This paper presents the adaptive zone
K-NNSS (AZ-NNSS) algorithm, which is an extension of the K-NNSS method.
For change in capture thread composition and web features to qualify as key innovations, we propose that three criteria must be met: (1) they must be synapomorphic for araneoids; (2) these features must confer a functional advantage over the plesiomorphic condition in deinopoids; and (3) they must be correlated with a change in or expansion in the "adaptive zone
" that orb-weaving spiders occupy.
Evolutionary biologists often suggest that an ancestral species evolved features that allowed entry into a new adaptive zone
(Simpson, 1953) and proliferation into the many niches available in this new zone, often to the detriment (extinction) of other organisms.
In the context of Simpson's adaptive zones
, Ctenomyidae is confined to the single zone of burrowing while Echimyidae-Capromyidae occupies at least 2 (burrowing and tree-dwelling).
The concept of a 'key innovation' as defined here is thus dependent upon the assumption that certain traits have enabled their corresponding lineages to proliferate (speciate, diversify) at an increased rate by opening up new adaptive zones