sentences:  For Darwin, they pointed out, evolution involved descent "and" modification, not just descent.Taxa, for them, are sets of organisms united by similarity; when the similarity is too weak, descendants are not in all of their ancestors' taxa.Phylogenetic nomenclature is a result of the general acceptance of branching in the course of evolution, represented in the diagrams of Jean-Baptiste Lamarck and later writers like Charles Darwin and Ernst Haeckel.