Art Forms in Nature
“A single life-form, a particular species, can conserve itself, however, not only in its status, but it can ‘allow’ for further modifications in development, and therefore further levels of morphological complexity. It is even possible--with this sort of form type, that two or more alternative paths of further development are open to a given species. Accordingly, the reconstructed kinship of forms does not depict a mere series of similarities in which we, as observers, order relatively similar looking forms. Rather, these series of similarities represent actual continuous lines of descent in evolution. An adequate depiction of the diversity of these forms does not only constitute a catalogue, in which similar-looking organisms are ordered with respect to one another, but rather a genealogical tree that displays the existing succession of forms,” -Art Forms in Nature by Ernst Haeckel