The BSCS program began in 1959 amid considerable debate about the approach to be taken in the teaching of biology. Should it be molecular, organismal, developmental, ecological, or other? Should it include one textbook or several? How much and what kind of attention to laboratory work should be given? Amidst all these debates, however, it was an early consensus that certain themes should be included in all biology programs, no matter what approach is selected, and whatever attention may be given to various details. These themes were identified and have consistently pervaded the several approaches and different materials developed by the BSCS during the past twelve years. They are:
- Change of living things through time: evolution
- Diversity of type and unity of pattern in living things
- The genetic continuity of life
- The complementarity of organism and environment
- The biological roots of behavior
- The complementarity of structure and function
- Regulation and homeostasis: preservation of life in the face of change
- Science as inquiry
- The history of biological conceptions
It should also be noted that evolution is not only one of the major themes but is, in fact, central among the other themes; they are inter-related, and each is particularly related to evolution.
The position of the BSCS on the importance of evolution in teaching biology has been clearly stated in both the first (1963) and second (1970) editions of the Biology Teachers' Handbook:
It is no longer possible to give a complete or even a coherent account of living things without the story of evolution. On the other hand, many of the most striking characteristics of living things are "products" of the evolutionary process. We can make good sense and order of the similarities and differences among living things to the particular environments in which they live, their distribution over the surface of the earth, the comings and goings of their parts during development, even the chemistry by which they obtain energy and exchange it among their parts -- all such matters find illumination and explanation, in whole or in part, from the history of life on earth.
On the other hand, another great group of characteristics of living things can be fully understood only as the means and mechanisms by which evolution takes place. There are first, and conspicuously, the events of meiosis and fertilization, universal in sexual reproduction. It is only in terms of the contribution of these processes to the enhancement and sorting out of a vast store of heritable variations that we make sense of them. The same point applies to the complex processes that go under the name of mutation. Similarly, we see everywhere the action and consequences of natural selection, of reproductive isolation of populations, of the effects of size and change on intrabreeding groups.
Evolution, then, forms the warp and woof of modern biology...*
Evolution is a scientific theory in the sense that it is based on scientific data accumulated over many years and organized into a unifying idea widely accepted by modern biologists. The BSCS is concerned with any scientific theory relevant to the biological sciences that can be dealt with in terms of scientific data accumulated and organized. It is not, on the other hand, concerned with religious doctrines that are based only on faith or beliefs, nor does it consider them relevant to the teaching of biological science.
The BSCS program was carried through an extensive tryout period during its early development; feedback and input from hundreds of scientist and science teachers were used in the initial edition that was made available to biology teachers in the United States. A revised second edition of the three major textbooks produced has been published, and a revised third edition is nearing completion. In spite of efforts of various groups to force changes in the content of the texts by exerting pressures on textbook selection committees and on local and state governments, throughout the last twelve years the BSCS position on using the unifying themes of biology remains unchanged.