Define 'species'

[lucaspa]

An increase in the survival capacity of a fraction of a hundredth of a percent is not macroevolution, thats microevolution, maybe.

It's evolution. Macro is simply accumulation of what you call "micro". As long as you have even 0.001 selection advantage, the trait is going to become "fixed" in the population.

Whats more you never told me how the changes are accumulated, we have a formula for equilibrium, wheres the one for evolution?

The discipline of population genetics did the basic mathematical formulas. Remember that, in the absence of any outside influence, such as natural selection, the frequency of an allele does not change from generation to generation. That is, if you have a population and 100 and 10 individuals have allele A and 90 have allele a, the next generation will be exactly the same: 10 A and 90 a. This is called the Hardy-Weinberg Law. Frequencies are symbolized mathematically by p and q. W is the relative fitness value. So we have W(A), W(B), and W(AB). The last is the fitness of the heterozygote in a sexually reproducting population.

So, for the first generation the frequency p of A in the population is: p^2 +2pq + q^2. Straight Mendelian genetics.

The frequency of p in the next generation after selection is: p' = p^2W(A) + pq W(AB)/p^2W(A) + 2pq W(AB) + q^2 (WB).

Now, if W(A) and W(AB) are higher than W(B), it can be seen that p' will increase. Not chance, but pure determinism.

You can see all this and a lot more in Chapters 4 and 13 in Futuyma's Evolutionary Biology, 1999.

Remember Hardy-Weinberg. The frequency of an allele remains unchanged from generation to generation in the absence of outside influence. Therefore, the fitness of a new mutation is defined as the ratio of the number of progeny actually produced divided by the number of progeny expected by Mendelian genetics. This is going to be greater than one in the case of favorable mutations. From that we get a selection coefficient such that fitness = 1 - s.

Now, doing the math we find that the advantageous allele A increases in frequency, per generation, by the amount delta p = (1/2)spq/(1-q).

If you look at the equation, you see that delta p is positive as long as s is greater than 0, even if it is very small. Eventually p will equal 1, which means that every member of the population will have the allele. Thus, a characteristic with even a miniscule advantage will be fixed by natural selection. "Fixed" means every individual will have the allele.

 

[lucaspa]

What has me puzzled the most is that microevolution is changes below the level of species, and macroevolution is changes above the level of specices.

Macroevolution is changes at or "above" the species level. Thus, speciation is macroevolution. After all, species (in terms of multicellular organisms) are the only biological reality -- as separate breeding populations.

This seems like some pretty fuzzy logic to me and not what I would expect from scientists that pride themselves on having precise and meticulas systems of thought.

Reality itself is the cause of the fuzziness.
" it does point up an issue of fundamental significance. In an evolutionary continuum, change occurs more or less gradually through time. At the early and late ends of such change, everyone agrees that different names are justified, but when one form slowly transforms into another without break, the point where the change of name is to be applied is a completely arbitrary matter imposed by the namers for their convenience only - it is not something compelled by the data." C. Loring Bruce, "Humans in time and space." In Scientists Confront Creationism, edited by LR Godfrey, 1983, pp. 254-255.

IOW, in a transition that takes 1,000 generations, we can't point to generation #500 and say "we still have 1 species" and to generation #501 and say "we have 2 species". Such precision is impossible. The transition is gradual and "fuzzy".

 

[gluadys]

But how do they add up? We have dominant and recessive genes in 3:1 ratios and there are times when no evolution actually occures and we have a mathmatical formula for that. So what happens to the ration of dominant and recessive genes since somehow the dominant genes don't keep the inheritance of traits at the normal ratio?

This seems to be a key to your difficulty.

First, the 3:1 ratio is not universal. It applies to situations when there are 2 alleles uniformly distributed through a species, with complete dominance of one over the other.

But this is not always the situation that occurs in nature. For example, there are three alleles for human blood type (A, B and O) and A & B are co-dominant, such that a person who is heterozygous for A & B does not have either blood type A or blood type B but blood type AB.

So instead of dealing with only two phenotypes you have four and you have to work out what the Mendelian balance would be differently than in the stereotypical text-book case. In some instances you have many more than two or three alleles in play for any given gene, and different modes of dominance, co-dominance, partial dominance, etc. so the ratios across a population become very complex.

