or.tho.gen.e.sis

n.（名詞）
Biology The theory that the evolution of a species is influenced most strongly by internal factors and is not subject to the external forces of natural selection.
【生物學】 直向進化論：關于物種的進化是受內部因素的強烈影響而非外部自然選擇的影響的理論
The theory that all cultures pass through sequential periods in the same order.
直向演化論：關于所有文化都以相同的順序經過一系列時期演化而成的理論

【引伸】
or.thogenet.ic
or.thogenet.ically
adv.（副詞）