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There is now a CONTENT FREEZE for Mercury while we switch to a new platform. It began on Friday, March 10 at 6pm and will end on Wednesday, March 15 at noon. No new content can be created during this time, but all material in the system as of the beginning of the freeze will be migrated to the new platform, including users and groups. Functionally the new site is identical to the old one. webteam@gatech.edu
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The aggregation of lower-level units into higher-level wholes seems to be correlated, in evolution, with two effects: 1) The loss of internal structure or complexity in the lower-level units; and 2) the emergence of complexity at an intermediate level. In effect, structural complexity is transferred from a lower level to a higher one. Thus, for example, cells in multicellular organisms seem to have fewer parts than free-living cells (protists), but multicellular organisms have intermediate-level parts, i.e., tissues and organs. At a higher level, the individuals in animal colonies seem to have fewer parts than their more solitary relatives, but individuals in colonies often collaborate to perform functions, again producing intermediate-level parts. These patterns have had little empirical support, so far, because operationalizing the key variable i.e., parts has been difficult. In this talk, I show how operationalization was achieved in a recent effort to document a part of the pattern, specifically the loss of parts in cell. Finally, this transfer of complexity across levels may be explained by a simple and fairly general logic, based on natural selection. If the explanation is right, the possibility arises that the pattern may be widespread, occurring in non-biological systems subject to similar constraints.