Also, alleles may not be uniformly distributed through a species. The 3:1 dominant-recessive ratio assumes a 1:1 ratio of the underlying alleles. (50% of each allele in heterozygous individuals and 50% in homozygous individuals). But what if the alleles occur in a different proportion? You can get something like the 9:1 ration lucaspa spoke of. And the same Mendelian process which conserves the 3:1 ratio will conserve the 9:1 ratio.

Finally, all of these ratios are conserved only in the absence of outside influence. Well, environmental pressure, selective pressure IS an outside influence. Lucaspa gave you the mathematical formula and I think you are capable of using it to see how a change in the survivability of one phenotype or genotype over another leads to it becoming more common in a population and possibly even the sole allele for that trait.

But even a mathematical ignoramus like myself can set it out in a simple spreadsheet and see the difference when all phenotypes have the same survival expectations as compared to favoring one over the other(s).

 

[mark kennedy]

You asked what it would do to my knowledge of evolution if it were known that the environment had not changed dramatically. My point is that no dramatic change or pressure is necessary. In fact, even when there is no change at all, there is environmental pressure. Any species that is not utterly invulnerable experiences enviromental pressure -- and if even one hundred-thousandth of a population die before childbearing age, that population is under environmental pressures that will bring about evolution.

There very slight variations here and nothing to indicate either a mechanism for the accumulation of the microevolutionary changes. Keep in mind the genes are either dominant or recessive and these genes have to be altered substantially for speciation to occur. The thing is the parent organism is passing on a blueprint for every aspect the offsprings development. Altering that blueprint is almost allways detremental to the organism and even when it is beneficial the tendancy to revert back to the original condition.

Of course you have no clue why I think it's a strawman argument -- you have no clue because you learned these arguments from creationists who build strawmen for a living. It's not your strawman, but someone else's; and then when you present it, you get attacked for it -- perhaps unfairly, since you honestly believed it to be a good argument, but you can hardly expect to present deceitful information, whatever the source, and not get attacked.

This is simply not true, I did not learn much from creationists, I learned everything I use in these threads from Christian apologetics. The one questions that skeptics never seem to want to contend with is how we know the historicity of an event, the viabilty of our evidence, and what warrants our unwavering confidence. The truth is that natural science has credible tests for demonstrating, quantifying and qualifying data. None of the standard rules of demonstration apply to this one central tenant of evoltution, namely the universal common ancestor. It is not a theory because the substantive reasoning is flawed, its not a hypothesis because there is no way of falsifying it, there is only the wonder and flights of fancy that produce these monstrocites. Evolution is the measurement of changes in genes in a population over time, the universal common ancestor model is a myth.

Thats why species had to be made so nebulas, it was the immutablity of species that was the strawman, and special creation the target. If you make species ambiguise then any change, no matter how slight, is the straw that breaks the creationists back. It an elaborate hoax.

Mark, I think you might be astounded at what you would find if you went to the trouble of reading peer-reviewed scientific papers on the subjects that the creationist arguments you've learned address. Do you know how and why I left the creationist camp for the evolution camp (this was long before I left Christianity, by the way)?

I have seen what you are talking about and the greatest minds in Europe were agreeing with Rome in scientific matters for centuries. They were wrong and everybody was standing around agreeing with one another. I don't think people change that much, party spirit is still a powerfull inducement.

Because I'd noticed that the arguments I used from A Beka and Kent Hovind and Bob Jones weren't getting many results. They generally got debunked pretty easily. I decided to check out all the scientific data in support of these arguments (data that I had no doubt was out there) so that I would truly understand what the arguments were saying and be able to answer objections to those arguments better. To my undying wonder, I discovered in my search that all the data -- even the data used by creationists -- supports evolution and none of it supports creationism. This was by doing my own research into scientific discoveries of the past century, not by reading creationism websites or evolution websites, or by listening to arguments for or against evolution.

I frankly dont find the work of creationists very helpfull either. I would have abandoned the creation/evolution controversy long ago had I not taken the time to actually look at the evidence myself. I find it especially offensive that theology is belittled and ridiculed right at the heart of the emphasis. If we had the truth right here in front of us and it were conclusive I think both camps would be sorely embarassed.

So again, may I suggest that you take the same path that I did? You may not come to the same conclusion that I did (although honestly, I can't for the life of me fathom how you wouldn't, if you looked at all the data that I've seen), but at least you can say that you truly know what you're talking about. At least you can avoid saying things like what I just chewed you out for -- and you can earn or lose respect on your own merits, instead of seeing your credibility cut out from under you through no fault of your own, because you used something you learned from a self-proclaimed "creation scientist" who is out to win souls at all costs -- even if it means lying through their teeth.

