Define 'species'

[mark kennedy]

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.
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.
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.

I certainly don't want to throw away what little hard earned respect I may have earned on here, certainly from such an avid opponent. That said, I don't see how you can have it both ways. Either it is a long successive accumulation of microevolutionary changes or something happens relativly suddenly and the species is inalterably changed. I actually believe that Darwinian thought has great merit but the level of change that is discribed by Darwinians has to be qualified, quantified and demonstrated.

In my own defense I never presented PE and gradualism as nessacarily mutually exclusive. What I was curious about is how the evolutionist reconciles the two points of interest. I am satisfied that these two are at least compatable and I just wanted you guys to try your hand at synthesising the two.

I don't allways come in here with an axe in my hand. Usually I have one handy but sometimes I am just curious how you think. I am still puzzeled by the content of the other posts and I'll work out a response to them as soon as I am able.

 

[Ishmael Borg]

I certainly don't want to throw away what little hard earned respect I may have earned on here, certainly from such an avid opponent. That said, I don't see how you can have it both ways. Either it is a long successive accumulation of microevolutionary changes or something happens relativly suddenly and the species is inalterably changed.

Why does it have to be one or the other? Selective pressure is not a constant.

 

[Tomk80]

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.

Pesky ethics. Always stands in the way of some good-ol' scientific expermenting

 

[mark kennedy]

Why does it have to be one or the other? Selective pressure is not a constant.

That true enough but I was pointing out the differences between gradualism and PE. Gould made nobel attempt to reconcil the two and to vidicate the work of a scientist who had become a wipping boy for the Darwinian. Like I pointed out earlier I was forced to descide between theistic evolution and YEC on certain points.

I am just curious how the evolutionists reconcils these two seemingly contradictory schools of thought. Is it the slow accumulation of slight successive modification or can it occur suddenly. The transitionals do appear relativly suddenly in the fossil record and they are precious few and far between. This has to drive the neo-darwinian up the wall.

 

[mark kennedy]

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:

That was really not what I was driving at, I can't imagine Gould ever opposing Darwinism. I just like the fact that this question comes from a guy who studied embryology and related what he learned to evolutionary thought. You may have guessed that I see signifigance for creationist thought here, this is what I had in mind:

"The diversity of the earliest stages of development, here illustrated strictly within the vertebrates, provides one of the strongest challenges to the neo-Darwinian conception of homology and macroevolution. Given the hierarchical, step-wise logic or "architecture" of animal development, early stages such as cleavage and gastrulation lay the groundwork for all that follows. Body plan structures in the adult, for example, trace their cellular lineage to these early stages. Thus, if macroevolution is going to occur, it must begin in early development. Yet it is precisely here, in early development, that organisms are least tolerant of mutations. Furthermore, the adult homologies shared by these vertebrates commence at remarkably different points (e.g., cleavage patterns). How then did these different starting points evolve from a common ancestor?"

http://www.arn.org/docs/odesign/od182/hbfig4.htm

Darwin was the first to suggest that the development of the embryo was a living demonstrating of how evolution actually developed. He directly related the common ancestor model to embryology and I think the above statement is a valid criticism with substantive questions for the Darwinian.

 

[Ishmael Borg]

That true enough but I was pointing out the differences between gradualism and PE. Gould made nobel attempt to reconcil the two and to vidicate the work of a scientist who had become a wipping boy for the Darwinian. Like I pointed out earlier I was forced to descide between theistic evolution and YEC on certain points.

I am just curious how the evolutionists reconcils these two seemingly contradictory schools of thought. Is it the slow accumulation of slight successive modification or can it occur suddenly. The transitionals do appear relativly suddenly in the fossil record and they are precious few and far between. This has to drive the neo-darwinian up the wall.

Here's what T.O. says on this matter:
6. Common errors in discussion of PE

Many errors can be found in discussion of the concept of PE. G&E 1977 point out several of these.

