Chapter 2

Question 1

one of the several animal phyla, most complex animals but not most numerous, some features shared with other related phyla (bilateral symmetry, coelum, deuterostomes)

Answer 1

phylum chordata

Question 2

fluid filled cavity in body

Answer 2

coelom (those that have these called coelomates)

Question 3

usually shows spiral cleavage, coelom formation by splitting of the mesoderm, and derivation of the mouth from the blastopore

Answer 3

protostome

Question 4

exhibit radial cleavage, coelom formation by outpocketing of the gut, and derivation of the anus from or in the vicinity of the blastopore

Answer 4

deuterostome

Question 5

dividing cells of the embryo are offset from each other

Answer 5

spiral cleavage

Question 6

dividing cells of the embryo are aligned

Answer 6

radial cleavage

Question 7

opening into the gastrulation which is when one wall of the embryo begins to indent and grow inward

Answer 7

blastopore

Question 8

central nervous system is hollow tube, neurocoele

Answer 8

dorsal tubular nerve cord

Question 9

fluid filled cavity inside

Answer 9

neurocoel

Question 10

flexible rod running along the length of the body, ventral to nerve cord

Answer 10

notochord

Question 11

part of the digestive tract located immediately posterior to the mouth, series of openings

Answer 11

pharynx

Question 12

acts as a sieve, capturing food particles, plus increasing surface area for oxygen absorption from water

Answer 12

pharyngeal slits

Question 13

where pharyngeal slits are located

Answer 13

atrium

Question 14

where atrium is able to secrete that which came from pharyngeal slits

Answer 14

atriopore

Question 15

this was able to line the pharynx helping to snatch food particles from suspended organic material

Answer 15

mucus

Question 16

this produces the water current in the pharynx and gathers the food-laden mucus to pass into the esophagus

Answer 16

ciliated cells

Question 17

tail extends beyond position of anus, important in swimming

Answer 17

post-anal tail

Question 18

myomeres are arranged sequentially along the body and tail as part of the outer body wall

Answer 18

segmentation

Question 19

blocks of muscle

Answer 19

myomeres

Question 20

chordates appeared during this period, difficult to figure out with few fossils, need to study protochordates to understand phylogeny

Answer 20

cambrian period

Question 21

sea urchin, star fish, have larvae similarity (also molecular studies) with hemichordates, also deuterostomes

Answer 21

phylum echinodermata

Question 22

acorn worms, have larvae similarity (also molecular studies) with echinodermata, have 1/2 chordate characteristics

Answer 22

phylum hemichordata

Question 23

includes cephalochordata, urochordata

Answer 23

phylum chordata

Question 24

amphioxus

Answer 24

subphylum cephalochordata

Question 25

sea squirt

Answer 25

subphylum urochordata

Question 26

fish, amphibians, reptiles, mammals, birds

Answer 26

subpylum vertebrata

Question 27

animals that show some features of the most important chordates: vertebrates. these are all marine animals that feed by filtering sea water, phylum hemichordata, subphylum cephalochordata, subphylum urochordata

Answer 27

protochordates

Question 28

hemichordata pass through a small planktonic stage called this

Answer 28

tornaria larva

Question 29

lacks notochord or post-anal tail
poorly differentiated nervous system
have pharynx with slits
larval stage very similar to echinoderms
include proboscis, collar, and trunk
some ingest sediment
some filter feed
some vessels pulsate to move blood through dorsal and ventral vessels

Answer 29

acorn worm

Question 30

wiggles and inflates to move into burrow, ciliated cells on surface move food towards mouth, also contains excretory organs and a heart

Answer 30

proboscis

Question 31

the region of hemichordate contains the mouth

Answer 31

collar

Question 32

this part of hemichordate contains pharynx (with slits), and gonads

Answer 32

trunk

Question 33

this is the last steps in acorn worms after water has passed through the pharynx, then the slits, then through one of the branchial pouches then through this

Answer 33

branchial pores

Question 34

inspired by the characteristic flexible outer body cover

Answer 34

tunicates (tunic)

Question 35

complex pharyngel slits, the stigmata, sieve the passing water before it flows from the branchial basket into this place

Answer 35

atrium

Question 36

slits in the pharynx walls proliferate and each subdivides repeatedly, producing smaller openings called this

Answer 36

stigmata

Question 37

mucus producing, mid-ventral groove

Answer 37

endostyle

Question 38

often send nerves to the rest of the body, brain, collections of neurons close to the sensory vesicle

Answer 38

cerebral ganglion

Question 39

located next to the rudimentary pharynx contains navigational equipment thought to be involved in orientating the larva during its planktonic existence

Answer 39

sensory vesicle

Question 40

capillaries end blindly, blood flow is reversible, blood not contained with vessels lined with epithelium, there are gaps where the blood can move into pockets of connective tissue or hemocoels

Answer 40

open vascular system

Question 41

all vessels completely lined with epithelial cells or endothelium, myoepithelium lines the heart, this helps contract so the blood flows easier

Answer 41

closed vascular system

Question 42

all chordate features present in adult
small, but very complex and efficient pharynx
complex mouth
intestines more complex with liver like hepatic cecum
closed vascular system
muscular beastie
more derived closed vascular system but no heart
powerful swimmer but prefers to sit in burrows and filter feed unless disturbed

Answer 42

amphioxus

Question 42

located in the pharynx, help divide the branchial bars and filter water through to catch food

Answer 42

primary and secondary bars

Question 43

encloses the anterior entrance to the pharynx and supports an assortment of food-processing equipment

Answer 43

oral hood

Question 44

prevents entrance of large particles project from the free edge of the oral hood, like a sieve

Answer 44

buccal cirri

Question 45

banks of ciliated cells that propel food into pharynx

Answer 45

wheel organ

Question 46

part of amphioxus that secretes mucus

Answer 46

hatchek’s pit

Question 47

provides a narrow opening to the pharynx

Answer 47

velum and attached tentacles

Question 48

fibrous connecting tissue support the pharyngeal bars internally

Answer 48

supportive rods

Question 49

dorsal channel in the pharynx

Answer 49

epibranchial groove

Question 50

oxygenated blood leaves from this place in amphioxus to travel to the rest of the body

Answer 50

dorsal aorta

Question 51

blood enters bars from this place in amphioxus

Answer 51

ventral aorta (endostylar artery)

Question 52

this gave the first hint of fish fins and tetrapod limbs in amphioxus

Answer 52

fins and metapleural folds

Question 53

return blood from the body, joining in pairs at the end

Answer 53

cardinal veins

Question 54

meets with cardinal veins

Answer 54

hepatic veins

Question 55

meets cardinal and hepatic veins and leads tot he endostylar artery

Answer 55

sinus venosus