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Two Wrongs Don’t Make a Right

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An article in Ecology letters, entitled: “Eco-evolutionary Dynamics in Response to Selection on Life-history,” deals with research conducted on “soil mites that were collected from the wild and then raised in 18 glass tubes.” The researchers
found significant genetically transmitted changes in laboratory populations of soil mites in just 15 generations, leading to a doubling of the age at which the mites reached adulthood and large changes in population size.

At Phys.Org, they write:

Although previous research has implied a link between short-term changes in animal species’ physical characteristics and evolution, the Leeds-led study is the first to prove a causal relationship between rapid genetic evolution and animal population dynamics in a controlled experimental setting.

Further, lead author Tom Cameron tells us:

“We saw significant evolutionary changes relatively quickly. The age of maturity of the mites in the tubes doubled over about 15 generations, because they were competing in a different way than they would in the wild. Removing the adults caused them to remain as juveniles even longer because the genetics were responding to the high chance that they were going to die as soon as they matured. When they did eventually mature, they were so enormous they could lay all of their eggs very quickly.”

Co-author Tim Benton states:

“This demonstrates that short-term ecological change and evolution are completely intertwined and cannot reasonably be considered separate.

There are two things to note:
(1) Darwin insisted on gradual change. This is not “gradual” change, but “rapid” change. You might remember those lizards on the Adriatic Islands that developed cecal valves in probably 20 generations or less.
(2) The vacuousness of the phrase “evolutionary change.” The term that should be used is “adaptive change,” for that is EXACTLY what is happening. The organisms doesn’t change in a way that has any evolutionary importance; it just simply changes.
(3) This “rapid” change indicates that “gene frequencies” cannot be changing, simply because the changes are occurring too rapidly. So, the likely instrument of these “rapid” changes is a change in gene expression, and hence, the turning on, and the turning off of gene promoters, which can easily happen via RNA–and, it can happen in a way that is inherited a la “Lamarkian” notions–not Darwinian.

None of what is being reported is consistent with either Darwinian, or neo-Darwinian, mechanisms. This is just a plain fact. You see, two “wrongs”—being wrong in the Darwinian and neo-Darwinian sense—does not make a “right.”

But “true believers” never let facts get in the way. However, there are so many of these inconvenient facts that day-by-day are collecting that it is but a matter of time before the whole Darwinian artifice comes tumbling down.

