Topic 22 Lophotrochozoa

Question 1

Mesoderm forms

Answer 1

muscles and most internal organs

Question 2

Most animals are ___ symmetrical - clade ____

Answer 2

bilaterally, Bilateria

Question 3

Most bilaterians have a coelom and a digestive track with __ openings

Answer 3

two

Question 4

Bilaterians are strongly differentiated along _____ axis

Answer 4

anterior-posterior

Question 5

Bilaterians have varying degrees of _____ (differentiation of head region)

Answer 5

cephalization

Question 6

basal phylum of bilaterians

Answer 6

acoela

Question 7

Phylum Acoela characteristics

Answer 7

flattened body,no brain or body cavity, have a mouth

Question 8

Clade lophotorochozoa

Answer 8

clade defined by molecular phylogeny, and include: flatworms, annelids, etc

Question 9

Phylum Platyhelminthes

Answer 9

known as free-living phabditophora, live in fresh-water and prey on smaller animals, one opening for mouth (spit food back out after eating), can reproduce sexually or asexually

Question 10

parasitic rhabditophorans include

Answer 10

trematodes and tapeworms (lack digestive system and absorb nutrients from host)

Question 11

Tapeworm body components

Answer 11

scolex (suckers and hooks for attaching to host) and segments that contain sex organs (proglottids)

Question 12

Phylum rotifera

Answer 12

tiny animals that inhibit fresh and marine waters

Question 13

Rotifers charachteritics

Answer 13

reproduce sexually and asexually, feed on microorganisms suspended in water, and have a complete digestive track

Question 14

Ectoprocts and Brachiopods have

Answer 14

a fan of ciliated tentacles surrounding mouth, coelom, aquatic organisms, sessile

Question 15

Ectoprocts

Answer 15

sessile colonial animals, most enclosed in a hard exoskeleton, suspension feeders using a retractable lophophore

Question 16

Brachiopods

Answer 16

suspension feeders using paired lophophores, most attach to the seafloor, have a complete gus + anal opening

Question 17

Trochozoa includes:

Answer 17

Annelida, Mollusca (snails, squid, clams)

Question 18

Trochozoans share patterns of

Answer 18

early embryonic development, including a microscopic motile trochophore larvae

Question 19

Trochozoans cilia

Answer 19

cilia control movement (swimming) and bring food towards the mouth, cilia bands is a sensory plate

Question 20

Phylum Mollusca includes:

Answer 20

slugs, oysters, and clams, octopus, and squids

Question 21

Mollusks are soft-bodied but are protected by s

Answer 21

hard shell

Question 22

Mollusc body plan main parts

Answer 22

muscular ventral foot used for movement, visceral mass above the foot that contains internal organs, a mantle ( thin layer of tissue that secreted the shell), it is NOT segmented

Question 23

Characteristics of mollusca

Answer 23

gills (within mantle cavity used for gas exchange), feeding using rasp-like radula, have an open circulatory system, most have separate sexes, life cycle includes a ciliated trochophore larval stage

Question 24

4 major classes of molluscs

Answer 24

polyplacophora, gastropoda, bivalvia, cephalopoda

Question 25

Phylum Annelida

Answer 25

segmented worms (repeated units of internal/external anatomy separated by septa)

Question 26

Two major clades of annalids

Answer 26

errantia and sedentaria

Question 27

Annelids Characteristics

Answer 27

segmented bodies: many repeated units separated by internal portions called septa
coelom: body cavity lined with tissue and is fluid filled cavity which functions as a hydrostatic skeleton
cephalization: well developed mouth and brain
closed circulatory system (blood in vessels)