When is it sensible to say that group selection has shaped organismal design? This question has prompted many replies but few credible solutions. This article provides new work that exposes the causal relationships between phenotypes and fitness.
- Group selection can be a useful concept when applied appropriately.
- Causal graphs, which show cause-and-effect relationships, can distinguish individual selection from group selection.
- Causal graphs can be applied to other areas of study.