自し然ぜん発はっ生せい

noun, noun which may take the genitive case particle 'no'

spontaneous generation; abiogenesis

Biology term for the now-discredited theory that living organisms arise from nonliving matter.

• 自し然ぜん発はっ生せい説せつはパスツールの実じっ験けんによって否ひ定ていされた。

  The theory of spontaneous generation was disproved by Pasteur's experiments.

noun, noun which may take the genitive case particle 'no'

natural occurrence; spontaneous occurrence

General use for something arising naturally without external cause.

• この地ち域いきでは地じ震しんの自し然ぜん発はっ生せいが多おおい。

  Earthquakes occur naturally and frequently in this region.