Organisms, History, and the Biological Character Concept · (A) only cranial characters (Tchernov...
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RESEARCH POSTER PRESENTATION DESIGN © 2012 www.PosterPresentations.com developmental continuity : spatiotemporal interrelation through advancement from juvenile to adult organismal characters have variable stages organismal characters are individuated in virtue of their developmental continuity comparable instances of historical characters can vary substantially historical character concept lends comparability organismal character concept lends independence Different researchers apply different character concepts differently. ancestral continuity : spatiotemporal interrelation through inheritance from ancestor to descendent historical characters have variable instances 2) Character Individuation Radiographs of full specimen (above) & cloacal region with pelvic bones highlighted (left) of Haasiophis terrasanctus (Rieppel et al. 2003) 1) Taxa Selection Taxa and their comparable characters are described or re-described and entered into an inference algorithm. Figures of Pachyrhachis problematicus cloacal region with hindlimb bones labelled (far left) & cranial region (left) photo-drawing-diagram (Lee & Caldwell 1998) The character individuation problem arises from inconsistent application of multiple biological character concepts Two distinct notions of character are in use but inconsistently applied historical character concept applied to establish comparability organismal character concept applied to establish independence Future approaches for development of a biological character concept: analyse application of organismal and historical character concepts in the biological literature and discussion of criteria already in use (e.g. independence) diagnose and analyse other philosophical problems arising from or solved by particular applications of these concepts (e.g. Adaptationist atomism as arising from unguided application of organismal character concept and exaptation- adaptation distinction as including criteria for application of historical character concept where organismal character concept is more prominent) PHIOLOSOPHICAL IMPACT & FUTURE APPROCHES Reconstruction of the evolutionary past requires comparison of taxa through character individuation. The concept applied explicitly to this task is a historical character concept, ensuring characters are comparable but failing to regulate individuation of characters. A distinct concept, the organismal character concept, is required to ensure reconstructions reflect evolutionary history instead of researcher bias. Combination of cladograms (right) showing the most parsimonious placement of Pachyrhachis when the character individuation includes: (A) only cranial characters (Tchernov et al. 2000), (B) cranial, post cranial, and a single hind limb character (Zaher 1998), or (C) cranial, post cranial, multiple hind limb and pelvic girdle characters (Lee & Caldwell 1998). Note that this figure does not show a true cladogram and that these hypotheses additionally differ by the ‘Other Squamates’ included and their placement with respect to snakes. SELECTED REFERENCES Haas, G. 1979. On a snakelike reptile from the Lower Cenomanian of Ein Jabrud, near Jerusalem. Bulletin de la Museum Nationale d'histoire Naturelle, Paris 4:51-64. Lee, M. S. Y., and M. W. Caldwell. 1998. Anatomy and relationships of Pachyrhachis problematicus, a primitive snake with hindlimbs. Philosophical Transactions of the Royal Society of London B 353:1521 - 1552. Richards, R. 2003. Character Individuation in Phylogenetic Inference. Philosophy of Science 70:264-279. Rieppel, O., H. Zaher, E. Tchernov, and M. J. Polcyn. 2003. The Anatomy and Relationships of Haasiophis terrasanctus, a Fossil Snake with Well-Developed Hind Limbs from the Mid-Cretaceous of the Middle East. Journal of Paleontology 77:536-558. Tchernov, E., O. Rieppel, H. Zaher, M. J. Polcyn, and L. L. Jacobs. 2000. A Fossil Snake with Limbs. Science 287:2010-2012. Wagner, G. P. (ed) 2001. The Character Concept in Evolutionary Biology. Academic Press, San Diego. Winther, R. G. 2009. Character Analysis in Cladistics: Abstraction, Reification, and the Search for Objectivity. Acta Biotheoretica 57:129-162. Zaher, H. 1998. The Phylogenetic Position of Pachyrhachis within Snakes (Squamata, Lepidosauria). Journal of Vertebrate Paleontology 18:1-3. ACKNOWLEDGEMENTS I would like to thank my supervisors, Gillian Barker and Eric Desjardins, for their ongoing guidance and support. Thanks to the faculty, post docs, students, and staff of the Rotman Institute of Philosophy for their assistance and helpful suggestions. Special thanks to Melissa Jacquart, Danny Booth, Emerson Doyle and Dylan Gault for their comments on drafts. Finally, many thanks to the Calgary Summit of Philosophers of Science for their