PE is not mutually exclusive of phyletic gradualism. Gould and Eldredge take pains to explicitly point out that PE is an expansive theory, not an exclusive one (1977).

PE sometimes is claimed to be a theory resting upon the lack of evidence rather than upon evidence. This is a curious, but false claim, since Eldredge and Gould spent a significant portion of their original work examining two separate lines of evidence (one involving pulmonate gastropods, the other one involving Phacopsid trilobites) demonstrating the issues behind PE (1972). Similarly, discussion of actual paleontological evidence consumes a significant proportion of pages in Gould and Eldredge 1977. This also answers those who claimed that E&G said that PE was unverifiable.

PE is essentially and exclusively directed to questions at the level of speciation and processes affecting species. The basis of PE is the neontological theory of peripatric speciation. The criteria by which "punctuations" are recognized by Gould and Eldredge involve temporal issues and geographic issues. PE is not expected to be as useful at lower or higher levels of change.

PE is by no means either synonymous with "saltationism", nor did Gould's essay on Richard Goldschmidt "link" PE with Goldschmidt's "hopeful monster" conjecture. Gould wrote an article that has caused much confusion. "Return of the hopeful monsters" sought to point out that a hatchet job had been done on some of the concepts that Richard Goldschmidt had formulated. The discussion of systemic mutations as mutations which affect rate or timing of development has caused many people to assume that Gould was somehow linking PE to this concept. A close reading of the article shows this to not be the case.

Gould and Eldredge did not specify any particular genetic mechanism for PE. PE does not require large scale mutations.

PE is not a saltational theory of evolution. The emphasis upon applying consequences of peripatric speciation to paleontology shows this critique to be unfounded. PE is no more saltational than peripatric speciation is in study of modern organisms.

 

[Vance]

Ask Gould whether he is still a Darwinian (or neo-Darwinian, if you prefer) and he would look at you oddly and say "well, of course, what a silly question."

 

[Physics_guy]

That true enough but I was pointing out the differences between gradualism and PE. Gould made nobel attempt to reconcil the two and to vidicate the work of a scientist who had become a wipping boy for the Darwinian. Like I pointed out earlier I was forced to descide between theistic evolution and YEC on certain points.

I am just curious how the evolutionists reconcils these two seemingly contradictory schools of thought. Is it the slow accumulation of slight successive modification or can it occur suddenly. The transitionals do appear relativly suddenly in the fossil record and they are precious few and far between. This has to drive the neo-darwinian up the wall.

You still do not get it - Gradulaism a PE are NOT contradictory.

 

[mark kennedy]

Here's what T.O. says on this matter:
6. Common errors in discussion of PE

Many errors can be found in discussion of the concept of PE. G&E 1977 point out several of these.

PE is not mutually exclusive of phyletic gradualism. Gould and Eldredge take pains to explicitly point out that PE is an expansive theory, not an exclusive one (1977).

PE sometimes is claimed to be a theory resting upon the lack of evidence rather than upon evidence. This is a curious, but false claim, since Eldredge and Gould spent a significant portion of their original work examining two separate lines of evidence (one involving pulmonate gastropods, the other one involving Phacopsid trilobites) demonstrating the issues behind PE (1972). Similarly, discussion of actual paleontological evidence consumes a significant proportion of pages in Gould and Eldredge 1977. This also answers those who claimed that E&G said that PE was unverifiable.

PE is essentially and exclusively directed to questions at the level of speciation and processes affecting species. The basis of PE is the neontological theory of peripatric speciation. The criteria by which "punctuations" are recognized by Gould and Eldredge involve temporal issues and geographic issues. PE is not expected to be as useful at lower or higher levels of change.

PE is by no means either synonymous with "saltationism", nor did Gould's essay on Richard Goldschmidt "link" PE with Goldschmidt's "hopeful monster" conjecture. Gould wrote an article that has caused much confusion. "Return of the hopeful monsters" sought to point out that a hatchet job had been done on some of the concepts that Richard Goldschmidt had formulated. The discussion of systemic mutations as mutations which affect rate or timing of development has caused many people to assume that Gould was somehow linking PE to this concept. A close reading of the article shows this to not be the case.

