SPONGES PHYLUM PORIFERA

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)

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.

Sponges

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.

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

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

BARREL SPONGES

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)

OLD PICTURE FROM FLORIDA OF SPONGE COLLECTORS

STINGING CELLED PHYLUM CNIDARIAN

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

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

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)

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

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!)

Video

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