Topic 26: introduction to Chordates

Question 1

Chordates

Answer 1

• bilaterian animals that belong to clade Deuterostomia

- bilaterally symmetrical coelomates with segmented bodies

Question 2

The majority (>95%) of chordate species have ______

Answer 2

vertebral columns

Question 3

Chordates consists of

Answer 3

all vertebrates and two groups of invertebrates, the

urochordates and cephalochordates

Question 4

Shared, derived traits of chordates

Answer 4

1. Notochord
2. Dorsal, hollow nerve cord
3. Pharyngeal slits or clefts
4. Muscular, post-anal tail

Question 5

Notochord

Answer 5

a longitudinal, flexible rod located dorsally between the digestive tract and nerve cord.

Question 6

The notochord provides

Answer 6

flexible skeletal support throughout most of the length of invertebrate chordates

Question 7

The notochord forms during

Answer 7

embryogenesis is when organ systems begin to develop from embryonic layers

Question 8

The notochord is present in

Answer 8

all chordate embryos and some adults

Question 9

Chordate Shared derived Traits

Answer 9

1. Notochord
2. Dorsal hollow nerve cord
3. pharyngeal slits or clefts
4. Muscular, post-anal tail

Question 10

Functions of pharyngeal clefts/slits

Answer 10

Filter-feeding and Gas exchange

Question 11

Use of muscular, post-anal tail

Answer 11

• it provides propulsive force in many aquatic chordates, i.e. fish.
• Tails act as rudders, provides balance, grip, etc.

Question 12

Most chordates have ____ body plans, at least during embryonic development

Answer 12

segmented

Question 13

Segmentally arranged muscle blocks present in all adult chordates except in the

Answer 13

Urochordata

Question 14

Muscle blocks develop from

Answer 14

blocks of mesoderm (somites) that flank the notochord (muscle blocks arranged in chevrons)

Question 15

How muscle blocks lead to swimming in marine chordates

Answer 15

Alternating muscle contractions causes notochord/ vertebral column to flex side-to-side

Question 16

Lancelets

Answer 16

named for their blade-like shape. marine sedentary suspension feeders that retain characteristics of the chordate body plan as adults.

Question 17

Tunicates

Answer 17

more closely related to vertebrates than they are to lancelets, are suspension-feeding, marine
invertebrate chordates. sessile, look like tadpoles as adults

Question 18

Tunicates

Answer 18

Adult tunicates are covered by a tough polysaccharide “tunic”, They draw water in through an incurrent siphon, filtering it through the mucus-covered pharyngeal basket that collects food particles; filtered water exits out excurrent siphon