[CliffordK]

Clifford, the point is-- if the centenarian can tell the whole tribe how to outrun the buffalo, because this happened when they were a stripling, they pay their way and evolutionary processes favor them. Steve 

The problem is if there was a tribe with only Centenarians...  then there would be no buffalo to eat!!!

Although, perhaps they would figure out a better way than chasing them down on foot like a teenager!!!

[SteveFish]

Geezer, I took your comment seriously and gave a thoughtful and, hopefully, informational answer. This is another of those frame of reference questions. To some a design requires a designer that is an entity, not a mechanism.