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TS-Si
is dedicated to the acceptance, medical
treatment, and legal
protection of individuals correcting the misalignment
of their brains and their anatomical sex, while supporting their transition
into society as hormonally reconstituted and surgically corrected citizens.
is dedicated to the acceptance, medical
treatment, and legal
protection of individuals correcting the misalignment
of their brains and their anatomical sex, while supporting their transition
into society as hormonally reconstituted and surgically corrected citizens.
| Could Misalignment of Brain Sex and Body Plan be Positive for Evolution? |
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| SciMed - Biology | ||||||||||||
| TS-Si News Service | ||||||||||||
| Monday, 04 May 2009 09:00 | ||||||||||||
 Durham, NC, USA. Whatever the source of the misalignment of a human's  brain and anatomical sex, an anomalous birth condition, where does such an event fit into the broader canvas of evolution and the natural world? But if nature drives toward the implementation of efficient body designs, how is it that variations can still occur — and even thrive — without threatening the long-term stability of the species? The answer may lie in the fundamental and common features shared within a species — without regard to variations — and their correctability over time to meet local conditions in the environment.
Humans, as biological organisms, are subject to chemical reactions at the most fundamental level, and corrective biological mechanisms — both elemental and conscious — that protect us and ensure long-term survival. Some of the corrective measures are so effective they can migrate away from happenstance and into our permanent genomic endowment. Can occasional misalignment persist as an exceptional birth condition, face extinction, or emerge as an evolutionary positive? How can we know?
Constructal
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| Adrian Bejan is a professor of mechanical engineering and inventor of the constructal theory of global optimization under local constraints. |
| Photo courtesy of Duke University. |
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| James Marden is a professor of Biology at Penn State, with research interests that include physiological ecology, functional genomics, evolutionary ecology, and behavior. |
| Photo courtesy of James Marden. |
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| A leaping Arctic Grayling shows a form honed by efficiency. |
| Photo courtesy of the US Fish and Wildlife Service (USFW). |
The constructal theory posits that in nature the generation of design (configuration, pattern,
geometry) is a phenomenon of physics that unites all animate and inanimate systems. Adrian Bejan stated the constructal law that
accounts for this phenomenon in 1996:
constructal law that
accounts for this phenomenon in 1996:- "For a finite-size (flow) system to persist in time (to live), its configuration must evolve such that it provides easier access to the imposed currents that flow through it."
Adrian Bejan taught at MIT until 1976 and is now J.A. Jones Distinguished Professor of Mechanical Engineering at Duke University. He coined the term constructal from the Latin verb construere
(to construct). From a theoretical point of view, constructal is to construct — in order to designate the naturally optimized forms. Examples include
rivers, trees and branches, lungs and the engineered forms that come
from an evolutionary process that maximizes flow access in time.
The main principle of the constructal theory is that every system is destined to remain imperfect. As a consequence, a perfect form is the least imperfect
form possible and constitutes the best outcome available. Achieving
this means that system imperfections must be optimally distributed,
directly generating the geometry (or shape) of the system under study.
The
constructal way of distributing the system's imperfection is to put the
more resistive regime at the smallest scale of the system. In common
parlance, this means that those imperfections least disposed to
optimization are most likely to be placed at a lower priority. The presence of such
resistive imperfections are the reason why the least imperfect form possible is the best available outcome.
Prediction & Test
Genotype & Phenotype. Every living organism exhibits the outward physical manifestation of its internally coded, inheritable information. A genotype is the internally stored set of instructions (the blueprint) for building and maintaining a creature throughout its life. Nearly all cells contain the instructions in a language called the genetic code).
The bluprint is inheritable because it is copied at the time of cell division or reproduction, then passed from one generation to the next. These instructions are intimately involved with all aspects of a cell or organism, controlling everything from the formation of protein macromolecules to the regulation of metabolism and synthesis.
The genetic code is stored on one of the two strands of a DNA molecules. It is a linear, non-overlapping sequence of the nitrogenous bases: Adenine (A), Guanine (G), Cytosine (C) and Thymine (T). The alphabet, AGCT, is used to write a sequence of three letter code words (triplets or codons). There are 64 code words possible from an alphabet of four letters.
