I'm at Indiana University this weekend, participating in a two-day symposium on “evolutionary novelties” sponsored by the National Science Foundation. Evolutionary what, you say? Well, assuming you believe (as in accept because of evidence and logic, not blind faith) in evolutionary theory, then you might have been intrigued by the question of how such “novel” structures as eyes, wings, turtle shells, flowers, or beetle's horns come about. That's what the symposium, co-hosted by Indiana University and the University of Oregon, is all about.The area of evolutionary biology currently studying novel traits is often referred to as “evo-devo,” which stands for evolution of development. The basic idea is that if we are to understand how, say, wings evolved as modifications of the front limbs of some groups of vertebrates (like birds), the answer must at least in part lie in an understanding of how development (the set of changes from embryos to adult forms) itself evolved.
The talks I have heard so far vary from studies of the evolution of hormone-receptor biochemical functions to how horned beetles get their horns, from the evolution of eyespots on butterflies' wings to that of new biochemical capabilities in bacteria like E. coli, and from how humans evolved big brains to why male and female flowers can be different from each other even though they share the same genes. This is a spectacular range of topics, and a feast for the brain of even mildly curious scientists (and most scientists are much more than just mildly curious about these sorts of things).
The keynote lecture that opened the symposium was delivered by Mary Jane West-Eberhard, of the Smithsonian Tropical Institute in Costa Rica,author of “Developmental Plasticity and Evolution.” West-Eberhard explained how organisms' developmental systems are flexible enough (plastic, in technical terms) to be able to accommodate to many external environmental stresses and even genetic defects, rapidly producing adjustments that allows them to survive and that can then be favorably selected during the course of evolution, resulting in the appearance of novelties. One of the most spectacular examples she presented was the case of a macaque (a not-too-distant relative of humans) who was born without the use of its forelimbs. The animal's developmental system was able to adjust its skeleton, muscles and even behavior, turning the monkey into a bipedal organism, something that has always been considered a crucial and difficult to explain step in human evolution. The picture of the mutant macaque shown by West-Eberhard (right) is in fact quite disturbing, this guy doesn't look that different from some people I encounter in the New York subway...
The symposium will close tomorrow, and yours truly will also present a talk by the title “What, if anything, is an evolutionary novelty?” which is already available on my web site.
Massimo,
ReplyDeleteI have a couple of questions.
(1)Would it be fair to say that some mutations are simply more "interesting" than others- to the extent that saying evolution is the result of Natural Selection working on random variation, by not telling the whole story, actually misinforms? I am thinking of the bipedal macaque & bipedal dog (on your slide show), and the bat's wing (which I understand may have lengthened considerably over a couple of mutations).
(2)This quote by Popper that you offer in your lecture:
"[Darwinian theory] never gives us a full explanation of anything's coming into being in the course of evolution",because it is a theory
that assumes variation and "therefore... cannot really explain it."[your quotation marks]
At first sight it appears that this is erroneous, because variation and evolution are two different things. Was the quote from before or after his "recantation."
Suffenus:
ReplyDelete>> (1)Would it be fair to say that some mutations are simply more "interesting" than others- to the extent that saying evolution is the result of Natural Selection working on random variation, by not telling the whole story, actually misinforms? <<
Some mutations are most definitely more "interesting" than others -- because of their long-term effects during evolution. However, I wouldn't say that the above statement is a case of misinformation, just only part of the story.
>> (2)This quote by Popper: "[Darwinian theory] never gives us a full explanation of anything's coming into being in the course of evolution", because it is a theory that assumes variation and "therefore... cannot really explain it." At first sight it appears that this is erroneous, because variation and evolution are two different things. Was the quote from before or after his "recantation." <<
The quote is correct in the sense that the Modern Synthesis version of evolutionary theory can only explain what happens (by natural selection or other processes) to variation in natural populations. The existence of such variation is assumed, and needs to be explained by other means. Two such means are Mendelian and population genetics, which -- when merged with the original Darwinian ideas -- give you the Modern Synthesis. However, Popper is saying that the picture is still incomplete because we need additional conceptual tools to account for the origin of entirely new structures, and my online lecture highlights some of these tools.
