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Junior Member (Idle past 6131 days) Posts: 2 From: Alabama, USA Joined: |
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Author | Topic: Mimicry: Please help me understand how | |||||||||||||||||||||||
Modulous Member Posts: 7801 From: Manchester, UK Joined: |
Wasps have many bird's predators who eat them. I'm willing to bet that lepidoptera has more predators than vespa/vespidae. This is doubly backed up by the fact that bee-eaters also eat moths anyway. I think it should be fairly apparant that reducing the number of potential predators conveys a significant advantage. Edited by Modulous, : No reason given.
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Nuggin Member (Idle past 2521 days) Posts: 2965 From: Los Angeles, CA USA Joined: |
1) Genera Micurus (according Robert Mertens 1954) in Brazil is very poisonous and no predator survive its biting. Consequently no one can remember the species as dangerous. You're mistake here is thinking that all animals are in the unfortunate situation we humans find ourselves in. In general, we don't know what is good to eat and what is not. We have to learn that information. Most species react to specific queues from their prey. A brightly colored poisonous moth may initially draw attention to itself from a sub-set of a predator species, but if it's highly toxic, that will impart a SIGNIFICANT negative selective force. That subset which likes to eat the brightly colored moths doesn't live to reproduce.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
I'm willing to bet that lepidoptera has more predators than vespa/vespidae. This is doubly backed up by the fact that bee-eaters also eat moths anyway. I think it should be fairly apparant that reducing the number of potential predators conveys a significant advantage.
I wouldn't bet. Such a conclusion follows only from darwinistic explanation of mimicry. A serious research is needed. I have written about it in the previous thread. Distinguished American ornitologist who disputed with Poulton about this issue was McAtee from Biological Survey Division from United States Department of Agriculture. He made great researches on this field and he came to the conclusion that birds eat same proportion of aposematics and mimetics species as are they proportions among insects. McAtee therefore thought that such aposematic/mimic colororation are inefficient. He also refuted that birds eat plentifully butterflies studying so-called beak marks. See my post 162 on it: http://EvC Forum: Mimicry and neodarwinism -->EvC Forum: Mimicry and neodarwinism Another problem is the discussed aposematic coloration of snakes. It would pressupose that almost all predators have experience with it if they avoid them. It is different for a bird to have experience with an unpalatble butterfly and with a deadly poisonous snake I would say. Avoiding aposematic snakes could be probably inborn. Same for avoiding poisonous mushrooms.
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Modulous Member Posts: 7801 From: Manchester, UK Joined: |
I wouldn't bet. Such a conclusion follows only from darwinistic explanation of mimicry. Or one could just apply reason and examine evidence. Bees only have to worry about bee-eaters, whereas moths have to worry about bee-eaters and other birds. The set that contains both bee-eaters and other birds is either the same size as, or bigger than the set that just contains bee-eaters. The evidence shows us that the set of bee-eaters n other birds is bigger than just bee-eaters. It could be shown to be false with closer examination but there is no need to appeal to Darwinism. Now you suggest further study is required, and that's fine. Further study is always required, and entomologists have a lot of work to do! If it turns out that looking like a wasp does not deter predation, why even consider mimicry? Why not just point to wasps and ask what explanation is there for their markings? No - I don't believe a cosmic Jewish zombie can make me live forever if I eat his flesh and telepathically tell him that I accept him as my master, so he can then remove an evil force from my soul that is present in all of humanity because a dirt/rib woman was convinced by a talking snake to eat from a magical tree about 6,000 years ago just after the universe was created. Why should I?
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Vacate Member (Idle past 4629 days) Posts: 565 Joined: |
I would appeciate if the experiment was accessible on-line for closer examination. I agree, it would be nice. The experiment was written about in my wifes biology textbook and I just read about it a few days ago. Further information would be nice.
Genera Micurus in Brazil Sorry for not being specific, the region in question was North and South Carolina. (I don't think this is important for the points you brought up however.)
Consequently no one can remember the species as dangerous. This is exactly what I thought. The interesting thing about the experiment though is that the animals in the region must be aware that such coloration indicates a poisonous snake. What else would explain the differences in the number of attacks within and without of the area? The experiment consisted of {hundreds} of snakes (thats the best information I have available).
I do not see what kind of natural selection is acting to diurnal species to look like bright colored poisonous model. It got eaten less in the experiment. That is an advantage in natural selection
Modulous writes:
From message 18:
I'm willing to bet that lepidoptera has more predators than vespa/vespidae.Such a conclusion follows only from darwinistic explanation of mimicry. Why? I think this would follow any explanation of mimicry. Even if it only saves one in a million by fooling a predator, there is an advantage to looking like something dangerous. What process did the making is not important (for this point), either God made things to look like bird droppings or natural selection did.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
This is exactly what I thought. The interesting thing about the experiment though is that the animals in the region must be aware that such coloration indicates a poisonous snake. What else would explain the differences in the number of attacks within and without of the area? The experiment consisted of {hundreds} of snakes (thats the best information I have available).
