biological adj.

"the science of life and living things," 1819, from Greek bios "life, one's life, lifetime" (from PIE root *gwei- "to live;" see bio-) + -logy "study of." The compound was suggested 1802 by German naturalist Gottfried Reinhold Treviranus, and introduced as a scientific term that year in French by Lamarck; the two seem to have hit upon the word independently.

compound adjectival word-forming element, usually interchangeable with -ic but sometimes with specialized sense (such as historic/historical, politic/political), Middle English, from Late Latin -icalis, from Latin -icus + -alis (see -al (1)). Probably it was needed because the forms in -ic often took on a noun sense (for example physic). Forms in -ical tend to be attested earlier in English than their twins in -ic.