Uncommon Descent Serving The Intelligent Design Community

Is “Directed Evolution” Darwinian? [with addendum]


I posted a reference the other day to a peer-reviewed paper by two Finnish ID-supporters that I claimed supported ID. The paper highlighted that evolutionary methods work to the degree that they are directed. As is typical with our detractors, whenever a pro-ID paper by pro-ID scientists comes out in a peer-reviewed biology journal, they try their best to show that it doesn’t actually support ID. An example is the following post at PT by Steve Reuland:


In reading Reuland’s critique, try to keep track of “rational design,” “directed evolution,” and “Darwinian methods.” Reuland conflates the last two. In so doing, Reuland completely misses the boat. So let me spell it out: DIRECTED EVOLUTION IS NON-DARWINIAN. DARWINIAN EVOLUTION IS NON-DIRECTED. I’ve been saying this now for close to a decade (see ch. 4 of my book No Free Lunch). Just because the word “evolution” is used doesn’t mean that homage is being paid to Darwin. “Directed evolution” properly falls under ID.

[Steve Reuland, commenting at the Panda’s Thumb on this post, claims that I’ve misrepresented him and the paper. If he but were to read the paper closely, he would find that it distinguishes between Darwinian evolution as an “inspiration” to directed search and “Darwinian blind search” as inherently limited. Darwinian evolution, which is blind, is the inspiration for evolutionary computing, which employs well-crafted fitness landscapes to achieve ends and therefore is not blind — and therefore is properly a branch of ID and non-Darwinian. Yes, we’re playing a turf war here. But it will not do to have Darwin discard teleology and then to claim teleological processes as Darwinian. This is an abuse of language. Leisola and Turunen skirted the edge yet nuanced their views adequately; but Reuland is guilty of it.]

Do you consider white fur on a fox to be a fitness variable? --michaels7 It depends upon the fox and its environment. a) is it fox in a snow-covered environment much of the time and b) is there in fact variation in the coloration of the fox's fur? c)does the color variation contribute to the probability of a successful hunt? If the coloration impacts its success at hunting, it almost certainly would be a fitness variable. There are also other things to consider, such as how mate choice may be influenced by color. My problem in “understanding” issues with NS is one of clarification between core and non-core variables for fitness. It's often not an easy thing to distinguish. Researchers try to gather as much information as possible about the system in question, but even then mistakes can be made and in many cases we still don't know. As Jerry indicated genetic drift plays a much larger role than people often assume. One thing which helps narrow the problem, though, is to consider relative fitness among organisms. This allows you to only focus on those traits that are, in fact, variable in the population under study. So while the length of the adult femur in a T-Rex likely contributed to its absolute fitness (whatever that is), it would be a non-factor in its relative fitness equation if all adults had the same length femur. (This was an admittedly contrived example, but hopefully illustrative of the point.) In other words, it's important to know what the variable traits are. One can only empirically test how a certain trait influences fitness of a species when there is *no* existing variation in that trait in question by introducing a new mutation for the trait and seeing how it fairs in the population. Hope that helps somewhat. great_ape
Atom, You said "Organisms X and Y are two different allele types (variations) of the same species." I have no idea what you are talking about so maybe some examples are in order. Consider the following. Organism X at time t1 (e.g. the year 1970) has a population frequency distribution d1 (e.g. 40%) of some allele (e.g. fur coloring). At time t2 (e.g. the year 2000) the frequency distribution for this allele is d2 (e.g. 50%) and it is considered substantially different from d1. What are the causes for the changes in this frequency distribution? Biologists and geneticists have hypothesized two main causes; the first is something they call natural selection based on environmental pressures and second is called genetic drift which is based on chance. There could be others such as a migration of species members but these are the two main ones. If you want to suggest other processes, then go ahead. If you want to eliminate one of the two main processes, then go ahead. But in either case you have to have evidence and reasoning to back up what you want to say. If you want to make the definition of natural selection more precise, then go ahead but I doubt anyone will believe that the process is non existent and does not act in the environment. jerry
Your examples of organisms x and y is inappropriate. Focus on variations of x alone.
