I see some have already commented on the leaf insect mimicry issue. In this specific case, however, the sources of the confusion are worth commenting on, I think. Mr. Bruno states in his essay:
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“The point is highlighted if we return to the walking leaf insect (Phyllium) from before. There are fossil records that indicate that these insects existed back in the early Jurassic Period- long before the emergence of any deciduous trees. (Wickler, 109) If this is true, then how can mimicry via natural selection be attributed to the Phyllium? How can the mimic come before the model?”
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Let’s go issue by issue. The reference provided (Wickler’1968) actually says the following:
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“It is claimed that this [i.e. Phyllium’s resemblance to angiosperm leaves] cannot be a case of leaf mimicry, since Handlirsch has found leaf-like fossil insects in the Upper Jurassic, when deciduous trees had not yet evolved.”
—
Now, I am not sure what the main source for Mr. Bruno’s information was (whether Wickler or a secondary source), but his quote does not seem to reflect the information in Wickler’s original.

First of all, as Nick mentioned above, Euphasmida (which include Phyllium) actually appear in the fossil record only in the Tertiary. So, whatever fossils Handlirsch described (Wickler provides no reference), they may have been “leaf-like”, as stated in the original, but they were not Phyllium. Since Phyllium are exquisitely adapted to mimic leaves of specific angiosperms, this is of course a significant difference.

Second, the “Upper Jurassic” is not the “early Jurassic”. In geology, “upper” and “lower” are stratigraphic terms - the “upper Jurassic” strata, laying above the “lower Jurassic” strata, were deposited more recently, and correspond therefore to the late, not early, Jurassic. This is not just a nitpick, because Angiosperms show their major radiation in the early Cretaceous, the period immediately following the late Jurassic. For this reason, and based on some (admittedly, limited) fossil evidence, it is now believed that Angiosperms (or at least angiosperm-like sister taxa, sharing features with them) in fact originated in the Jurassic, which would make them contemporaries to Handlirsch’s “leaf-like” fossils (whatever they were).

Third, of course, leaves existed long before Angiosperms, and in fact there are Gymnosperm fossils at the way back to the Permian with angiosperm-like leaves. Thus, there was abundant opportunity for insects to develop leaf-like mimicry, thanks to the selective pressure coming from visual predators, long before the Angiosperms took over the botanical world.

Not to make too big of a deal out of it, this seems to be just the product of a bit of sloppiness by a student. That’s OK, but should serve as a warning about making far-reaching arguments based on limited information.

The reference provided (Wickler’1968) actually says the following:It is claimed that this [i.e. Phyllium’s resemblance to angiosperm leaves] cannot be a case of leaf mimicry, since Handlirsch has found leaf-like fossil insects in the Upper Jurassic, when deciduous trees had not yet evolved. Now, I am not sure what the main source for Mr. Bruno’s information was (whether Wickler or a secondary source), but his quote does not seem to reflect the information in Wickler’s original.

First of all, as Nick mentioned above, Euphasmida (which include Phyllium) actually appear in the fossil record only in the Tertiary. So, whatever fossils Handlirsch described (Wickler provides no reference), they may have been “leaf-like”, as stated in the original, but they were not Phyllium. Since Phyllium are exquisitely adapted to mimic leaves of specific angiosperms, this is of course a significant difference.

Second, the “Upper Jurassic” is not the “early Jurassic”. In geology, “upper” and “lower” are stratigraphic terms - the “upper Jurassic” strata, laying above the “lower Jurassic” strata, were deposited more recently, and correspond therefore to the late, not early, Jurassic. This is not just a nitpick, because Angiosperms show their major radiation in the early Cretaceous, the period immediately following the late Jurassic. For this reason, and based on some (admittedly, limited) fossil evidence, it is now believed that Angiosperms (or at least angiosperm-like sister taxa, sharing features with them) in fact originated in the Jurassic, which would make them contemporaries to Handlirsch’s “leaf-like” fossils (whatever they were).

Third, of course, leaves existed long before Angiosperms, and in fact there are Gymnosperm fossils at the way back to the Permian with angiosperm-like leaves. Thus, there was abundant opportunity for insects to develop leaf-like mimicry, thanks to the selective pressure coming from visual predators, long before the Angiosperms took over the botanical world.

Not to make too big of a deal out of it, this seems to be just the product of a bit of sloppiness by a student. That’s OK, but should serve as a warning about making far-reaching arguments based on limited information.

A clarification on the genetics. There are three phenotypic ‘morphs’, and they are the result of multiple alleles at a single locus:

1. The pale grey, mottled morph, known as “typical.”

2. The dark, melanic morph, known as “carbonaria”

3. A set of morphs intermediate between typical and carbonaria, known collectively as “insularia”

The dominant/recessive relationships between the alleles are as follows:

a. The carbonaria allele is fully dominant over all insularia and typical alleles.

b. The insularia alleles show incomplete dominance (not codominance) over the typicals.

