Co-evolution redux
With all the hoopla about intelligent design, non-ID criticisms of evolution are often ignored. The overemphasis on ID has gotten so bad that there seems to be a "contrived dualism" where the only alternatives are Darwinism and ID, so many Darwinists figure that all they have to do is discredit ID and they're in like Flint.
Non-ID criticisms of evolution have a big advantage. With no design, there is no supernatural designer. With no supernatural designer, there is no religion. With no religion, there can be no violation of the establishment clause in public schools. Beautiful.
Sometimes I wonder -- would Darwinists emphasize the religious aspect of ID so much if they were not trying so hard to keep ID out of the public schools? I think that otherwise they would focus more on the scientific issues.
One example of a non-ID criticism of evolution is criticism concerning co-evolution. Co-evolution is defined as the mutual evolutionary influence between two kinds of organisms that become dependent on each other -- e.g., flowers and bees. Criticism concerning co-evolution is my favorite criticism of Darwinism, and one of the reasons is the simplicity of this criticism -- for example, criticism concerning the propagation of beneficial mutations in sexual reproduction requires a good knowledge of genetics. It has been several months since I last discussed co-evolution and I think that it is time to revisit it. Co-evolution presents the following problems:
(1) Unlike the kind of evolution which is adaptation to widespread fixed physical features of the environment, e.g., land, water, and air, in co-evolution there is often nothing to adapt to because the co-dependent trait is likely to be initially absent in the other organism.
(2) Where the co-dependent traits in both organisms are harmful in the absence of the corresponding traits in the other organism, co-evolution is virtually impossible. Even where the traits are not harmful when the corresponding traits are absent, there is no selective advantage when the corresponding traits are absent.
(3) Often, co-dependent organisms can interact only in large numbers -- e.g., a bee visits many flowers and a flower is visited by many bees. Hence, it may be necessary for large numbers of both kinds of organisms to simultaneously appear in the same place at the same time.
(4) Often a co-dependent relationship consists of an "irreducibly complex" combination of pairs of traits rather than a single pair of traits -- e.g., a flower must both produce nectar and have colors and/or scents that attract pollinators, and the pollinators must be able to both consume the nectar and have the ability to detect the colors and/or scents. This compounds the problems presented by co-evolution and irreducible complexity. In some cases, the irreducible complexity involved in co-evolution could involve multiple organs, e.g., bees' digestive systems that process nectar and bees' sensory organs for seeing and/or smelling the flowers.
(5) Even if the problems of co-evolution and irreducible complexity or a combination of the two do not prevent evolution from occurring, they might slow it down. This slowdown could be a problem because some major evolutionary changes have at most just a few million years to take place.
The mechanisms of Darwinian evolution are natural genetic variation and natural selection. Intelligent design primarily raises questions about natural genetic variation whereas criticism of co-evolution primarily raises questions about natural selection.
Darwinists just talk in vague, nebulous terms like "mutual evolutionary pressure" instead of looking at the nitty-gritty details of co-evolution.
Co-evolution is a very important part of evolution and IMO has not gotten the attention it deserves.
Here are some references on co-evolution, from my first post on the subject:
One kind of pollination by insects is so specialized that the resonant vibration of the insect's wingbeating shakes loose the pollen -- this is called "sonication pollination" or "buzz pollination." See -- http://en.wikipedia.org/wiki/Buzz_pollination
The following reference describes -- among other things -- what I can only call "masturbatory pollination" -- a male wasp mistakes a flower for a female wasp:
The following reference describes co-dependence between deep flowers and long-nosed insects:
http://www.naturalhistorymag.com/0305/0305_feature.html
Non-ID criticisms of evolution have a big advantage. With no design, there is no supernatural designer. With no supernatural designer, there is no religion. With no religion, there can be no violation of the establishment clause in public schools. Beautiful.
Sometimes I wonder -- would Darwinists emphasize the religious aspect of ID so much if they were not trying so hard to keep ID out of the public schools? I think that otherwise they would focus more on the scientific issues.
