Cnidarian (Jellyfish, Anemones, ect.) Flashcards
anthozoa
sea anemones, corals sea pens polyps only has a pharynx (opens into the siphonoglyph) 3 cnidocytes septa
medusozoa
jellies
- medusa stage
- linear mitocondrial DNA
reproduction (medusa-planula-polyp)
scyphozoa
w/in medusozoa
- medusa with rhopalia
- strobilation (transverse fission)
cubozoa
w/in medusozoa - medusa with box-like body - small polyps lacking septa tentacles on pedal at 4 corner of bell (BOX JELLY) - highly venomous - ocellli at rhopalia - velarium
hydrozoa
w/in medusozoa - greater representation of the polyp morph, medusa with velum, cnidocytes absent
cnidaria apomorphies
10 000 SPECIES
- cnidocytes (stinging cells)
- polyp adult and planula larva
- nerve nets
- longitudinal and circular muscle
- endodermal gonads
- circular mitochondrial DNA
- Diploblast (2 layers, endo & ectoderm)
metagenesis
alternation between medusa and polyp
morphology
- alternating sessile and motile generations
- radial symmetry or medusa stage
- gastrovascular cavity (coelenteron)
nematocysts
injection of toxins
similar to protozoan
for defence and prey capture
colonial forms of cnidaria polyp
fruiticose - generated by two different kind of budding polyp from other polyps
coenosarcal - stolonate mat, continuous
stolonate - tink strawberry runner
skeletong
chitin (hydroids) calcium carbonate (coral) spicule endoskeleton (sea plumes) hydrostatic (fluid filled cavity) foreign material (zooanthellae & zoochlorellae)
musculature
polyps - antagonistic sheets of smooth muscle (epidermal-longitudinal/shortening of the body and gastrodermal-circular/elongation of the body)
medusae - ring of muscles called the coronal muscle
nervous system
sensory, motor, interneurons
nerve nets in the manubrium (both polyp and medusa)
concentrated eurons in coronal muscle
cnidocytes
explosive cell contains one secretory organelle
capture prey and defence from predator
releases a toxin
rhopalia
sense organs in-between each lappet
