orthoselection n. [Gr. orthos, straight; L. selectus, select] Natural selection continuously acting in one direction over a long period of time.
orthosomatic a. [Gr. orthos, straight; soma, body] Having a body in a straight line.
orthostasy n. [Gr. orthos, straight; stasis, standing] (ARTHRO: Chelicerata) Stage in acarology life-cycle evolution showing only stases and no stasoids.
orthostrophic a. [Gr. orthos, straight; strophe, to turn] (MOLL: Gastropoda) Coiled in a normal manner, as opposed to hypertrophic.
orthotaxy n. [Gr. orthos, straight; taxis, arrangement] The arrangement of similar organs that have ancestral characters, and have preserved their normal position.
orthotriaenes a.pl. [Gr. orthos, straight; triaina, trident] (PO-RIF) In tetraxons, having clads in the angular form of about 90° with the axis of the rhabdome.
orthotrichy n. [Gr. orthos, straight; trichos, hair] (ARTHRO: Chelicerata) In acarology, all setae that have not disappeared have maintained their ancestral position.
oscillation n. [L. oscillare, to swing] A single swing from one extreme limit to the other of a sine wave.
osculant a. [L. osculare, to kiss] 1. Adhering closely. 2. A connecting link between two groups; having intermediate characters, as in genera and species.
Was this article helpful?