Gould and Eldredge did not specify any particular genetic mechanism for PE. PE does not require large scale mutations.

PE is not a saltational theory of evolution. The emphasis upon applying consequences of peripatric speciation to paleontology shows this critique to be unfounded. PE is no more saltational than peripatric speciation is in study of modern organisms.

Of course Gould and Elderedge could not identify the genetic mechanism, mutations are almost allways harmfull to the species. We know that nature does not make leaps and this principle is obvious to anyone who has looked at the actual fossil evidence. There are major problems with this, evolution's step child, the universal common ancestor, must have a demonstrated mechanism for it to be viable as natural science. Micoevolution happens and you would have to be woefully misinformed the say that it doesn't. Where this translates into macroevolution is where homology has to provide real world demonstrable proof. Every microevolutionary change is offered as proof for the universal common ancestor model, this is begging the question of proof.

I opened with the definition that Darwin mystified the term species calling the essense 'undiscoverable'. There is one major problem with this, it renders the terms microevolution and macroevolution meaningless. If we can't define the central term the changes below and above the level of species is nothing more then a mere opinion. I realize that taxonomy encounters things that defy classification, like the platypus which is a mammal that lays eggs.

Dispite the dificulty somehow they managed to classify this creature and there is no reason to mystify this term 'species'.

 

[Physics_guy]

1. Most mutations are NOT harmful. The vast majority of mutations are neutral to the survivability of the organism.

2. There is a demonstrated mechanism for macroevolution and the Common Ancestor model - variation and natural selection. This is exactly the same mechanism for microevolutionary changes, and Gould would agree that the mechanisms are identical. Furthermore, this mechanism is identical in both Dawkins' Gradualism and Gould's PE - you seem incapable of understanding this.

3. It would be impossible to demonstrate a macroevolutionary change to you, because you would just say that it is a microevolutionary change. Dogs all diverged from wolves a few thousand years ago. Is the change from a timber wolf to a pug macroevolution or micro? How can you tell? Could they still possible interbreed? Maybe - not likely, but maybe with a lot of help (such as artificial insemination and surgical removal of the infant puppies).

4. The term species is difficult to define because no definition works in all cases. There are marginal cases that make the definition less than absolute. This is exactly what you would expect to find if the Theory of Evolution (inclusive of Common Descent) is true. It is not what you would expect to find if "creation science" is true (unless of course you are going to use the incredible flexibility of the word "kind" and say that all the changes at the species level are just microevolution).

5. The physical evidence is not on your side. YEC fails to explains the evidence we have from astronomy, geology, chemistry, and biology because it is a faith based belief system that is developed without regard for the physical evidence. If you would admit that you hold your position on faith that your interpretation of the Bible is absolutely true, I would have no problem with you. If you are going to however keep arrogantly asserting that your position is somehow supported by science, then I am going to have to call you on it. It is not, and in fact tha physical evidence is contradictory to your faith-based story.

 

[Ishmael Borg]

Of course Gould and Elderedge could not identify the genetic mechanism, mutations are almost allways harmfull to the species.

Actually, most mutations are neutral. Environment determines the benefit or detriment a mutation poses for an organism.

We know that nature does not make leaps and this principle is obvious to anyone who has looked at the actual fossil evidence. There are major problems with this, evolution's step child, the universal common ancestor, must have a demonstrated mechanism for it to be viable as natural science.

Of course nature makes leaps. A comet strikes the earth, and the fallout leads to mass extinction. This is a leap.

The mechanisms by which modern species are derived from a common ancestor are mutation and natural selection. The fact that all organisms utilize dna as the information molecule is a strong piece of evidence for common descent.

Micoevolution happens and you would have to be woefully misinformed the say that it doesn't. Where this translates into macroevolution is where homology has to provide real world demonstrable proof. Every microevolutionary change is offered as proof for the universal common ancestor model, this is begging the question of proof.

