L 13 - chaetognatha and aschelminth

Question 1

aschelminthes

Answer 1

thought to have pseudocoeloms. - some do, some dont.

- now used as grouping of convenience

Question 2

common names
chaetognatha 
nematoda
nematomorpha
priapulida
rotifera

Answer 2

C - arrow worms
nematoda - roundworm.
nematomorph - horsehari worms 
penis worm
rotifers. include acanthocephala (spiny-headed worms.

Question 3

phylum chaetognatha

how scientific name arose?

Answer 3

swims in open ocean water

array of movable raptorial bristles surrounding mouth.
arrow worm bc long, slim with stabilizing fins.

Question 4

molecular data puts chaetognaths with protostomes

- morphological support?

Answer 4

ventral nerve cord, circumesophageal connectives

Question 5

chaetognatha deuterostome-like characteristics

Answer 5

multiple eucoelomic cavities, arose by enterocoely.

blastopore - not mouth. mouth 2nd. but coelom =/= deutero bc blastopore =/= anus.

Question 6

heterocoelous development of chaetognath led to what thought?

Answer 6

transitional phylum btw proto & deutero.

- fossils found from around that time

Question 7

coelem sets in chaetognatha

- other characteristics?

Answer 7

3 sets, separated by septae
1 in head, pair in trunk, pair in tail

• continuous gut, anal opening. no specialized gas/circulatory systems. - movement allows for circulation.
• mouth surrounded by set of long movable grasping spines: retracted by hood-like extension.
• non-image forming eyes

Question 8

repro in chaetognatha
- mating?
- fertilization? 
-brooded?
- development?
cleavage?
blastopore?

Answer 8

• simultaneous hermaphrodites.
• mating observed - mating dance
  -transfer of masses of sperm. mass placed nearby and swim over to fertilize.
• most lay egg immediately
  direct development
  cleavage more like spiral
  blastopore opens on posterior end, closes. not mouth or anus.

Question 9

feeding of chaetognatha

Answer 9

detect disturbance of water by arrays of vibration - detecting cilia.
- subdue prey w tetrodotoxin

Question 10

phylum rotifera

Answer 10

all endoparasites

includes acanthocephala

Question 11

non-acanthocephalan rotifera

Answer 11

small, move w beating cilia
corona . 
pseudocoelomate. 
most solitary, few colonial. 
free-swimming; some sedentary. 
- build cases out of sand or fecal pellets. / armor called lorica
- eutely.

Question 12

lorica =

Answer 12

rigid intracellular protein layer within syncytial epidermis.

Question 13

internal mouthparts of non-acanthocephalan

Answer 13

mastax (mast = chew) made up of number of small parts - called trophi

Question 14

internal characteristics

Answer 14

protonephridia, simple NS, no circulatory, gas-exchange.

eyespot detect light.

Question 15

cyclic pathenogenesis

Answer 15

asecual repro of diploid daughters by amictic females = good condition
bad condition = haploid sons produced by mictic females.
sons copulate w other mictic females, eggs stay dormant until conditions are better.

Question 16

anhydrobioasis

Answer 16

eggs dry “hibernate” - add water = back to life

Question 17

feeding of rotifers

Answer 17

active hunters - grab prey w raptorial trophi. feed on small particles, chew off substrate, whirl toward mouth usuing coronal cilia.

Question 18

seisonidea

Answer 18

small group of non-acanthocephalans. 
 ectoparasitic 
- live on crustacean
- feed on host eggs or body fluid. 
very reduced corona, entirely sexually reproducing.
sister to parasitic acanthocephala

Question 19

acanthocephalans
characteristics
habitat?
coelom?

Answer 19

endoparasitic. live in guts of vertebrates, crustaceans.
no corona, mastax, mouth, gut.
large pseudocoelem.
spiny eversible head to anchor in gut lining.

Question 20

5 phyla in achelminthes

- which are spiralian? ecdysozoan?

Answer 20

chaetognatha - non-spiralian, non-ecdysozoan

rotifera - spiralian

priapulida - ecdysozoan
nematoda - ecdysozoan
nematomorpha - ecdysozoan

Question 21

feature that rotifers & acanthocephalan share?

Answer 21

syncytial epidermis

Question 22

repro of non-acanthocephalan rotifers

Answer 22

direct development
separate sexes.
- may be pathenogenetic. amictic female = asexual amictic females. mictic female = haploid son copulates with other mictic female

Question 23

repro in acanthocephalan

Answer 23

separate sex. sperm transferred via copulation.

Question 24

acanthocephalans famous for?

Answer 24

changing behaviour or intermediate hosts to ensure they get eaten by final hosts

Question 25

what are ecdysozoan animals?

3 phyla?

Answer 25

moulting animals. shed cuticle at least once in life cycle
– priapula
nematoda
nematomorpha

Question 26

phylum nematoda: common name?
x-section?
habitat?

Answer 26

round in x-section.

terrestrial, freshwater, marine.

Question 27

gut, circulation, body muscles in nematoda

Answer 27

mouth, muscular pumping phrynx, straight gut, terminal anus.

• no circulatory or gas-exchange systems.
• body wall muscles exclusively longitudinal.

Question 28

coelom of nematode?

Answer 28

pseudocoelomate: mesodermally derived tissue on one side of coelom

Question 29

how many nerve cords? functions?

Answer 29

4 - dorsal + ventral for locomotion. 2 lateral - sensory

Question 30

different about muscle/nerve interaction?

Answer 30

muscle sends projections to nerves instead of normal opposite

Question 31

repro in nematodes

Answer 31

herm, separate sex or combo.

• sperm transfer via copulation.
• direct development
• determinate cleavage and eutely.

Question 32

feeding in nematodes

Answer 32

free-living. strong pharyx to suck in liquids. pedators with hooked teeth.
some are human parasites

Question 33

use by humans to control insects

Answer 33

entomopathogenic

Question 34

phylum nematomorpha

- different life stages

Answer 34

free living. mostly freshwater. juvenile are parasitic.

adults are long, dark thick cuticle

Question 35

nematomorpha - pseudocoelom?

Answer 35

no filled with mesenchyme

Question 36

muscles, gut in nematopmorph

Answer 36

gut is reduces, lack circular muscles.

Question 37

head in larva of nematomorph

Answer 37

larva has spiny eversible head.

• parasitize terrestrial insects.
• grow to gigantic size in hosts body and burst out

Question 38

phylum priapulida

Answer 38

penis worm
- free-living benthic
thick-bodied. predatory

Question 39

distinct feature of priapulida

Answer 39

distinctive caudal appendage.

Question 40

cns, coelom in priapulida

Answer 40

single large pseudocoelom.

not much of a brain, but have circumesophageal connectives.

Question 41

repro in priapulida

Answer 41

separate sexes, free-spawning.

deuterostome-like development.