I would like to drawn some more attention to E. Broaddus paper on the “innate” tendency to infer purpose in nature. I have long suspected that humans (and perhaps many vertebrates, especially mammals) have this tendency. As an evolutionary psychologist, I at least partially subscribe to the idea that the human mind is composed primarily of “modules” whose functions are to process particular kinds of sensory information in such a way as to yield adaptive responses to complex environmental information. This is precisely what Broaddus argues for in her paper: that the human mind (and, by extension, the vertebrate “mind” in general) has a module that is adapted specifically for the precise and rapid inference of intentionality in nature. That such an “agency detector” (to use the commonly accepted term for such a module) would have immense adaptive value is obvious. In an environment in which other entities do indeed have “intentions” (i.e. predators, competitors, potential mates, etc.), the ability to detect and infer the possible consequences of acting upon such intentions would confer immense adaptive value on any organism with such an ability.

Furthermore, as Broaddus points out (and as we discussed briefly in the seminar), to be most effective such a detector should be tuned in such a way as to detect virtually all such “intention-indicating” behaviors. This would have the effect of producing a significant number of “false positives,” as any detector that is tuned high enough to detect all actual cases would have such a side-effect.

As Broaddus points out, one of the side-effects of such an “agency detector” would be the detection of intentionality in entities that clearly had no such intentions. If, for example, one of the most important functions of such a detector in humans is to quickly “read” and assess the intentions betrayed in human facial expressions, then it would almost certainly detect human facial expressions in objects in the environment that clearly do not have such expressions, such as rocks, foliage, water stains, etc. This would explain the ability of many humans to “see” human facial expressions in such things as water stains, cinnamon buns, rocks, etc.

Clearly, there are some “natural objects” that do, indeed, have human facial expressions impressed upon them: the faces of the presidents at Mount Rushmore are an example cited ad nauseam by ID theorists. However, I am much more interested in “faces” that humans detect in rocks and other environmental objects that are clearly not produced by human agency. Indeed, the faces at Mount Rushmore constitute a kind of “control” for this ability, as they are clearly the result of intentionality, and therefore can be used to anchor that end of the “agency detection” spectrum (at the other end of which are things like “faces” in clouds, tree foliage, etc.). Somewhere in this spectrum is a cross-over point at which actual intentionality/agency disappears and facticious intentionality/agency takes over. It is the location of that cross-over point that constitutes the hinge of the argument between evolutionary biologists and ID theorists.

Broaddus’s analysis of autism as a possible example of malfunctioning “agency detection” is, IMO, brilliant, and presents an immediately testable hypothesis: that autistic children lack well-tuned “agency detectors,” and that this at least partially explains their well-known indifference to intentional agents, such as other people (including their parents), animals, etc. In people with both full-blown autism and the milder Asperger’s syndrome (sometimes called Aspies”), a common attribute is an impaired ability to infer intentionality (or, in many cases, the mere existence of other minds) on the part of autistics and Aspies. As Broaddus points out, there are clear anatomical and functional differences between autistics, Aspies, and non-impaired people, and that these differences may be correlated with the etiology of these conditions. For example, it is very interesting that there appears to be more (rather than less) neurons in the brains of autistics than in non-impaired people. This lends credence to the generally accepted hypothesis that the information processing “modules” proposed by evolutionary psychologists are the result of “pared down” neural networks that are speciallized for particular cognitive tasks. Clearly, the agency/intentionality detector in humans functions extremely well and, as the parlance goes, “in the background.” We are rarely conscious of its operation, despite the fact that it is virtually always “on.” This explains, for example, something I first noticed as a young child: that no matter how much I tried, I couldn’t NOT see faces in the patterns in the linoleum on the floor of my grandmother’s kitchen, in the foliage of trees, in rocks, and in photographs of billowing smoke, splashing water, etc. The agency/intentionality detector works extremely efficiently in people of all ages, but especially in children. Indeed, as Broaddus points out, part of becoming an adult consists in learning (usually by trial-and-error) which of the seemingly intentional entities which we perceive all the time actually are intentional agents and actually have intentions vis-a vis ourselves. We must learn, in other words, to critically analyze the constant stream of “positive” agency/intentionality detection events, and discriminate between those that affect us and those that do not. It may be that this discrimination process actually involves the neurological “re-wiring” of the parts of the sensory/nervous system that produces such detection events, and this might explain, at least in part, the decreased ability of adults to believe in the existence of intentional agents in the natural environment.