Organisms X and Y are two different allele types (variations) of the same species. Better? Atom
natural selection or whatever you feel comfortable calling it is only applicable to a population. Your examples of organisms x and y is inappropriate. Focus on variations of x alone. You are literally comparing apples and oranges with a whole milieu of allele difference maybe as much as humans and bananas. So looking at one allele that may be common to both organisms may not be meaningless but most likely inappropriate. jerry
A short follow-up: Can fitness be defined apart from differential reproduction? (As a set of envrionmental constraints and phenotypic traits, for example) Imagine a desert environment shared by two organisms, X and Y. Both live in the same exact location and share the same constraints. X needs to drink 10% its body weight in water each day to survive; Y needs 50%. Organism X in this enviornment will reproduce and have 3 offspring each generation. Organism Y will have 100. Generation times are the same as are times of reproduction. Q1: Which organism is more fit, in this environment? (If you say X, then fitness has no bearing reproductive success.) Q2: If organism Y is more fit, then that means that those traits are more fit, by your definition. (When its traits "interact" with the environment it produces more offspring, meaning it has a greater survivalability.) So if this is the case, lower water consumption has a negative correlation with fitness. But for two other organisms, P and Q, also living in the exact location and environment, maybe the opposite is true. But in all cases, we can't define fitness in relation to an ideal set of traits, since a trait will give us different results in the same environment; we can't know beforehand what the outcome will be. So we then define fitness based not on possession of this or that trait, but on actual outcome success. This poses the problem of circularity. Either way we lose. I invite your discussion. I may be missing something. Atom
jerry, great_ape, I appreciate your interaction on the topic. jerry, I recognize that this isn't the biggest problem for Darwinism, but this is just a single thread discussion on one weblog. I have a suspicion that many people are interested in seeing these issues worked through, however. A couple quick items: great_ape, good analogy with F=ma. I wanted to think about this before I responded. You don't need to respond back, I won't press for answers. Let's take gravity again. You are correct that we can associate the label "force" simply with the outcome, ma, an accelerated mass. In the same way, we can associate the label "Natural Selection" with the outcome, differential reproduction. But then we'd need to ask "what causes the 'force'"? For gravity, I'd be foolish to reply "the accelrated mass (ma) is the cause of the force." Imagine a universe with a single object at constant velocity. It begins to accelerate. Was that accelration caused by "the mass accelerating (ma)"? If so, the acceleration was uncaused. So if we identify the force with the outcome (effect) we now need an explanation for the "force", since the outcome still needs an explanation. For gravity we have one: bent spacetime or graviton exchange. Notice, "acceleration" is not needed to explain the force. In the case of NS, yes we can also identify it with the outcome. But then we need to explain the cause of "NS", since we still need to explain the cause of the outcome. And invoking "differential reproduction" or even "differential fitness" (which is based on differential reproduction) is the same as saying "the differential reproduction caused the differential reproduction". In fairness, you brought up environment interaction which I'm guessing you will say "causes" the differential reproduction. How it does so apart from differential reproduction, I have yet to see explained. Atom
Apparently genetic drift explains more changes in population allele frequencies than natural selection. This is what the population geneticists say. To me this whole argument is over minutiae. If there is a change in the frequencies of alleles it could be due to environmental factors that led one set of alleles to increase in frequency and I would say that this is an example of natural selection or it could be due to statistical differences due to chance that end up favoring one set of alleles over another. Modern biologist and geneticists recognize there is a problem with the term "selection" in natural selection and sometimes use the terms "natural interaction" or "natural fit." In any given situation it may be impossible to figure which is happening or what combination is happening. If you have a frequency change, then it might be interesting to see which may be operating but it may not be answerable unless some experiment is possible. Throw out the term fitness if you want. Change the term selection to something else if you want. It doesn't add or subtract anything from the discussion. The underlying processes are still there and easy to understand. This all takes away from the central discussion. Whatever you want to call the processes involved in allele frequency changes, they are a minor, minor, minor processes in terms of the evolution debate. They can be very important for medical research but in terms of evolution they are at best a side show. That is the important point. Focus on this and we may get someplace, not whether the proper terminology is being used which current biologists already admit. jerry
