Cnidarians - Jellies and Such

Cnidarians include what animals?

Jellyfish, corals, anemones…

Cnidarians - number of tissues and names

2: epidermis, gastrodermis

Do cnidarians have one opening or two

One

What are the two different body plans of cnidarians?

Medusa and polyp

Cnidarians: freshwater or marine?

Mostly marine - 0.2% FW

Cnidarian symmetry type

Radial

Specialized stinging thread

Cnidae

Stinging cell that contains harpoon structure

Nematocysts

What do cnidarians eat?

eggs, larvae, small fish, inverts, plankton, other jellies

True Jellyfishes Class

Scyphozoa

Scyphozoa: ________ connects mouth to _________ canals

Manubrium, gastrovascular

Scyphozoa digestive system: Food particles captured by ____1____ on the ___2___, ingested at mouth. Transport via manubrium to ____3____, then distributed among four __4__ ___4___. Gastric filaments secrete ___5___, then partially digested stuff ____6____ intracellularly. Canals distribute nutrients and O2.

1. nematocysts

2. tentacles

3. “stomach”

4. gastric pouches

5. enzymes

6. phagocytosed

Scyphozoa “balance organs”

Statocysts

Scyphozoa light receptors

Ocelli

Scyphozoa: club shaped structure contains statocysts and ocelli on margins of bells

Rhopalia

Scyphozoa: Gonads develop in what

gastrodermal tissue

Describe the Scyphozoa life cycle

Gametes release, fertilization leads to planula larvae (non-feeding). Planula attaches to substrate - scyphistoma (polyp form). Mouth oriented up, starts feeding. Strobilation occurs: body column divides. Module breaks away called ephyra and starts swimming. Grows to an adult.

Box jellyfish class

Cubozoa

Cubozoa: ___ tentacles or ___ clusters of tentacles from ___ corners of bell; ___ rhopalia

4

Cubozoa: Difference in life cycle from Scyphozoa

Polyp doesn’t strobilate. Polyp buds off more polyps which produce a single medusa each.

True or false: Cubozoa have eyes

True - complex eyes that form images (general shapes)

Hydroids class

Hydrozoa

3 major orders of Hydrozoa

Hydroida, Siphonophora, Anthoatheca/Hydrocorallina

Hydrozoa: mostly marine, ____ is a freshwater species

Hydra

Hydrozoa: mostly _______ as adults

Medusoid

Hydrozoa: shelf of tissue that extends inward from the bell to the manubrium

Velum

Hydrozoa: _______ morph may be just a mass of ______ tissue

Medusa, gonadal

Hydrozoa order Siphonophora: Free floating Hydrozoan ______ in which ______ and ______ forms are present simultaneously

colonies, medusoid, polypoid

Well-known Siphonophora animal

Portuguese man-of-war

Hydrozoa Order Hydrocorallina: secrete what

calcium carbonate skeleton

True or false: Order Hydrocorallina are true corals

False, they are colonial hydroids

Name some husbandry considerations for Cnidarians

Adequate water flow, kriesels, remove waste, chiller, no air contact

1. Exumbrella

2. Gastric cavity

3. Radial canal

4. Subumbrella

5. Rhopalium

6. Tentacle

7. Oral arm

8. Epidermis

9. Mesoglea

10. Gastrodermis

11. Circular canal

12. Gonad

13. Mouth