phenomenon occurs, we’re still figuring out the nuts & bolts of how it occurs”. In many cases, probably gravity for one, we will keep learning new things, but never acquire total understanding. Humans have finite minds, and we can never do better than to approximate the infinite.

  118. #118 Larry Moran
    August 24, 2006

    Steve LaBonne puts his foot in it, once again,

    Let’s consider species sorting (I like Gould’s use of “sorting” by the way, to emphasize that selection is not necessarily involved) and let’s consider a drastic case of it, mass extinctions and their aftermaths.

    Here’s a short description of species sorting. Species sorting refers to the differential survival of species within a clade. (You really should read “Structure” or some other book if you want to continue this disussion.) If species sorting exists then it is a clear example of a higher level phenomenon. Mass extinctions are something else entirely, although they do illustrate why microevolution isn’t sufficient to explain macroevolution.

    We know which side of this question you’re on. But what are the arguments and models you find most convincing on your side?

    I don’t think species sorting – at least the kind described by Gould and his colleagues – exists. I don’t find any of the arguments convincing.
    ———————–

  119. #119 Steve LaBonne
    August 24, 2006

    Larry, I’m sorry but I simply don’t agree with what you write above, and I don’t really think you understood what I was getting at. Try thinking for once instead of looking for “gotchas” so you can parade your air of superiority, OK? Differential clade survival can be merely a random matter of being in the right or wrong) place at the right (or wrong) time, as implied in Wilkins’s quote. (And that would make the inability to “explain” macroevolution on purely microevolutionary principles essentially a trivial matter with little real intellectual content, as implied by Wilkins.) OR it can indeed be a result of something that in a non-Pickwickian sense can really be called a “process”, and that results from emergent properties of species that allow them to be regarded as evolutionary individuals which can be visible to some type of selection. So by itself, it’s compatible with either of the alternatives I laid out in my previous comment.

    Let’s clarify this point with a much-studied example of the species sorting you apparently don’t agree with. Species sorting has been invoked repeatedly (starting with a famous 1973 paper by Stanley in Evolution) to explain Cope’s rule, the trend in many lineages toward generating species whose individuals have larger body size, as an alternative to “traditional” explanations that invoke only selection pressures within lineages. To quote from the abstract of Stanley’s paper:

    Cope’s Rule, the generalization that most animal groups have evolved toward larger body size, cannot be explained by intrinsic advantages of large size. Rather, it is the tendency of groups to arise at small body size relative to their optima that produces the widely observed pattern of net size increase. The specialized nature of large species of a given body plan, required by problems of similitude, renders these forms unlikely potential ancestors for major new descendent taxa. The adaptive discontinuity that must be crossed for invasion of a new adaptive zone at large body size exists because of the need for descendent taxa to be specialized along new lines. These factors tend to restrict large-scale adaptive breakthroughs to small body sizes. Size changes probably tend to occur sporadically, during speciation events. Size increase is not inherently favored in speciation, but prevails during diversification because origin of a higher taxon at small body size concentrates many early species in the small size range.

    It’s puzzling indeed that you’re so gung-ho for the separate status of macroevolution but appear to reject one of the oldest and most widely acccepted examples of a proposed genuine regularity in evolution that can’t be explained strictly on the basis of forces acting within populations. If you don’t agree with that, then what are some examples of macroevolutionary principles and processes you DO agree with? Alternatively, if you do accept Stanley’s idea, why did you say that you don’t believe in species sorting?

    Unlike you, I’m not interested in trying to trip you up so I can gloat; I’m genuinely trying to help you elucidate your thinking. I won’t bother again if the result is yet another content-free snark, so feel free to provide one if you’re tired of the discussion.

  120. #120 Mike C
    August 24, 2006

    Myth 21 is only a myth about Darwinian evolution. Lamarckian evolution happens to take that as a premise to the theory.

    And, incidentally, Lamarckian evolution is a completely useful theory for a wide range of phenomena (consider any natural language, for instance), just not for biological cellular evolution.