Question, Great_Ape, Do you consider white fur on a fox to be a fitness variable? My problem in "understanding" issues with NS is one of clarification between core and non-core variables for fitness. I think there is confusion in these areas in relation to micro vs macro outcomes which no experiment has yet to overcome. and yes, the typing slows down. Michaels7
For the record, I also think the "outcome" explanation of fitness is inadequate for much the same reason Lewontin does. And I'm not sure it is fair to say modern evolutionary theorists think of fitness purely in terms of outcome. "Some theorists" does not imply a consensus. It is probably fair to say that in experiments, for the sake of quantitation, fitness is effectively treated that way. If you're working with flies, for example, you might measure fitness in terms of viable offspring. Now that I see your excerpts, I think that Lewontin's essay was one of our assigned readings way back when. great_ape
great_ape, thank you for your response. If you feel you have explained yourself as well as possible, feel free to let your responses remain, as I won't press past that point. In the essay Sal linked, Lewontin explains that the definition you and jerry are using was that used by Darwin, but is not that used in Modern Darwinian Theory. They use the definition I refer, that based on outcome, which I (and others) find problematic. But it seems that an outcome based definition is the only one that "works" for doing any kind of quantatative work. Two excerpts from the essay. Sal already posted portions of these two excerpts but they highlight the very problems I bring up:
The difficulties of the concept of fitness are, unfortunately, much deeper than the problem of frequency and density dependence. The problem is that it is not entirely clear what fitness is. Darwin took the metaphorical sense of fitness literally. The natural properties of different types resulted in their differential “fit” into the environment in which they lived. The better the fit to the environment the more likely they were to survive and the greater their rate of reproduction. This differential rate of reproduction would then result in a change of abundance of the different types. In modern evolutionary theory, however, “fitness” is no longer a characterization of the relation of the organism to the environment that leads to reproductive consequences, but is meant to be a quantitative expression of the differential reproductive schedules themselves. Darwin’s sense of fit has been completely bypassed. The natural properties of organisms lead to differential reproductive schedules and these must somehow be mappable onto a quantitative function, fitness that can enter into formal prediction structures.
There is no obvious common feature that would have allowed us to predict these classes. How, then, are we to assign relative fitnesses of types based solely on their properties of reproduction? But if we cannot do that, what does it mean to say that a type with one set of natural properties is more reproductively fit than another? This problem has led some theorists to equate fitness with outcome. If a type increases in a population then it is, by definition, more fit. But this suffers from two difficulties. First, it does not distinguish random changes in frequencies in finite populations from changes that are a consequence of different biological properties. Finally, it destroys any use of differential fitness as an explanation of change. It simply affirms that types change in frequency. But we already knew that.
Atom, One last thing. I took a graduate seminar on the philosophy of biology several years back with one of the main players in the field. I remember from that course that issues such as yours have come up in the literature over the years, and I only wish my memory served me better so that I could reference relevant articles and arguments. I just wanted to point out that, while I do think you're wrong, I don't think the conceptual issues surrounding NS and evolution are as clear and obvious as some folks make them out to be, and I find it very understandable that disagreements can ensue as people try to get the bottom of just what these terms signify in reality. Ultimately, however, what matters to me is whether there are useful and meaningful distinctions to be made by invoking these terms in the manner they are invoked. And I think there are very few who would claim that there are no such meaningful distinctions to be made. great_ape
