Wouldn't it be more accurate to say "evenly" rather than "randomly" split? Let's say you know that there are 10,000 people between the age of 60-80 in the study. You should identify them and split them evenly right?

"One knows the way I feel tonight only if they are lonely." -Roy Orbison

When I first read it, I thought it meant that the genetic differences between shrimp are less significant than the genetic differences of other species. Even if that were true, it makes more sense in the context of the argument that the genetic differences between shrimp populations are less significant than shrimps and turtles.

Yippee!!