I would like to know more about the research.I have tried to find it out at inet but without success. Your mentioned research contradicts other observation done by S.M.Smith (1975, 1977, 1978 ,1980) that young birds (Tyrannidae) have aversion to coloration of Corals. Generally speaking there is probably an aversion in vertebrata to black and red color patterns. So considering this conclusion the research you quoted contradicts this fact - birds from other area attacked coral snakes. S.M.Smith: Innate recognition of coral snake pattern by a possible avian predator. Science 187:759-760 1975 So or so the aversion to corals are most probably innate to some birds. Because such aversion is not heritable it origin should be only random mutation that was selected by NS (according darwinism of course). Dunn (1954) mentioned that snakes having this coloration in Panama are feeding with other snakes (85%). Most of them are hunting during night so vision oriented predators probably do not play any role. Dunn: The coral snake "mimic" in Panama.Evolution 8:97-102, 1954. I don't have access to the article, but it is here with interesting first page. JSTOR: Access Check(195406)8:2%3C97:TCS'PI%3E2.0.CO;2-Q And to confuse the situation even more, a research from 1995:
quote: http://www.springerlink.com/content/l60j183265852v30/ The problem of mimicry of coral snakes is more complicated as it may seems at first glance.
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Nuggin Member (Idle past 2521 days) Posts: 2965 From: Los Angeles, CA USA Joined: |
The interesting thing about the experiment though is that the animals in the region must be aware that such coloration indicates a poisonous snake. "aware" is probably a bad choice of words here. I don't know that the animal needs to think "this is poisonous" so much as it's just pre-programed by instinct to avoid bright color and patterns.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
Now you suggest further study is required, and that's fine. Further study is always required, and entomologists have a lot of work to do!
The problem of the so-called mimicry had been studied very thoroughly before second WW in Germany. The problem of evolution of coloration of butterflies (and lizards) seems to follow a rule. Theodor Eimer observed the fact that evolution of color patterns on butteflies wings (and lizards) follows transformation rules (Homoegenesis). Many authors confirmed that this observation is correct. First lungitudinal stripes, their dissolution into spots and tranformation of these spots into transverse striping and finally into one-coloured appereance. He described even leaf-mimic butterflies and their trasformation from the beginning to the end (break-up of mimicry patterns which should have given "survival advantage" to species and should be strongly selected against its break-up according darwinism.) This is only one page, but very interesting about undulatory development, have a look if you like:
http://links.jstor.org/... In the described process natural selection plays no role. Edited by MartinV, : No reason given. Edited by Adminnemooseus, : Shorted display form of link, to restore page width to normal.
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Modulous Member Posts: 7801 From: Manchester, UK Joined: |
The problem of the so-called mimicry had been studied very thoroughly before second WW in Germany. I'd prefer the post WWI stuff, you refer to a paper in 1903 which came a long time before the modern synthesis.
In the described process natural selection plays no role. So? The Modern Synthesis does not require that all evolutionary events are the sole result of natural selection, and that includes colouration. Mimicry is more than just having similar colouration, of course, and I'd be surprised if you can find a good reason for some of the more elaborate mimics that did not require some reference to natural selection. I'd urge you to pick papers from after the discovery of genetics and the synthesis of same with other evolutionary mechanisms. Also, the paper you refer is much longer than the single page you posted, so we'd need to read the whole thing before coming to any conclusions, no? Finally, I don't see any mechanisms proposed here - just the changing of patterns throughout a lizards life being described - perhaps you'd like to fill me in?
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
In the described process natural selection plays no role. Well the described process covers several different levels only at some of which we might expect to see natural selection operating. Once again you seem to assume that century old research on a topic is the definitive study, even when such research predates virtually the whole of modern genetics. The progression from stripes to tails and the posterior sounds very reminiscent of the research into patterning as a Turing reaction-diffusion system. It would be interesting to see how the variations in pattern end points which Eimer noticed in Lacerta muralis correspond to the variations of proportions in the body and tail of Lacerta muralis which Alfred Russel Wallace discussed in his book 'Darwinism'(1889). No one is saying that there aren't mathematical or physical principles which govern the way forms are generated. But to ignore such patterns basis in the genetic complement of the organism and the subsequent implication of evolutionary mechanisms in their maintenance and development is to throw out the patently obvious genetic baby with your own ideological bath water. TTFN, WK
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
Mimicry is more than just having similar colouration, of course, and I'd be surprised if you can find a good reason for some of the more elaborate mimics that did not require some reference to natural selection.
