Ok, I think I can explain it.
Picture 1 - This image shows two long life forms which have not yet reproduced.
Picture 2 - This image shows that one of the life forms has reproduced and is now split into many parts, while the other life form remains.
Picture 3 - This image symbolizes the long life form had died of because it didn't reproduce, while the one that did remains.
Picture 4 - This image shows that the life form had reproduced many times and also evolved. There are now many different variations of the original life form.
I hope I'm right!
