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Definition of Ernst heinrich haeckel
1. Noun. German biologist and philosopher; advocated Darwinism and formulated the theory of recapitulation; was an exponent of materialistic monism (1834-1919). 
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1. Noun. German biologist and philosopher; advocated Darwinism and formulated the theory of recapitulation; was an exponent of materialistic monism (1834-1919).