G F Striedter, University of California, Irvine, CA, USA
© 2007 Elsevier Inc. All rights reserved.
1.01.1 Common Plan versus Diversity 1
1.01.2 Scala Naturae versus Phylogenetic Bush 3
1.01.3 Relative Size versus Absolute Size 4
1.01.4 Natural Selection versus Developmental Constraints 7
1.01.6 Conclusions and Prospects 10
The notion that changes in the size of an object (e.g., the body or the brain) entail predictable changes in the proportional sizes of its components. In contrast, isometric scaling involves no changes in an object's proportions. The independent evolution of similar structures or functions from non-homologous ancestral precursors. The notion that the mechanisms of development bias the production of phenotypic variants that natural selection can act on.
Brain size relative to what one would expect in an organism of the same type (i.e., species or other taxonomic group) and body size. Synonym: relative brain size.
Phylogenetic changes in the relative timing of developmental events or in the relative rates of developmental processes.
The relationship between two or more characters that were continuously present since their origin in a shared ancestor. For a more detailed definition, especially for neural characters, see Striedter (1999). The notion that, as brains evolve, individual brain regions may change in size independently of one another. In contrast, concerted evolution indicates that brain regions must change their size in concert with one another.
The field of evolutionary neuroscience is more than 100 years old, and it has deep pre-evolutionary roots. Because that illustrious history has been reviewed convergence developmental constraint encephalization heterochrony homology mosaic evolution repeatedly (Northcutt, 2001; Striedter, 2005) and is treated piecemeal in several articles of this book, I shall not review it fully. Instead, I will discuss a selection of the field's historically most important ideas and how they fit into the larger context of evolutionary theory. I also emphasize ideas that are, or were, controversial. Specifically, I present the field's central ideas in contrast pairs, such as 'common plan versus diversity' and 'natural selection versus constraints'. This approach scrambles the chronology of theoretical developments but helps to disentangle the diverse strands of thought that currently characterize evolutionary neuroscience. It also helps to clarify which future directions are likely to be most fruitful for the field.
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