support. Rotman Institute of Philosophy, Department of Philosophy, The University of Western Ontario Shari Monner, PhD Student, [email protected] Organisms, History, and the Biological Character Concept points of comparison among biological entities ancestral continuity prevalent in discussions of homology and phylogeny ORGANISMAL CHARACTERS HISTORICAL CHARACTERS Pachyrhachis problematicus by Karen Carr http://www.karencarr.com/larger.php?CID=309 parts or properties of biological entities developmental continuity prevalent in discussions of adaptation and ontogeny 3) Phylogenetic Inference Pachyophis woodwardi Python regius Haasiophis terrasanctus ORIGINS OF SNAKES Using Characters To Infer: Haasiophis terrasanctus Pachyrhachis problematicus Determining where Pachyrhachis fits in evolutionary history requires deciding which taxa to include in the study and then which characters to compare. Character Individuation Decisions Of Researchers The Character Individuation Problem Number Of Evolutionary Changes Represented By Input Data Application Of A Biological Character Concept Accepted Hypothesis Historical Characters & Ancestral Continuity CONTINUITY AND INDIVIDUATION Using A Distinction To Explain: “Femur development” by Caroline Needham http://lucidminds.files.wordpress.com/2010/06/fem-dev-final-copy.jpg Organismal Characters & Developmental Continuity http://witmerlab.files.wordpress.com/2010/09/holliday_et_al_fig8_ridgely_femora.jpg historical characters are comparable in virtue of their ancestral continuity Character Individuation Solutions Character Individuation Decisions Of Researchers Number Of Evolutionary Changes Represented By Input Data Application Of Historical Character Concept Accepted Hypothesis Application Of Organismal Character Concept http://scienceblogs.com/pharyngula/2010/03/16/ how-to-make-a-snake/ http://www.nature.com/nature/journal/v399/n6735/images/399474ae.tif.2.gif
Transcript of Organisms, History, and the Biological Character Concept · (A) only cranial characters (Tchernov...
RESEARCH POSTER PRESENTATION DESIGN © 2012
www.PosterPresentations.com
developmental continuity: spatiotemporal interrelation through advancement from
juvenile to adult
organismal characters have variable stages
organismal characters are individuated in virtue of their developmental continuity
comparable instances of historical characters can vary substantially
historical character concept lends comparability
organismal character concept lends independence
Different researchers apply different character concepts differently.
ancestral continuity: spatiotemporal interrelation through inheritance from ancestor to descendent
historical characters have variable instances
2) Character Individuation
Radiographs of full specimen (above) & cloacal region with pelvic bones highlighted (left) of Haasiophis terrasanctus (Rieppel et al. 2003)
1) Taxa Selection
Taxa and their comparable characters are described or re-described and entered into an inference algorithm.
Figures of Pachyrhachis problematicus cloacal region with hindlimb bones labelled (far left) & cranial region (left) photo-drawing-diagram (Lee & Caldwell 1998)
The character individuation problem arises from inconsistent application of multiple biological character concepts
Two distinct notions of character are in use but inconsistently applied
historical character concept applied to establish comparability
organismal character concept applied to establish independence
Future approaches for development of a biological character concept:
analyse application of organismal and historical character concepts in the biological literature and discussion of criteria already in use
(e.g. independence)
diagnose and analyse other philosophical problems arising from or solved by particular applications of these concepts (e.g. Adaptationist
atomism as arising from unguided application of organismal character concept and exaptation-adaptation distinction as including criteria for application of historical character concept where organismal character concept is more prominent)
PHIOLOSOPHICAL IMPACT & FUTURE APPROCHES
Reconstruction of the evolutionary past requires comparison of taxa through character individuation. The concept applied explicitly to this task is a historical character concept, ensuring characters are comparable but failing to regulate individuation of characters. A distinct
concept, the organismal character concept, is required to ensure reconstructions reflect evolutionary history instead of researcher bias.
Combination of cladograms (right) showing the most parsimonious placement of Pachyrhachis when the character individuation includes:
(A) only cranial characters (Tchernov et al. 2000),
(B) cranial, post cranial, and a single hind limb character (Zaher 1998), or
(C) cranial, post cranial, multiple hind limb and pelvic girdle characters (Lee & Caldwell 1998).
