A reflection on biological thought: whatever happened to the organism?

Biological thought requires at least both a concept of organism and a concept of evolution to be causally efficient; this is above and beyond any materialistic cause or causes, however formulated. Although the concept of evolution has been much debated and developed over the last century and a half, the concept of organism has been neglected, despite promising modern beginnings with the works of W. E. Ritter and others. The independent efforts of five biologists, including Ritter, to develop a concept of organism are outlined, key works are cited, and some similarities and differences of their approaches are outlined. E. S. Russell's teleology of organism, far from being a failed worldview, is considered to be a major significant step towards a more complete biology.