Atom, I don't think I can my position any more clearly than motthew has. Personally, I think you have lost yourself in linguistic analysis, as has been the case with many-a-problem in philosophy. I will, however, attempt to answer your questions, then I will likely bow out b/c the thread is becoming unwieldy. (Is it just me, or when we hit > 120 posts or so there is an annoying lag with typing, etc.?) 1) Is differential reproduction required (in the causal antecedent sense) as a prerequisite for NS to occur? (you used the word prerequisite earlier) Yes. If differential reproduction did not result from the environmental "forces" doing the filtering, then we would not refer to that combination of environmental factors as contributing to "natural selection." Again, "natural selection" was darwin's attempt to put a label on a certain phenomenon in nature consisting of the interaction between environment and traits and the differential reproduction that ensues. The whole system: environment + traits + ensuing differential reproduction is what we refer to as "natural selection." 2) Is differential reproduction the result of “natural selection”? Again, linguistic issues. You're banking on the common linguistic sentiment that something can't be both part of the definition of a something *and* the result of that something. Yet consider F=ma. Would you make the argument that the acceleration of a body can't be caused by a force, because acceleration is necessary to define force to begin with? 3) Does not the “selecting” occur as replicators reproduce against a backdrop of environmental factors and constraints (self-selecting as it were by their acts of reproduction)? If not, when exactly does the act of “selecting” take place? When the environment was first set up in the big bang? Every moment? Or only when things actually reproduce and survive? It occurs precisely when things reproduce and survive, differentially, based on environmental influences. That is, when a process meets the criteria outlined for "natural selection." Is this process different from other material/biological processes and worthy of its own title? You bet. And the fact that Darwin received such accolades for putting his finger on why it's different and noteworthy is a testament its being a well-applied label. Also, I should add, NS is a population-level phenomenon. It happens when a *population* of organisms begins to change as a result of the interaction of the environment and their respective heritable traits. Again, I think the term "force" is questionably relevant to this discussion and may add more confusion than its worth. I prefer "process". And clearly the process of natural selection is distinguishable from other processes, such as genetic drift, etc. The word "force" is often and understandably used because, again, it's a blanket label/metaphor for diverse environmental factors leading to differential reproduction. Feel free to not call NS a force, if it makes you feel better. But just be fair and treat artificial selection the same way. A quick analogy. "Fire" is what we call a certain chemical rxn between a range of substances and oxygen. Fire is a process. The transformation of a substance (e.g. wood to ash) is part of the definition of the process of fire. Yet according to your philosophical deconstruction of "natural selection," it would not be accurate to say that fire burns wood and produces ashes. Think about it. Because in a certain restricted semantic sense, you could be correct about some aspects of the usage of "NS" as a label. Yet have you thereby accomplished anything of any significance to the real world? Have you unveiled anything that wasn't already understood? 4) If differential reproduction is required to cause “Natural Selection”, then how can it also be the result of “Natural Selection”? (see #3) great_ape
MatthewTan, I believe that current mammals have over 200 or more different cell types, each working with one or more of the other cell types. Quite a complicated system to develop by design let alone by random events and still getting all the "bugs" worked out. Another good analogy. jerry
Re: Comment #123 by gpuccio Interesting and insightful “soliloquy”. I think gpuccio has a strong point. Increasing complexity not only does not really improve survival "fitness", but becomes a "burden" opening itself to multitude of potential "bugs" in the "operating system". MatthewTan
The combination of alleles and environment can lead to differential reproduction depending upon the particular combination.
The combination of alleles and environment may lead to the differential aspect of differential reproduction once the reproduction actually begins to take place. The reproduction and the "act" of selection are one in the same. If an organism has the right combination of alleles for an environment but withholds from reproducing, then the "selection" has changed even though environment and alleles have not. So it is the organism that selects itself, in a sense. Some are better at doing so than others. The environment just provides the arena, with hazards and constraints. Natural Selection, then, is not a force. It is merely a description we give to what happens when replicators out-replicate one another. In other words, it is a description of differential reproduction. As I said in my first post on this...
Natural “Selection” on the other hand is a-causal; it doesn’t cause differential reproduction, because it IS differential reproduction. What does differential reproduction cause? Differential allele frequencies…but then again, isn’t that what differential reproduction refers to anyway, since we talk about populations on the level of genes? So differential reproduction “causes” differential reproduction.
