Consider that a litter of sharks born in year 100 would be very closely related to a litter sharks born in year 400. Imagine the same pair of sharks mate over t

Consider that a litter of sharks born in year 100 would be very closely related to a litter sharks born in year 400. Imagine the same pair of sharks mate over that span of time, those siblings are even closer. To me, evolution is a very deep graph of descendants. The scenario you propose is a very wide and shallow graph. N.B.: I'm a layman on this topic as well.