cnidaria Flashcards
synapomorphies of cnidaria
gap junctions
gonads
synaptic NS - from embryonic ectoderm.
epithelium- lined gut w digestive enzymes
ciliate larva - bearing sensory apical organ.
opsins - light reactive chemical.
3 subphyla of cnidarians
anthozoa
meduzosoa
myxozoa
general features of cnidaria
- 2 main body forms roughly radially symmetrical true tissue level or organization cnidocyte epithelio-muscular cell.
what are 2 main body forms
ssexual repro in each?
- polyp = benthic – asexual
medusa = pelagic. – sexual
body structure of cnidaria
roughly radially symmetrical. oral-aboral axis.
1 gut opening, mouth, no anus
tentacles - capture prey and transport food to mouth
gastric cavity may have branches/canals = gastrovascular cavity.
true tissue level of organization
- what are the 2 layers of tissue?
endoderm = gastrodermis ectoderm = epidermia
have mesoglea and middle, non-cellular tissue
- diploblastic
talk about cnidocyte
- derive from?
cell, organelle? sensory organ?
purpose?
derive from gastroderm interstitial cells
- cnidocyte cell, nematocyst organelle = harpoon-like stingger, contains toxin.
cnidocil = sensory organ
purpose = defense, aggression, prey capture.
use once only tho
epithelio-muscular cell
- arranged how?
- msucular contraction antagonist for?
epitheliall cell with basal myofibrils.
longitudinally + circularly.
antagonist for hydrostatic skeleton.
other cells in epithelium
interstitial = totipotent
receptors = sensory cilium
gland cell - gastrodermis
nerve cell - loosely organized net
nerve nets
epidermal + gastrodermal.
diffuse net.
3 categories of cnidae
nematocysts - spines, toxins
spirocysts - sticky
ptychocysts - making tubes (anthozoa)
larval type considered synapomorphy?
describe it;
what type of cleavage?
planula larva.
free-swimming, flattened, ciliated, bilaterally symmetrical.
radial cleavage
planuloid hypothesis
first multicellular animal might have looked like planula form
planula of medusozoa
no mouth or digestive tract.
lecithotrophic
planula of anthozoa?
planktotrophic
class scyphozoa
- name of polyp
- juvenile medusa called?
scyphistoma - polyp
juvenila = ephyra
anthozoa - main body form. 2 subclass names?
polyp - medusa form absent.
octocorallia + hexacorallia
octocorallia
anthozoan subclass. colonial, sea pens, soft corals
8 tentacles per polyp.
calcareous endoskeleton
hexocorallia
anthozoan subclass.
stony corals.
more than 8 tentecles. gastrovascular septae aka mesentaries typically in 6 pairs.
- massive calcareous exoskeleton
5 classes of medusozoa
hydrozoa scyphozoa cubozoa staurozoa polypoidozoa
2 subclasses of hydrozoans
hyroids: solitary or colonial polyps. can be thecate or naked.
siphonophores: medusoid or polypoid. swimming or polymorphic
class scyphozoa - true jellyfish
all marine, thick mesogleal layer. 8-lobed larval medus called ephyra, produced by strobilation
class cubozoa
box jellyfish.
marine, medusa, 4 tentacles. complex eyes, potent stings, direct sperm transfer
class staurozoa
stalked jellyfish.
marine. benthic. non-ciliated planula larva