One example of a non-ID criticism of evolution is criticism concerning co-evolution. Co-evolution is defined as the mutual evolutionary influence between two kinds of organisms that become dependent on each other -- e.g., flowers and bees. Criticism concerning co-evolution is my favorite criticism of Darwinism, and one of the reasons is the simplicity of this criticism -- for example, criticism concerning the propagation of beneficial mutations in sexual reproduction requires a good knowledge of genetics. It has been several months since I last discussed co-evolution and I think that it is time to revisit it. Co-evolution presents the following problems:
(1) Unlike the kind of evolution which is adaptation to widespread fixed physical features of the environment, e.g., land, water, and air, in co-evolution there is often nothing to adapt to because the co-dependent trait is likely to be initially absent in the other organism.
(2) Where the co-dependent traits in both organisms are harmful in the absence of the corresponding traits in the other organism, co-evolution is virtually impossible. Even where the traits are not harmful when the corresponding traits are absent, there is no selective advantage when the corresponding traits are absent.
(3) Often, co-dependent organisms can interact only in large numbers -- e.g., a bee visits many flowers and a flower is visited by many bees. Hence, it may be necessary for large numbers of both kinds of organisms to simultaneously appear in the same place at the same time.
(4) Often a co-dependent relationship consists of an "irreducibly complex" combination of pairs of traits rather than a single pair of traits -- e.g., a flower must both produce nectar and have colors and/or scents that attract pollinators, and the pollinators must be able to both consume the nectar and have the ability to detect the colors and/or scents. This compounds the problems presented by co-evolution and irreducible complexity. In some cases, the irreducible complexity involved in co-evolution could involve multiple organs, e.g., bees' digestive systems that process nectar and bees' sensory organs for seeing and/or smelling the flowers.
(5) Even if the problems of co-evolution and irreducible complexity or a combination of the two do not prevent evolution from occurring, they might slow it down. This slowdown could be a problem because some major evolutionary changes have at most just a few million years to take place.
The mechanisms of Darwinian evolution are natural genetic variation and natural selection. Intelligent design primarily raises questions about natural genetic variation whereas criticism of co-evolution primarily raises questions about natural selection.
Darwinists just talk in vague, nebulous terms like "mutual evolutionary pressure" instead of looking at the nitty-gritty details of co-evolution.
Co-evolution is a very important part of evolution and IMO has not gotten the attention it deserves.
Here are some references on co-evolution, from my first post on the subject:
One kind of pollination by insects is so specialized that the resonant vibration of the insect's wingbeating shakes loose the pollen -- this is called "sonication pollination" or "buzz pollination." See -- http://en.wikipedia.org/wiki/Buzz_pollination
The following reference describes -- among other things -- what I can only call "masturbatory pollination" -- a male wasp mistakes a flower for a female wasp:
The reward offered is not always food. There is a tropical orchid with flowers that look and smell like females of a certain species of wasp. Males of this species emerge a week before the females. A male who smells a flower of this orchid, think it’s a female wasp, gets closer and the flower looks like a female, lands on it and it feels like a female, tries to copulate, gives up in frustration, and goes on to the next thing that smells like a female, and ends up transferring pollen. -- from http://biology.clc.uc.edu/courses/bio303/coevolution.htm
The following reference describes co-dependence between deep flowers and long-nosed insects:
http://www.naturalhistorymag.com/0305/0305_feature.html
Labels: Non-ID criticisms of evolution
posted by Larry Fafarman | 9/14/2006 07:14:00 AM
37 Comments:
Fake Larry(?) says...
> The overemphasis on ID has gotten so bad that there seems to be a "contrived dualism" where the only alternatives are Darwinism and ID <
You seem to be the only one contriving it. In the mean time it is good to see that you have finally seen the absurdity of ID. You have never attempted to answer how you can have intelligent design without a designer.
> so many Darwinists figure that all they have to do is discredit ID and they're in like Flint.<
Also reminiscent of your tactics. You make a lame attack on one aspect of evolution and you think you have shot everything down. In reality you have done no damage at all.
