FERRIS: THE CONTRIBUTION OF NATURAL HISTORY TO HUMAN PROGRESS 85 



Above all was this true of the earlier explorer naturalists. So a very large body 

 of information that went into the development of early natural history grew up 

 in this way. In fact, all of these things really went together, for a person finding 

 a strange plant or animal naturally wished to talk about it and he could not 

 very well do so with any definiteness unless he had some sort of name for it. It 

 was only later that a knowledge of the kinds of plants and animals moved to the 

 laboratory and became at times completely detached from the natural world. 



It was out of this combination of the knowledge of plants and animals as 

 things living in the natural world and the describing and naming of them by 

 what came to be called the "closet naturalist" that there came the ideas which 

 led to that great philosophical concept, evolution. Darwin himself was a great 

 field naturalist, but he did not disdain the work that had to be performed, for 

 example, on barnacles in his study. He was that very desirable combination, a 

 field naturalist and a closet naturalist. 



So the mere describing and naming of the different kinds of animals had its 

 place in the development of those concepts which, broadened and deepened, led 

 to biology as we Imow it. 



But apart from these philosophical concepts biological systematics has had 

 a profound effect in the development of other aspects of biology. After all, it is 

 at least intellectually satisfying to know what the world was like in past ages 

 and our knowledge of what the world was like depends upon historical geology. 

 Historical geology in turn rests upon paleontology and paleontology rests upon 

 a study of the kinds of animals and plants that existed in the past and have 

 come down to us as fossils. Here the recognition of the various kinds is nothing 

 more than an extension of the knowledge of present-day species embodied in 

 systematic biology. Any conclusions as to what the world was like when these 

 fossils lived must be based upon observations of how similar kinds now live. If 

 fossil plants are found which are known only from tropical regions, it is a fair 

 assumption that these fossils must have been laid down under tropical conditions. 

 So, reasoning from the conclusions concerning the kinds of organisms involved 

 and field natural history concerned with the habits of similar organisms, we 

 come finally to some understanding of the climates of the past. Thus another 

 step is taken in broadening our outlook on the world. 



BiogeograpJiy : Another matter that has at least an intellectual interest as well as 

 some practical concern is the problem of how animals and plants are arranged 

 naturally about the world. This is what is known as biogeography. It depends 

 entirely upon the results of systematics. The data utilized are merely those of 

 systematics, further systematized by embodying them in maps of the world or 

 portions of the world. The validity of its conclusions depends, then, upon how 

 well the world has been explored and how well the systematic work has been done. 

 The practical aspect of this may be indicated by examples from economic 

 entomology. Let us say that a hitherto unknown pest is found in the United 

 States — as has happened many times. For various reasons we wish to know 

 where that pest came from. Some of these reasons are merely concerned with 

 satisfying curiosity, others with practical considerations. In entomology that 

 practical consideration has to do with the question of what we call "biological 

 control," which is an aspect of applied ecology. We know that in its natural habi- 