Its ironic, I agree with the creation scientist and yet find so much of their work useless for me. I dispise the universal common ancestory and yet I am spending as much time as I can spare to learn as much about it as I can. Why, because thats where most of the science is. I listen to both side with equal interest but at the end of the day you have to think for yourself.

I liked the last part and I really have no problem with that line of thinking, I just take exception to the suggestion that this characterizes my thinking. Saving souls even thought it means lying is a perversion of every aspect of the genuine article of faith. Maintaining a confidence in the Scriptures and giving reasons for faith, even in an empirical context, is a Christian duty. It wrong to accuse someone of lying just because you don't happen to agree with them. I never once in all my debates and discussions resorted to that, I address the facts to the best of my knowledge.

I just wanted to get that off my chest.

Again, you misunderstand.

Say we have Mutation A that appears in a single individual in a population. If A gives that individual a survival advantage of a fraction of a hundredth of a percent over the other individuals in that population, then it is only a matter of time before virtually every individual in the population has the mutation. Do you see what I'm saying? Thus, no catastrophic or major environmental change is necessary for evolution to happen. As long as survival is a needed ability (that is, as long as organisms die before childbearing age), the necessary pressures exist to make evolution happen. This is so even when the environment is completely static and unchanging.

One little problem with this, most of the diverse species are in areas where there is an abundance and conditions are lush. The survival of the fittest, red in tooth and claw mentality has it backwards. Its not competition that is driving evolutionary change, its cooperation.

 

[mark kennedy]

It's evolution. Macro is simply accumulation of what you call "micro". As long as you have even 0.001 selection advantage, the trait is going to become "fixed" in the population.

I am not even slightly convinced that these micro changes are accumulated but lets see if I can sort the rest of this post out before jumping to any conclusions.

The discipline of population genetics did the basic mathematical formulas. Remember that, in the absence of any outside influence, such as natural selection, the frequency of an allele does not change from generation to generation. That is, if you have a population and 100 and 10 individuals have allele A and 90 have allele a, the next generation will be exactly the same: 10 A and 90 a. This is called the Hardy-Weinberg Law. Frequencies are symbolized mathematically by p and q. W is the relative fitness value. So we have W(A), W(B), and W(AB). The last is the fitness of the heterozygote in a sexually reproducting population.

You know what lucaspa, I may live to regret this but I'm going to try to help translate this into english. The Hardy-Weinberg formula is a baseline for measuring evolution, it kind of like in geometry when they say that a line has no width or limit. Now this is, as you seem to have grasped, based on the number of alleles but you forgot to mention the conditions that are nessacary. One of the biggest problems with gageing microevolutionary change is isolating it, mainly because there are so many genes and things that influence them. The HW equalibrium is only possible when the populations are large, its members mate at random and produce fertile offspring, and there is no migration, mutation, or natural selection. Now if you know anything about nature, this isn't going to happen much.

Its just a way of getting to 0. Now since I am wanting to explore the ideas of the evolutionist on the meaning of the word 'species', I don't think this is off-topic but its a little distracting from what I am most interested in.

So, for the first generation the frequency p of A in the population is: p^2 +2pq + q^2. Straight Mendelian genetics.

Yep, thats the formula they use.

The frequency of p in the next generation after selection is: p' = p^2W(A) + pq W(AB)/p^2W(A) + 2pq W(AB) + q^2 (WB).

You do know that these slight changes are as minor as fur color right? That no amount of changes in color, size, and form that do not alter the phenotype, much less the genotype right?

Now, if W(A) and W(AB) are higher than W(B), it can be seen that p' will increase. Not chance, but pure determinism.

I will think the is a reference to determinate cleavage so we are still in a basic biology context.

You can see all this and a lot more in Chapters 4 and 13 in Futuyma's Evolutionary Biology, 1999.

Remember Hardy-Weinberg. The frequency of an allele remains unchanged from generation to generation in the absence of outside influence. Therefore, the fitness of a new mutation is defined as the ratio of the number of progeny actually produced divided by the number of progeny expected by Mendelian genetics. This is going to be greater than one in the case of favorable mutations. From that we get a selection coefficient such that fitness = 1 - s.