> Sometimes I wonder -- would Darwinists emphasize the religious aspect of ID so much if they were not trying so hard to keep ID out of the public schools? I think that otherwise they would focus more on the scientific issues. <
There doesn’t seem to be any science to ID.
> criticism concerning the propagation of beneficial mutations in sexual reproduction requires a good knowledge of genetics. <
Perhaps that is why you have avoided it.
> It has been several months since I last discussed co-evolution and I think that it is time to revisit it. <
Good grief! After admitting his ignorance, he plows ahead.
> Often a co-dependent relationship consists of an "irreducibly complex" combination of pairs of traits rather than a single pair of traits <
The theory of irreducible complexity only shows a lack of understanding of the evolution mechanism.
> Darwinists just talk in vague, nebulous terms... <
You nearly always talk in vague, nebulous terms. To you, however, vague, nebulous terms are any terms you don't understand. This covers an almost limitless area.
It suddenly occurred to me just how much difference there could be in animals having nearly identical genes. Both Fake Larry(?) and Real Dave must share a very significant number of genes, yet Real Dave has shown himself to be quite logical while you have shown a complete inability for logical thought of any kind.
If the comparative quality of the posts on this blog aren't enough, we can also look at the fact that both Dave and his son outscored you by a considerable margin on the SAT test. (Of course your old friend Bill Carter also topped you.)
The lucky thing is that, due to your fear of women, you won't be reproducing.
Chris HIghland said,
>>>>> "Sometimes I wonder -- would Darwinists emphasize the religious aspect of ID so much if they were not trying so hard to keep ID out of the public schools? I think that otherwise they would focus more on the scientific issues."<
Since all attempts to get ID into schools appear to be religious in nature, it seems reasonable to me. <<<<<<
All attempts? So you are saying that all those who are trying to get ID into public schools are motivated by religion? Isn't that stereotyping? Anyway, in their efforts to exploit the establishment clause, Darwinists always make the argument that ID is just religion -- just arguing that ID is bogus science wouldn't work in the courts because there is no constitutional separation of bogus science and state.
>>>>> An alteranative would be to put in the science curriculum in the hands of scientists. <<<<<
It is in the hands of scientists, particularly Darwinist scientists -- only evolution is actually being taught even where there have been attempts to add evolution disclaimers.
>>>>>>It seems your coevolution ideas suffer from the same problem as IC, in that you are assuming that current adaptations arose simeltanously in their current form. <<<<<<
I am not assuming anything. I am only saying that such an assumption may be necessary to explain coevolution.
There are substantial differences between the problems presented by IC and those presented by co-evolution:
(1) In co-evolution, there may be nothing to adapt to because the corrresponding trait(s) may be initially absent in the other organism.
(2) In co-evolution, it may be necessary for large numbers of the co-dependent forms of both organisms to appear at the same time and place if the organisms can interact only in large numbers.
(3) In co-evolution, a trait that is beneficial when the corresponding trait is present in the other organism may be harmful when the corresponding trait is absent. In isolated evolution, a beneficial trait is always beneficial, assuming that the associated fixed physical feature of the environment -- e.g., water, land, and air -- is always present.
(4) I said that irreducible complexity in co-evolution might involve multiple organs, but this could also be true of isolated evolution.
Also, the co-evolution issue presents problems for the idea of "front-loaded" or "prescribed" (I believe that is John A. Davison's term for it) evolution --i.e., the idea that genetic changes were pre-programmed rather than random -- because co-evolution might require that the changes appear simultaneously in large numbers of both kinds of the co-dependent organisms.
> So you are saying that all those who are trying to get ID into public schools are motivated by religion? <
I would say nearly all. Your belief in extraterrestrials may be considered a sort of religion. Then we could say all.
> Isn't that stereotyping? <
No. It is an observation of an apparent fact (subject to the above limitation). If we were to say that all NFL quarterbacks were males, would we be stereotyping?
> Anyway, in their efforts to exploit the establishment clause, Darwinists always make the argument that ID is just religion <
ID is just religion. This is not "exploiting" the establishment clause. This is enforcing the establishment clause just as demanding that bank robbers be punished is not "exploiting" the robbery laws.
