Book contents
- Frontmatter
- Contents
- Preface to the First Edition
- Preface to the Second Edition
- 1 Macroevolution: The Problem and the Field
- 2 Genealogy, Systematics, and Macroevolution
- 3 Genetics, Speciation, and Transspecific Evolution
- 4 Development and Evolution
- 5 The Constructional and Functional Aspects of Form
- 6 Patterns of Morphological Change in Fossil Lineages
- 7 Patterns of Diversity, Origination, and Extinction
- 8 A Cambrian Explosion?
- 9 Coda: Ten Theses
- Glossary of Macroevolution
- References
- Author Index
- Subject Index
5 - The Constructional and Functional Aspects of Form
Published online by Cambridge University Press: 14 January 2010
- Frontmatter
- Contents
- Preface to the First Edition
- Preface to the Second Edition
- 1 Macroevolution: The Problem and the Field
- 2 Genealogy, Systematics, and Macroevolution
- 3 Genetics, Speciation, and Transspecific Evolution
- 4 Development and Evolution
- 5 The Constructional and Functional Aspects of Form
- 6 Patterns of Morphological Change in Fossil Lineages
- 7 Patterns of Diversity, Origination, and Extinction
- 8 A Cambrian Explosion?
- 9 Coda: Ten Theses
- Glossary of Macroevolution
- References
- Author Index
- Subject Index
Summary
You cannot fly like an eagle with the wings of a wren.
– William Henry HudsonI loosely follow the prescription of Adolph Seilacher (1970, 1973, 1979), who coined the term constructional morphology, to argue that form in organisms evolves under the combined influence of
How a structure might be formed by nature of the materials (and, I would add, developmental scheme)
Phylogenetic origin, meaning the ancestral character states belonging to immediate ancestors, and
Adaptation, as guided by natural selection
This spirit of this very reasonable explanation of phenotypic evolution is also to be found in Jacob's (1983) idea of tinkering, which admits to the eccentric history of evolutionary pathways and co-optation of structures for new functions. The extremists (e.g., Gould 1997), however, would have us believe that nonadaptive aspects of form have been woefully neglected. They claim that evolutionary biologists have sought adaptive explanations in every structure they encounter, to the extent that the structures are perfectly shaped by evolution to perform a function in the very best way possible (Gould and Lewontin 1979; Lewontin 1978). This point of view is a misunderstanding of typical biological practice, fueled by an overly idealized view of biological science. It is true that when seeing a structure for the first time, nearly all biologists ask: “What does this do?” Thus has the function of so many previously mysterious structures (e.g., islets of Langerhans, Golgi bodies) been eventually discovered. Such an approach is surprisingly conserved in all areas of biology, from the subcellular to the whole organism (e.g., what does the springlike backbone of the cheetah do?). That is because it has been so universally successful.
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- Genetics, Paleontology, and Macroevolution , pp. 227 - 284Publisher: Cambridge University PressPrint publication year: 2001