Adaptive zones of the class Asteroidea (Echinodermata)

Modern asteroid orders occupy more or less distinct adaptive zones, with key characters allowing specialization in resource (food and space) acquisition, and protection. The fundamental separation of zonal strategies is based on relative importance of defense, stressing protection, and offense, stressing use of resources; within their basic strategy, offensive zones are further structured by prey type and habitat. Asteroid form, which varies largely in terms of proportion and armor development, reflects adaptive zone, and evolved primarily in response to demands of protection, body flexibility, support on soft substrata, and internal capacity. -from Author