before vowels phyl-, modern word-forming element, mostly in the sciences, often meaning "phylum," from Greek phylon, phylē "a tribe," also a political subdivision in ancient Athens, from base of phyein "to bring forth, produce, make to grow," whence also physis "nature" (from PIE root *bheue- "to be, exist, grow").
word-forming element meaning "birth, origin, creation," from Greek genesis "origin, creation, generation," from gignesthai "to be born," related to genos "race, birth, descent" (from PIE root *gene- "give birth, beget," with derivatives referring to procreation and familial and tribal groups).
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Definitions of phylogenesis
(biology) the sequence of events involved in the evolutionary development of a species or taxonomic group of organisms;