Ok, we have the Hardy-Weinberg formula and this coefficient formula. All very interesting but we still have undefined boundries for speciation. How does the formula read when we start making the transition from one distinct species to another irreversably?

Now, doing the math we find that the advantageous allele A increases in frequency, per generation, by the amount delta p = (1/2)spq/(1-q).

If you look at the equation, you see that delta p is positive as long as s is greater than 0, even if it is very small. Eventually p will equal 1, which means that every member of the population will have the allele. Thus, a characteristic with even a miniscule advantage will be fixed by natural selection. "Fixed" means every individual will have the allele.

You give me this elaborate discussion on mathmatical formulas for measuring microevolutionary change and then you just hand it over to natural selection and say, 'there you have it!'

It really doesn't carry a lot of weight with me even though everything up to the word, natural selection, was perfectly true and totally reliable. Natural selection like the 'undiscoverable' species are the keys to the mystification of natural science that has plaqued the sciences from the dawn of time.

Ok, I'll make a deal with you, leave my theology alone and I'll take my time trying to sort out the science from the mythos of universal common ancestor mythology.

 

[bevets]

It's evolution. Macro is simply accumulation of what you call "micro".

The central question of the Chicago conference was whether the mechanisms underlying microevolution can be extrapolated to explain the phenomena of macroevolution. At the risk of doing violence to the positions of some of the people at the meeting, the answer can be given as a clear No. ~ Roger Lewin

Can you explain why Dr Lewin's observation was inaccurate?


Darwinists believe that the mutation-selection mechanism accomplishes wonders of creativity not because the wonders can be demonstrated, but because they cannot think of a more plausible explanation for the existence of wonders that does not involve an unacceptable creator, i.e., a being or force outside the world of nature. ~ Phillip Johnson

 

[mark kennedy]

Macroevolution is changes at or "above" the species level. Thus, speciation is macroevolution. After all, species (in terms of multicellular organisms) are the only biological reality -- as separate breeding populations.

Reality itself is the cause of the fuzziness.
" it does point up an issue of fundamental significance. In an evolutionary continuum, change occurs more or less gradually through time. At the early and late ends of such change, everyone agrees that different names are justified, but when one form slowly transforms into another without break, the point where the change of name is to be applied is a completely arbitrary matter imposed by the namers for their convenience only - it is not something compelled by the data." C. Loring Bruce, "Humans in time and space." In Scientists Confront Creationism, edited by LR Godfrey, 1983, pp. 254-255.

IOW, in a transition that takes 1,000 generations, we can't point to generation #500 and say "we still have 1 species" and to generation #501 and say "we have 2 species". Such precision is impossible. The transition is gradual and "fuzzy".

That is exactly where evolutionary thought just loses me. I am told on the one hand that the process is the gradual accumulation of microevolutionary changes. The I look at, for instance, the human family tree. You have prolong periods where there is no real change and the boom! Two lines are extinct and a new one has taken their place. I just don't buy into this arbitrary random variation concept. I like causation and I just can't accept the central cause being fuzzy. Precision is possible even when our understanding is incomplete, and by the way, there is an art and science of defining 'essense'. There are also ways of determining whether or not our confidence is warranted and its not material cause exclusivly. Sometimes its deliberatly directed.

See you later.

 

[ego licet visum]

Isn't the typical definition of a species a group of organisms that are able to reproduce with each other, and have offspring that are also able to reproduce with members of the same group?

 

[Jet Black]

I would consider it a very distinct possibility -- but I would also consider it a great cruelty to bring such a hybrid child into the world. The child would be neither chimp nor human, yet most likely intelligent enough to be aware of this and feel not without a community, or without a social life, or without a nation, but without even a species to call his own. For less intelligent creatures who don't really understand this, it's not so bad. But for a half-chimp, half-human child, I think it could very well be horribly damaging.

oh I don't know. we live with our lot don't we? It might be a bit distressing because of all the attention that the child got, but remember that retarded human children are in a similar situation in many ways. I think many gorillas and chimps can appreciate this sort of thing already, though perhaps not at such a sophisticated level as us.

 

[Jet Black]

Isn't the typical definition of a species a group of organisms that are able to reproduce with each other, and have offspring that are also able to reproduce with members of the same group?

that is a fairly basic definition yes, although it is more complex in reality because the species are artificial constructs put in place in order to allow classification. for example are horses and donkey the same or different species? well they are pretty much different species, but sometimes hinnys (female mules) can actually reproduce, although it is extremely rare. so they are 99% different species, but not totally. it isn't hard to imagine though that with some more genetic changes, horses and donkeys would be totally unable to breed.