DNA molecules. It is a linear, non-overlapping sequence of the nitrogenous bases: Adenine (A), Guanine (G), Cytosine (C) and Thymine (T). The alphabet, AGCT, is used to write a sequence of three letter code words (triplets or codons). There are 64 code words possible from an alphabet of four letters. Each 3-letter code word can be interpreted as a single amino acid in a polypeptide chain, a sequence of words along the length of the DNA strand. The start signal word begins all sequences coding for amino acid chains; three words are stop signals that close the message.
All the other sequences code for specific amino acids. Some amino acids are only coded for by a single 'word', while some others are coded for by up to four 'words'. The genetic code is redundant.
A phenotype is the physical manifestation of an organism — the outside. The living organism is the sum total of its physical parts. They include anything that is part of an organism's observable structure, function or behavior (atoms, molecules, macromolecules, cells, structures, metabolism, energy utilization, tissues, organs, reflexes and behaviors).
The relationship is direct: the genotype codes for the phenotype. The internally coded and inheritable information, the genotype, holds the critical instructions that are used and interpreted by the cellular machinary of the cells to produce the outward, physical manifestation, or phenotype of the organism.
The molecules, macromolecules, cells, and other structures act and interact with one another over time, producing larger and more complex phenomena (such as metabolism, energy utilization, tissues, organs, reflexes and behaviors).
A genetic trait is a small part of an organism's phenotype. The tools of molecular and cellular biology can see into the cell cytoplasm and observe chemical reactions that result in the ever more complex structures obervable to our eyes. The action of proteins produces almost all traits.
The information flow insures a a trait can be observed. DNA molecules store the essential instructions for building a protein macromolecule. These instructions are copied from the DNA molecule into the form of an RNA molecule. One, or many copies can be made of these instructions.
Each of these messenger RNA (mRNA) copies move away from the DNA templates and enter the cytoplasm of the cell. They then encounter the machinery that will convert the biological information (the instructions) into the correct linear sequence of amino acids that will become a functioning protein.
Once the protein has been correctly assembled and folded it can go to work and produce a particular trait.
Bejan writes that “The constructal law is the time direction of the movie: toward flow configurations (designs, drawings) that flow more easily,” describing it as an animated movie, where one screen is replaced by another
screen on which the currents flow with greater ease.
“Indeed, the constructal literature of the past decade has focused on showing that the constructal law covers ‘natural design’ phenomena across the board, from biology and geophysics to social dynamics and technology evolution,” Bejan writes. It is a "... compact summary of common observations, the tape of evolution running
in one direction, which may be expressed in physics terms simply as:
time and configuration.”
The unification of principles of nature’s design to include both biological and geophysical phenomena "... is an exciting development for physicists, but it should also resonate with biologists,” Bejan said.
“The idea that organic evolution is analogous to the way form evolves in inanimate flow systems is a novel concept that has the potential to unite perspectives and approaches across disparate disciplines."
Bejan has published numerous papers over the past decade that demonstrate how the constructal law predicts the design of a wide range of flow systems seen in nature. From biology and geophysics to social dynamics and technology evolution, the law is testable in practice; as a result, it has the potential for wide application. [Cf. References]
“When thinking of evolution and Darwin, most people think of animals or trees,” Bejan said. “That’s too bad, because design features are everywhere in nature. The constructal law can be seen as a universal principle of evolution, which applies in many fields, from physics to economics.”
Evolution: Swim, Run, or Fly
Following a chance encounter, Bejan began work with James Marden, a biologist at Penn State and extended the constructal law and unified both the biological and geophysical principles of nature’s design. This can be viewed as the physics of evolution. Bejan and Marden published their findings in Physics of Life Reviews. [Cf. Citation]
Bejan and Marden wondered if the same laws applied to an acid test: the two very different form of locomotion exhibited when fish swim, as distinct from what happens when animals run or fly. Biologists have commonly viewed fish locomotion as different than other animal locomotion because fish live in water and are not subject to gravity.
The two scientists saw an underlying similarity: birds and animals could be viewed as weight-lifters, since their means of locomotion required effort with an unyielding base (the ground) and a limitless top (the air). He argued that as fish swim, they too have an unyielding floor — the sea bed. Hence, water flowed over and around them like the air over runners and flyers.
