You might think that once evolution has found one way to get something done, it will stick with it. But similar physical forms can hide radically different wiring, finds Tanguy Chouard.
"It is not birth, marriage or death, but gastrulation, which is truly the most important time in your life," British embryologist Lewis Wolpert famously said. That's when the primordial sheets of embryonic cells are instructed to fold inwards on their way to becoming more specialized tissues.
http://www.nature.com/news/2008/081119/full/456300a.html
/https%3A%2F%2Fassets.over-blog.com%2Ft%2Fcedistic%2Fcamera.png)