Posted by Nick Matzke on July 8, 2004 01:28 PM

It’s quite handy. Just today I discovered that adaptive immune systems have evolved not once, but at least twice — once in the jawed vertebrates, and again, in an entirely different way, in their sister group, the lampreys (left). You may recall that Intelligent Design proponent Michael Behe listed the adaptive immune system as one of several “irreducibly complex” systems that supposedly scientists had no idea how to explain with evolution. This was debunked in rather excruciating detail a few years ago, but it is worth pointing out that every month brings out new discoveries filling in details on the evolution of the vertebrate immune system.