Origins and evolution of bilateral symmetry

Question 1

What are the 4 non-bilaterally symmetrical phyla?

Answer 1

1. Sponges (Porifera)
2. Comb jellies (Ctenophora)
3. Cnidaria (Jellyfish, anemones, corals, hydra)
4. Placozoa (simple blob-like invertebrate)

Question 2

Did bilateral symmetry evolve before the split of bilateral and cnidarians?

Answer 2

Yes.