Tools sound like a wonderful thing to have, Massimo. But you must know just as well as I do, that there are a variety of insurmountable problems that even normal (not gifted persons like you) will quickly recognize.
ReplyDeleteWhat I noticed about Ariel A. Roth's commentary here is that he aptly describes your concerns and present interests and some that I that I have thought important also.
'Dr Roth is a former director of the Geoscience Research Institute in Loma Linda, California. He holds a B.A. in biology from Pacific Union College and an M.S. in biology and a Ph.D. in biology from the University of Michigan.'
"In the middle of the 20th century, leading evolutionists proposed the “modern synthesis.” Hailed as the final evolutionary model, it incorporated Darwin’s natural selection, de Vries’ mutations and studies in population genetics. At the same time, other evolutionists were calling for much larger sudden changes than those noted for mutations.
These larger changes were needed because of major gaps between groups of organisms in assumed evolutionary lineages, as seen in the fossil record, and also because of the inadequacy of the survival value of small evolutionary changes while developing complex systems with interdependent parts.5 The term “hopeful monster” was suggested for these proposed suddenly appearing new forms. But they would need matching mates to be able to breed with, and as one critic commented, “Who will breed with a monster, hopeful or otherwise?”6
The modern synthesis did not remain as the dominant evolutionary mechanism for very long, although a number of leading evolutionists still defend the model. One evolutionist comments, “And today the modern synthesis—neo-Darwinism—is not a theory, but a range of opinions which, each in its own way, tries to overcome the difficulties presented by the world of facts.”7 We are now in a period of diverse evolutionary opinions. A variety of new ideas and controversies have appeared. They revolve around such questions as:
Can one really identify the evolutionary relationships of organisms?
Are evolutionary changes gradual or sudden?
Is natural selection important to the evolutionary process?
How does complexity evolve without the advantage of foresight?"
AND MY USUAL COMPLAINT
"Animals require plants for food in order to survive. Yet in several of our important geologic formations we find good evidence for the animals, but little or no evidence for the plants necessary to support the animals. The fossil assemblages found represent incomplete ecosystems. How did the animals survive for the millions of years postulated for the deposition of these formations without adequate food? Examples include:
The Protoceratops dinosaur-bearing layers of the Gobi Desert of Mongolia, where the paucity of plants is considered “baffling.”17
The Coconino Sandstone of the southwestern United States, which has many hundreds of good animal trackways, but no plants.
The important dinosaur-bearing Morrison Formation of the western United States, where “identifiable plant fossils are practically non-existent.”18 What did these behemoths eat as they evolved over the millions of years? It is estimated that a large dinosaur would eat 32 tons of vegetation in one day.
A more plausible scenario for these deposits is that they represent layers laid down rapidly during the biblical Flood, with the waters of the Flood sorting the organisms into various deposits, the plants forming some of our huge coal deposits.
When we look at our present earth, it appears that geologic changes are very slow. On the other hand, the creation scenario proposes very rapid changes during the biblical Flood. It turns out that even if we ignore the Flood, the relatively slow geologic processes we now observe are actually so fast that they challenge the thousands of millions of years proposed for the development of life on earth, as suggested for evolutionary processes.19 As an example, the present rate of erosion of our continents by rain and consequent rivers into the ocean is so rapid that we would expect the continents to be eroded down to sea level in about 10 million years. Why are our continents still here if they are thousands of millions of years old? A number of geologists have alluded to this problem.20 Even after correcting for man’s agricultural activities, which hasten erosion, the rate is so fast that our continents could have been eroded to sea level over 100 times (if they could be revived) in a conservative postulated age of 2,500 million years for the continents. Renewal of the continents from below is sometimes proposed to resolve the dilemma. This does not seem to be a solution, since the geologic column which contains very ancient layers is still well represented on the continents, and we don’t seem to have completed even one full cycle of continent erosion and uplift."
