 In philosophy of biology, reduction involves questions about how different biological disciplines and theories are related, and how biology is connected to physics and chemistry (e.g., is biology autonomous, possessing its own theoretical principles, explanations, and methods?). Over the past four decades, discussion has concentrated primarily on the question of whether classical genetics can be reduced to  molecular genetics  and biochemistry. This discussion was motivated by the increasing significance of  molecular biology  within the life sciences, and revolved around specific accounts of reduction in science, such as Nagel’s (1961) model. A less central concern has been whether evolutionary biology and ecology are autonomous disciplines or reducible to molecular biology (Beatty 1990, Brandon 1996, Dupré 1993, Rosenberg 2006). For example, a notable issue in evolutionary contexts is the relationship between functional explanation  (“teleology”)  and causal-mechanistic explanation (Wouters 2005). The  levels of selection  debate includes questions about whether all evolutionary explanations can be cast in terms of genes and whether selection operates primarily or exclusively on the genetic level (Okasha 2006). The main debate about reduction in genetics has lost some intensity as many philosophers developed a skeptical consensus regarding the possibility of substantive theory reduction (but see Waters 1990). This decline has been accompanied by increasing attention to models of explanatory reduction (e.g., Kaiser 2015, Sarkar 1998, Weber 2005) across a wider variety of domains in biology (e.g., development, ecology, evolution, cell biology, and neuroscience). For example, the question of whether developmental biology can be reduced to developmental genetics and molecular biology has become salient due to recent progress in developmental genetics and growing philosophical interest in  developmental biology  (Love 2008b, Robert 2004, Rosenberg 1997, 2006). Less attention has been given to the question of whether biology can be reduced to physics (but see Rosenberg 2006). This has been an issue of concern to many biologists (e.g., Mayr 2004), both with respect to methodology (e.g., the adequacy of analyzing a system by dissecting it into component parts) and whether modes of explanation from physical science are inherently inappropriate for biological science (Love and Hüttemann 2011).