The words 'evidence' and 'proof' are not interchangeable. Homology, along with genetics and the fossil record provide ample evidence for common descent.

I opened with the definition that Darwin mystified the term species calling the essense 'undiscoverable'. There is one major problem with this, it renders the terms microevolution and macroevolution meaningless. If we can't define the central term the changes below and above the level of species is nothing more then a mere opinion. I realize that taxonomy encounters things that defy classification, like the platypus which is a mammal that lays eggs.

Dispite the dificulty somehow they managed to classify this creature and there is no reason to mystify this term 'species'.

I don't think he mystified the term, he just evaluated it as useless when considering that life is a non-static continuum. This does not render micro/macro evo useless. If you have a snowball rolling down a snowy hill, can you say that the idea of its accumulating snow is invalid because its diameter is constantly changing?

 

[mark kennedy]

Actually, most mutations are neutral. Environment determines the benefit or detriment a mutation poses for an organism.

Envirnment can account for adaptive changes but should it be presumed or demonstrated. There is no question that change occurs but at the level of the universal common ancestor model? That is an extraordinary leap in logic and frankly the evidence for it is highly questionable.

Of course nature makes leaps. A comet strikes the earth, and the fallout leads to mass extinction. This is a leap.

Extinction is the key element in natural selection. You are describing how species become extinct due to a devastating event. Natural selection actually includes a lot more then extinctions.

The mechanisms by which modern species are derived from a common ancestor are mutation and natural selection. The fact that all organisms utilize dna as the information molecule is a strong piece of evidence for common descent.

It frankly doesnt prove any universal common ancestor is nessacary. In fact if the DNA is being continually morphed and changed you would expect that organisms seperated by eons would have radically different dna.

The words 'evidence' and 'proof' are not interchangeable. Homology, along with genetics and the fossil record provide ample evidence for common descent.

The fossil record huh, ok, what are these fossils that provide ample evidence for common descent?

I don't think he mystified the term, he just evaluated it as useless when considering that life is a non-static continuum. This does not render micro/macro evo useless. If you have a snowball rolling down a snowy hill, can you say that the idea of its accumulating snow is invalid because its diameter is constantly changing?

He did mystify it and in biology this is absolutly unacceptable. I'm not saying that we have to be limited to organisms that produce fertile offspring. I am saying that if you are going to write a treatise on speciation you should at least define you central term. If we don't know what a species is then how do we know that the changes are above or below the level of species? I'm not buying the snowball effect of the microevolutionary changes. Are you aware that Darwin's finches and the peppered moths of England have now referted back to their original forms? They didn't evolve and they are icons of evolutionary thought. You said yourself that most mutations are neutral and yet they are credited with all the changes and modification in living systems all the way back to single cell ancestors. Thats not just a leap in logic, or a hypothesis, or even a theory. It a myth.

 

[Vance]

They reverted because the evolutionary pressure was released or reversed. Evolutionary change flows with the tide of "pressure". If the pressure continues, then the change continues. If ongoing pressures continue long enough, they will eventually create "macro" change by *anyone's* definition.

My question would be that if you accept that pressures will create micro-evolutionary changes, where is the brake? What scientifically based theory is there to explain why the micro changes will NOT eventually add up to a macro change if the pressure continues? What would stop the adjustments from going on to break the species barrier however it is defined? What would prevent a common ancestor from developing into an elephant on the one hand and a manatee on the other (the first macro change that came to mind)?

 

[mark kennedy]

Ok, australpithicus garhi spite into homo rudolfensis and homo habilis. What was the environmental pressure that produced this and what was the level of mutation that is nessacary for this crucial change. You can use whatever baseline for equilibrium you like but there is little indication homo rudolfensis and homo habilis were accumulating microevolutionary mutations. In fact their supposed descendant appears rather suddenly in the fossil record. Your thoughts.