> I am only saying that such an assumption may be necessary to explain coevolution. <
And then again, it may not. Then you go on to repeat yourself.
The point is that there can be no intelligent design without a designer. If it is a conventional god of religion or your little green men makes no difference.
Voice In the Wilderness said,
>>>>>You seem to be the only one contriving it.<<<<<
Nope. When something is not ID, I don't call it ID. But to Darwinists all criticisms of evolution are ID.
>>>>>You have never attempted to answer how you can have intelligent design without a designer.<<<<<<
And you have never attempted to answer how you can have evolution without a designer.
>>>>>>You make a lame attack on one aspect of evolution and you think you have shot everything down. <<<<<<
It is not a lame attack. And co-evolution is a very important aspect of evolution.
>>>>There doesn’t seem to be any science to ID. <<<<<<
At least ID does not make presumptions beyond what can be demonstrated by science.
>>>>>> criticism concerning the propagation of beneficial mutations in sexual reproduction requires a good knowledge of genetics.<
Perhaps that is why you have avoided it. <<<<<<
I have not avoided it completely -- I have an article on the subject. Genetics greatly complicates the discussion and a lot of readers do not have a good knowledge of it -- so it makes sense to focus on co-evolution.
>>>>>The theory of irreducible complexity only shows a lack of understanding of the evolution mechanism. <<<<<<<
On the contrary, I now realize that irreducible complexity may involve several organs rather than just one organ.
The scientific method has served us well for several centuries, but in many areas of science we have arguably reached the limit of what the scientific method can demonstrate.
> Nope. When something is not ID, I don't call it ID. But to Darwinists all criticisms of evolution are ID. <
You have failed to give any evidence of this fantasy.
>>>>>You have never attempted to answer how you can have intelligent design without a designer.<<<<<<
> And you have never attempted to answer how you can have evolution without a designer. <
Dodging the questionas usual, Fake Larry(?)? Evolution, of course, does not require a designer.
> At least ID does not make presumptions beyond what can be demonstrated by science. <
None of ID's presumptions can be demonstrated by science.
>>>>>The theory of irreducible complexity only shows a lack of understanding of the evolution mechanism. <<<<<<<
> On the contrary, I now realize that irreducible complexity may involve several organs rather than just one organ. <
Thank you for proving my point. You obviously don't understand it. You even inferred that evolution requires a designer. Your posts under this topic are the best evidence so far that you have no clue what you are talking about.
> The scientific method has served us well for several centuries, but in many areas of science we have arguably reached the limit of what the scientific method can demonstrate. <
What nonsense!
Fake Dave said,
>>>>>why not just concede Chris's point? <<<<<
Why should I quit while I'm ahead?
>>>>> Your coevolution "arguments" are IC arguments, exactly. <<<<<
No they're not. For example, the co-dependent traits in each of the two kinds of organisms are not necessarily irreducibly complex, though they can be.
>>>>> Even in coevolution situations, changes take place one individual at a time. <<<<<
I am saying that that is often not possible because the two co-dependent kinds of organisms often can interact only in large numbers -- e.g., an individual hummingbird visits many flowers and an individual flower is visited by many hummingbirds. In co-dependence (mutualism), the co-dependent partner is part of the general environment, in the same way that land, water, and air are parts of the general environment. And even for corresponding co-dependent features to simultaneously appear in two individuals at the same time in the same place would be something of a miracle.
>>>>> Why do you assume that the bet is one-time, all or nothing? <<<<<<
If the odds are a trillion-to-one against you on each bet, you don't have much chance of winning anything.
Anyway, even if co-evolution is like the evolution of irreducibly complex systems because both kinds of evolution require highly unlikely coincidences, I am not aware of IC ever being discussed in terms of co-evolution.
>>>>>Another clue: All traits involve tradeoffs (economic if nothing else). To take one rather conspicuous example, human intelligence requires brain size that is too large for safe child-bearing. <<<<<<
I don't get it. What does brain size have to do with safe child-bearing?
Real Dave said...
