The original function of consciousness was probably to direct a mobile self that was short of energy to a fresh supply of food. On the smaller scales of life, you don't need to be aware to find food. Trichopax adhaerens - one of the simplest of all animals moves around haphazardly. 00:02:54 It slows down in the presence of food, and speeds up in its absence. This is highly effective, and makes the tiny creature spend more time where there is food spend more time where there is food than where there is not. But it never moves in a particular direction towards a particular target, and there's no need for it to be conscious of its environment.