  121. #121 windy
    August 24, 2006

    Larry’s post behind the link seems to say the opposite of what he’s saying here about species sorting vs. species selection:

    In the case of species sorting, microevolution is uncoupled from macroevolution because a proper explanation of evolution requires this description of the birth and death of stable species. This is true even though there may not be profound new mechanisms of evolution that can’t be explained by competition between organisms within populations. “In this version, we need a descriptive, but not a causal, account of macroevolution based on species as individuals.” (Gould, p. 784)

    In the case of species selection, the differential survival of species within a clade arises from properties of the species as a whole. These properties cannot be reduced to the level of organisms within a population. Gould presents the case for true species selection and argues that “validation of this argument would establish a genuinely causal and irreducible theory of macroevolution.” (Gould, p. 784)

  122. #122 Steve LaBonne
    August 24, 2006

    And the contrast between those paragraphs very clearly outlines the alternatives I was trying to present- whether macroevolution is non-reducible to microevolution in a relatively trivial “thin” sense that doesn’t invoke genuinely new principles, or whether it is really non-reducible in a “thick”, intellectually exciting sense. (IMHO he should not follow Gould, however, in confusing the issue by dragging in the entirely detachable issue of punctuated equlibrium.) What I would be interested to hear from Larry is what he thinks about that question. Or if he doesn’t follow Gould on the “thicker” notion of species selection, does he believe there are other genuinely new principles in macroevolution that are irreducible in the non-trivial sense. This I think is a very interesting question and while I am currently sceptical of “thick” macroevolution I am by no means closed to persuasion. (I’m interested in understanding evolution, not in any imagined eschatological struggle between Intrepid Paleontologists and Evil Ultra-Darwinians.)

  123. #123 Steve LaBonne
    August 24, 2006

    To further clarify, I would tend (consistent, I think, with what Gould says in the first quote above) to put the type of species sorting Stanley invoked to explain Cope’s Rule perhaps on the borderline but leaning toward the “thin” side of the divide. It’s basically a negative statement, that organism-level selection need not be invoked, and the sorting process that remains is a stochastic one that doesn’t seem to me to qualify as a novel “mechanism” in any really robust sense. On the other hand, it is a statement of a macroevolutionary regularity, and not just the kind of unpredictality that arises from the unpredictability of the enviroment. At any rate I have no trouble accepting that sort of thing (though I certainly don’t pretend to be in a position to judge how well it’s supported by the evidence.)

  124. #124 Aaron Thomas
    August 25, 2006

    Interesting argument, though its clear some of you are well trained in yesterday’s genetics. #21 is not completely false: go here – http://en.wikipedia.org/wiki/Epigenetics – those of you who have closed your textbooks. Its not evolution (a person can’t evolve) but it makes #21 a little iffy. Furthermore, don’t be content with your simple understanding of evolution, or our current understanding of complex biological processes. It’s when scientists have determined they already know the answers that they are most like the creationists – they’ll both suffer from confirmation bias.

  125. #125 tegekkedude
    August 26, 2006

    I HAVE READ SOMETHING ABOUT MACROEVOLUTION BUT HAVE FORGOTN AGAIN. SOMETHING LIKE QUANTITY AND QUALITY MAYBE ORE I HAVE MY EYE ON YOU BUT I CANยดT SEE YOU YET BUT I KNOW YOU MUST BE HERE SOMEWHERE
    HAVING YOUR VISION IN A SIGHT SEEING WHAT YOU ALREADY LOOKED AT WHEN YOU SAW THAT HAPPEN WHEN YOU WAS A HIPPY IN 2006.SO be a hippy and DO SOMETHING GOOD AND MAYBE IN THE FUTURE YยดLL THINK ………… !!!!IยดM HAPPY!!!!!!!!
    aaah new word !! Im a ยดhappy from the 06ยดs
    PEACE ALREADY BOMBED TO 100 PIECES ARE SHURLY 100 PIECES ,AND
    PEACE NOT BOMBED IS COOL AND 100 PIECES BOMBED TO PEACE IS A COOL THING TO DO!!!ยฎ

  126. #126 Mickey Coke
    August 27, 2006

    This is lame. Poorly written and could use some editing. It appears to be failed jabs at creationist dogma, but don’t really get it. It appears that the writer is uneducated in young earth geology and just enjoys poking at stuff randomly? I don’t know, nor get it, but read it all. Yikes – what does that say about me?

  127. #127 Amira
    February 15, 2008

    Evolution of man…. a money had a science project.. he won 1st place and decided to make it the pet… soon other monkeys wanted the science project soo they paid the monkey to make more… later the humans(pets) got together had a party… then we all dominated the world….

  128. #128 turk pornosu
    August 2, 2008

    Hi admin,
    What I would be interested hear from Larry is what he thinks about that question. Or if he does not following Gould on the -thicker- notion of species selection, does he believe there are other genuinely new principles in macroevolution that are irreducible in the non trivial sense.

    Thanks.

New comments have been temporarily disabled. Please check back soon.