Phylogeny and ontogeny are, therefore, the two coordinated branches of morphology. Phylogeny — Ernst Haeckel
In the course of individual development, inherited characters appear, in general, earlier — Ernst Haeckel
Both of these branches of evolutionary science, are, in my opinion, in the closest causal — Ernst Haeckel
The real cause of personal existence is not the favor of the almighty, but the sexual love of one’s earthly parents. — Ernst Haeckel