>>>>>why not just concede Chris's point? <<<<<
To which Fake Larry(?) replied...
> Why should I quit while I'm ahead? <
But you are behind. Let's face it, Larry(?), you have never been ahead on this blog.
> And even for corresponding co-dependent features to simultaneously appear in two individuals at the same time in the same place would be something of a miracle. <
You don't seem to realize that every criticism of creationism depends on miracles.
> If the odds are a trillion-to-one against you on each bet, you don't have much chance of winning anything. <
If you have more than a trillion bets, you have a very good chance. If you have many trillions of bets, it approaches a certainty.
> I don't get it. What does brain size have to do with safe child-bearing? <
Get a clue. I would think that the answer is obvious. Do you have any idea how babies are born? They are not created out of the air by your little green men.
Fake Dave said ( 9/17/06 @ 9:16:47 AM )--
>>>>> No, Chris, you're falling into Larry(?)'s IC trap. <<<<<
There are no "traps" here. Everything is above board.
>>>>> There is always a range of existing traits in a given population. In addition, life forms are constantly generating adventitious "new traits" which may or may not find fertile ground. When two interacting species in an ecosystem are both practicing these population dynamics, the chances of their "connecting" are excellent. <<<<<
Sometimes co-dependent traits are harmful when the corresponding co-dependent traits in other species are absent. For example, pollen that is well-suited to be carried by the wind is generally not well-suited to be carried by pollinators, and vice-versa. In the case of "buzz pollination" (see opening post), the pollen adheres so strongly to the flower that it must be dislodged by the vibrations from an insect's wing beats. Where the co-dependent traits in both co-dependent organisms are harmful when the corresponding traits are absent, co-evolution is difficult or impossible. And even where the traits are not harmful when the corresponding traits are absent, there is no selective advantage when the corresponding traits are absent.
>>>>> Dynamics are quite different from statics, as any engineer should recognize <<<<<
Utterly irrelevant.
Fake Dave said,
>>>>> I don't get it. What does brain size have to do with safe child-bearing? >
Do you not know what a Caesarean section is? Or why they're needed? Or why horses and tigers never need them? Do the arguments regarding "partial birth abortion" go over your head entirely? <<<<<<
Though a baby's head is relatively large in comparison to its body, I don't think that the head is the largest part of the baby that has to pass through the birth canal. Anyway, the volume of the brain increases in proportion to the cube of the diameter, so a mere 26% increase in diameter would result in a doubling of brain volume.
Anyway, if this is a problem, there are ways of dealing with a larger brain size: (1) a larger birth canal, or (2) being marsupials, whose young are born prematurely and then develop in an external pouch.
As for "partial birth abortions," fetuses are not supposed to be stabbed in the skull with scissors in late-term abortions. Only a quack would do that. The proper way to perform a late-term abortion is to euthanize the fetus in the womb prior to removal.
> Though a baby's head is relatively large in comparison to its body, I don't think that the head is the largest part of the baby that has to pass through the birth canal. <
What a dolt! Perhaps you should take the advice of anonymous and remain silent on subject of which you are totally ignorant. Then again there would be no blog here for our entertainment if you were to do so.
> Anyway, if this is a problem, there are ways of dealing with a larger brain size <
Perhaps when you create some people you will take your ideas into account. We can call this ID or idiot's design.
Anonymous said...
>>>>> What an idiot. A larger birth-canal negates the advantages of bipedalism. Stop talking about things that you have no clue on. <<<<<<
You stupid fathead, there is no reason why having the birth canal pass through an opening in the pelvis and having the hip joints on the outside of the pelvis are the only possible arrangements.
BTW, women have already lost some of the advantages of bipedalism -- it is believed that the sideways bend in the knee joint that is a result of their wide hip-joint spacing is a factor in women athletes' proneness to knee injury.
> You stupid fathead <
Temper, Temper, Larry(?). It looks like you are losing this argument too. Several of us find it hard to believe that you are really as ignorant on this subject as you are seeming to be. Perhaps this is actually tied in to your fear of women?