 

[Jet Black]

That is exactly where evolutionary thought just loses me. I am told on the one hand that the process is the gradual accumulation of microevolutionary changes. The I look at, for instance, the human family tree. You have prolong periods where there is no real change and the boom! Two lines are extinct and a new one has taken their place. I just don't buy into this arbitrary random variation concept. I like causation and I just can't accept the central cause being fuzzy. Precision is possible even when our understanding is incomplete

no not really. the less complete our information, the lower the integrity of the data, since there may be a large amount of uncontrollable or immeasurable variables contributing to the outcome. As a result of this low data integrity, any cause and effect conclusions that we reach are bound to be suspect, because the cause could well be something else that we haven't taken into account (something we don't know about) That being said, nature is often unstable, and works kinfd of like a Shishi-Odoshi in which the water fills a bamboo pipe until it tips, spilling out all of it's contents in a sudden rush. Essentially this is the principle of punctuated equilibrium, in which evolution occurs in smaller more isolated areas, and then for some reason, the newly evolved species spreads out, and if it is fortunate enough to have adaptations that render it better (at breeding and surviving) than other species that would occupy its niche, the present species do not have time to evolve quickly enough and are driven extinct by the new species. note however that in the human family tree, there is pretty steady change, the difference is in the distribution of the different species of homonid, it is these that change suddenly.

 

[mark kennedy]

no not really. the less complete our information, the lower the integrity of the data, since there may be a large amount of uncontrollable or immeasurable variables contributing to the outcome. As a result of this low data integrity, any cause and effect conclusions that we reach are bound to be suspect, because the cause could well be something else that we haven't taken into account (something we don't know about) That being said, nature is often unstable, and works kinfd of like a Shishi-Odoshi in which the water fills a bamboo pipe until it tips, spilling out all of it's contents in a sudden rush. Essentially this is the principle of punctuated equilibrium, in which evolution occurs in smaller more isolated areas, and then for some reason, the newly evolved species spreads out, and if it is fortunate enough to have adaptations that render it better (at breeding and surviving) than other species that would occupy its niche, the present species do not have time to evolve quickly enough and are driven extinct by the new species. note however that in the human family tree, there is pretty steady change, the difference is in the distribution of the different species of homonid, it is these that change suddenly.

Punctuated equilibrium is a concept that was treated as disease in natural science. It was actually first proposed by Richard Goldschmidt in the 60s. Gould said in the mid-eighties that he would be vindicated, in fact he claimed that PE had allways been a part of evolutionary thought from the beggining. Darwin did mention the monstrocity but admitted that these mutations (usually during the cleavage or embryo stage) were allmost allways detremental. Keep in mind that Godschmidt was a geneticist and had studied, among other things, embryology.

There is one major problem with gradualism that has to be an embarssment for the neo-darwinian, the transitional forms appear relativly quickly suddenly and quickly transpose into something else just as quick. Darwin predicted the a long succession of slow slight gradual changes would be found in the geologic strata, in fact they have found the exact opposite.

The Berkley Creationist J. Wells pointed to the fact that for evolutionary change to occur it would have to happen in the cleavage stage. The main problem here is that this is the place where the organism is least resistant to change. This has to be a head scratcher for an evolutionist because I don't think you can have PE and gradualism as a demonstrated mechanism since the dynamics of one neutralizes the causative chain of the other.

I cannot be a theistic evolutionist and YEC creationist at the same time. Even if I incorporate the two and say that the original creation was way in the distant past I have to either decide on a fairly recent introduction of life as an act of special creation or abandon the Genesis account as factual, except in the most figurative sense. The evolutionist is left with the same choice, you have to decide if its the accumulated, slight, successive accumulation of microevolutionary changes or a sudden dramatic change.If PE is your flavor then you are at odds with traditional Darwinian thought, if Darwinian logic is your choice then the fossil record is an embarassment.

You just can't eat your cake and have it to.

