It’s so elegantly simple, why didn’t anyone think of this before? Animals evolved because they evolved.
Simple, small, and worldwide in distribution, the placozoa don’t fit any clear evolutionary picture.
For the first time it has been discovered that an organism from the Precambrian Ediacaran fauna may have survived into the Cambrian period.
True arthropods are among the most sophisticated animals that appeared without ancestors in the Cambrian explosion.
Many claim the Cambrian explosion was triggered by a sudden global increase in oxygen levels.