If Natural Selection is a force, what does it cause? What does it require? Does it require the phenomena it is supposed to cause? Atom
I am aware of ecothermic animals for which homeostasis is less important so my opening comment could be limited to most endothermic animals. jerry
Good work motthew. I don't see anything controversial with your mathematical abstraction. I'd like to focus in more on "who is doing what" (environment as backdrop of constraints vs. as "active" filter), but I like the way you're describing it. Since I have taken so much time in tearing down the popular (mis?)understanding of NS as "force" separate from the result of differential reproduction, in other words what it is NOT, I probably owe it to all the partcipants to explain what I think NS actually IS. I do think a phenomena exists and it is repeatable. I just differ on "who is doing what" and on whether or not we can define it in a non-circular way. Hopefully I can pull away from my lovely girlfriend long enough this weekend to write up a short summary of what I think NS is. Lets hope. Atom
Can we agree that homeostasis is good for the prolonging of life? I am sure it is not the only variable but it seems like a very healthy situation for living organisms. So that organisms with alleles that promote homeostasis are more likely to reproduce and have more offspring because they will probably live longer. Also organisms with alleles that disrupt homeostasis are more likely to die and not reproduce and thus have less offspring. Also the alleles that promote homeostasis in one environment may not promote it in another environment. And vice versa. The combination of alleles and environment can lead to differential reproduction depending upon the particular combination. How hard is to understand. It is not circular; it cause and effect. jerry
I wonder if some mathematical terminology might not help me get my point across (this is dangerous for me to do since I only minored in mathematics and have forgotten much of it). Please bear in mind that this discussion is probably worse than the proverbial elephant going down a slide. I'm not intending to deal with details, just provide a theoretical framework. Suppose we have a equation for fitness f(p,e) where p is a certain phenotype and e is an environment. The result of the function is a real number from 0 to 1, representing the scale from totally unfit to totally fit. The phenotype is, of course, evaluated in the context of the given environment, and phenotypes which produce higher values of f will be more reproductively successful than other phenotypes in the same environment. Now, it's true that specific traits in the phenotype cannot tell us its overall fitness for an environment, but that's why we have black box fitness function that gives us a phenotype's overall score. An individual of a given phenotype is of course going to have wildly different success in reproduction. We could possibly predict the pattern of individual's success by using a statistical bell curve centered at the individual's phenotype's f(p,e) score. A certain subset of phenotypes for a given environment will, of course, score closer to 1 than the rest will. That means this subset (however wildly different their traits may be) of phenotypes will dominate reproductively, and thus the environment acts a preset filter and unintelligently directs the phenotypes in it toward certain outcomes. While my theoretical fitness function is designed to be a universal, unchanging function, the trouble is that both phenotype and environment are in a constant state of flux. How strong is this flux? Sometimes it can be extremely chaotic and other times only be wiggling around a little bit. This messes with the directional aspect that exists when using constant values for f(p,e). In actuality p and e would have to be some sort of differential equations. For breeding programs, however, the environment variable would have to be substituted for a goal (g). So we have a new but similar function f(p,g). In this function, however, constant variable are used. So we can accurately predict the overall outcome. I'll stop there and wait for input. motthew
Yes, differential reproduction is *required* for natural selection in the sense that it is necessary to *fulfill* the full criteria for “natural selection.” *BUT JUST AS IMPORTANT* for meeting the criteria for natural selection is the *action* of various aspects of the environment towards *generating* that differential reproduction. It is this latter component of the criteria that I think Atom is neglecting in his argument.
great_ape, I will ask you to be straight-forward. (No "metaphorical" terms are needed to precicely and quantifiably describe the FORCE of gravity, mind you.) 1) Is differential reproduction required (in the causal antecedent sense) as a prerequisite for NS to occur? (you used the word prerequisite earlier) 2) Is differential reproduction the result of "natural selection"? 3) Does not the "selecting" occur as replicators reproduce against a backdrop of environmental factors and constraints (self-selecting as it were by their acts of reproduction)? If not, when exactly does the act of "selecting" take place? When the environment was first set up in the big bang? Every moment? Or only when things actually reproduce and survive? 4) If differential reproduction is required to cause "Natural Selection", then how can it also be the result of "Natural Selection"? Here is that same double-talk applied to gravity: For the falling of a body to occur we need: 1) the falling of a body, 2) *disparate* environmental factors which interact with the falling body, helping it along its way down (density factors, air particle collisions, solar photons, etc) and 3) any other prerequisties or disparate causes you want to throw in there. If you have all those factors (don't ignore any of them Atom!) then you will get the result of the falling of a body. You see, once you include the result as an explanation for how the result was caused you have lost your way. It doesn't matter what else you throw into the equation at that point. Atom