> there is no reason why having the birth canal pass through an opening in the pelvis and having the hip joints on the outside of the pelvis are the only possible arrangements. <
How would your Intelligent Designer have done thie?
How would a mammal evolve a complete replumbing to be different from every other mammal on the planet? Spend a little more time learning basic devolpmental biology and less time pontificating upon topics that you are completely ignorant of.
Anonymous said...
>>>>>How would a mammal evolve a complete replumbing to be different from every other mammal on the planet? Spend a little more time learning basic devolpmental biology and less time pontificating upon topics that you are completely ignorant of. <<<<<<
You stupid ignoramus, have you ever compared the anatomies of different mammals? Or compared mammals to their supposed predecessors? Or compared organisms in the different phyla? They are as different as they could possibly be.
Having a degree in Zoology, I can confidently state that I have completed comparative anatomical studies including both vertebrate and invertebrate specimens. It is this experience rounded out with a several years of teaching anatomy and physiology that gives me the confidence to state unequivocally that you are completely clueless.
Anonymous said --
>>>>> Having a degree in Zoology, I can confidently state that I have completed comparative anatomical studies including both vertebrate and invertebrate specimens. It is this experience rounded out with a several years of teaching anatomy and physiology that gives me the confidence to state unequivocally that you are completely clueless. <<<<<<
A bat and a baleen whale are as different as they can possibly be even though both are mammals. The monotremes lay eggs even though they are classified as mammals. If jaws can evolve into middle-ear bones as has been claimed (I am not kidding), then anything is possible. So take your qualifications and shove 'em.
> You stupid ignoramus, have you ever compared the anatomies of different mammals? Or compared mammals to their supposed predecessors? Or compared organisms in the different phyla? <
As an ignoramus, you have made these comparisons and the similarities went right over your head. You should be able to see a direct comparison between the lesser apes and youself, the fact that you have less hair notwithstanding.
> A bat and a baleen whale are as different as they can possibly be even though both are mammals. <
They are only "as different as they can possibly be" if you lack the ability to make a valid scientific comparison. A more intelligent and educated person would easily see the similarities.
"A bat and a baleen whale are as different as they can possibly be even though both are mammals."
And yet both of them have the outlets for their reproductive tracts posterior to the pelvic girdle, just like any other mammal. Get a god damn clue! Why do you disparage my qualifications when it was you who requested them?
Nimrod!
Anonymous said,
>>>>>>"A bat and a baleen whale are as different as they can possibly be even though both are mammals."
And yet both of them have the outlets for their reproductive tracts posterior to the pelvic girdle, just like any other mammal. <<<<<<<
Well, what an interesting coincidence! What about the monotremes and the marsupials, who have just one external opening for the digestive, urinary, and reproductive tracts? And the monotremes are egg laying. What you are saying is that evolution is impossible because the possible amount of variation is limited!
If jawbones can evolve into middle-ear bones, then anything is possible.
>>>>>> Get a god damn clue! <<<<<<<
You're the one who needs one.
>>>>>>Why do you disparage my qualifications when it was you who requested them? <<<<<<
I can't recall requesting your qualifications.
>>>>> Nimrod! <<<<<
Oooooh! I'm going to get back at you for that one.
Dave, thanks for the help and you're spot on about the qualifications issue.
Larry, once again you demonstrate your lack of knowledge in this area. Monotremes have a cloaca however marsupials do not. The anus opens externally and separate from the excretory and reproductive tracts. You are still in desperate need of a clue.
What a maroon!
Fake Dave said --
>>>>> I can't recall requesting your qualifications.
He is referring to these remarks:
"... have you ever compared the anatomies of different mammals? Or compared mammals to their supposed predecessors? Or compared organisms in the different phyla?" Which he then proceeded to answer directly.
I agree that you were "requesting his qualifications." <<<<<<<
He gave me his professional qualifications, which he was of course welcome to give me, but I did not specifically request them. So there was a misunderstanding here.
>>>>>Prior creatures like amphibians and reptiles had a cloaca (and birds still do). <<<<<
Wikipedia says "Some birds, such as some species of swans and ducks, do not use the cloaca for reproduction but have a penis." So I guess that these birds are the exception that proves the rule.