Note that this figure does not show a true cladogram and that these hypotheses additionally differ by the ‘Other Squamates’ included and their placement with respect to snakes.
SELECTED REFERENCES Haas, G. 1979. On a snakelike reptile from the Lower Cenomanian of Ein Jabrud, near Jerusalem. Bulletin de la Museum Nationale d'histoire Naturelle, Paris 4:51-64.
Lee, M. S. Y., and M. W. Caldwell. 1998. Anatomy and relationships of Pachyrhachis problematicus, a primitive snake with hindlimbs. Philosophical Transactions of the Royal Society of London B 353:1521 - 1552.
Richards, R. 2003. Character Individuation in Phylogenetic Inference. Philosophy of Science 70:264-279.
Rieppel, O., H. Zaher, E. Tchernov, and M. J. Polcyn. 2003. The Anatomy and Relationships of Haasiophis terrasanctus, a Fossil Snake with Well-Developed Hind Limbs from the Mid-Cretaceous of the Middle East. Journal of Paleontology 77:536-558.
Tchernov, E., O. Rieppel, H. Zaher, M. J. Polcyn, and L. L. Jacobs. 2000. A Fossil Snake with Limbs. Science 287:2010-2012.
Wagner, G. P. (ed) 2001. The Character Concept in Evolutionary Biology. Academic Press, San Diego.
Winther, R. G. 2009. Character Analysis in Cladistics: Abstraction, Reification, and the Search for Objectivity. Acta Biotheoretica 57:129-162.
Zaher, H. 1998. The Phylogenetic Position of Pachyrhachis within Snakes (Squamata, Lepidosauria). Journal of Vertebrate Paleontology 18:1-3.
ACKNOWLEDGEMENTS I would like to thank my supervisors, Gillian Barker and Eric Desjardins, for their ongoing guidance and support. Thanks to the faculty, post docs, students, and staff of the Rotman Institute of Philosophy for their assistance and helpful suggestions. Special thanks to Melissa Jacquart, Danny Booth, Emerson Doyle and Dylan Gault for their comments on drafts. Finally, many thanks to the Calgary Summit of Philosophers of Science for their support.
Rotman Institute of Philosophy, Department of Philosophy, The University of Western Ontario
Shari Monner, PhD Student, [email protected]
Organisms, History, and the Biological Character Concept
points of comparison among biological entities
ancestral continuity
prevalent in discussions of homology and phylogeny
ORGANISMAL CHARACTERS HISTORICAL CHARACTERS
Pachyrhachis problematicus by Karen Carr http://www.karencarr.com/larger.php?CID=309
parts or properties of biological entities
developmental continuity
prevalent in discussions of adaptation and ontogeny
3) Phylogenetic Inference
Pachyophis woodwardi
Python regius
Haasiophis terrasanctus
ORIGINS OF SNAKES Using Characters To Infer:
Haasiophis terrasanctus
Pachyrhachis problematicus
Determining where Pachyrhachis fits in evolutionary history
requires deciding which taxa to include in the study and then
which characters to compare.
Character Individuation Decisions Of Researchers
The Character Individuation Problem
Number Of Evolutionary Changes Represented By Input Data
Application Of A Biological Character Concept
Accepted Hypothesis
Historical Characters & Ancestral Continuity
CONTINUITY AND INDIVIDUATION Using A Distinction To Explain:
“Femur development” by Caroline Needham http://lucidminds.files.wordpress.com/2010/06/fem-dev-final-copy.jpg
Organismal Characters & Developmental Continuity
http://witmerlab.files.wordpress.com/2010/09/holliday_et_al_fig8_ridgely_femora.jpg
historical characters are comparable in virtue of their ancestral continuity
Character Individuation Solutions
Character Individuation Decisions Of Researchers
Number Of Evolutionary Changes Represented By Input Data
Application Of Historical Character Concept
Accepted Hypothesis
Application Of Organismal Character Concept
http://scienceblogs.com/pharyngula/2010/03/16/how-to-make-a-snake/
http://www.nature.com/nature/journal/v399/n6735/images/399474ae.tif.2.gif