And, of course.
"The problem of complexity
The presence of complexity—interdependent parts that do not function unless other parts are also present—poses another major problem for evolution. For instance, a muscle is useless without a nerve going to the muscle to direct its contracting activity. But both the muscle and the nerve are useless without a complicated control mechanism in the brain to direct the contracting activity of the muscle and correlate its activity with that of other muscles. Without these three essential components, we have only useless parts. In a process of gradual evolutionary changes, how does complexity evolve?
Interdependent parts, which represent most of the components of living organisms, would not be expected from random, undirected changes (mutations) as is proposed for evolutionary advancement. How could these develop without the foresight of a plan for a working system? Can order arise from the turmoil of mixed-up, undirected changes? For complicated organs that involve many necessary changes, the chances are implausibly small.
Without the foresight of a plan, we would expect that the random evolutionary changes would attempt all kinds of useless combinations of parts while trying to provide for a successful evolutionary advancement. Yet as we look at living organisms over the world, we do not seem to see any of these random combinations. In nature, it appears that we are dealing largely, if not exclusively, with purposeful parts. Furthermore, if evolution is a real ongoing process, why don’t we find new developing complex organs in organisms that lack them? We would expect to find developing legs, eyes, livers, and new unknown kinds of organs, providing for evolutionary advancement in organisms that lacked desirable advantages. This absence is a serious indictment against any proposed undirected evolutionary process, and favors the concept that what we see represents the work of an intelligent Creator.
The simple example of a muscle, mentioned above, pales into insignificance when we consider more complicated organs such as the eye or the brain. These contain many interdependent systems composed of parts that would be useless without the presence of all the other necessary parts. In these systems, nothing works until all the necessary components are present and working. The eye has an automatic focusing system that adjusts the lens so as to permit us to clearly see close and distant objects. We do not fully understand how it works, but a part of the brain analyzes data from the eye and controls the muscles in the eye that change the shape of the lens. The system that controls the size of the pupil so as to adjust to light intensity and to reduce spherical lens aberration also illustrates interdependent parts. Then there are the 100,000,000 light-sensitive cells in the human eye that send information to the brain through some 1,000,000 nerve fibers of the optic nerve. In the brain this information is sorted into various components such as color, movement, form and depth. It is then analyzed and combined into an intelligible picture. This involves an extremely complex array of interdependent parts.
But the visual process is only part of our complex brains, which contain some 100,000,000,000 nerve cells connected by some 400,000 kilometers of nerve fibres. It is estimated that there are around 100,000,000,000,000 connections between nerve cells in the human brain. That we can think straight (we hope most of us do!) is a witness to a marvellous ordered complex of interdependent parts that challenges suggestions of an origin by random evolutionary changes. How could such complicated organs develop by an unplanned process?"
http://www.creationontheweb.com/content/view/3573/
cal
Massimo,
ReplyDeleteI just wanted to thank you again for participating in our symposium. I really enjoyed your talk (as well as those from all of the other speakers), and it was great to meet you at the banquet Saturday night.
Dr. Pigliucci -
ReplyDeleteI would love to know more about that macaque (especially regarding any anatomical changes it may have undergone,). Are you aware of any online resources where I could read more read about this case? Thanks!
Dave
Nevermind. I did my own homework. :)
ReplyDelete"this guy doesn't look that different from some people I encounter in the New York subway..."
ReplyDeleteLOL :)
Maybe you should consider changing your means of transportation.
Once again, Cal is making the argument from incredulity.
ReplyDeletegary
Now I remember where I've seen that picture.
ReplyDelete"Charlton Heston strides to the podium to address meeting of the NRA."