Clueless Anonymous said --
>>>>>Monotremes have a cloaca however marsupials do not. <<<<<<
Well, if you're right, then Wikipedia is wrong. I always found Wikipedia to be pretty reliable. A recent study found Wikipedia to be as reliable about science as the online Encyclopedia Britannica.
Anyway, the difference is unimportant. What astonishes me is to see Darwinists argue that the possible amounts of evolutionary change are very limited. The change I was talking about here -- a larger birth canal in humans to accommodate a larger brain -- is trivial compared to the evolutionary changes that must have occurred if Darwinism is correct.
>> Monotremes have a cloaca however marsupials do not. <<
< Well, if you're right, then Wikipedia is wrong. >
Say what? According to http://en.wikipedia.org/wiki/Monotreme --
Monotremes (monos, single + trema, hole; refers to the cloaca) ...
So, Anonymous is correct. (Must be those !#$% qualifications again!)
< What astonishes me is to see Darwinists argue that the possible amounts of evolutionary change are very limited. >
You are trying to have this both ways. If the single-step change is "too" large, you claim it is Irreducible Complexity. If it is "too" small, you claim it is trivial. If evidence appears showing phased changes (such as mammals evolving warm-bloodedness and mammary glands earlier than live-bearing young), you obfuscate. But, stepwise refinement with relatively small changes is the way that evolution proceeds.
From Fake Dave --
>>>>>>> Monotremes have a cloaca however marsupials do not. <<
< Well, if you're right, then Wikipedia is wrong. >
Say what? According to http://en.wikipedia.org/wiki/Monotreme --
Monotremes (monos, single + trema, hole; refers to the cloaca) ...
So, Anonymous is correct. (Must be those !#$% qualifications again!) <<<<<<<
According to
http://en.wikipedia.org/wiki/Cloaca ---
In zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, urinary, and genital tracts of certain animal species. The word comes from Latin, and means "sewer". All birds, reptiles, and amphibians possess this orifice, by which they simultaneously evacuate both urine and feces. Marsupials and Monotremes also possess one.
<<<<<< What astonishes me is to see Darwinists argue that the possible amounts of evolutionary change are very limited. >
You are trying to have this both ways. If the single-step change is "too" large, you claim it is Irreducible Complexity. If it is "too" small, you claim it is trivial.<<<<<<<
Whaddya mean, I am "trying to have this both ways"? You Darwinists are the ones who are trying to have it both ways. First you talk about goo-to-you evolution and now you are saying that something as simple as producing a larger birth canal in humans is too much for evolution.
It would appear at first blush that the two Wikipedia articles (Monotreme and Cloaca) contradict each other. However, the apparent discrepancy yields when you read further.
The marsupials have a cloaca that combines just the urinary and intestinal tracts; their reproductive system is separated. (This article also claims that marsupials are not all that "primitive" compared to placental mammals -- just "different". Hmm.)
Truth is stranger than fiction on that one. The diverse ingenuity of life forms is amazing.
Fake Larry(?) said:
"First you talk about goo-to-you evolution and now you are saying that something as simple as producing a larger birth canal in humans is too much for evolution."
I realize that your attention span is extremely short, but if you recall this topic came up in the context of tradeoffs and the need to optimize (economically and otherwise) within an historical context.
Fake Dave said --
>>>>> I realize that your attention span is extremely short, but if you recall this topic came up in the context of tradeoffs and the need to optimize (economically and otherwise) within an historical context. <<<<<<<
And what does the context of tradeoffs and the need to optimize have to do with the possibility of evolving a larger human birth canal to accommodate a larger human brain size or evolving some other means of allowing a larger human brain size?
Wikipedia is wrong. In fact the cloaca page has several errors in it.
Marsupials do not have a cloaca. Since the digestive tract has a separate opening the other systems exit through the urogenital sinus. If you still call it a cloaca then humans possess a cloaca as well.