So, fish too are weight-lifters, and these forms of locomotion are predicted by the constructal law.
Implications
Bejan does not expect his latest publication to be warmly embraced. It has something to annoy just about every scientific camp. He uses the constructal law to predict such diverse phenomena as human organ sizes, turbulence and river basins. He sees the constructal law as a universal principle of evolution, with diverse applications ranging from physics to economics.
“Our discovery that animal locomotion adheres to the constructal law tells us that — even though you couldn’t predict exactly what animals would look like if you started evolution over on Earth, or it happened on another planet — with a given gravity and density of their tissues, the same basic patterns of their design would evolve again.”
Bejan and Marden also suggest that the constructal law provides a tool for ".. examining and understanding variation in both the animate and inanimate compartments of nature.” Most directly, this means variation between species or types in nature, but it has more general implications for the overall diversity of life and specific, but enduring, variations within a species.
Perhaps the constructal theory also provides insight and a methodology that accounts for the existence of Harry Benjamin Syndrome (HBS, or classic transsexuality). If every system is destined to remain imperfect, men and women born transsexual may be the best outcome available when asynchronous execution of the human genome results in a sex mismatch of the brain and the rest of the body.
Thus, men and women born transsexual are not necessarily the optimal outcome of human reproduction, but they are a viable outcome. Their birth with a mismatched mind and body) may be the only outcome that does not terminate the transsexual fetus inside the womb. This view poses challenging questions best addressed by intense research.
FundingThis research was supported by the U.S. Air Force Office of Scientific Research (AFOSR) and the National Science Foundation (NSF).
References[R1] Advanced Engineering Thermodynamics. A. Bejan. Wiley-Interscience, 2nd edition. ISBN 0-471-14880-6; 3rd edition (2006). ISBN 0-471-67763-9.
[R2] Shape and Structure, from Engineering to Nature. A. Bejan. Cambridge University Press. (2000). ISBN 0-521-79388-2.
[R3] Proceedings of the Symposium "Bejan’s Constructal Theory of Shape and Structure". Edited by Rui N. Rosa, A. Heitor Reis & A. F. Miguel, Centro de Geofísica de Évora. Évora Geophysics Center, Portugal (2004). ISBN 972-9039-75-5.
[R4] Constructal theory of organization in nature: dendritic flows, allometric laws and flight. A. Bejan. Design and Nature. CA Brebbia, L Sucharov & P Pascola (Editors). ISBN 1-85312-901-1.
[R5] Constructal theory of flow architecture of the lungs. A. H. Reis, A. F. Miguel, M. Aydin. Journal of Medical Physics 31(5): 1135-1140. (May 2004).
[R6] Constructal theory of global circulation and climate. A. H. Reis, A. Bejan. International Journal of Heat and Mass Transfer.
[R7] La loi constructale; traduction [de l'anglais] et avant-propos d'Angèle Kremer-Marietti. Adrian Bejan, Sylvie Lorente. Paris ; Budapest ; Torino : l'Harmattan, DL 2005 (14-Condé-sur-Noireau : Impr. Corlet numérique). 1 vol. (109 p.) : ill., couv. ill. ; 24 cm. (Collection Épistémologie et philosophie des sciences). Bejan, Adrian (1948-....) Bibliogr. p. 99-109. - DLE-20050511-22456. - 530.4 (21) . - ISBN 2-7475-8417-8 (br.) : 11,50 EUR.
[R8] Trois Etudes sur la loi constructale d'Adrian Bejan. Abdelkader Bachta, Jean Dhombres, Angèle Kremer-Marietti. Paris:L'Harmattan (2008). Théorie constructale. BN 39967557 05-38009.
[R2] Shape and Structure, from Engineering to Nature. A. Bejan. Cambridge University Press. (2000). ISBN 0-521-79388-2.
[R3] Proceedings of the Symposium "Bejan’s Constructal Theory of Shape and Structure". Edited by Rui N. Rosa, A. Heitor Reis & A. F. Miguel, Centro de Geofísica de Évora. Évora Geophysics Center, Portugal (2004). ISBN 972-9039-75-5.
