Invertebrate Phylum:CNIDARIANS

(Coelenterates)

Vocabulary"Cnidarian” = nettle

"Coelenterata" = hollow gut

polyp = "vase" shaped body form

medusa = "bell" shaped body form

Cnidocyte = stinging cell

Vocabularynematocysts = capsule with coiled,

threadlike tube; inside cnidocytes

endoderm= inner layer of skin

ectoderm= outer layer of skin

mesoglea= jelly-like layer between ectoderm and endoderm

Types

anemones, jellyfish, hydras, coral, Portuguese-man-o-war

Characteristics* Polyp - sedentary, nonmotile, cylindrical body with mouth and tentacles

* Medusa - upside down bowl, mouth and tentacles facing down; modified for swimming

Characteristics* Food digestion

- Paralyze prey with cnidocytes - Tentacles push food to mouth - Cells in gastrovascular cavity release enzymes over prey - Waste ejected through mouth

"Nerve Net" = simple nervous system around mouth

Habitat

Fresh and salt waterWorldwide

Mostly South Pacific and Caribbean

ReproductionAsexual

Buds grow tentacles and separate (warm)Sexual

Eggs and sperm made in testes and ovaries

Sperm fertilize egg; zygote with protective cover shed in spring (fall,

cool)