Yes, you can draw a very clean line. It's the line of self-replication. Self-replicators have an internal goal - that is to maintain their existence by growing and replicating. The more advanced ones develop complex responses to changes in their environments. Humans are just the apex of this process. A toaster or a thermostat don't self reproduce, so they have no goals. Having no goals, means no consciousness, because goals are shaping the development of consciousness.