Cnidaria

Question 1

What is Cnidaria?

Answer 1

Phylum - anemones, coral, hydroids, sea pens, sea fans, and others

Question 2

Cnidaria Ecology

Answer 2

Mostly marine

Pelagic and benthic

Habitat engineers

Question 3

Cnidaria Body Plan

Answer 3

Polyp and medusa

Coloniality and polymorphism

True tissue, symmetry, digestive tube

2 layers - epidermis and gastrodermis

Question 4

Cnidaria Skeleton

Answer 4

Hydrostatic Skeleton

Internal spicules, external CaCO3 or chitin

Question 5

Cnidaria Feeding

Answer 5

Small plankton to large animals

Have GVC

Use tentacles and nematocysts

Question 6

Cnidaria Sensory Equipment

Answer 6

Nerve net

Question 7

Cnidaria Respiration

Answer 7

Diffusion

GVC for circulation

Question 8

Cnidaria Waste

Answer 8

Diffusion or back out of the mouth

Question 9

Cnidaria Reproduction

Answer 9

Sexual

• dioecious
• gonads in the gastrodermis or epidermis
• free spawn -> settling larvae

Asexual

• Dividing, colony formation, budding
• Regeneration

Question 10

What is Anthozoa?

Answer 10

Class - anemones, coral, and others

Polyp only

GVC divided in sections with septa

Question 11

What is Zoantharia?

Answer 11

Subclass - stony corals and anemones

Numerous tentacles, not branched

External Skeleton

Question 12

What is Alcyonaria

Answer 12

Subclass - soft coral, sea pens

Only 8 tentacles, branched

Almost all colonial

Internal Skeleton - spicules, tubes, or rods in mesoglea

Question 13

Cnidaria Symbionts

Answer 13

Coral have symbiotic unicellular algae in tissue

CO2 -> O2

Produce food

Question 14

What is Scyphozoa?

Answer 14

Class - true jellyfish

Mostly medusae, but polyp stage seen in some groups

• Sexual reproduction: creating of polyp
• Asexual reproduction: polyp with stacks of medusa

GVC branches out into many radial canals

Gonads in GVC

Mostly tentacle/nematocyst feeding; few mucus and cilia (moon jellies)

Question 15

What is Cubozoa?

Answer 15

Class - box jellies

Fatal to humans

Box shaped bell

Question 16

What is Hydrozoa?

Answer 16

Class - hydrozoans

Polyp and medusa forms
- Polyp stage is colonial and polymorphic

GVC is not divided

Gonads are epidermal

Question 17

Gastrodermis

Answer 17

Layer of cells surrounding the GVC

Glandular cells that excrete enzymes and absorb nutrients

Question 18

Mesoglea

Answer 18

Thin and membranous or thick and jelly-like, secreted, non-cellular

Question 19

Gastrovascular Cavity (GVC)

Answer 19

A sac with a mouth as the only opening, surrounded by tentacles bearing stinging nematocysts

Question 20

Hydrostatic Skeleton

Answer 20

Muscles surrounding a fluid-filled mass

Question 21

Nematocysts

Answer 21

Organelle with thread that turn inside out as it leaves the capsule

Barbed, sticky, or toxins

One time use - replaced by cell or cell replaced

Question 22

Polymorphism

Answer 22

Individuals in a colony have a different shape and function

Question 23

Statocysts

Answer 23

Stabilization mechanism in medusae

Use of statolith and sensory hair

Question 24

Perisaic

Answer 24

Non-living, chitinous layer around hydrozoans

Used for support

Excreted by epidermis

Question 25

Gonozooid

Answer 25

Sexual zooid that contains either the male or female parts

Release the hydromedusae

Question 26

Gastrozooid

Answer 26

Feeding zooid with nematocysts and tentacles

Question 27

Dactylzooid

Answer 27

Defense zooid with nematocysts