The Indivisible Individual

Abstract

Living organisms change in the course of many generations due to mutation and selection. To portray this as the “mechanism” of evolution as has been done in the past and how it usually appears in many contemporary biology text books is, strictly speaking, confusing. The term “mechanism”, borrowed from the language of human technology, implies that a product is made from certain materials in the same way as a machine. The results of this process are then called living organisms and represent the provisional products of the manufacturer who, in this case, is evolution. No matter how lucid this metaphorical representation may be, when used uncritically it has proved itself to be just as confusing as most other expressions borrowed from human affairs. Animals are not subject to a superordinate or completely methodical controlling mechanism which allows them to become increasingly better adapted to living on this planet. Animals live, reproduce, change, and, while doing this, experience various destinies—some successful, others less so—and that is the whole story, that is all there is to it. The result is called biological evolution without any special principle or natural law having to be associated with it. Again, caution is advised with regard to old entrenched terms and concepts.

No one supposes that all the individuals of the same species are cast in the same actual mould. These individual differences are of the highest importance for us, for they are often inherited, as must be familiar to every one; and they thus afford materials for natural selection to act on and accumulate, in the same manner as man accumulates in any given direction individual differences in his domesticated productions.

Charles Darwin