Subject: Why are taste buds clustered in different parts of the tongue?

The tip of your tongue is best able to taste sweetness and
saltiness. The sides of your tongue can best taste sourness. The back 
of your tongue, and a bit on the front/side, can best
taste bitterness.  But it would seem more reasonable to have each 
taste distributed evenly over the tongue.  What's the advantage of 
only being able to taste sweetness at the tip of your tongue, for 
example?  Does the taste bug distribution derive from something 
peculiar during development?

Re: Why are taste buds clustered in different parts of the tongue?