cnidaria

Question 1

synapomorphies of cnidaria

Answer 1

gap junctions
gonads
synaptic NS - from embryonic ectoderm.
epithelium- lined gut w digestive enzymes
ciliate larva - bearing sensory apical organ.
opsins - light reactive chemical.

Question 2

3 subphyla of cnidarians

Answer 2

anthozoa
meduzosoa
myxozoa

Question 3

general features of cnidaria

Answer 3

- 2 main body forms
roughly radially symmetrical
true tissue level or organization
cnidocyte
epithelio-muscular cell.

Question 4

what are 2 main body forms

ssexual repro in each?

Answer 4

• polyp = benthic – asexual

medusa = pelagic. – sexual

Question 5

body structure of cnidaria

Answer 5

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.

Question 6

true tissue level of organization

- what are the 2 layers of tissue?

Answer 6

endoderm = gastrodermis
ectoderm = epidermia

have mesoglea and middle, non-cellular tissue
- diploblastic

Question 7

talk about cnidocyte
- derive from?
cell, organelle? sensory organ?
purpose?

Answer 7

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

Question 8

epithelio-muscular cell

• arranged how?
• msucular contraction antagonist for?

Answer 8

epitheliall cell with basal myofibrils.
longitudinally + circularly.
antagonist for hydrostatic skeleton.

Question 9

other cells in epithelium

Answer 9

interstitial = totipotent
receptors = sensory cilium
gland cell - gastrodermis
nerve cell - loosely organized net

Question 10

nerve nets

Answer 10

epidermal + gastrodermal.

diffuse net.

Question 11

3 categories of cnidae

Answer 11

nematocysts - spines, toxins
spirocysts - sticky
ptychocysts - making tubes (anthozoa)

Question 12

larval type considered synapomorphy?
describe it;
what type of cleavage?

Answer 12

planula larva.
free-swimming, flattened, ciliated, bilaterally symmetrical.

radial cleavage

Question 13

planuloid hypothesis

Answer 13

first multicellular animal might have looked like planula form

Question 14

planula of medusozoa

Answer 14

no mouth or digestive tract.

lecithotrophic

Question 15

planula of anthozoa?

Answer 15

planktotrophic

Question 16

class scyphozoa

• name of polyp
• juvenile medusa called?

Answer 16

scyphistoma - polyp

juvenila = ephyra

Question 17

anthozoa - main body form. 2 subclass names?

Answer 17

polyp - medusa form absent.

octocorallia + hexacorallia

Question 18

octocorallia

Answer 18

anthozoan subclass. colonial, sea pens, soft corals
8 tentacles per polyp.
calcareous endoskeleton

Question 19

hexocorallia

Answer 19

anthozoan subclass.
stony corals.
more than 8 tentecles. gastrovascular septae aka mesentaries typically in 6 pairs.
- massive calcareous exoskeleton

Question 20

5 classes of medusozoa

Answer 20

hydrozoa
scyphozoa 
cubozoa 
staurozoa 
polypoidozoa

Question 21

2 subclasses of hydrozoans

Answer 21

hyroids: solitary or colonial polyps. can be thecate or naked.
siphonophores: medusoid or polypoid. swimming or polymorphic

Question 22

class scyphozoa - true jellyfish

Answer 22

all marine, thick mesogleal layer. 8-lobed larval medus called ephyra, produced by strobilation

Question 23

class cubozoa

Answer 23

box jellyfish.

marine, medusa, 4 tentacles. complex eyes, potent stings, direct sperm transfer

Question 24

class staurozoa

Answer 24

stalked jellyfish.

marine. benthic. non-ciliated planula larva

Question 25

class polypoidozoa

Answer 25

freshwater, parasitic in eggs of sturgeons

Question 26

subphylum myxozoa

-myospores?

Answer 26

myospore = cnida-like structures.

cause whirling disease in fish

Question 27

what came first the polyp or medusa?

Answer 27

thought anthozoa (polyp) was most basal. has ancestral circular mtDNA, medusozoa (medusa) has linear mtDNA

Question 28

features uniting cnidarians

Answer 28

cnidae
epitheli-muscular cell
planula larva

Question 29

features uniting medusozoa

Answer 29

medusa + alternate w polyp

linear mtDNA

Question 30

featues untiing anthozoa

Answer 30

hexa/octa-radial symmetry

Question 31

features uniting hydrozoa

Answer 31

gamete forming tissue in epidermis

Question 32

features uniting staurozoa, cubozoa, scyphozoa

Answer 32

evolution of unique life cycle

Question 33

features uniting cubozoa, scyphozoa

Answer 33

reduction/loss of polyp

rhopalia

Question 34

features uniting cubozoa

Answer 34

lensed rhopaliar eyes

Question 35

feature uniting scyphozoa

Answer 35

ephyrum buds off

Question 36

feeding in cnidarians

• feeding mechanism?
• augment?

Answer 36

predators (few are parasites)

• use tentacles to stuff food into mouth. sometimes externally digested. undigested goes out the mouth.
• augment with symbiotic algae

Question 37

bumps below tentacles of sea anemonees?

Answer 37

acrorhagi = filled with nematocysts and spirocysts. cause necrosis.