1.Our fingertips and our lips are the most sensitive parts of our bodies; relatively large amounts of the primary somatosensory cortex are devoted to analyzing information from these parts of the body. It is easy to understand why fingertips are so sensitive: We use them to explore objects by touch. But why are our lips so sensitive? Does it have something to do with eating?

2. Bees and birds can taste sweet substances, but cats and alligators cannot. Obviously, the ability to taste particular substances is related to the range of foods a species eats. If, through the process of evolution, a species develops a greater range of foods, what do you think comes first: the food or the receptor? Would a species start eating something new (say, something with a sweet taste) and later develop the appropriate taste receptors, or would the taste receptors evolve first and then lead the animal to a new taste?