1
Q
Lophotrochozoan
A
- triploblastic
- one of the protosomes (along with ecdysozoans)
- all have bilateral symetry (lead to cephalization = center of nervous sytem at head)
- classified by presence of trocophore (larval stage) or a lophophore (tuft-like feeding structure)
2
Q
coelem
- what is it?
- what are the 3 ways to describe animals based on it?
A
- internal body cavity that devolops from mesoderm in protosomes
- Acoelomate = no enclosed body cavite (platyhelminthes and nemertea)
- pseudocoelomate = hae body cavities but no mesoderm lining (mesenteries) –> nematoda and rotifera
- coelomate = animals with body cavity lined with mesoderm tissues (molluska, annelida, arthropoda, echinodermata, chordata)
3
Q
coelem pros
A
- greater organ complexity
- allows movement w/o compression of organs
- hydrostatic skeleton
- shock absorbent
4
Q
coelom development
A
- begins during gastrula stage
- developing digestive tube forms pouch called archenteron
- Protosomes form coelom w/ schizocoely –> mesoderm splits into visceral and parietal layers and the space in b/t is the coelom
- Deuterostomes form coeloms w/ enterocoely –> mesoderm buds from walls of archenteron and hollows (forms from endoderm)
5
Q
Circulatory system
A
- some lack one, most have open, few have closed
- open requires less energy than closed
- open: hemolymph (blood+lymph) is pumped into hemocoels where it bathes organs and returns to heart thru ostia —> open ended vessels (found in arthropods and most mollusks
- closed: blood circulated uniderectionally from heart around body and back to heart–> capillaries, arteries, veins–> distinct separation of blood and tissue fluid–> all vertebrates and some invertebrates (cephalopods and annelids)
6
Q
Lophotrochozoan phyla
A
flatworms
rotifers
annelids
mollusks
bryozoans
brachiopods
phronids
ribbon worms
7
Q
Rotifera
A
-triploblastic pseudocoelomates
-“rotifera” = wheel –> crown of cilia draw in prey –> “corona”
-same size as some unicellular protists
-complex internal anatomy
mouth with mastax (jaw-like thing)
complete digestive tract
well developed excretory system
ocellus = light sensing eye spot
8
Q
Platyhelminthes (flatworms)
A
- 4 classes: turbellaria, monogenea(don’t care), trematoda, cestoidea
- triploblastic acoelomates
- 2 way digetive tract (w/ pharynx and gastrovascular cavity)
- no circulatory system or respiratory organs
- gas exchange thru diffusion
- aquatic or terrestrial
- free living or parasitic
9
Q
Turbellaria
A
- class of platyhelminthes
- common name = plaaria
- most are free living (non-parasitic) and marine
- bottom dwellers
- predatory or scavengers
- ciliated body surfaces
10
Q
trematoda
A
- class of plaryhelminthes
- called “flukes”
- obligate parasites w/ 2 hosts
- attach to host with suckers
- intermediate usually gastropod
- final host is often vertebrate, but can be plant
- clonorchis = human liver fluke
11
Q
cestoidea
A
- class of platyhelminthes
- tapeworms
- internal parasites (endoparasitic)
- vertebrate hosts’ guts
- no mouth or digestive tract
- scolex with hooks and suckers
- strobila = body
- proglottids = body segments –> each contains complete, sexually mature reproductive system
12
Q
annelida
A
- 3 classes: polychaetes (mostly marine), terrestrial earthworms, and freshwater leeches
- coelomates –> fluid filled coeom allowing hydrostatic movement surrounded by circular and longitudinal muscles
- metamerism (segmentation) –> each segment has own excretory, nervous, and circulatory system –> coupled with coeom, creates hydrostatic skeleton
- stae = external bristles
13
Q
oligochaeta
A
- class of annelida
- earthworm
- terrestrial
- hermaphroditic, but out-cross
- movement thru alternating contractions of longitudinal and circular muscles
- clitellum = excretes a chitnous band that collects sperm and its own eggs to form an externally shed cocoon where fertilization takes place
14
Q
mollusca
A
- 7 classes: gastropoda, bivalvia, aplacophora, monoplacaphora, polyplacaphora, scaphopoda, cephalopoda
- mostly marine
- soft bodies
- no segmentation
- coelomates
- CaCO3 shells
- visceral mass = concentration of internal organs
- mantle = dorsal body wall of all mollusks (functions in respiration and motion)
- muscular foot = muscular surface on ventral side (functions in locomotion and feeding)
15
Q
cephalopod
A
- class of mollusca
- octopuses, squids, nautiluses, cuttlefish
- fast ocean predators
- highly developed nervous system with fused ganglia (brain)
efficient circulatory and gas exchange systems:
- only mollusk class with closed circulatory
- dual pumping mechanisms = 2 branchial (gill) hearts send blood to gills for gas exchange-> blood returns from gills to systemic heart where its pumped to the rest of the body
- fascilitates pretty high metabolic rates and supports active muscles
