On the Origin of Species · ¶524
Let us see how far these several facts and inferences accord with the theory of descent with modification. As the subject is somewhat complex, I must request the reader to turn to the diagram in the fourth chapter. We may suppose that the numbered letters represent genera, and the dotted lines diverging from them the species in each genus. The diagram is much too simple, too few genera and too few species being given, but this is unimportant for us. The horizontal lines may represent successive geological formations, and all the forms beneath the uppermost line may be considered as extinct. The three existing genera, a¹⁴, q¹⁴, p¹⁴, will form a small family; b¹⁴ and f¹⁴ a closely allied family or sub-family; and o¹⁴, e¹⁴, m¹⁴, a third family. These three families, together with the many extinct genera on the several lines of descent diverging from the parent-form A, will form an order;…Read in context ›
Charles Darwin · John Murray, London, 1859, first edition · Gutenberg #1228; original diagram from Darwin Online F373
Charles Darwin · John Murray, London, 1859, first edition · Gutenberg #1228; original diagram from Darwin Online F373
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