Morphological Correspondence and the Concept of Homology

Abstract

In a stimulating essay called ‘On Biological Transformation’1 published in 1945, Woodger attempted to make precise the concept of morphological correspondence which, as he showed, is basic to the concept of homology. He indicated how the concept of morphological correspondence might need modifying if it were to cover the same ground as the concept of homology covers in contemporary biological thought. If one considers the ways in which the concept of homology is applied it turns out that it covers a number of related but different ideas. We talk of a wing of a bird being homologous with a leg of a mammal. We talk of the fore and hind limbs of a vertebrate being serially homologous. We find parts being designated as homologous because they develop from embryonic parts which are homologous, and that the adult homology is based on this. We find two parts are homologous because they have common ancestors. We even find chromosomes are said to be homologous as well as genes, and recently the concept of homologous sera has been put forward.