lec 7

Question 1

Eumetazoa who is in there

Answer 1

all animal phyla except Porifera
and Placozoa

Question 2

what unites eumetazoa
(7)

Answer 2

1. presence of true tissues derived from embryonic germ layers
2. gap junctions- particular type of intercellular junction
3. gonads- organs specialized for making games(ovaries for eggs and testes for sperm
4. synaptic nervous system
5. epithelium lined gut w digestive enzymes
6. primary larva
   7.presence of particular opsins

Question 3

primary larva

Answer 3

ciliated larva bearing a
sensory apical organ

Question 4

epithelium lined gut w digestive enzymes derived from

Answer 4

embryonic endoderm)

Question 5

synaptic nervous system derived from

Answer 5

(derived from embryonic ectoderm

Question 6

opsins

Answer 6

proteins that bind to
light-reactive chemicals

Question 7

Phylum Cnidaria how many spcs marine and freshwaer

Answer 7

13,300 sps total
mostly marine’
100 freshwater

Question 8

subphyla of cnidaria

Answer 8

Anthozoa-coral, sea anemone
Medusozoa- jellyfish
Endocnidozoa- morphologically reduced and completely parasitic

Question 9

two main body forms of free living cnidaria

Answer 9

polyp benthic
medusa pelagic

Question 10

how do some cnidarians species alternate bw life forms

Answer 10

polyp being for asexual reproduction
medusa for sexual

Question 11

body axis for cnidaria

Answer 11

oral to aboral

Question 12

symmetry for cnidaria

Answer 12

radially symmetrical: rarely perfect,
more often have 4-fold radial symmetry

Question 13

cnidarian gut

Answer 13

gut has one opening: mouth only, no anus

Question 14

what surrounds oral end of cnidarian
what is their function

Answer 14

tentacles
capture prey and transport food to mouth

Question 15

water-filled branches or canals that go into different parts of the body

Answer 15

gastrovascular cavity

Question 16

cnidarian tissues
and layers

Answer 16

true tissue level of organization- diploblastic
epidermis
mesoglea(not true)
gastrodermis

Question 17

epidermis

Answer 17

outer, from embryonic ectoderm

Question 18

gastrodermis

Answer 18

inner, from embryonic endoderm

Question 19

mesoglea

Answer 19

middle layer mostly non-cellular and not a true tissue

Question 20

do cnidaria have organs

Answer 20

yes

Question 21

cnidocyte

Answer 21

-a synapomorphy of cnidaria
-derived from gastrodermal interstitial cells
-used for prey capture, defence, and movement to a lesser extent

Question 22

organelle of cnidocyte

Answer 22

cnida
- capsule w sticky or harpoon like tube
-may contain toxins

Question 23

what cool about cnidae structure

Answer 23

most complex intracellular structures of all metazoa

Question 24

nematocysts

Answer 24

type of cnidae, has spines and toxins

Question 25

where are nematocysts found?

Answer 25

all free living taxa

Question 26

myoepithelial cell

Answer 26

epithelial cells w basal myofibrils

Question 27

myoepithelial cell function

Answer 27

functions as skin and muscle

Question 28

how are myofibrils aranged?

Answer 28

longitudinally in epidermis and circularly in gastrodermis

Question 29

what acts as a hydrostatic skeleton

Answer 29

muscular contraction against the gastrovascular cavity

Question 30

myoepithelial cell contraction
mouth open, longitudinal contract

Answer 30

H2O leaves gastrovascular cavity, total volume decrease
tentacle shortens and thickens

Question 31

myoepithelial cell contraction
circular contract

Answer 31

H2O leaves gastrovascular cavity, total V decrease
tentacle lengthens and thins

Question 32

Mouth closed, circ and longitudinal contract

Answer 32

-H2O doesnt leave, volume remains
therefore, hydrostatic skeleton
-tentacle stiffens, doesnt change much in diameter

Question 33

what do nerve cells form in cnidaria

Answer 33

form loosley organized net rather than CNS–> no ganglia and no brainnski

Question 34

two arrays of nerve net

Answer 34

,
epidermal and gastrodermal separated by mesoglea

Question 35

planula larva

Answer 35

larva common to almost all
groups of Cnidaria

Question 36

planula larva features

Answer 36

free-swimming, flattened, ciliated
bilaterally symmetrical

Question 37

what does planula develop from

Answer 37

fertilized egg of a medusa

Question 38

planulae of the subphylum Medusozoa

Answer 38

lecithotrophic
have no mouth or digestive tract–> do not eat

Question 39

planulae of some Anthozoa can be lecithotrophic, others are

Answer 39

planktotrophy- eat smaller orgs

Question 40

depending on the species, the planula either

Answer 40

1) swim till settling and transforms into a polyp
2) metamorphoses directly into a free-swimming, mini version of the adult

Question 41

hydrozoa life cycle

Answer 41

medusa–>fert egg–> planula–> polyp–>medusa

Question 42

actinula larva

Answer 42

tentacled larva develops from planula sometimes

Question 43

Hydra life cyle weirdness

Answer 43

lacks both a medusa stage
and a planula larva

Question 44

Class Scyphozoa- aurelia life cycle

Answer 44

scyphistoma buds off more polyps or ephyra

Question 45

scyphistoma

Answer 45

polyp of aurelia

Question 46

ephyra

Answer 46

budded off polyp or medusa

Question 47

all anthozoans lack(life cycle)

Answer 47

a medusa stage

Question 48

Endocnidozoa (Myxozoa) life cycle lacks

Answer 48

polyp or medusa

Question 49

molecular data provides support for what hypothesis?

Answer 49

polyp-first

Question 50

what data supports polyp first hypothesis?

Answer 50

anthozoans and endocnidozoans have ancestral state of circular mitochondrial DNA chromosome.
Medusozoa have a derived state of linear mtDNA

Question 51

four synapomorphies for cnidaria

Answer 51

(1) polyp stage; (2) cnidae; (3) myoepithelial
cells; (4) planula larva