Cnidaria Flashcards
(27 cards)
What is Cnidaria?
Phylum - anemones, coral, hydroids, sea pens, sea fans, and others
Cnidaria Ecology
Mostly marine
Pelagic and benthic
Habitat engineers
Cnidaria Body Plan
Polyp and medusa
Coloniality and polymorphism
True tissue, symmetry, digestive tube
2 layers - epidermis and gastrodermis
Cnidaria Skeleton
Hydrostatic Skeleton
Internal spicules, external CaCO3 or chitin
Cnidaria Feeding
Small plankton to large animals
Have GVC
Use tentacles and nematocysts
Cnidaria Sensory Equipment
Nerve net
Cnidaria Respiration
Diffusion
GVC for circulation
Cnidaria Waste
Diffusion or back out of the mouth
Cnidaria Reproduction
Sexual
- dioecious
- gonads in the gastrodermis or epidermis
- free spawn -> settling larvae
Asexual
- Dividing, colony formation, budding
- Regeneration
What is Anthozoa?
Class - anemones, coral, and others
Polyp only
GVC divided in sections with septa
What is Zoantharia?
Subclass - stony corals and anemones
Numerous tentacles, not branched
External Skeleton
What is Alcyonaria
Subclass - soft coral, sea pens
Only 8 tentacles, branched
Almost all colonial
Internal Skeleton - spicules, tubes, or rods in mesoglea
Cnidaria Symbionts
Coral have symbiotic unicellular algae in tissue
CO2 -> O2
Produce food
What is Scyphozoa?
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)
What is Cubozoa?
Class - box jellies
Fatal to humans
Box shaped bell
What is Hydrozoa?
Class - hydrozoans
Polyp and medusa forms
- Polyp stage is colonial and polymorphic
GVC is not divided
Gonads are epidermal
Gastrodermis
Layer of cells surrounding the GVC
Glandular cells that excrete enzymes and absorb nutrients
Mesoglea
Thin and membranous or thick and jelly-like, secreted, non-cellular
Gastrovascular Cavity (GVC)
A sac with a mouth as the only opening, surrounded by tentacles bearing stinging nematocysts
Hydrostatic Skeleton
Muscles surrounding a fluid-filled mass
Nematocysts
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
Polymorphism
Individuals in a colony have a different shape and function
Statocysts
Stabilization mechanism in medusae
Use of statolith and sensory hair
Perisaic
Non-living, chitinous layer around hydrozoans
Used for support
Excreted by epidermis
