156 THE SCIENCE OF BIOLOGY 



The origin of our solar system may be removed from the 

 present by billions of years and the origin of our earth 

 may seem too remote for explanation. But the records of 

 the geological changes which have given the earth its present 

 surface are within our comprehension; and there is no ade- 

 quate reason for not extending the same kind of scientific 

 explanations to beginnings that antedate what is ordinarily 

 encompassed by the science of geology. The geologist takes 

 up the problem where the astronomer leaves it. The latter 

 may be vague and uncertain in his conclusions, but the pre- 

 sumption favors his evolutionary theories, because evolu- 

 tion so clearly appears to have taken place from the period 

 at which the record began to be written upon the crust of 

 our planet. As a part of the geological record, the history 

 of animal and plant life is found imperfectly recorded in the 

 rocks. 1 



Organic evolution is, therefore, not a theory of the origin 

 of men from monkeys, but is concerned with the origin and 

 development of all the animal and plant bodies which now 

 exist; and it is part of the larger theory of cosmic evolution, 

 which postulates that the visible universe has reached its 

 present state by a process of change. This change is going 

 forward in the present, and will, presumably, continue in 

 the future. Concepts of infinite space and infinite time are 

 involved. Man's claim to importance, in the dynamic 

 system thus revealed, lies not in the pretense that this planet 

 was prepared for his coming, but in the claim that he tran- 

 scends the visible universe in so far as he comprehends it. 



ir The limitations of the palseontological evidence are well set forth in a 

 famous chapter in Darwin's "Origin of Species," entitled "On the Imper- 

 fection of the Geological Record." Despite the additions to knowledge which 

 have since been made, the record must always remain fragmentary. Yet the 

 evidence is sufficient to completely establish the fundamental fact of progres- 

 sion. 



