Cnidaria

Question 1

Two basic forms

Answer 1

Polypoid (polyp): stalked and attached​ (pedal disc)
Asexual reproduction & colony formation
Medusoid (medusa): bell-shaped, generally pelagic​

Question 2

Polymorphic body plans

Answer 2

Hydroids have specialized polyps, or zooids
- Gastrozooid
- Dactylozooids
- Gonozooids

Question 3

Gastrozooid

Answer 3

feeding

Question 4

Dactylozooids

Answer 4

defensive

Question 5

Gonozooids

Answer 5

reproductive

Question 6

Muscle cells

Answer 6

Control extension and contraction

Question 7

Myoepithelial cells-

Answer 7

function as
epithelial and muscular cells

Question 8

Medusa: thickness and rigidity of mesoglea

Answer 8

Pulsations through circular muscles led to jet propulsion
Move upward and then slowly sink down

Question 9

Myonemes run parallel to surfaces

Answer 9

Make longitudinal and circular sheets

Question 10

Polyps:

Answer 10

• Water-filled coelenteron creates hydrostatic skeleton
• Build calcareous skeletons, axial rods or sclerites
• Sessile or sedentary –creep, float, somersault, swim

Question 11

Neurons-

Answer 11

Create the “nerve net” a loose network of neurons

Question 12

Mechancoreceptors & chemoreceptors

Answer 12

abundant on tentacles

Question 13

Phototaxis is common using opsins-

Answer 13

light-sensitive proteins

Question 14

Rhopalia –

Answer 14

club shaped structure with statocysts, “eyes” and chemosensory receptors

Question 15

Cnidocytes -

Answer 15

“stinging cells”
Specialized weapon in prey capture, defense and habitat use
5- 100 um long, cigar or flask shaped

Question 16

Nematocysts-

Answer 16

piercing
Tend to have neurotoxins too

Question 17

Spirocytes –

Answer 17

ensnaring

Question 18

Ptychocytes –

Answer 18

adherent

Question 19

Label Cnidocytes -

Answer 19

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Question 20

Label Madusa and Polyp

Answer 20

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Question 21

Coelenteron(GVC)

Answer 21

• Serves as site of digestion via extracellular digestive enzyme breakdown
• Absorbed via phagocytosis intracellularly
• Undigested waste gets removed through the mouth

Question 22

Mucus Layer

Answer 22

• First line of defense
• Used in food capture
• Prevents desiccation during low tides

Question 23

Gland cells

Answer 23

• Secrete digestive enzymes
• Contribute to mucus development

Question 24

pre-protostomes =

Answer 24

Mouth forms at site of gastrulation

Question 25

Sexual -

Answer 25

• Involves planula larvae in all species
• Tied to dimorphic life stage transitions into sexual medusa
• In hydrozoans, polyp or medusa stage may be completely missing

Question 26

Asexual -

Answer 26

In form of budding, fission, laceration, fragmentation

Question 27

Cubazoa -

Answer 27

Have rhopalia with very complex lens eyes that can probably form images

Question 28

Skyphozoa

Answer 28

• The medusa (jellyfish) dominates life cycle
• Polyps tiny (solitary or colonial)
• Undergo strobilation

Question 29

Hydrozoa -

Answer 29

• The only cnidarian class with freshwater species​, 3800 spp.
• Mostly colonial​
• Either the medusa or the polyp is the dominant form in the life cycle (mostly the polyp)​
• Medusa often remains attached to the polyp and effectively becomes its gonad

Question 30

Actinospore -

Answer 30

Larvae infect vert. host and release sporoplasm spreading over tissues disrupting structure and behavior

Question 31

Myxospores -

Answer 31

are released and infect annelids

Question 32

Coelenteron is divided by ____ vertical septa into radial compartments​

Answer 32

mesenteries

Question 33

Some have ciliated groove ____ and ____

Answer 33

siphonoglyph, pharynx

Question 34

Octocorallia -

Answer 34

• Soft corals
• Tend to be long-lived, slow growers
• Gorgonians – produce mineralized spicules/sclerites of calcite and proteinaceous material called gorgonin that makes up the central core, attach to substrate by holdfast
• Thrive in nutrient-rich waters, deep water

Question 35

(Sea Anemones) Specialized defensive structures like ____, ____ or _____

Answer 35

acontia (threads), acrorhagi (beads), or verrucae (adhesive warts)

Question 36

Scleractinia -

Answer 36

• Stony Coral
• Make up the dominant reef-builders today, ~800 species, Skeleton of aragonite, Solitary or colonial
• Growth is upwards and out
  
  • Asexual budding within or outside the tentacle ring
  • Colony shape and size is impart determined by budding patterns
• Suspension feeders – eat a night
• Can be symbiotic or not