Task: Text Simplification
Input (English): Haeckel promoted and popularised Charles Darwin 's work in Germany and developed the influential but no longer widely held recapitulation theory ( " ontogeny recapitulates phylogeny " ) claiming that an individual organism 's biological development , or ontogeny , parallels and summarises its species ' evolutionary development , or phylogeny .
Output (English): Haeckel promoted and popularised Charles Darwin 's work in Germany and developed the controversial recapitulation theory ( " ontogeny recapitulates phylogeny " ) .