The Origin of Species: A Variorum Text

CHAPTER XIII.

1 t i] XIV. CHAPTER XIII. 2 MUTUALAFFINITIESOF ORGANICBEINGS:MORPHOLOGY: EMBRYOLOGY: RUDIMENTARY ORGANS. 3 CLASSIFICATION, groups subordinate to groups-Natural systemRules and difficulties in classification, explained on the theory of descent with modification-Classification of varieties-Descent always used in classification-Analogical or adaptive characters -Affinities, general, complex and radiating-Extinction separates and defines groups-MORPHOLOGY, between members of the same class, between parts of the same individuaIEMBRYOLOGY , laws of, explained by variations not supervening at an early age, and being inherited at a corresponding ageRUDIMENTARY ORGANS; their origin explained-Summary. 3.I:d [Center] Classification. [Space] 4 FROM the first dawn of life, all organic beings are found to resemble each other in descending degrees, so that they can be classed in groups under groups. 4:e FROMa very remote period in the history of the world organic beings have resembled 4:f FROMthe most remote period in the history of the world organic beings have been found to resemble 5 This classification is evidently not arbitrary like the grouping of the stars in constellations. 5:e is not 6 The existence of groups would have been of simple signification, if one group had been exclusively fitted to inhabit the land, and another the water; one to feed on flesh, another on vegetable matter, and so on; but the case is widely different in nature; for it is notorious how commonly members of even the same SUb-group have different habits. 6:/ simple significance, if/different, for 7 In our second and fourth chapters, on Variation and on Natural Selection, I have attempted to show that it is the widely ranging , the much diffused and common, that is the dominant species belonging to the larger genera, which vary most. 7:c that within each country it/genera in each class, which 8 The varieties, or incipient species, thus produced ultimately become converted, as I believe, into new and distinct species; and these, on the principle of inheritance, tend to produce other new and dominant species. 8:c produced, ultimately 8:d converted into 9 Consequently the groups which are now large, and which generally include many dominant species, tend to go on increasing indefini tely in size. 9:C increasing in 10 I further attempted to show that from the varying descendants of each species trying to occupy as many and as different places as possible in the economy of nature, there is a constant tendency in their characters to diverge. IO.} nature, they constantly tend to diverge in character. II This conclusion was supported by looking at the great diversity of the forms of life which, in any small area, come into the closest competition, and by looking to certain facts in naturalisation . I t :e This latter conclusion is supported by observing the great diversity of forms which/and by certain 12 I attempted also to show that there is a constant tendency in the forms which are increasing in number and diverging in character, to supplant and exterminate the less divergent, the less improved, and preceding forms. I2:d exterminate the preceding, less divergent and less improved forms. I2:f is a steady tendency 13 I request the reader to turn to the diagram illustrating the action, as formerly explained, of these several principles; and he will see that the inevitable result is that the modified descendants proceeding from one progenitor become broken up into groups subordinate to groups. I3:f is, that 14 In the diagram each letter on the uppermost line may represent a genus including several species; and all the genera on this line form together one class, for all have descended from one ancient but unseen parent, and, consequently, have inherited something in common. I4:C this upper line/ancient parent I4:e and the whole of the genera along this upper line form together one class, for all are descended from one ancient parent and 15 But the three genera on the left hand have, on this same principle , much in common, and form a sub-family, distinct from that including the next two genera on the right hand, which diverged from a common parent at the fifth stage of descent. I5:f that containing the next 16 These five genera have also much, though less, in common; and they form a family distinct from that including the three genera 647 still further to the right hand, which diverged at a still earlier period. I6:e farther I6:! much in common...