Nikolaas Tinbergen’s 1962 paper “On aims and methods of Ethology,” defined complementary categories for analyzing and explaining animal behavior as proximate (developmental: both ontogenic and mechanistic) and ultimate (evolutionary: both phylogenetic and adaptive).
- Proximate/Ontogeny: How does the trait develop in individuals?
- Proximate/Mechanism: How does the trait work?
- Ultimate/Phylogeny: What is the trait’s evolutionary history?
- Ultimate/Adaptation: Why does the trait perform better than evolvable alternatives?