 

[Vance]

No, you didn't answer my question (assuming your post was addressing mine). What are the brakes on the evolutionary process that would prevent micro-evolutionary changes to continue to the point of "macro" changes? If you accept micro-evolution as a process, and acknowledge that it will result in morphological changes, what is the scientific basis for a halt in this process short of macro changes?

 

[mark kennedy]

No, you didn't answer my question (assuming your post was addressing mine). What are the brakes on the evolutionary process that would prevent micro-evolutionary changes to continue to the point of "macro" changes? If you accept micro-evolution as a process, and acknowledge that it will result in morphological changes, what is the scientific basis for a halt in this process short of macro changes?

Ok, but I really don't think there is a brake per se, its actually subordinate to the genetic blueprint. In all the changes in the 7 traits of bean plants Mendel noted in some 22,000 experiments there was never an indication that they will ever be anything other then beans. I'd say the evolutionary changes are limited by the genetic determinism of the parents. Life has to be kept in balance which is why most mutations are either harmfull or neutral. They certainly do not account for the transition from single celled to modern diversity.

Please note, you didn't answer my question about the transitionals in the human family tree either.

 

[Vance]

So, really, your only reason to disbelieve in the "macro" aspects of evolutionary processes is akin to argument by incredulity.

As for your question, I do not know whether "australpithicus garhi spite into homo rudolfensis and homo habilis". But I do not think the paucity of the fossil record would (or could) provide a full record of the changes, as you know. We have only snapshots here and there regarding how the development took place. There is no basis that I have seen to show that no micro-evolutionary changes were taking place along the way, between snapshot 1 and 2. As for the suddenness of the emergence of any species, this is well-covered ground. PE and the rarity of fossils will create this seeming "suddenness", and even when the term is used in the science, it means something akin to "over hundreds of thousands of years rather than millions of years".

 

[mark kennedy]

The guys at the Smithsonian seem to think so.

http://www.mnh.si.edu/anthro/humanorigins/ha/a_tree.html

I couldn't find any explanation for this spit from the ancestors of apes and men or the ancestors of humans only. What I did find in looking at these fossils is that they are hardly conclusive proof. This guys aren't shy about asking the tough questions and I guarantee you that they are died in the wool evolutionists.

It was interesting that you are not convinced that they split, why is that?

 

[Loudmouth]

Ok, but I really don't think there is a brake per se, its actually subordinate to the genetic blueprint. In all the changes in the 7 traits of bean plants Mendel noted in some 22,000 experiments there was never an indication that they will ever be anything other then beans.

How long did Mendel run these experiments? 10 years, maybe? Do you think this is long enough for macro-evolution? If not, then why do you use it as an example of how macro-evolution can not occur?

How about an analogy. The other day I stopped by a construction site. The guys at the site said they were going to build a 100 story sky scraper like the one across the street. Looking across the street I noticed a very tall building. I thought to myself that man could not build such a monstrosity, that it had to be created by the gods. Sure enough, I was correct. After watching the construction crew for 15 minutes they weren't even able to build a part of one floor. I can believe in micro-building, since making small things is observed in 15 minutes, but macro-building is just a myth.

Our ability to observe macroevolution first hand is limited because of the time-spans involved. However, we are able to establish common ancestory through genetic phylogenies and such things as ERV similarities. Also, the fossil record matches with genetic phylogenies. Needless to say, common ancestory is actually well supported. The resulting differences between species sharing common ancestory is theorized to be a result of evolution through mutation and natural selection. We observe micro-evolution (micro-building) today and we see nothing that would prevent such changes accruing over time to result in large differences (the skyscraper). If you think that there is a difference between micro-evolution and macro-evolution due a difference in mechanism then it is up to you to show that evidence.

 

[Vance]

Mark, I don't know whether they split because I have not read up on those hominids, not because of any *disbelief* in a presented theory. I have only recently turned to the hominid line-up, having read the Scientific American special edition covering the various debates and currently listening to a college lecture series on Bilogical Anthropology.

You are not heading for a "God of the gaps" concept, are you? Always dangerous.