 Different views about what consciousness is, qua cognitive process, and how it relates to other biological processes such as behavior, development and ecological interaction, largely determine biologically oriented views about which animals have consciousness and when, how, and why it evolved. To illustrate this, we can start with a crude distinction between views that see consciousness as fundamental to the basic perceptual and cognitive processes involved in controlling an animal body, or as something that can be added on or plugged in to a system that is already sufficient for basic control of perception-guided action. The more fundamental consciousness is to basic animal functioning, the more widely distributed and ancient consciousness must be; if, however, consciousness is relatively modular, functionally narrow, and conceptually high level, then it should be narrowly distributed among animals and relatively recently evolved. The views surveyed in the following section all exploit the connections between function, structure, distribution and evolutionary origin.  