When you look at this it doesn't appear to really have been a hard image to create. However I supposed sometimes the simplest images hold the nicest value. I must say I love this image. I feel that so many people do not understand evolution although it when really broken down is not that hard. Yet you've managed to take even the simplest of objects and turn it a evolutionary artifact. Kudos to you for the idea.

My only real recommendation is that on the 4th stage you clean up the image a little bit, it gives the image a bit of a fake photoshoped look. Perhaps sharpen the 2 stage a bit.

Other than that I love what you've done here.