Phylum Cnidaria: More than Just Jellyfish

Don’t Forget Sponges! Phylum: – Porifera Anatomy & Physiology: – Osculum, Spongocoel (asymetrical) – Archaeocytes, choanocytes, spicules Ecology: – Filter feeders

Cnidarians have Cnidocytes Cnidocytes are stinging cells that produce toxins and inject it into prey. They are used to stun and capture prey. Cnidocyte

Two Major Groups of Cnidarians Sea anemones Corals Sea Pens hydrozoa True jellies Box jellies

Cnidarian Life Cycle Two main phases: – Polyp (stationary) – Medusa (mobile) Some Cnidarian species have only a single phase. This is a general description.

Cnidarian Anatomy

Sea Anemones Anemones spend most of their time attached to rock or coral, though they can move. They are predators

Clownfish & Anemone One of the best examples of symbiosis in all of biology What does each organism get from the other?

Corals Brain coral shown at left Corals are colonies of many tiny polyps.

They are carnivores. They have no medusa stage in their life cycle – all polyp Flower Coral

Coral Reefs Corals CaCO 3 holdfasts are what coral reefs are made of.

Sea Pens & Sea Fans: “Soft” Corals – No CaCO 3 “bones”

Box Jellyfish: Deadliest Venom? Cnidocytes on the tentacles of box jellies may have killed more people than any other venom!

True Jellies: Scyphozoa

Hydrozoa: Weird Misfit Cnidarians Many sizes and shapes Many variations on life cycle Poorly defined group Deadly Portugese-Man-O-War Hydra

In Summary Cnidarians have stinging cells called cnidocytes. The Cnidarian life cycle includes polyp and medusa stages. Cnidaria includes a wide variety of species, including jellifish, anemones, and hard and soft corals. They are all predators.