Phylum Cnidaria Hydra jellyfish coral sea anemones Cnidaria

Phylum Cnidaria Hydra, jellyfish, coral, & sea anemones

Cnidaria – get name from cnidocytes or stinging cells along their tentacles • Class Anthozoa: Sea Anemones

Giant Sea Anemone

Rosy Sea Anemone

Clown fish and sea anemone

Class Anthozoa: Corals and Sea Anemones

Brain Coral

Coral

Colt Coral

Elkhorn Coral

Cabbage Coral

Flower Coral

Sun Coral

Sea Pen

Sea Fan

Sea Plume

Class Hydrozoa: Hydra, Portuguese Man 0’ War

Portuguese Man 0’ War (A colonial hydrozoan) One specialized polyp is enlarged and full of air to keep it afloat, while the other are below the water for feeding and reproduction

Portuguese Man 0’ War Tentacles of Physalia physalis

Class Scyphozoa: True Jellyfish Fried egg jelly

Jellyfish Purple lion’s mane

Sea Nettle

Giant Jelly off Coast of Japan

Class Cubozoa: Box Jellyfish

Characteristics: • Soft bodied • 2 Body forms – Polyp and Medusa

• Have stinging tentacles with nematocysts

• Radial symmetry • Internal space – gastrovascular cavity • Hydrostatic skeleton (such as sea anemones

Specialized structures: • 2 Tissue layers: Ectoderm and Endoderm Jellylike substance in between - mesoglea

• Contracting cells contain muscle fibers • Nerve cells form a nerve net – detect stimuli • Cnidocytes that contain nematocysts (stinging structures) mostly on tentacles.

Mode of nutrition: • Carnivores • Catch prey using tentacles. • Digestion in gastrovascular cavity • Mouth is used for ingestion and excretion.

Movement: • Sea anemones uses its hydrostatic Skeleton for the body to get taller. • Jellyfish move by jet propulsion. • Hydras often do somersaults!

Reproduction: 1. Sexually: • Sexes are often separate* • External fertilization takes place in the H 2 O • Zygote develop into a larva (the planula) • Larva develop into a polyp. • Polyp buds to form a medusa. *Hydra is a hermaphrodite and contains male and female structures.

2. Asexual reproduction: • Budding Bud becomes new Hydra