The OLFACTORY AND THE GUSTATORY SYSTEMS have receptors which die out after sometimes because of direct exposure to the environment.
The olfactory system has to do with the perception of smell while the gustatory system has to do with taste stimuli. For these two basic sense organs, their perception rate is always highest when they are newly exposed to a stimuli, after continuous exposure to the stimuli their receptors die out.
Producers, because according to food pyramid, only 10% of energy is passed onto the next layer, where the other 90 is passed off as heat, so there must be more producer in order to sustain the ecosystem.
