The Place of Botany in a Unified Science of Biology

G. Ledyard Stebbins University of California at Davis Before we can discuss basic concepts in botany in relation to teaching an initial college course, one fact must be made absolutely clear: there are no basic concepts in botany as such, apart from those which govern biology as a whole. This generalization is not peculiar to botany; it applies equally well to zoology, microbiology, or any other discipline which is limited to the study of only one kind of organism. In short, if the discoveries which biologists and biochemists have made during the past 20 years have taught us anything, they have shown us with crystal clarity that biology is a unified science. If it is to be divided into compartments at all, its vertical, taxonomic division into botany, zoology, and microbiology is not necessarily any more desirable than a horizontal division into molecular, cellular, developmental, organismal, environmental, and evolutionary biology. At the outset, we might ask ourselves the question: Why, as late as the middle of the twentieth century, do we need to make such a radical alteration in our teaching and general philosophy of the life sciences that it threatens the integrity or even the existence of teaching departments which, in some instances, have flourished for as long as a century? The answer to this question lies, I believe, in the history of biology, which has in at least one important respect been entirely different from that of the physical sciencesphysics, chemistry, astronomy, and geology. Each of the latter has grown outward from a single focal point. Physics and chemistry began with the interest of ancient and medieval scholars in the nature of matter and its possible transformation from one kind to another. From the beginning, astronomy has been concerned with one central theme, the heavenly bodies, while geology has always had a central focus on the earth as a whole. The central focus of the life sciences, however, which is and should be the nature of life as a whole, could not be approached in a truly scientific fashion until well into the present century. The reasons why earlier generations of philosophers and scientists could not do this were partly religious. As long as all learned men were conditioned by their religious training and emotional attitudes to believe that each living thing was created separately by their Lord and Creator, the only possible focal point for all forms of life was the mind of the Creator himself. When the acceptance of the Darwinian theory of evolution enabled scientists to focus their attention on the general nature and origin of life, physics and chemistry had far outstripped the life sciences in the development of general concepts. Hence, many biologists naturally turned toward the generalizations or "laws" which physicists and chemists had formulated for their disciplines as a springboard for the development of similar laws which might form a focal point for the life sciences. As a result, many other biologists became afraid that the life sciences would eventually become nothing more than a series of extensions of physics and chemistry, with no focal point of their own. Now, however, these fears have been dispelled, at least in the minds of many biologists, including myself. We have come to realize the full significance of the spectacular discoveries about the nature of life at the molecular level which have been made during the past 20 years. We cannot doubt that living