Radiata Flashcards
What symmetry do Porifera express?
Asymmetry
What is the substance between the cell layers in radiata?
Mesohyl
What groups have HOX genes?
Placazoa and Cnidaria
Name the 4 cell types of Placozoa
Epithelial
Fibre
Gland
Shinysphere
Name the one species in Placozoa
Trichoplax adhaerens
Most diverse group?
Porifera
What groups show biradial symmetry?
Ctenophora & Cnidaria
What are Cnidaria characterised by?
Stinging cells (Cnidocytes)
Give 2 reasons as to why we know Porifera did not evolve from choanoflagellates
- Choanoflagellates are monophyletic
- No pure colonial choanoflagellates
What groups are Coelenterata?
Cnidaria
Crenophora
What is the placula hypothesis?
Animals evolved from 2 laters of protists which became invaginated to form a gut.
Trichoplax could be evidence
What disproves the Placula hypothesis?
mtDNA showed Trichoplax is basal with metazoans but mtDNA isnt good for deep phylogencies
