Chordata

Question 1

exact phylogenetic position of chordates

Answer 1

still unclear but have two possible lines of descent

Question 2

prostomia branch

Answer 2

arthropod-annelid-mollusc group

Question 3

deuterostomia branch

Answer 3

echinoderm-hemichordate group

Question 4

features (?) of chordates shared with some invertebrates

Answer 4

• bilateral symmetry
• anterioposterior axis
• coelom
• tube-within-a-tube body plan
• metamerism
• cephalization

Question 5

chordates as deuterostomes

Answer 5

• radial cleavage, anus from blastopore
• mouth from secondary opening
• coelom from enterocoelous pouches
• have fundamental unity of organs and organ systems

Question 6

hallmarks of chordates

Answer 6

• notochord
• pharyngeal pouches and slits
• dorsal tubular nerve chord
• endostyle or thyroid gland
• postanal tail

Question 7

a slender rod of cartilage-like connective tissue lying near the dorsal side and extending most of the length of the animal

Answer 7

notochord

Question 8

found in early development or throughout life

Answer 8

notochord

Question 9

stiffens the body

Answer 9

notochord

Question 10

a series of paired slits in the pharynx, serving as passageways for water to the gills

Answer 10

pharyngeal pouches and slits

Question 11

may persist or be modified to from other structures

Answer 11

pharyngeal pouches and slits

Question 12

forms the brain and spinal chord

Answer 12

dorsal tubular nerve cord

Question 13

derivative of endostyle

Answer 13

thyroid gland

Question 14

found in all chordates; secretes mucus and traps small food particles for protochordates and lamprey larvae

Answer 14

endostyle

Question 15

projects beyond the anus at some stage and serves as a means of propulsion in water

Answer 15

postanal tail

Question 16

demonstrate each of the chief chordate characteristics at some point in their life cycle

Answer 16

protochordates

Question 17

subphylums

Answer 17

• urochordata
• cephalochordata
• vertebrata

Question 18

superclasses

Answer 18

• cyclostomata
• gnathostomata

Question 19

classes under superclass cyclostomata

Answer 19

• myxini
• petromyzontida

Question 20

classes under superclass gnathostomata

Answer 20

• chondrichthyes
• actinopterygii
• sarcopterygii
• amphibia
• reptilia
• aves
• mammalia

Question 21

tail chordates, tunicates

Answer 21

subphylum urochordata

Question 22

a touch, nonliving tissue containing cellulose that surrounds tunicates

Answer 22

tunic

Question 23

tunicates are

Answer 23

marine, sessile as adults

Question 24

T or F: (tunicates) in most species, only the larval form bears all the chordate hallmarks but adults loose many of these characters and retain the notochord only in the tail region

Answer 24

true

Question 25

three classes of urochordata

Answer 25

- ascidiacea - appendicularia - thaliacea

Question 26

most common and most diverse class under urochordata that are common sea squirts

Answer 26

ascidiacea

Question 27

why are sea squirts named as such

Answer 27

they forcefully discharge water from the excurrent siphon when irritated

Question 28

forms of ascidians

Answer 28

may be solitary, colonial, or compound forms

Question 29

terminal siphon

Answer 29

incurrent or oral siphon

Question 30

outer covering of a tunicate

Answer 30

tunic or test

Question 31

tunic is secreted by what

Answer 31

the mantle

Question 32

respiratory system of sea squirts

Answer 32

branchial sac or pharynx

Question 33

space between the pharynx and the mantle

Answer 33

atrium

Question 34

reproduction of sea squirts

Answer 34

hermaphroditic

Question 35

slender, laterally compressed, translucent animals that are about 3-7 cm long

Answer 35

lancelets

Question 36

habitat of lancelets

Answer 36

sandy sediments of coastal waters around the world

Question 37

name of lancelets

Answer 37

originally had the generic name amphioxus but priority is now in the genus branchiostoma

Question 38

chordate features of amphioxus

Answer 38

- has all the chordate features but also have more that show the vertebrate body plan - hepatic cecum - trunk muscles - possess basic circulatory plan of vertebrates

Question 39

a diverticulum resembling the vertebrate pancreas in secreting digestive enzymes along with liver

Answer 39

hepatic cecum

Question 40

resemble vertebrate patterns in amphioxus

Answer 40

trunk muscles

Question 41

segmentally arranged muscles along the sides of the animal

Answer 41

chevronlike myotomes

Question 42

large chamber beneath the rostrum which is bounded laterally by fleshy, curtainlike folds and is open ventrally

Answer 42

buccal cavity

Question 43

circulatory system of amphioxus

Answer 43

they don't have a heart but peristaltic contractions of the ventral aorta keep the colorless blood in motion

Question 44

subphylum vertebrate (craniata)

Answer 44

- adaptations that guided early vertebrate evolution - larger than protochordates, more active - modification of skeletal and muscle structures - speed and mobility - structures req'd/specialized: location, survival, digestion - adaptation