CHAPTER V 



VISIBLE AND INVISIBLE EVOLUTION OF THE 

 VERTEBRATES 



Chromatin evolution. Errors and truths in the Lamarckian and Darwinian 

 explanations of the processes of evolution. Character evolution more 

 important than species evolution. Individuality in character origin, 

 velocity, and cooperation. Origin of the vertebrate type. The laws 

 of convergence, divergence, and adaptive radiation of form. 



Simon Newcomb^ considered the concept of the rapid 

 movement of the solar system toward Lyra as the greatest 

 which has ever entered the human mind. He remarks: ''If I 

 were asked what is the greatest fact that the intellect of man 

 has ever brought to light, I should say it was this: Through all 

 human history, nay, so far as we can discover, from the infancy 

 of time, our solar system — sun, planets, and moons — has been 

 flying through space toward the constellation Lyra with a 

 speed of which we have no example on earth. To form a con- 

 ception of this fact the reader has only to look at the beauti- 

 ful Lyra and reflect that for every second that the clock tells 

 off we are ten miles nearer to that constellation." 



The history of the back-boned animals (Vertebrata) as the 

 visible expression of the invisible evolution of the microscopic 

 chromatin presents an equally great concept of the potential- 

 ities of matter in the infinitely minute state. 



According to this concept our study of the evolution of 

 the back-boned animals at once resolves itself into two parallel 

 lines of inquiry and speculation, which can never be divorced 

 and are always to be followed in observation and inference: 



' Newcomb, Simon, 1902 (ed. of 1904, p. 325). 

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