Broaddus not only presents a cogent hypothesis concerning the existence of such an agency/intentionality detector/module in humans, she proposes several possible ways of testing whether or not such a detector actually exists, and to “map” its dimensions, capabilities, biases, and limitations. I believe that this opens up a very fruitful area of empirical research into such detectors, and can ultimately lead to much more clarity about an issue that so far has generated much more heat than light. I hope that her ideas and suggestions will be followed up by others (I certainly intend to do so), and that further empirical research into this fascinating and little-known capability will add to our understanding of what makes us the peculiar creatures we are.

The result is an inference upon which alternative hypotheses are propped. Sinervo writes that, “despite the limitations of combining laboratory and field studies, [this combination] allows a biologist to predict the evolutionary trajectory that a population might experience in the future if the intensity of selection and the heritability remain constant.” Or, in other words, while these statements are not robust statements about natural selection in the wild, but they do generate questions for further study. In is incumbent, however, that these new questions will also require rigorous, scientific testing in order to make robust conclusions from the data. If not, we have not science, but speculation built upon speculation.

So, sure, there’s a warning that science must be conducted with rigorous methodologies, and hints that any one scientific study by itself does not prove much. Quite true. But it also affirms the validity of the scientific method against Behe’s accusations of “wishful speculation.”

Nicely done.

Also, his account (p. 8) of “natural selection as a tool of intelligent design” sounds rather more like directed evolution than intelligent design.

J. Bruno’s paper on mimicry and camoulflage provides a “design-friendly” perspective on a perennial topic in evolutionary biology, and provides a “synthetic” perspective that tries to reconcile the two viewpoints.

…in the interests of nitpicking pedantry, which is my special superpower and I really can’t help myself, I offer a few comments:

1. The dark allele in the peppered moth is not recessive, rather the dark and light alleles are codominant IIRC, and there are a number of intermediate alleles etc. The alleles have not been biochemically characterized but perhaps they simply control the amount of melanin produced.

But the author gets points because he didn’t get sold down the river by the typical creationist obfuscations about the peppered moth.

2. Calling Ronald Fisher an advocate of “intelligent design” is fairly dubious, when he is perhaps the most important evolutionary biologist of the 20th century and probably the closest thing to a founder of “Neo-Darwinism.” I know what the author means — Fisher believed in God and was a traditional Anglican. But the usual term for this position is “theistic evolutionist”, and since the ID people mostly deny common ancestry and believe in the special creation of “kinds”, they are not buddies with the theistic evolutionists.

I quote Dembski:

Design theorists are no friends of theistic evolution. As far as design theorists are concerned, theistic evolution is American evangelicalism’s ill-conceived accommodation to Darwinism. What theistic evolution does is take the Darwinian picture of the biological world and baptize it, identifying this picture with the way God created life. When boiled down to its scientific content, theistic evolution is no different from atheistic evolution, accepting as it does only purposeless, naturalistic, material processes for the origin and development of life.

William A. Dembski (1995). “What Every Theologian Should Know about Creation, Evolution, and Design.” Center for Interdisciplinary Studies Transactions 3(2):3.

3. Lastly, the ironic bit about walking sticks at the end:

Lastly, I feel that there are certain indicators that may give credibility to intelligent design.
The point is highlighted if we return to the walking leaf insect (Phyllium) from before. There are
fossil records that indicate that these insects existed back in the early Jurassic Period- long before
the emergence of any deciduous trees. (Wickler, 109) If this is true, then how can mimicry via
natural selection be attributed to the Phyllium? How can the mimic come before the model?
These questions indicate that there are certain gaps within natural selection that need to be filled,
thus giving hope to creationists everywhere that maybe ID can be the perfect fit.

The idea that leaf-mimics preceded leaves is derived from an old reference, and that reference seems to be part of a kind of legend that has been handed down over the years. It recently came up in a book heavily promoted by the Discovery Institute, and Michael Behe himself specifically emphasized the leaf-mimicry-before-leaves claim in his endorsement of the book (so Bruno was quite right about the ID reaction).

But the truth is roughly this:

(a) The modern group of phasmids, which includes Phyllium, is not that old, only maybe 50 million years.

(b) fossils related to the phasmids go back much futher, I think to 150 million years ago, but they do not look like leaves (neither do many modern phasmids) as far as I know

(c) And anyway, plant leaves are not restricted to flowering plants (angiosperms). Several modern gymnosperm groups (such as gingko trees and Gnetales) and and many extinct gymnosperms and other fossil seed plants had leaves, long before angiosperms originated maybe 130 million years ago.

The Panda’s Thumb folks were beating the Discovery Institute up on this one awhile ago:

Behe and bugs: Genesis of a Creationist canard?
http://www.pandasthumb.org/archives/2005/08/behe_buys_sermo.html

The Panda’s Thumb: Hey, “Evolution News”: correct this!
http://www.pandasthumb.org/archives/2005/09/glaring_error_o.html

Anyway, thanks for a fun read!