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HOMEMental Tools - Table of Contents
Selective Systems
"Several writers have misapprehended or ojected to the term Natural Selection. Some have even imagined that natural selection induces variatiability, whereas it implies only the preservation of such variations as arise and are beneficial to the being underits conditions of life."
(Charles Darwin, 1859, Ch. 4 2nd paragraph)
Gerald Edelman's
Requirements for a Selective System
- A source of diversification leading to variants.
- A means for effective encounter with or sampling of an independent environment that is not intially categorized in any absolute or predetermined fashion.
- A means of differential amplification over some period of time of those variants in the population that have greater adaptive value.
Natural Selection
Environmental selection of favorable variants within a species over multiple generations.
The Theory of Natural Selection Rests on Three Necessary Principles:
(Dubrovsky, 2002, pp. 5)
- Specific individuals within a species differ from one another in physiology, morphology and behavior (the principle of variation).
- The variation is in some way heritable, so that the average offspring resemble their parents more so than other individuals (the principle of heredity).
- Different variation leave different numbers of offspring either immediately or in remote generations [the principle of differential amplification ]
Somatic Selection
Selection of favorable variants amongst differentiated cell types/groups within the life span of the organism.
Developmental Selection
Behavioral Selection
Degeneracy vs. Redundancy
Historical Contingency
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