 

[Physics_guy]

cannot be a theistic evolutionist and YEC creationist at the same time. Even if I incorporate the two and say that the original creation was way in the distant past I have to either decide on a fairly recent introduction of life as an act of special creation or abandon the Genesis account as factual, except in the most figurative sense. The evolutionist is left with the same choice, you have to decide if its the accumulated, slight, successive accumulation of microevolutionary changes or a sudden dramatic change.If PE is your flavor then you are at odds with traditional Darwinian thought, if Darwinian logic is your choice then the fossil record is an embarassment.

This is simply wrong. Gould and Dawkins, the big battlers for PE and gradualism respectively, both admit that the other does occur, they simply disagree on what was the main process by which life diverge. Furthermore, PE uses the exact same mechanisms as gradualism - variation and natural selection. PE has nothing to do with the "Hopeful Monster" concept that you seem to be implying here.

All PE states is that most species remain in relative stasis for long periods of time while the environment is stable. Rapid environmental change (and we are talking about geological time frames here, so rapid is actually quite a long time) or isolation of a group can lead to rapid changes of the species (again in geologic time). PE is totally Darwinian in its processes - variation and natural selection. It simple says that variants will more easily become fixed in the population with environmental pressure keeping the populations low.

 

[mark kennedy]

This is simply wrong. Gould and Dawkins, the big battlers for PE and gradualism respectively, both admit that the other does occur, they simply disagree on what was the main process by which life diverge. Furthermore, PE uses the exact same mechanisms as gradualism - variation and natural selection. PE has nothing to do with the "Hopeful Monster" concept that you seem to be implying here.

All PE states is that most species remain in relative stasis for long periods of time while the environment is stable. Rapid environmental change (and we are talking about geological time frames here, so rapid is actually quite a long time) or isolation of a group can lead to rapid changes of the species (again in geologic time). PE is totally Darwinian in its processes - variation and natural selection. It simple says that variants will more easily become fixed in the population with environmental pressure keeping the populations low.

Then perhaps you could clear something up for me:

"He broke sharply with the synthetic theory, however in arguing that new species arise abruptly by discontinuous variation, or macromutation. He admitted that the vast majority of macromutations could only be viewed as disastrou—these he called "monsters." But, Goldschmidt continued, every once in a while a macromutation might, by sheer good fortune, adapt an organism to a new mode of life, a "hopeful monster" in his terminology. Macroevolution proceeds by the rare success of these hopeful monsters, not by an accumulation of small changes within populations."

(The Return of Hopeful Monsters
by Stephen Jay Gould)

Must we choose between the hopefull monster of Goldschmidt and the gradualism of Darwin or do you have a synthesis of the two views?

 

[Physics_guy]

I'm pretty sure that Gould is not supporting Goldschmidt's Hopeful Monsters as the same or even similar to Punk-Eek. I would put money that this article, which I haven't read, actually has to do with the emergence of research into the Hox genes and discusses how mutations in those genes may be similar to Goldschmidt's Hopeful Monster scenario.

Now, even if some macroevolution takes place through a single generational Hopeful Monster mutation, that in no way suggests that it is a major driver of evolutionary change. Gould's ideas of PE were based on geological timeframes and suggest that macroevolutionary changes occurred over a much shorter time period than traditional gradualism suspected, but certainly was not a single generational change as Goldschmidt suggested.

Regardless, however, they are both still fundamentally variation and differential reproductive success. I personally do not believe the Hopeful Monster scenario was a major driver of evolutionary change, but it could certainly have been one way that organisms diversified. All the idea is, is a mutation that has very noticable physical expression, which is fundamentally subjective. For example, is a bacteria with a mutation that allows for the digestion of nylon a "Hopeful Monster?" Why or why not?

 

[Physics_guy]

Just found the article, and although I would lose my bet that it had to do with the Hox gene, you seem to be presenting it as something Gould supports as opposed to Darwinism, which is clearly not the case. He is making a sublte distinction that I think you are missing.

From the article:

I want to argue that defenders of the synthetic theory made a caricature of Goldschmidt's ideas in establishing their whipping boy. I shall not defend everything Goldschmidt said; indeed, I disagree fundamentally with his claim that abrupt macroevolution discredits Darwinism. For Goldschmidt also failed to heed Huxley's warning that the essence of Darwinism—the control of evolution by natural selection—does not require a belief in gradual change.

 

[Jet Black]

Evolution does not reverse itself according to popular convention. So the descent is traced back to an all together ancestor and one of the things that is supposed to have caused this is the environment the organism finds itself in. Let me ask you this, if it was demonstrated that the earths conditions have not changed dramaticlly since, say, the time of homo hablis how would you account for the evolution from early transitionals to modern human?

how on earth could you demonstrate that? remember the environment is not just the wearther and the number of empty caves, it is all the living things as well, including members of the same species.

