gelata

Question 1

what subphylum and 2 phylums are included in the gelata taxonomy

Answer 1

• Salps (Subphylum Tunicata)
• Comb jellies (Phylum Ctenophora)
• True Jellyfishes (Phylum Cnidaria, Class Scyphozoa)
• Box Jellyfishes (Phylum Cnidaria, Class Cubozoa)
• Hydromedusae (Phylum Cnidaria, Class Hydrozoa)
• Siphonophores (Phylum Cnidaria, Class Hydrozoa)

Question 2

gelata characteristics

Answer 2

• planktonic lifestyle
• 95% or higher water content
• sometimes form massive blooms

Question 3

salps (Subphylum Tunicata) characteristics

Answer 3

• Gelatinous zooplankton
• Non-vertebrate chordates
• Adult = barrel-like filter feeders with 2 siphons; 1 inhalant and 1 exhalent
• soft but tough outer covering -> the tunic
• know they are closely aligned to vertebrates by their tadpole larvae (possess a notochord, dorsal nerve chord, and pharyngeal slits)

Question 4

what kind of larvae do salps have and its 3 characteristics

Answer 4

tadpole
- notochord
- dorsal nerve chord
- pharyngeal slits

Question 5

4 classes included in Tunicata (salps)

Answer 5

Class Ascidiacea (sea squirts, benthic)
Class Sorberacea (benthic, predatory)
Class Appendicularia (larvaceans, planktonic)
Class Thaliacea (pyrosomes and salps, planktonic)

Question 6

3 orders within Class Thaliacea and their characteristics

Answer 6

• Order Pyrosoma
  >identical colonial zooids
  >Colonies can be enormous and bioluminescent
  >Inhalent siphon outside; exhalent siphon inside
• Order Salpidae
  Salps = individual animals (up to 20 cm)
  >resemble barrels with muscle bands
  >Often colonial – form chains
  >slow moving
• Order Doliolida
  >Resemble small salps individual (but fast moving)
  >non colonial

Question 7

Comb jellies (Phylum Ctenophora) characteristics

Answer 7

• delicate
• oval / lobate shape
• 8 set of comb-rows (cilia) for locomotion
• Carnivorous
• Swarm forming

Question 8

2 classes included in Comb jellies (Phylum Ctenophora) and their characteristics

Answer 8

• Class Tentaculata
  >2 tentacles with sticky cells: colloblasts
  >Also contains the benthic forms
• Class Nuda
  >no tentacles

Question 9

Phylum Cnidaria feeding characteristics

Answer 9

• Predatory jellyfish - nematocysts to capture prey
• Jellyfish without feeding tentacles - mucilage to catch plankton

Question 10

4 classes within Phylum Cnidaria and their characteristics

Answer 10

• Class Scyphozoa – true jellyfish
  >Not all have a benthic polyp stage
  >Sensory organs = Rhopalium
• Class Cubozoa – box jellyfish
  >complex eyes
• Class Hydrozoa – diverse forms (includes siphonophores)
  >Up to 40m long
  >delicate
  >Colonial
  >entirely pelagic
• Class Anthozoa – corals, sea anemones

Question 11

what are the sensory organs in true jellyfish (Scyphozoans) called

Answer 11

Rhopalium

Question 12

what are sticky cells called that Class Tentaculata (Comb jellies) have

Answer 12

colloblasts

Question 13

why is it hypothesised that jellyfish can outcompete fish population once they are established

Answer 13

• higher consumption rates
• respond more rapidly to pulses in prey (reproduce asexually + rapid growth rates)
• prey upon early life stages of many fish

Question 14

why have Gelata been historically considered unimportant in food webs and biogeochemical cycles (“trophic dead-ends”)

Answer 14

their high water content + low calorific value

Question 15

gelatinous bloom consequences

Answer 15

• Burst nets
• Impacts on fisheries
• Impacts on aquaculture and other industries – fish kills
• Tourist impacts
• Promotion of toxic red tides

Question 16

explain the fall and rise of the Black Sea