I am now feeling smugly self-satisfied. I started reading the lengthy post that begins "Tools sound like a wonderful thing to have, Massimo. But you must know just as well as I do, that there are a variety of insurmountable problems that even normal (not gifted persons like you) will quickly recognize...", and I immediately asked myself, "This wouldn't be Cal, would it?" (Note that Cal is evidently incalpable of creating a personal account, and still signs into all posts as "Anonymous".
ReplyDeleteSo I fast-forwarded to the end of the post and--[i]mirabile dictu![/i]--Yes, it's the purveyor of all nonsense on RS. Does this mean I win the JREF award for psychic phenomena...?
"Yes, it's the purveyor of all nonsense on RS. Does this mean I win the JREF award for psychic phenomena...?"
ReplyDeleteKimpatsu,
Ah come on, give the guy some credit. Cal did give me some good advice on raising a teenager, (see comments on Massimo's The Teenage Brain) and all of it non-religious and rational!
Speaking of monkees and such, check out this
ReplyDeleteYoutube
Instead of merely claiming incredulity, the alternative would have been to sincerely ask the question why there are no plants in some areas of the fossil record where they would have been required by the particular species to survive. (as Ariel Roth in the quote had suggested)
ReplyDeleteThere are other areas of the fossil record that represent huge gaps in the food chain also. (so if one does not place "God in the gaps", what does he place there?) Plants are only a small fraction of the problem. Look it up and study the fossil record for yourselves.
think, gentlemen
& Thank you, Sheldon. You're right, of course. I do like skeptics. Most of us all start out that way, you know.
And I really don't mind if you accept most or none of what I say, just as long as you have the will left to keep your mind open.
NO psychic awards for anyone tho. too bad. cuz I am the "mom" of my teens. ;)
cal
question why there are no plants in some areas of the fossil record where they would have been required by the particular species to survive. (as Ariel Roth in the quote had suggested)
ReplyDeleteIt would have been even better if the guy who wrote all that rubish would stop embarassing himself in public, wasting paper and all that...
1. Consider the simple fact that different organisms have different probabilities of fossilizing, due to their biology and structure. Who said plants fossilize as easily as animals?
2. Even when there are lots of fossilized plants, they are not as glamourous as dinossaurs (sorry, Massimo), therefore you don't hear much about them.
J
"J said... question why there are no plants in some areas of the fossil record where they would have been required by the particular species to survive. (as Ariel Roth in the quote had suggested)"
ReplyDeletePlants are only a small fraction of the problem, J. Where do insects, reptiles and rodents appear on the most currently favored fossil record? I do know, that in most cases, they are too far apart to make any sense.
I am certain of that.
"It would have been even better if the guy who wrote all that rubish would stop embarassing himself in public, wasting paper and all that..."
Yeah, yeah, yeah. If I had a dime for every time someone said something silly like that, I'd be a ba-zillionare.
"1. Consider the simple fact that different organisms have different probabilities of fossilizing, due to their biology and structure. Who said plants fossilize as easily as animals?
2. Even when there are lots of fossilized plants, they are not as glamourous as dinosaurs (sorry, Massimo), therefore you don't hear much about them."
I know that. But it isn't too much of a problem where I live. Ferns, fishes and trilobites are all fossilized together up the road to the south about 20 minutes from me. Rather exciting, isn't it?
It's called "Kinney Brick yard" quarry, if I remember correctly.
Come on, you unembarassed,(presumably) intelligent man. Let's see who REALLY knows what their talking about. ;)
cal
"I know that. But it isn't too much of a problem where I live. Ferns, fishes and trilobites are all fossilized together up the road to the south about 20 minutes from me. Rather exciting, isn't it?"
ReplyDeleteHmmm... un"sorted" flora and fauna. Yes, it's exciting!