[R4] Constructal theory of organization in nature: dendritic flows, allometric laws and flight. A. Bejan. Design and Nature. CA Brebbia, L Sucharov & P Pascola (Editors). ISBN 1-85312-901-1.
[R5] Constructal theory of flow architecture of the lungs. A. H. Reis, A. F. Miguel, M. Aydin. Journal of Medical Physics 31(5): 1135-1140. (May 2004).
[R6] Constructal theory of global circulation and climate. A. H. Reis, A. Bejan. International Journal of Heat and Mass Transfer.
[R7] La loi constructale; traduction [de l'anglais] et avant-propos d'Angèle Kremer-Marietti. Adrian Bejan, Sylvie Lorente. Paris ; Budapest ; Torino : l'Harmattan, DL 2005 (14-Condé-sur-Noireau : Impr. Corlet numérique). 1 vol. (109 p.) : ill., couv. ill. ; 24 cm. (Collection Épistémologie et philosophie des sciences). Bejan, Adrian (1948-....) Bibliogr. p. 99-109. - DLE-20050511-22456. - 530.4 (21) . - ISBN 2-7475-8417-8 (br.) : 11,50 EUR.
[R8] Trois Etudes sur la loi constructale d'Adrian Bejan. Abdelkader Bachta, Jean Dhombres, Angèle Kremer-Marietti. Paris:L'Harmattan (2008). Théorie constructale. BN 39967557 05-38009.
CitationThe constructal unification of biological and geophysical design. Adrian Bejana and James H. Mardenb. Physics of Life Reviews6 (2009). doi: 10.1016/j.plrev.2008.12.002
Abstract
Here we show that the emergence of scaling laws in inanimate (geophysical) flow systems is analogous to the emergence of allometric laws in animate (biological) flow systems, and that features of evolutionary “design” in nature can be predicted based on a principle of physics (the constructal law): “For a finite-size flow system to persist in time (to live) it must evolve in such a way that it provides easier and easier access to its currents”, meaning that the configuration and function of flow systems change over time in a predictable way that improves function, distributes imperfection, and creates geometries that best arrange high and low resistance areas or volumes. This theoretical unification of the phenomena of animate and inanimate flow design generation is illustrated with examples from biology (lung design, animal locomotion) and the physics of fluid flow (river basins, turbulent flow structure, self-lubrication). The place of this design-generation principle as a self-standing law in thermodynamics is discussed. Natural flow systems evolve by acquiring flow configuration in a definite direction in time: existing configurations are replaced by easier flowing configurations.
Keywords: Design in nature; Constructal law; Scaling laws; Animal locomotion; Lung design; River basins; Organ sizes.
Abstract
Here we show that the emergence of scaling laws in inanimate (geophysical) flow systems is analogous to the emergence of allometric laws in animate (biological) flow systems, and that features of evolutionary “design” in nature can be predicted based on a principle of physics (the constructal law): “For a finite-size flow system to persist in time (to live) it must evolve in such a way that it provides easier and easier access to its currents”, meaning that the configuration and function of flow systems change over time in a predictable way that improves function, distributes imperfection, and creates geometries that best arrange high and low resistance areas or volumes. This theoretical unification of the phenomena of animate and inanimate flow design generation is illustrated with examples from biology (lung design, animal locomotion) and the physics of fluid flow (river basins, turbulent flow structure, self-lubrication). The place of this design-generation principle as a self-standing law in thermodynamics is discussed. Natural flow systems evolve by acquiring flow configuration in a definite direction in time: existing configurations are replaced by easier flowing configurations.
Keywords: Design in nature; Constructal law; Scaling laws; Animal locomotion; Lung design; River basins; Organ sizes.
Ms. Lisa Jain Thompson is a Co-Founder & Principal of TS-Si. She also serves as a Contributing Editor and columnist for the TS-Si website. She maintains another site, StarPoet.com, for her poetry and literary works.Ms. Thompson's signed articles contain her own opinions and do not necessarily convey an official position of TS-Si, its partners, or affiliates. Lisa welcomes your comments. Use the form below or email via her TS-Si Contact Page. We will not divulge any personal details or place you on a mailing list without your permission.
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