1. SPONGES
PHYLUM PORIFERA

4. Major Characteristics of
the Phylum Porifera
Sponges are:
asymmetrical
multicellular
sessile
Heterotrophic
eukaryotic
No body cavity
evolved from Kingdom Protista
No systems (digestive, excretory, circulatory, or respiratory)

6. Water flowing through sponges provides food and oxygen, as well as a means for waste removal.
Green dye was placed next to a sponge-- note the flow from the osculum!
Small incurrent pores allow water in.

8. Sponges

9. Cell types (3 types)
1. Choanocyte cells (a.k.a. “collar cells”) have “nets” and flagella. They surround pores, bring water in, and filter food particles.

10. 2. Epithelial cells—often brightly colored.
Cell types (2nd type)
2. Epithelial cells—often brightly colored.

12. Amoebocyte cells have many jobs: transport food replace damaged parts
Cell types (3rd type)
Amoebocyte cells have many jobs:
transport food
replace damaged parts
produce spongin spicules
form gametes
amoebocyte

13. BARREL SPONGES

14. Reproduction
Most are hermaphrodites-- produce both male and female gametes.
Sexual Reproduction
Amoebocytes become:
Eggs--retained and fertilized internally
Sperm-- released through osculum
{sperm  osculum other sponge’s choanocytes
amoebocyte carries sperm to egg) fertilization forms larva (plankton) released from mesenchyme, then floats/swims to new spot  develops to adult}
Asexual reproduction is also possible:
gemmules (freshwater sponges only)
fragmentation (following damage)

15. OLD PICTURE FROM FLORIDA OF SPONGE COLLECTORS

16. STINGING CELLED
PHYLUM CNIDARIAN

17. Characteristics of Cnidarians
Evolved by gaining body symmetry and tissues
Radially-symmetrical
no body cavity
Digestive cavity and mouth for digestion, excretion, circulation, and respiration

18. Cnidarian Characteristics
Cnidocytes -- stinging cells-- barbed &/or sticky &/or poisonous-- used for feeding / protection

19. Gastrovascular cavity-- food and oxygen in / waste and CO2 out
Tissues-- muscular, nervous (sensory and nerve-net cells), mesoglea (from ectoderm and endoderm)
Hollow body form(s)-- sessile, vase-shaped polyp &/or free-swimming, bowl-shaped medusa
Planula-- free-swimming larval form resulting from sexual reproduction (sexual and asexual reproduction)

20. Three Classes of Cnidarians
1. Hydrozoans-- (Hydra, Portuguese man-of-war, Obelia)
Polyp form
Mostly asexual reproduction
Freshwater and marine types

22. 2. Scyphozoans-- jellyfish (stinging nettle, blue wasps...)
Medusa form dominant
1/2 inch to 7 feet diameter
Nerve cells in margin of bell (coordinate swimming)
Sense organs-- statocysts (gravity) and ocelli (light)
Some are edible (juicy mesoglea!)

23. Video

25. 3. Anthozoans-- anemones and corals (red coral, sea fans…)
Polyp form only (thus sessile except for planula and those living on backs of snails)
Anemones lack skeleton; corals secrete CaCO3 (limestone)
Many have symbiotic dinoflagellates &/or green algae
Sexual and asexual reproduction
Divided, sophisticated gastrovascular cavity
Form coral reefs of limestone skeletons-- most diverse marine communities-- provide food and shelter for fish, shellfish, etc.
Red coral used for money/jewelry