Invertebrate.

Ian Tattersall’s NYRB review (October 8, 2026; archived) of The Power of Life: The Invention of Biology and the Revolutionary Science of Jean-Baptiste Lamarck, by Jessica Riskin, is full of fascinating ideas and details; it begins: In the eighteenth century, human knowledge was not as compartmentalized as it is today. Indeed, the boundaries between intellectual disciplines that we now view as distinct remained tenaciously blurry until remarkably recently. To give just one example, your admittedly venerable reviewer once attended a university that still awarded its physics and chemistry graduates degrees in natural philosophy, while those who actually studied philosophy received theirs in the moral sciences. This difference goes a long way toward explaining why, from the perspective of our own age of specialization, it is so hard for us to appreciate just how different our planet must have appeared to the people who were observing it during the era in which the fledgling United States…