== Dolphins, etc. == 

 You said: 
 :as a side-note, tho, i wonder how you can consider the creationist arguments crappy, when it would seem the mainstream side has no cogent explanation whatsoever for these things.    

 What does one have to do with the other? Your dolphin scenario is ridiculous. You're proposing that from a few individuals (two, I'm assuming), you were able to produce a highly diverse population of individuals in only 6000 years. This is not possible. 

 Regardless, the picture of dolphin evolution is perfectly sensible. Phylogenetic analysis suggests that some land-based ancestor of hippos adapted to the sea and developed into the cetaceans. This population eventually diverged over a period of several million years (about 30 My for the branch that covers all river dolphins) into various genera, the four river dolphins amongst them. Simple enough. Why is this not a cogent explanation?