Download cnidarians

Invertebrate Phylum:
CNIDARIANS
(Coelenterates)
Vocabulary
"Cnidarian” =
nettle
"Coelenterata" = hollow gut
polyp =
"vase" shaped body form
medusa =
"bell" shaped body form
Cnidocyte =
stinging cell
Vocabulary
nematocysts = 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 water
Worldwide
Mostly South Pacific and Caribbean
Reproduction
Asexual
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)