DanaMagee, One problem with birds is that they have an oxygen delivery system that is different from any other class of animals on the planet. It is uniquely suited to flight and without it birds would not be able to fly. It seems so unlkiely the might TRex which is similar to reptiles would have the same unique oxygen delivery system. Even if they did, where and why did it develop. It is not just small difference but a major reconstruction. jerry
gpuccio, Wonderful soliloquy! This philosophcal analysis you did, along with all the unliklihoods that must be assumed to support the opposite Darwinist viewpoint is very convincing. The problem is that the current holders of the keys to the world won't let this discussion get out. Even many who are supposed to be God's disciples on earth will not even let the discussion proceed. We have to keep on fighting. jerry
[...] Is directed evolution Darwinian? [...] Questions on natural selection « Omnipotent Grace
Wow, this thread has grown so quickly that I scarcely had the time to read it. That's the proof of one thing I have always thought, that NS is anything but simple. Only a very tricky concept could have generated so much discussion in such a short time! I'll try some more elaboration, just to add to the pool. The environment. Is it random or not? That's important because, as I have already written, there is little doubt that NS, however tricky and elusive the definition may be, is related to the "interaction" between the environment and the organism. So, if the environment is random, the only non random component of NS remains the organism, that is the already existing information plus the variation induced by mutation, which is by definition random. In that sense, NS could be considered random in regard to the creation of new information, as the only non random component is the already existing information. But is the environment random? And if yes, in what sense? I don't know if the environment is random in absolute. That depends if you consider the existence of a planet like ours only the random product of random forces in one of many random universes, or if you entertain any less drastical and more teleological view of reality. But that's not the point. The point is if the environment is random in regard to life, and in particular in regard to the new information necessary for important transformations in life. Let's make an example. At a certain time in the past, if we have a stable environment and stable organisms, what is the role of environment in NS? Has it only a "censorhip" role, in the sense of eliminating random errors in organisms? Or has it a "permissive" role, intended as boundary, for new organisms with new information? Probably both. There is no doubt that the environment, even if stable, is a constraint. Life as we know it would not be possible on Saturn. But the environment can also change. If it changes, life that was possible could become impossible, and vice versa. So we can say that the environment is certainly significant for the existence of life, but if we believe that its being what it is was not designed, then its relationship with the appearance of life is random, and if we believe that its fluctuations are not designed for life, then its relationship with further modifications of life is random. In other words, unless we believe that environmental characteristics and fluctuations are intended to help or modify life in a certain direction, their influence on life can be considered random. In that scenario (non designed environment) environmental conditions would act as a background randomly favouring or hampering life, because the laws which govern its temporal development have no pre-connection with life. In that case, it is life and only life which acts non randomly, adapting to the fluctuations of environment, or changing to interact differently with a stable environment. In both cases, the mechanism of that adaptation or transformation remains a mystery, it is certainly connected to the nature of life itself, and it is best explained by the concept of design. But the problem is that I do believe (while darwinists certainly don't) that the environment and its fluctuations may have been designed, at various levels, to help life. After all, I believe in a designer. But even in that case, even if the designer has in some way planned the environment for life, I still think that the role of environment is only passive, "permissive". It's a brilliant passivity, if you want, as is suitable to the designer, but always a passivity. Indeed, in all discussions about NS, a point is always underestimated: the characteristics of life itself. I see it this way. Too much fuss has been made of concepts like surviving fitness, reproductive advantage, and environmental landscapes and niches, and the result is that our reasoning has become biased, and we can't any more see what has always been under our eyes. And what is under our eyes is life itself, its obvious characteristics and properties, its apparent purposes. Surviving is not all. In any landscape, what are the entities which survive better? I would say, certainly, inorganic entities. Stones are very difficult to destroy, some of them have existed for