Comments
More design, more complexity, more contingency - its amazing that the physical bodies of the lizards can change when needed!
"...exhibited a reduction in digestive tract length and a total loss of cecal valves after having been fed an exclusively arthropod diet for 15 wk.
butifnot
April 9, 2013
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JLAfan2001, those lizards did not generate a new body plan, de novo, in a few generations. All observed evidence shows that change can not be continued indefinately - organisms steadfastly remain what they are.butifnot
April 9, 2013
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Box, thanks. It might be worth it if the documented examples are abundant.Chance Ratcliff
April 9, 2013
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"...If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down." - Charles Darwin, Origin of Species, Chapter 6Chance Ratcliff
April 9, 2013
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Chance Ratcliff (11), no I haven't read her book. I am an amateur but I believe that West-Eberhard is on the wrong track. She believes that phenotypical change somehow precedes (and induces) genetic change.
Here, I argue that the origin of species differences, and of novel phenotypes in general, involves the reorganization of ancestral phenotypes (developmental recombination) followed by the genetic accommodation of change.
She doesn't present a mechanism for this - as far as I know - and I cannot imagine that there is a mechanism which translates changes in morphology into DNA code. So although I enjoy the examples of plasticity she has presented I'm personally not that curious about her book.Box
April 9, 2013
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I think Darwin got it right terms of change in a species or adaptation to an environment. He may have got the timing wrong but that it still up for debate. I don't think that modern biologists have thrown the theory out just yet. Just imagine if that lizard went through hundreds of adaptations in hundreds of environments in hundreds of years. Would it be a lizard then or something else? That's Darwin's theory more or less.JLAfan2001
April 9, 2013
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JLAFan2001 @14, Don't you find it amusing that labeling non-Darwinian evolution "Rapid Evolution" baically translates into "rapid gradual change"? Can you not see the irony there? :)Chance Ratcliff
April 9, 2013
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This is kinda funny, BA77. I've seen you ask for evidence of new genetic material or new body plans arising in organisms many times here. When you finally get the evidence, you say "So what, it was already built into the genes so this doesn't count." No body plans or information: ID New body plans and information: ID Congratulations, guys. Intelligent Design is well on it's way to replacing the Neo-Darwinian dogma of unfalsifiable science.JLAfan2001
April 9, 2013
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Collin also see: Lizard Plasticity - March 2013 http://biota-curve.blogspot.com/2013/03/lizard-plasticity.htmlbornagain77
April 9, 2013
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Collin @9, see lifepsy's video here: Phenotypic Plasticity.Chance Ratcliff
April 9, 2013
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Box @8, thanks for the link to West-Eberhard's treatise. Have you read her book? If so, do you recommend it?Chance Ratcliff
April 9, 2013
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What is in need of explanation, in the case of Slijper's goat, is ’the expression of a whole suite of correlated and adaptive changes in behavior, muscle, and bone.’ Slijper's goat developed into a 'new' coherent animal that in some respects looks more like a kangaroo than a goat. How do we explain this 'suite of correlated and adaptive changes'? How can the kangaroo-like development be explained considering the goat’s hereditary makeup? IMO the only explanation, since the parts cannot account for this, is that the organism - at the level of the whole - is doing the reorganization.Box
April 9, 2013
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Tell me about those cecal valves that appeared in those lizards.Collin
April 9, 2013
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Thanks PaV & Chance Ratciff for the valuable information. There is an article about phenotypic plasticity at evolutionnews.org, based on the work of Mary Jane West-Eberhard. In her treatise Developmental plasticity and the origin of species differences she writes about Slijper’s goat:
Slijper’s two-legged goat was born with a congenital defect of the front legs so that it could not walk on all fours, and so it learned to walk and run by using its hind legs alone. Then, when it died an accidental death, Slijper dissected it and documented remarkable changes in muscle and bone, including striking changes in the bones of the hind legs; the leg muscles, including a greatly thickened and elongated gluteal tongue and an innovative arrangement of small tendons, a modified shape of the thoracic skeleton, and extensive modifications of the pelvis.
West-Eberhard’s definition of phenotypic plasticity from her book Developmental Plasticity and Evolution (Oxford UP, 2003):
Phenotypic plasticity enables organisms to develop functional phenotypes despite variation and environmental change via phenotypic accommodation -- adaptive mutual adjustment among variable parts during development without genetic change.
Box
April 9, 2013
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Correction in #6: James *Barham*Chance Ratcliff
April 9, 2013
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This is interesting, developmental plasticity as part of ontogenesis. This is from an article by James Bahram at thebestschools.org:
"What is developmental plasticity? It is the property that all living things possess of being able to compensate during ontogenetic development for variations in either internal or external conditions. Note that “compensation” is a teleological concept. It implies that there is a particular end- or goal-state that one is trying to attain by means of the compensatory maneuvers." -- Seeing Past Darwin III: Mary Jane West-Eberhard
He goes on to cite a rather fascinating experiment:
"Everhard Johannes Slijper (1907–1968) was a Dutch zoologist who during World War II published a report on a goat that had been born without forelegs.(4) He had reared the animal to the age of one year, then sacrificed it in order to study its anatomy. With human help, the goat had learned to hop about on its hind legs. Slijper demonstrated that this ability was supported by a whole suite of coordinated changes in the animal’s skeleton and musculature. In fact, upon dissection the animal’s body was found to resemble that of a kangaroo more closely than that of a normal goat. ... As West-Eberhard explains:
. . . the point is to dramatize how a change in one aspect of the phenotype—in this case the front legs—can lead to correlated changes that show a degree of complexity and functional integration that we usually assume to require generations of natural selection and genetic change at many loci.(5)
The example of Slijper’s goat is useful because it helps us to represent to ourselves the abstract notions of “developmental plasticity” and “phenotypic accommodation” in a more vivid way. In cases like Slijper’s goat and Faith the Dog, we can see the power of these phenomena in action. But they are equally active in less extreme cases, as well. In fact, whenever any change whatsoever is introduced at the genetic level, some goal-directed compensation must take place in order for a viable adult form to be attained."
The article is here: Seeing Past Darwin III: Mary Jane West-Eberhard A subsequent related article is here: Seeing Past Darwin IV: Some Experiments Mary Jane West-Eberhard's book: Developmental Plasticity and Evolution.Chance Ratcliff
April 9, 2013
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JLAfan2001 you ask:
Wouldn’t that mean that there is new genetic information in the DNA to introduce those plans that wasn’t there before?
Does rapid, and repeatable, cyclical variation mean 'new genetic information' to you? Or does it mean 'front loaded' variation to you? Did you even watch lifepsy's video? Phenotypic Plasticity - Lizard Cecal Valve - Cyclical Variation - video http://www.youtube.com/watch?feature=player_detailpage&v=zEtgOApmnTA#t=583s
Anatomical and Physiological Changes Associated with a Recent Dietary Shift in the Lizard Podarcis sicula - 2010 Excerpt of Discussion: Many comparative studies have tacitly assumed that the distinctive features of plant-eating lizards (large body size, skull dimensions, special dentition, gut morphology) are a product of genetic adaptation to the special demands of a plant-based diet (e.g., Van Damme 1999; Cooper and Vitt 2002; Espinoza et al. 2004; Herrel et al. 2008). Our results suggest that in P. sicula, at least some of the changes associated with a dietary shift toward a higher proportion of plant material may be plastic. Specimens from the Pod Mrc?aru population, which in nature eat substantial amounts of plant material (Herrel et al. 2008), exhibited a reduction in digestive tract length and a total loss of cecal valves after having been fed an exclusively arthropod diet for 15 wk. Although parts of their gastroinstestinal systems were still better developed than those of specimens feeding mainly on arthropods in the wild, it seems likely that a prolonged exposure to an animal-based diet would have erased even those differences. These observations call for a more flexible view of the digestive system in lizards. Plasticity of gastrointestinal morphology and function has long been described in birds (Savory and Gentle 1976a, 1976b; Karasov 1996; reviews in Starck 1999; McWilliams and Karasov 2001) and mammals (e.g., Sibly et al. 1990; Lee and Houston 1993; Munn et al. 2006). Gut morphology and performance in these animals vary seasonally in concert with changes in internal demand (e.g., reproduction, migration, hibernation) or environmental conditions (food availability, nutrient composition). In reptiles, there is evidence that digestive function may change in response to dietary demands on ontogenetic, seasonal, and instantaneous timescales. Many reptiles shift toward a more herbivorous diet as they age (Kennett and Tory 1996; Bjorndal 1997b ; Rocha 1998; Spencer et al. 1998; Durtsche 2000; Fialho et al. 2000; Bouchard and Bjorndal 2006; but see Cooper and Vitt 2002 on the generality of this phenomenon). At least in some of the species studied, this ontogenetic dietary shift is accompanied by changes in digestive efficiency (Durtsche 2004; Bouchard and Bjorndal 2006). Reptiles living in a seasonal environment have been described as regulating their digestive apparatus according to activity or prey availability (Latif et al. 1967; Tracy and Diamond 2005; Naya et al. 2008; Iglesias et al. 2009). And in snakes and other reptiles with irregular feeding patterns, eating is followed by an immediate up-regulation of digestive functions, resulting in an increased mass of the small intestine and intensified enzyme activity and brush-border transport rates (Secor and Diamond 1995, 2000; Secor and Phillips 1997; Jackson and Perry 2000; Starck and Beese 2002; Ott and Secor 2007). All of these observations suggest that many lineages of vertebrates, including lizards, exhibit considerable phenotypic plasticity in the morphology and physiology of their digestive system. In these lineages, dietary shifts from carnivory to omnivory (as observed in many lizard families; Cooper and Vitt 2002) may constitute less of an evolutionary challenge than previously thought. It has been argued that the transition to exclusive herbivory (typically folivory) would require more substantial adaptations (Cooper and Vitt 2002). However, with the potential exception of the need for specialized dentition for cutting or reducing leaves, most of the changes deemed necessary in this context (elongation of the intestines, development of valves, prolonging retention time, acquisition of commensals, increasing digestive efficiency) have been shown to occur in a short to very short time span in this study and many of the studies cited above. http://webhost.ua.ac.be/funmorph/publications/Vervust%20et%20al%202010%20Pysiol%20Biochem%20Zool.pdf
