Abstract

Different types of explanations coexist in present-day biology. Functional explanations describe mechanisms, whereas evolutionary explanations provide answers to the question “why?” mostly by appealing to the past and present action of natural selection. But the relations between these two types of explanations, as well as the relative insights they offer, vary from one domain of research to another. We will illustrate this complex landscape of biological explanations with three examples involving aging, the sex ratio, and the phenomenon of genomic imprinting. We will show that the two types of explanations have recently often progressed towards each other. In consequence, they cease to be “pure” functional or evolutionary explanations and become explanations that may be alternatively considered as functional or evolutionary.