16 RESEARCH IN BIOLOGY 



Biological problems 



Many of the most serious problems remaining for the biologist today 

 are problems which can only be solved by experimental methods. Even 

 the areas of biology which have classically used descriptive methods are 

 now turning to experiments. The taxonomist who used to be concerned 

 only with the sizes, shapes, and colors of various parts now performs 

 experiments to learn the effect of environmental changes on these sizes, 

 shapes, and colors. The embryologist who formerly described the embryo 

 at the ages of one, two, three, . . . n days has become concerned with 

 the reasons for the observed changes. 



The general nature of the major remaining problems in biology 

 might be grouped into the following interrelated categories: 



(1) Relationships of materials 



(2) Energy relationships 



(3) Control and integration phenomena 



The relationships of materials, that is, the kinds of chemical com- 

 pounds present and the chemical reactions that occur, make up the prov- 

 ince of biochemistry. The general pattern of cellular biochemistry has 

 been evolved within a period of about the last thirty years. Many details 

 of cellular chemistry remain to be discovered, but as most of the tech- 

 niques are available, it is difficult to visualize any major changes in con- 

 cepts. Such statements are dangerous, however, because new concepts 

 have a way of appearing without advance warning. 



Energy relationships involve a more difficult problem. Energy is an 

 abstract concept in its simplest forms. Living organisms bring about 

 transformations of chemical energy, heat, electricity, motion, and Hght, 

 from one to almost any of the others, usually with high efficiency. The 

 physics comprising these energy relationships is among the most inter- 

 esting and challenging of biological problems. 



The control and integrative systems constitute a series of almost purely 

 biological problems. Certainly some man-made control systems operate 

 on similar principles, but it might not stretch the imagination too much 

 to call these systems biological, at least in origin. The questions of the 

 regulation of all of the various processes within an animal, or the in- 

 tegration of the activities of all the individual plants or animals within 

 a group, are among the most interesting but most frustrating. It has been 

 exceedingly difficult to find means of investigating these elusive phe- 

 nomena. 