bornagain77
April 9, 2013
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JLAFan2001,
"Wouldn’t the appearance of the cecal valves mean that there was a new novel function or body plan introduced?"
I think the question to ask is, introduced how? Just because seemingly new features emerged does not imply that Darwinian evolution occurred. Darwinian evolution calls for gradualism -- slight, successive changes accumulating over time, moving an organism from a state of being less-fit to more-fit with regard to environmental pressures. It requires the changes to be entirely random with respect to outcome, and filtered gradually by natural selection. There's nothing about this so-called Rapid Evolution that appears Darwinian. Why not just call it "Spontaneous Evolution" or "Non-Darwinian Evolution"? If a lizard can increase its head size, jaw strength, behavior, and gut configuration without the changes being gradual or selective, then there is no Darwinian evolution happening there.
"Wouldn’t that mean that there is new genetic information in the DNA to introduce those plans that wasn’t there before?"
No, I don't think so. This relation is not the same as genotype determining morphology, with changes in genotype brought on by random mutations expressing a different morphology. This appears to be a case of a pre-existing developmental program mapping environmental factors to the expression of morphological features. In other words, the genetic material is already present, and how it expresses itself is determined by environmental triggers; in the case of the podarcis sicula lizards, the trigger appears to be diet.
"Wouldn’t that refute the claim that we have never seen any new body plans or genetic information introduced in an organism along the lines that BA77 seems to cite?"
It shows that the introduction of a "novel" feature was part of the organism's existing developmental program and genomic makeup. The lizards of Pod Mrcaru are not an example of Darwinian evolution, they appear to be expressions of phenotypic plasticity, which is a very non-random mechanism of change that is goal directed.Chance Ratcliff
April 9, 2013
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Wouldn't the appearance of the cecal valves mean that there was a new novel function or body plan introduced? Wouldn't that mean that there is new genetic information in the DNA to introduce those plans that wasn't there before? Wouldn't that refute the claim that we have never seen any new body plans or genetic information introduced in an organism along the lines that BA77 seems to cite?JLAfan2001
April 9, 2013
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Worth watching: Non-Random and Targeted Mutations Phenotypic plasticity Biological research is revealing the non-random nature of, well, practically everything biological.Chance Ratcliff
April 9, 2013
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"However, there are so many of these inconvenient facts that day-by-day are collecting that it is but a matter of time before the whole Darwinian artifice comes tumbling down."
I wonder what will replace it. From Darwin's God:
"Evolution may make no sense, but it will always be true. It must be, for god would never make this world. So evolution will flit from nonsensical idea to nonsensical idea in its never ending attempt to make sense. Who knows what the theory of origins will be in the future, but it will be called evolution. And it will be true. " -- What Will be the 21st Century's Theory of Origins?
I think phenotypic plasticity may well mean death for neo-Darwinism, and perhaps Darwinism in general, but it won't go quietly, and power-word "evolution" will likely be retained for whatever theory goes in under the hood. There's too much invested in, change means evolution means natural means all-by-itself. This is already hinted at with regard to James Shapiro, who is pushing for the conception of natural genetic engineering to be the mechanism of evolution, but also the result:
"In elaborating on these generic DNA operations, the vast majority of free-living prokaryotes and eukaryotes have evolved biochemical systems that permit them to mobilize and restructure their genomes in more specialized ways. Essential to any contemporary account of evolution is the inclusion of these well-documented genomic mobilization and restructuring (natural genetic engineering) operators." -- James Shapiro, Evolution: A View from the 21st Century, Kindle location 1121
In the introduction he writes,
"But the capacity to change is itself adaptive. Over time, conditions inevitably change, and the organisms that can best acquire novel inherited functions have the greatest potential to survive." -- ibid, Kindle location 311
So regardless of whether RM+NS survives the next few decades, evolution may not go quietly. Even so, I'm enjoying watching RM+NS crumble to dust.Chance Ratcliff
April 9, 2013
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