Almost as exciting as the
Egg Mountain site, with its unsorted fossilized remains of eggs, embryos and juveniles.
suff,
ReplyDeleteThe fossil record should not exist strictly to serve the purposes of evolution. That would be the all too obvious equivalent of evo-centrism. The flat-earth people and the geocentrists fell for the same unproven, fallacious pattern of thinking.
That something is "unsorted" is just an assumption, but a mostly true one I think. What precisely makes one KNOW that the fossils in question ARE NOT "where they are supposed to be"? Catastrophes are usually somehow a factor where most fossils are found. So one naturally wonders, which types of catastrophic events unsettle the fossils enough to make any of the fossil arrangements credible or less than credible?
So I think for a variety of reasons, one cannot pick and chose here as to what "unsorted" is supposed to mean. And although the existance of fossils certainly does mean something, I fear that evolutionists really do throw their whole fate and future into the hands of randomness and disorganization by accepting the results of catastrophes as some kind of model of what is "true" about the universe.
That is, one is more likey to be following after what is the exception, not "the rule".
cal
Cal
ReplyDeleteI'm not sure I've got the gist of everything you said in your comments. For example, I don't see myself as picking and choosing what "unsorted" is supposed to mean.
In your earlier comment you referred to a theory that the fossil-organisms were deposited during a biblical flood, and sorted at that time- presumably by weight? (in a pebbles-on-the-beach effect).
Well, the Egg Mountain site that I referred to provides a good counterexample to this theory, because the nesting site represents at least part of a larger ecosystem- nests, eggs, and some partly grown juveniles, all of different weights (unsorted). It seems obvious that these artifacts have been preserved in situ, not picked up and dropped in a worldwide catastrophe.
By the way, this statement by your friend Roth is a non sequitur:
" The fossil assemblages found represent incomplete ecosystems. How did the animals survive for the millions of years postulated for the deposition of these formations without adequate food?"
The fact that the record is incomplete does not warrant the conclusion that the dinos had nothing to eat.
I believe that my link to the UCMP website indicated that in some cases the fossilized remains of stomach contents have been found (or so inferred). And some of the contents are pretty rough- e.g., pine cones. Kind of demonstrates how the absent flora were nevertheless present, but required a storage medium in order to be preserved, in this case a stomach.
suff,
ReplyDeleteBut even so, the conditions that allow for this arrangement or placement of fossils are rather exceptional, don't you agree? And pardon me if I wasn't terribly clear about the direction of my comments. I'm not as systematic in my thinking (or writing) sometimes as I'd like to be. I didn't mean to imply that everything that is fossilized was strictly the result of catastrophes.
And even the cases of exceptionalism do say something. I just think that we might not agree as to what they are saying.
And that's always the problem, isn't it. :)
The site up here in the mountains, btw, is so very, very interesting. I was asked by a friend with a phd in paleontology some time ago to help find him a way to get in to the quarry with total ligit access, but we didn't follow through on it for some reason. Probably because he had bigger fish (specifically fossilized birds) from china to fry.
- cal
"Well, the Egg Mountain site that I referred to provides a good counterexample to this theory, because the nesting site represents at least part of a larger ecosystem- nests, eggs, and some partly grown juveniles, all of different weights (unsorted). It seems obvious that these artifacts have been preserved in situ, not picked up and dropped in a worldwide catastrophe."
Cal
ReplyDeleteI'm sure that flash floods, mudslides and that sort of thing figure in a lot of fossilizations. No quarrel there. But I don't think that catastrophe is the explanation for the geologic column itself, which is the theory that some people advance. Peace out.
For more details on the bipedal macaque, see this story (thanks to Dario Maestripieri at the University of Chicago for the heads up):
ReplyDeletehttp://www.msnbc.msn.com/id/5479501
In this case it seems that the behavior was catalyzed by a stomach virus. Note also the observation that it isn't unusual for macaques to engage in bipedal behavior.
To the untrained me this seems like a fascinating article.
ReplyDelete