You know we have different opinions and resources but preliminary I would like to stick at Eimer's theories. First I am not sure if his work has been ever translated into English. German and English biology developed almost independently before first WW. Eimer agreed with Darwin that dull colors precedes development of brighter ones. Darwin considered the most brighter animals as evolutionary more developed. Eimer saw the transformation sequence closing with black or white color. Comparing many butterflies species he came to conclusion that one-colored coloration is more progressive and it ended developmental cycle. Transformation of color patterns on butterfly wings proceeds from original 11 stripes towards one-color. According Eimer the mimetism in butterflies is due to the fact that different species are in differnt transformation sequence from 11 stripes towards black color (Papilionidi) or white (Pieridi). Mimetism is therefore pure chance of being on the same transformation level during development. It is indepent from selection and what's more it is independent from geographical area it occurs. For Eimer there is consequently no problem of mimetism between species living in different geographical areas - something I mentioned in previous thread.Darwinism (Poulton) tried to explain such mimetism by selective pressure by migratory birds. It is just some of Eimer thoughts and I hope my english is underestandable for you. Take it as a history of biological thinking.I am unable to judge if his conclusions he devoted his life are to be scietfically proved.
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
Wounded King,
much of your objections I adreesed in my previous post to Modulous.Anyway I am not sure - as we discussed before - that genetical background can explain mimetism. Color sequences in butterflies were studied by Piepers (1898), Reuss (1918), Tshirvinskij (1925), Giesberg (1929). Lucas. H. Peterich (1972,1973) Their works are almost ignored by Nijhout whom we discussed before. He has never mentioned Eimer, who described the same phenomena of so-called Liesegangs figures btw. Nijhout called them "ripple pattern", wheras for Eimer it is "Rieselung" and for Suffert (1929) "Rhytmische Flugelmusterung". Much more can be found in Stanislav Komarek book:"Mimicry, Aposematism and Related Phenomena in Animals & Plants: Bibliography 1800-1990" Stanislav Komarek: used books, rare books and new books @ BookFinder.com Edited by MartinV, : No reason given.
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
Anyway I am not sure - as we discussed before - that genetical background can explain mimetism. You have never given any coherent reason why however. All you seem to do is stick your fingers in your ears and ignore any genetic research, except when trying to quote mine it to fit your preconcieved ideas. I don't quite see why you expect Nijhout to reference every study of colour patterning in butterflies the paper wasn't a historical review but novel genetic research.
Mimetism is therefore pure chance of being on the same transformation level during development. It is indepent from selection This makes no sense unless you are claiming that the patterning is not heritable, which itself makes no sense. The fact that there may not be an infinite number of possible patterns of wing colouration and that some patterns reoccur partially by chance, is in no way inconsistent with modern developmental genetics. When we discussed this previously I referencd research showing distinct genetic origins for the same pattern in two different species of Heliconius (Naisbit et al, 2003). All you really seem to be saying is that the origin of the traits is independent from natural selection and geography, which would of course be entirely consistent with modern evolutionary theory in the same way that the de novo occurence of a mutation is independent from natural selection and (with some possible exceptions for changes in rate) geography. TTFN, WK
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MartinV  Suspended Member (Idle past 5857 days) Posts: 502 From: Slovakia, Bratislava Joined: |
You have never given any coherent reason why however. All you seem to do is stick your fingers in your ears and ignore any genetic research, except when trying to quote mine it to fit your preconcieved ideas.
Eimer seems to be some kind of lamarckist but I am not sure. But I have read that he proposed temperature etc as source of changes. In such cases genes might have play no signifficant role. We are probably facing phenocopies, what have been observed in many interesting experiments.
quote: Goldschmidt was a prominent saltationist who coined the term phenocopy.
quote: Just for a record. "Genetic research" do not explain deep secrets of life sometimes. Out of Print Edited by MartinV, : No reason given. Edited by MartinV, : No reason given.
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Dr Adequate Member (Idle past 313 days) Posts: 16113 Joined: |
1) Genera Micurus (according Robert Mertens 1954) in Brazil is very poisonous and no predator survive its biting. Consequently no one can remember the species as dangerous. Well, that made me chuckle. Natural selection operates on genes, not memories.
2) I don't know if the species are diurnal or nocturnal. At least Scarlet snake you mentioned as mimic is nocturnal species. I do not see what kind of natural selection is acting to diurnal species to look like bright colored poisonous model. Mmm ... I wonder if there's such a thing as a nocturnal predator? I wonder if diurnal species ever eat nocturnal species? Golly, nature's such a puzzle, isn't it?
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