Slides 26

Question 1

porifera distinguishers

Answer 1

sac perforated with pores; filter feeder; water is drawn into the spongocoel and flows out through the osculum;

Question 2

porifera lacks tissues

Answer 2

two layers of cells separated by gelatinous region called mesohyl; choanocytes: flagellates collar cells, food particles by phagocytosis;
amoebocytes: cells within the mesohyl that igest food, transport nutrients, make skeletal fibers

Question 3

cnidaria distinguishers

Answer 3

radially symmetrical, diploblastic animals, gastrovascular cavity; corals, jellies, hydras; basic body plan is sac with central digestive compartment; single opening functions as both mouth and anus

Question 4

cnidaria body plan

Answer 4

sessile polyp: adhere to the substrate by the aboral end of the body, medusa: free-swimming form that has a bell-shaped body with the mouth on the underside

Question 5

cnidarians hunt

Answer 5

predators use tentacles, armed with cnidocyetes (unique cells used in defense and prey capture), nematocysts (specialized organelles within cnidocytes that eject a stinging thread

Question 6

medusozoans

Answer 6

both body plans; life cycle is dominated by diploid stage; alternates between polyp and medusa body forms; can reproduce asexually or sexually through production of medusae

Question 7

lophotrochozoa clade

Answer 7

first to be biletarian and have triploblastic development; some have lophophore for feeding, others have trochophore larval stage, some have neither

Question 8

lophotrochozoa diversity

Answer 8

18 phyla: flatworms, rotifers, acanthocephalans, ectoprocts, brachiopods, molluscs, annelids

Question 9

flatworms

Answer 9

marine, freshwater, damp, terrestrial habitats; many parasitic; dorsoventrally flattened acoelomates, gastrovascular cavity branches throughout body

Question 10

rotifera

Answer 10

tiny, inhabit freshwater, marine, and damp soil habitats; truly multicellular and have specialized organ systems; cilia draw water and food particles into mouth and food is ground up in trophi

Question 11

ectoprocts

Answer 11

lophophore (crown of ciliated tentacles around mouth), U-shaped alimentary canal, absence of distinct head, coelom; sessile colonial animals, some colonies encased in hard exoskeleton

Question 12

brachiopods

Answer 12

resemble clams and hinge-shelled molluscs, two halves of shell are dorsal and ventral, are marine and attack to seafloor by stalk

Question 13

mollusca

Answer 13

snails, slugs, oysters, clams, octopuses, squids; soft bodies surrounded by protective calcium carbonate shell

Question 14

mollusca body plan

Answer 14

3 parts; muscular foot for movement, visceral mass containing most internal organs, mantle tissue fold draping over the visceral mass that secretes the shell

Question 15

annelids

Answer 15

segmented worms, live in marine, freshwater, and damp soil habitats, coelom and range 1mm-3mm length, have segmented body plan ONLY