Exam 6 Material (Chordata: Part of Deuterostome Group)

Question 1

Does Chordata have an open or closed circulatory system?

Answer 1

They have a closed circulatory system

Question 2

Where is the heart located in Chordata?

Answer 2

The heart is ventrally located

Question 3

What kind of skeleton does Chordata have?

Answer 3

They have an endoskeleton

Question 4

What type of body does Chordata have?

Answer 4

They have a segmented body

Question 5

What feature is no longer a synapomorphy for the Chordates?

Answer 5

The pharyngeal slits (we have learned that extinct Echinoderms had them and Hemochordates are not in the same class as Chordates)

Question 6

What features are being described (present in Chordates)?:
- Notochord
- Tubular nerve cord
-Postanal tail
- Endostyle

Answer 6

Synapomorphies for Chordates

Question 7

What is being described?:
- A synapomorphy for Chordates
- A firm/flexible rod of cartilage and its dorsal longitudinal rod
- Runs along the dorsal side of the body
- Its role is to support the body
- Muscles attach to it so when they contract, they’ve got something to pull on

Answer 7

Notochord

Question 8

What is being described?:
- A synapomorphy for Chordates
- Is dorsal
- Everyone else has solid nerve cords
- Is a single nerve cord
- Not a pair like everyone else’s

Answer 8

Tubular nerve cord

Question 9

What is being described?:
- A synapomorphy for Chordates
- Sometimes called muscular postanal tail
- tail extends posteriorly to the anus
- Have muscular segments, not just cartilage

Answer 9

Postanal tail

Question 10

What is being described?:
- A synapomorphy for Chordates
- lies on the floor of the pharynx/ventral portion
- is a groove in the floor of the pharynx that is lined with mucus and traps food
- however, in the Chordates, the thyroid came from this

Answer 10

Endostyle

Question 11

Which group of Chrodates has been recently shifted (no longer placed farther away from the vertebrates on the phylogeny than it is now) (is now sister taxa to vertebrates) and includes the sea squirts?

Answer 11

Urochordates

Question 12

Is Urochordata motile or sessile as larvae?

Answer 12

They are motile as larvae

Question 13

Is Urochordata motile or sessile as adults?

Answer 13

They are sessile as adults

Question 14

What is being described (about Urochordata)?:
- Their _______ has all of the Chordate synapomorphies, but when they become adults, they attach to a surface w/ adhesive papilla and they smooch down/the tail gets absorbed along w/ the notochord and nerve cord leaving just the incurrent and excurrent siphons
- We still have pharyngeal slits and endostyle
- Will take water in through the incurrent siphon, pass it through the pharyngeal slits, w/ the endostyle catching the food and they will send the water out into the atrium and then out the excurrent siphon and since the anus is right by the excurrent siphon, waste leaves as well

Answer 14

What makes Urochodata’s larvae unique

Question 15

What kind of feeders are Urochordates?

Answer 15

They are suspension feeders (will remove any food that travels through the pharynx)

Question 16

What are Urochordates (reproductively)?

Answer 16

They are hermaphroditic and can be colonial/living together by sharing a tunic (or reproducing through budding)

Question 17

Do Urochordates have a neural crest?

Answer 17

Yes, they do

Question 18

What is being described (present in Urochordates)?:
- Special cells during embryological development that migrates to other parts of the body and act in ways that you’d expect)
- Presence of this is why Urochordates are sister taxa to the Vertebrates)

Answer 18

Neural crest

Question 19

Which group of Chrodates are referred to as lancelets?

Answer 19

Cephalochordates

Question 20

What is special about the notochord of cephalochordates?

Answer 20

Their notochord runs all the way to the tip of their head

Question 21

What does the name Cephalochordates mean?

Answer 21

The name means “head cord”

Question 22

What features do Cephalochordates not have?

Answer 22

• Paired fins (only have single ones on the center of their body)
• Sensory organs
• A heart
• Well-developed head
• A brain

Question 23

What makes the nerve cord of Cephalochordates unique?

Answer 23

They have specialized parts of the nerve cord (homologous to the separated areas of the vertebrate brain)

Question 24

What do Cephalochordates have despite not having a heart?

Answer 24

They have circulation (is ventrally located and goes anterior)