Before the Cambrian Explosion simple bilateral soft animals existed, simple sacks with an opening for a mouth. Now dated back to 585 million years ago: > > http://phys.org/news/2012-06-resets-date-earliest-animal-life.html-This is the same time as the frond-like Ediacarans were developing. A new finding from that group:-http://phys.org/news/2012-06-ash-fall-nursery-earliest-animals.html