1. Fossil Algal Megaflora
Stromatolites & Oncolites – cyano-bacterial colonies, layered sediment (flat/columnar vs spherical “algal biscuits”)

2. Fossil Algal Megaflora
Calcareous Green Algae (Chlorophyta) – Ord-R modern Halimeda and Penicillus

3. Fossil Algal Megaflora
Fossil Receptaculites – Dasycladacean Green Algae?

4. Fossil Algal Megaflora
Coralline Red Algae (Rhodophyta) – Ord - R
Solenopora – Ord – Jr

5. Porifera Simplest metazoa – heterotrophic multicellular
Limited differentiation of cells, no coelom
All sessile suspension feeders
Record Cambrian – R, generally poor fossilization
Marine & fresh

6. Sponge Biology Choanocyte – “collar” cells, make current
Sclerocyte – make spicules
Spongocyte – make spongin
Archaeocyte – general purpose in mesohyl
Ostum – incurrent
Spongocoel – cavity
Osculum – outcurrent
Reproduction – asexual by budding, sexual by release of egg (from archaeocytes) and sperm (from choanocytes) into water
Gemmules – armored archaeocytes

7. Sponge Systematics
Class Hexactinellida – Cambrian-R - “glass sponges”, spicules of silica. Today common in cold deep waters.
Hydnoceras Euplectella

8. Sponge Systematics
Class Calcarea – Cambrian-R - “calcareous sponges”. Today warm shallow waters.
Heteroactines Sphinctozoans
ex. Astraeospongia ex. Girtyocoelia

9. Sponge Systematics
Class Demospongea – Cambrian-R – framework primarily spongin, a few siliceous spicules (monaxons, tetraxons 60/120, demas)
Astylospongia

10. Sponge Systematics
Class Sclerospongea – Sil-R – calcareous & siliceous spicules or none. May occupy cryptic habits. Stromatoporoids now included here.

11. Psammobiotic sponges
Sponges living in sediment. Facilitate cementation of carbonate sand to produce hardgrounds. Beginning point for modern reefs.

12. Archaeocyathids
Early – Middle Cambrian, marine. Shallow current-washed water, high tolerance to turbidity. Passive filterer?
Cambrian reef builders, symbiotic algae?