• Asymmetrical (no symmetry at all)

• No true body cavities (coeloms), just cells and tissues surrounding a water-filled space.

• Two germ layers BUT they are not true germ layers.

• Multicellular with few tissues and no true organs.

• No nervous system.

• Sessile, meaning sponges live attached to something and cannot move freely.

• Most are hermaphrodites meaning they each function as a male and female in sexual reproduction, most of the time either male or female gametes are made at one time

• Sperm released into water• Eggs fertilized in the mesohyl

• Do not have any tissue but they do have specialized cells (collar cells, amoebocyte, skeletal material: spicules and spongin).

• Amoebocyte: named because they move by pseudopods, have many functions- take food from the choanocyte, form the skeletal fibers within the mesohyl.

• Spongin: a network of flexible fiber proteins, the fibers that make up spicules

• Spicules: fibers made from the amoebocyte, they are sharp and made from calcium carbonate or silica. Function: provide structural support as well as defense against predators.

• Choanocyte: flagellated cells, also called collar cells, theses collar cells line the spongocoel and trap food

• Porocytes: donut shaped pores that open and close to control water flow

• Ostia: small pores in the walls of sponges, water comes through these pores carrying food.

• Osculum: large opening that water flows out of, under certain conditions cells around the osculum contract (open and close)

• Spongocoel: the central cavity of a sponge

Wire Sponge Vase Sponge Tube Sponge

Sun Sponge Red Sponge

• Radial symmetry (infinite lines of symmetry)

• Two germ layers (TRUE germ layers)

• No true body cavities (coeloms)

• Polyp form: the sessile form of Cnidaria (asexual reproduction stage)

• Medusa form: the motile form of Cnidaria (sexual reproduction stage)

• In some classes of Cnidaria, the medusa form does not exist and thus sexual reproduction does not exist. In most, however, there are both the polyp and medusa life stages (medusa being dominant most of the time), meaning that they can do both sexual and asexual reproduction.

• Life cycle (includes jellyfish):

Planula

(larva)

Attaches to a substratum

Polyp form

Reproduces asexually by budding to create a colony

Medusae are produced asexually

Medusae are relased and reproduce sexually

• Nematocysts - specialized stinging cells used to capture food or fight off predators

• Combs - Ctenophores are characterized by eight rows of cilia, which are used for locomotion. The cilia in each row are arranged to form a stack of combs, also called comb plates, or ctenes.

• Colloblasts - The cells found within the tentacles of Ctenophores.• Cnidocytes - Specialized cells that carry stinging organelles called cnidocysts.• Mesoglea – Jelly-like layer between the epidermis and gastrodermis• Gastrovascular cavity - Extracellular digestion takes place within the

gastrovascular cavity of the sac-like body. This cavity has only one opening to the outside and, in most cnidarians, that is surrounded by tentacles which serve to capture prey.

* Ctenophora is just a phylum usually classified with Cnidaria consisting of comb jellies, a certain type of jellyfish.

• Comb jellies:

• Portuguese Man-of-War are colonies of four kinds of highly modified polyps that are dependent on one another for survival.

Coral Reef types:

• Fringing reefs - Fringing reefs border shorelines of continents and islands in tropical seas. Fringing reefs are commonly found in the South Pacific Hawaiian Islands, and parts of the Caribbean.

• Barrier reefs - Occur farther offshore. Barrier reefs form when land masses sink, and fringing reefs become separated from shorelines by wide channels. Land masses sink as a result of erosion and shifting crustal plates of the earth.

• Atolls - surround a central lagoon

• Coral reef:

• Other Cnidaria:

Hydra

Giant Green Anemone