aeons. Molecules, atoms, barions, are very long lasting, sometimes almost immortal. Life, on the other hand, is extremely frail, in all its manifestations. The reason for that is very obvious. Love is not realized because of the basic laws of nature, as darwinists still think. Life is realized "in spite" of all laws of nature, perhaps not violating them, but certainly manipulating them against all odds. That's why abiogenesis is still such a complete mystery for everyone. Because life cannot come out of inorganic matter, unless some really hard and fundamental event (we could say "miracle") takes place. Life is the only way the second law of thermodinamics can be ridiculized, without violating it. Living beings are so improbable that they can survive only through an incredibly complex inventory of continuous magics, and still only for a short span of time. Life is so improbable and frail, that the only way it has to survive is by cloning itself before dying, so that the unlikely miracle may be perpetuated in spite of all contrasting realities. But that's not all. Not only I really don't understand how one can think that life arises as a necessity from inert matter, but I don't understand either how one can suggest that the increasing complexity of life in progressively higher organisms may have as its own purpose "a better reproductive fitness". Are we kidding? I know no living being reproducing itself better than bacteria, the simplest living organisms. Bacteria are perfect: they live, they reproduce in an extremely efficient way, they exploit the environment certainly better than we do. They are beautiful, they are clever and cooperative (see the Shapiro paper), and, above all, they are many. Think about it. The simplest living species, the first one to appear on this planet 4 billion years ago, is still the prevailing living thing here. Why add complexity to that, to attain more reproductive fitness? Is the environment non randomly preferring elephants to bacteria? Why? Are humans better than arthropods, in regard to survival? Are they better than rats, in regard to reproduction? Why the added complexity? Was it the environment? The fact is, the increasing complexity in progressively higher beings is not really necessary for higher fitness: it is necessary for higher functions. Life "evolves" not because it has not already found efficient ways to reproduce or to survive. Life evolves to do "new things", things which were impossible in the simpler forms. And, although some (but, absolutely, not all) of this new things can be usefully recuited to help survival, survival in itself is not their motivation. Because, in reality, complexity provides new functions, but in itself it undermines survival. Life is extremely unlikely in a bacterium, but it becomes ever more unlikely and frail in a fish, in a bird, in man. Complexity is frail, as every PC programmer (or even simple user) well knows. That reminds me of operative systems. Who remembers the wonderful simplicity and stability of 16 bit Windows? (I am old enough to remember) So, why has Microsoft devised increasingly complex OSs, and still does, requiring higher and higher resources, higher and higher error managing (not always successful, I'm afraid), and higher and higher competence (and patience!) in the user? The answer is simple: because these new OSs, however complicate, however frail, "do more" than their ancestors. They are more powerful, and so they can manage more complex information, manage video and 3D rendering, true multitasking, and so on. So, I really think that function, and not mere survival, is the real motivation of increasing complexity in living things. And function is related to the inherent mechanisms of life itself, and of its main expression, that is consciousness. So, movement evolves so that living beings can move, and is then exploited to help survival, and compensate for the lower fitness intrinsecally related to higher complexity. The eye, in its various implementations, is necessary to see, to perceive the world in a new dimension of representation, and not only to survive. But it can help survival. The purpose of life is to express itself, to express qualities and experiences which are inherent to life and consciousness. They are expressed as higher functions, to know the environment and interact with it, and not only to survive without any goal. The higher organisms must pay a very heavy cost to be able to express these new functions: their bodies must become bigger and more complex, intelligently manage an incredible number of cells, highly intricate immune systems must be designed to defend them from insults, billions of billions of neurons must control what takes place in the inner world of the body, and interpret and organize myriads of information from the outside, and correctly respond to them. The chance to survive, even for short periods, is brought beyond any reasonable limit of likelihood. But, luckily, the designer is up to the challenge: he knows his task. So, excuse me for this long soliloquy, but sometimes, when I hear and read about randomness and the environment as "shaping" a whole living universe, an universe before which we should just feel inclined to bow in reverence, I lose my (scarce) self-control. gpuccio
http://www.cnn.com/2007/TECH/s.....index.html Now if Behe has no trouble with Common Descent then I assume he should have no trouble with a Bird-Dino link. Having "no trouble" with a bird-dino link (being able to accept the possibility) is not the relevant issue. The relevant thing is being able to be skeptical of it -- namely not accepting the certainty based on a CNN report. Frankly, I'm more fascinated at the unquestioned acceptance that protein can survive 68 million years. tribune7