 

[Jet Black]

This is simply wrong. Gould and Dawkins, the big battlers for PE and gradualism respectively, both admit that the other does occur, they simply disagree on what was the main process by which life diverge.

dawkins' main problem with punk eek is that it is not really as revolutionary as people would claim. to be honest Gould et al did science a disservice by claiming that it was as revolutionary as it was, because it really isn't. It's an interesting footnote perhaps, bu the problem is that it has been jumped on by a bunch of creationists who claim that it is something it is not.

 

[gluadys]

I'm pretty sure that Gould is not supporting Goldschmidt's Hopeful Monsters as the same or even similar to Punk-Eek. I would put money that this article, which I haven't read, actually has to do with the emergence of research into the Hox genes and discusses how mutations in those genes may be similar to Goldschmidt's Hopeful Monster scenario.

No, he's not. They are really two entirely different matters and one does not depend on the other.

He is also not saying that there will be a macro-leap of genetic change from one generation to another. But he does propose that in some instances, a small genetic change in the genes that control embryological development may explain some curious traits for which there is no obvious alternate evolutionary pathway. And this may include some of the transitions that occurred at significant points of evolutionary history.

An example he mentions are chipmunks which, contrary to most of the species, have the storage pouches in their cheeks on the exterior (furry side) of their face instead of the inside of the cheek. Quoting Charles Long who did the definitive study on these rodents he suggests that a genetically controlled developmental inversion of the cheek pouch may have occurred. This could be the result of a fairly minor change in the regulatory gene or its expression.

 

[Jet Black]

Punctuated equilibrium is a concept that was treated as disease in natural science. It was actually first proposed by Richard Goldschmidt in the 60s. Gould said in the mid-eighties that he would be vindicated, in fact he claimed that PE had allways been a part of evolutionary thought from the beggining. Darwin did mention the monstrocity but admitted that these mutations (usually during the cleavage or embryo stage) were allmost allways detremental. Keep in mind that Godschmidt was a geneticist and had studied, among other things, embryology.

The monstrosity has little or nothing to do with punctuated equilibrium!!!!! nobody has really said that punk eek is a disease to science, it is the misunderstanding of it which is the disease! Even Dawkins, who was one of Gould's most vocal opponents, was not an opponent of the idea of punk eek, he simply didn't think that it was as big an issue as gould made it out to be. It certainly wasn't any revultion as it were, and more just an explanation as to fossil diversity.

There is one major problem with gradualism that has to be an embarssment for the neo-darwinian, the transitional forms appear relativly quickly suddenly and quickly transpose into something else just as quick. Darwin predicted the a long succession of slow slight gradual changes would be found in the geologic strata, in fact they have found the exact opposite.

but the point is that they have been found mark, even though they are rare, and this agrees with the punctuated equilibrium model that evolution often takes place fairly rapidly in a small region, and then the produced species rapidly spreads into any accessible niches. Gould and Eldredge presented evidence of this in the distributions of trilobytes.

The Berkley Creationist J. Wells pointed to the fact that for evolutionary change to occur it would have to happen in the cleavage stage. The main problem here is that this is the place where the organism is least resistant to change. This has to be a head scratcher for an evolutionist because I don't think you can have PE and gradualism as a demonstrated mechanism since the dynamics of one neutralizes the causative chain of the other.

ans we already pointed out what alot of nonsense this was, perhaps it wasn't your thread, but I suggest you look it up. the cleavage stage and the earliest stages of embryonic development do not express any genes and organisation of the cells up to gastrulation is purely the result of yolk density. therefore it is nonsense to suggest that evolutionary change has to occur at this stage, because the genes aren't even expressed. The most notable effect of the clevage stage is that it expresses the yolk distribution, but remember that the amount of yolk put into the cell in the first place can change, and be controlled by the mother's genes as she produces the oocyte in the first place.

so far you have pointed out 2 lots of nonsense that you have already been told about. please don't take this path of ignoring things you have already been told about, as it is a real damaging blow to your intellectual integrity. you are an intelligent poster, though I disagree with you of course, and I don't want you to wreck any respect I have of you by hearing you repeat things that you should know to be wrong by now.