http://judson.blogs.nytimes.com/2008/01/29/the-repeater/index.html?8ty&emc=ty

Interesting NYT blog—today a discussion of how freshwater sticklebacks evolved from marine sticklebacks after their habitats were cut off from the ocean at the end of the ice age.

Point is that once cut off they evolved independently and the differences are of keen interest to evolutionary biologists.

Includes pictures to make it clearer to the layreader.

Jackson