If you accept Common Descent then you should have no problem believing in a Dinosaur - Bird connection right? For Old Earth Creationists this shouldn't be much of a problem either. For instance "there could potentially be NUMEROUS ancestors (perhaps each with a unique body plan?) and that evolution produced various versions of organisms from those established themes". Who knows. Scordova is right though we shouldn't reject scientific findings from the secular world just because of our bias against them. DanaMcgee
What are Dr. Dembski's views on the Bird-Dinosaur link? Take a look at this: http://www.cnn.com/2007/TECH/science/04/12/dinosaur.reut/index.html Now if Behe has no trouble with Common Descent then I assume he should have no trouble with a Bird-Dino link. DanaMcgee
Great_Ape, "Yes, differential reproduction is *required* for natural selection in the sense that it is necessary to *fulfill* the full criteria for “natural selection.” *BUT JUST AS IMPORTANT* for meeting the criteria for natural selection is the *action* of various aspects of the environment towards *generating* that differential reproduction. It is this latter component of the criteria that I think Atom is neglecting in his argument. Hmmm, not speaking for Atom, but I think he is being a good reductionist, yes? He's picked up on a valid point I think. Intelligent agency at the very least speeds up what the environment does, but does not stop there. It leaps over environmental considerations for "survival" with the unique creation of curious minds utilizing breeding techniques creating species based upon specialized and directed mutations for artificial consumption of the mind. What would normally only appear as short lived errors in any environmental surroundings and blip out as bad mutations - are kept alive by artificial means for whimsical curiosities in some cases. Still, I do not see how selection, plus random mutation, and environment converge to new life forms - without a centralized, animated code programmed to conserve information, but allow varience on the edge. This is what we observe today. Enjoyed this discussion everyone. Ps. Lucy is in trouble btw.... http://creationsafaris.com/crev200704.htm#20070410a Michaels7
Motthew? or Matthew? "There are important qualitative differences. Importantly, in breeding, those with the best selected-for traits are only allowed to mate with others with the best selected-for traits; in the wild organisms are allowed to mix freely, which is a serious hindrance." This is a good point. But not just a hindrance. In the wild, some artificially selected "best" traits could be a killer. In my above example the hairless cat survives due to the benevolent curiosity of individual breeders. http://en.wikipedia.org/wiki/Sphynx_(cat) "Wild organisms" living in the wild would not survive for long with such best selection procedures by us curious business minded and playful humans. Natural Selection is not a force. It is the end result of the environmental surroundings and available gene pool. Michaels7
#49, Atom, Very good. I almost posted the same subject matter last night, but my comments grew to long. Will try again, especially after Great_Ape, Salvador responded with good follow thrus. Environment is random. No animal would survive on Saturn. Lets truly step back. We have one "safe habitat" for life in our solar system(please, lets not argue ove Mars or moons). In our "safe habitat" we have more environmental influences within safe parameters. Sure, some are extreme to us - artic pole - produces polar bears. But allow that polar bear to migrate south, interact, you have part of the normal environmental influences wher most life flourishes at greater rates. Extreme environments cannot suffice to replace artificial selection, only point to selective qualities that are pre-determined within the gene pool influenced by environment or artificial choices. Dave's dog breeding example shows different boundary or limits. Or better, take the hairless cat(please). Bred uniquely for people with odd taste, would not survive in normal environmental surroundings. Artificial selection pushes the extreme mutations past even extreme environments. While mutations survive, switched off in normal environments. The breeder captures the mutated offspring and reproduces beyond population normals. Artificial selection creates artificial normality of mutational traits that would otherwise a)die off, b) limit numbers, low percentage. So we have... 1) "Normal boundary" genetic conditions within certain environmental thresholds. All genomes drift back to this boundary in normal environments. Call it a "Blemished gene pool" 2) "Extreme boundary" genes in exteme environments, randomly directed by environmental surroundings of hot, cold, moist, dry. "Exteme edge boundary gene pool" 3) "Artificial broken boundary" genes which would not go past certain population contraints in "normal or extreme boundary" conditions - like the hairless cat, just like a hairless polar bear would not survive. There are no beneficial traits - except - in the eye of an intelligent beholder. What I cannot agree to is these minima/maxima conditions lead to any novel type cell forms or macro structures. I think we mistake migration paths across great environmental boundaries with the equivalence of creating new species. While original migration may take time for specialization of traits - hair color, webbed feet, it only takes a generation or two for those specialized features to be absorbed back into the great "Blemished gene pool" Michaels7
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