What was the first animal in the whole world??

Question: What was the first animal in the whole world??
- Keywords:
  animal,
  evolution,
  evolve,
  world
Asked by katiejean to Alex, Matt, Rika on 23 Jun 2011.
- Chandrika Nair answered on 23 Jun 2011:
  
  Sponges were actually the first animals (Metazoans), and fossils of these that are 665-million-year-old have been found. Most other ancestral animals appeared about 542 million years ago during what is called the Cambrian period (things like worms).

Question: What was the first animal in the whole world??