Marsupials do not have a joined digestive and urinary system. Theirs is more like a placentals (with significant differences). Just one more piece in the puzzle showing that marsupial mammals diverged from placentals more recently than the monotreme split.
>And what does the context of tradeoffs and the need to optimize have to do with the possibility of evolving a larger human birth canal to accommodate a larger human brain size or evolving some other means of allowing a larger human brain size?<
This goes back to my original comment. A larger birth canal requires significant modification of the pelvic region reducing the efficiency gained through bipedal motion. More inefficient movement increases energy cost which would not be offset by a larger brain. Seriously, this is not that hard to understand!
Anonymous said...
>>>>> This goes back to my original comment. A larger birth canal requires significant modification of the pelvic region reducing the efficiency gained through bipedal motion. More inefficient movement increases energy cost which would not be offset by a larger brain. Seriously, this is not that hard to understand! <<<<<<
Seriously, it is hard for a sensible person to understand. You are saying that evolution is capable of changing jaws into middle-ear bones and changing goo into you but is not capable of producing a larger human birth canal without reducing the efficiency gained through bipedal motion. You have strained at a gnat and swallowed a camel.
For the time being, I prefer to remain anonymous. I don't plan on making a large number of comments here. Larry's ranting happened to wander into an area I'm interested in.
One possible marsupial plumbing reference is: http://www.naturalworlds.org/thylacine/naturalhistory/anatomy/internal_anatomy_7.htm
I little error correction. Because of further research, I need to make an admission of error. Marsupials do have a cloaca (barely). It is greatly reduced in most marsupial species. Many biologists use the term urogenital sinus in place of cloaca. However, I will have to defer to an anatomist that specializes in marsupials, R. Leon Hughes: http://www.publish.csiro.au/paper/ZO00022.htm#search=%22R.%20Leon%20Hughes%20thylacine%22
Larry,
The jaw bones to ear bones took a long time (millions of years). All of the intermediate steps were new species in their own right. You are trying to compare a huge anatomical change over massive amounts of time with a huge anatomical change within a single species existence.
>Seriously, it is hard for a sensible person to understand.<
Your own ignorance about paleontology is not an argument against evolution.
Of course, if the Earth is only 6000 years in age then the whole issue is moot right?
One last cloaca comment, then I'll shut up. Placental mammals do have a cloaca, but only for a brief period of time during development (long before birth, the anus separates from the urogenital sinus).
Anonymous said...
>>>>> The jaw bones to ear bones took a long time (millions of years). All of the intermediate steps were new species in their own right. You are trying to compare a huge anatomical change over massive amounts of time with a huge anatomical change within a single species existence. <<<<<<
Making a bigger human birth canal seems to me to be a small evolutionary change compared to changing jawbones into middle-ear bones. Apparently the limitation on the size of the human birth canal is that this canal passes through an opening in the pelvis -- but is there any reason why this is necessary and/or why it is hard for evolution to change it?
To exit the body by a different location would require relocating most of the abdominal organs, muscle attachments, nerves and etc. You're basically changing an anatomical arrangement that has been conserved throughout all of the chordate subphylum. At least, I'm not aware of any chordate that has digestive, reproductive or excretory system exits anterior of the pelvic girdle. We're talking about every fish, amphibian, reptile, bird and mammal species on the planet. The fact that none vary from the standard arrangement likely indicates that the arrangement is not easily modified. The genes responsible during development are highly conserved. Strong selective pressure against modification indicates that modification would be difficult if not impossible.
Fake Dave said --
>>>>> you speak flippantly of this change as if it had not already occurred.
Human females have at least two sex-linked adaptations in the direction of a larger birth canal:
First is wider hips. <<<<<<
Yes, I was aware of this change. I pointed out that one of the effects of the wider hip joint spacing is a side angle in the knee joints (I don't call this knock-knees because the knees don't normally knock together in women) and it is believed that this side angle makes female athletes more prone to knee injury.
Anyway, my point was that if evolution can change goo to you and change jawbones into middle ear bones, then it should be able to make a bigger human birth canal or find some other way of making humans with bigger brains.
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