Definition: directly or indirectly modulating the availability of resources to other species, by causing physical state changes in biotic or abiotic materials; modifying, maintaining and/or creating habitats
Definition: Component found in mineralized skeletal tissue, (a specialized form of biogenic tissue in which the extracellular matrix is mineralized, and which functions in mechanical and structural support.)
Definition: Eye-spots which may be set into a pit to reduce the angles of light that enters, to allow the organism to deduce the angle of incoming light. Lens-like structures may be present, but stemmata, unlike lens eyes, cannot form an image, either for lack of refractive power or retinal resolution.
