Chordates I (Tunicates, lancelets, and fish)

Question 1

What are the characteristics of Phylum Chordata?

Answer 1

1) Notochord
2) Pharyngeal gill slits
3) Dorsal Hollow Nerve Cord
4) Post-anal tail
5) Endostyle

Question 2

What kind of embryological developmental pattern does Phylum Chordata undergo?

Answer 2

Deuterostome

Question 3

What period did Chordates originate? When did they undergo rapid diversification?

Answer 3

Originated during the Precambrian period and diversified during the Paleozoic.

Question 4

Are chordate body plans constrained?

Answer 4

No, least constraint of body plan = amazing diversity

Question 5

What two invertebrate subphyla are included in Phylum Chordata?

Answer 5

Cephalochordata and Urochordata

Question 6

What is the Notochord?

Answer 6

Works a endoskeleton for early muscles

-lost or replaced in some

Question 7

What is the Hollow dorsal nerve cord?

Answer 7

Controls muscles, including brain (CNS)

-lost or replaced in Urochordates

Question 8

What is the Pharyngeal gill slits (pouches)?

Answer 8

• Open to outside
• Used for respiration and feeding
• Become other structures in vertebrates

Question 9

What is the endostyle?

Answer 9

• Thyroid Gland in vertebrates

- generates mucus for feeding

Question 10

What is the post anal tail?

Answer 10

Synapomorphic feature in Chordates

• Propulsion, often with fins
• Vestifial trait in humans (coccyx)

Question 11

What are the defining features of Phylum Chordata, Subphylum Cephalochordata?

Answer 11

Lancelets or “amphioxus”

• All 5 chordate features present
• Segmental muscles called myomeres
• Filter-feeders by passing water over pharyngeal gill slits covered in mucus

Question 12

What is the body plan of Phylum Chordata, Subphylum Cephalochordata?

Answer 12

Filter feed with mucus sheet on pharyngeal gill slits (not for respiration)

• H2O is sucked through oral cirri
• food caught is sent to gut for digestion
• Water exits through atriopore

Closed Blood Vascular System

• No heart - peristalsis of vessels
• No blood pigments or cells

Question 13

How do Phylum Chordata, Subphylum Cephalochordata reproduce?

Answer 13

External Fertilization with Simple Gonads

-Gametes shed directly into atrium and out atriopore

Question 14

What is significant about Phylum Chordata, Subphylum Urochordata?

Answer 14

Loss of adult chordate features

Greater adaptation toward filter-feeding

Question 15

What are the classes of Phylum Chordata, Subphylum Urochordata?

Answer 15

Class Ascidiacea - Benthic sea squirts
Class Thaliacea - Pelagic (drifter-planktonic)
Class Appendicularia (larvacea) - pelagic

Question 16

What are the characteristics of Phylum Chordata, Subphylum Urochordata, Class Ascidiacea?

Answer 16

• Solitary and Colonial.
• Tadpole larvae have all 5 Characteristics but adult only have 2 (endostyle and pharyngeal gill slits)
• Feed like Cephalochordates
• No respiratory/excretory organs b/c it takes in so much water it accomplishes this through diffusion

Question 17

Why is Phylum Chordata, Subphylum Urochordata, Class Ascidiacea important to humans?

Answer 17

They make unusual secondary metabolites so they are used in marine pharmocology

Question 18

What are the characteristics of Phylum Chordata, Subphylum Urochordata, Class Thaliacea?

Answer 18

• Solitary and Colonial

- Take to open ocean by drifting (planktonic)

Question 19

What are the characteristics of Phylum Chordata, Subphylum Urochordata, Class Appendicularia?

Answer 19

Pelagic and retain all 5 chordate features

• Makes up to 16 mucus houses per day (external struc)
• Abandoned houses source of “marine snow”
• Developing eggs fatally rupture body

Question 20

What is significant about the mucus houses that What are the characteristics of Phylum Chordata, Subphylum Urochordata, Class Appendicularia make?

Answer 20

They are carbon sponges that draw carbon out of atmosphere and soak it up

Question 21

What are the characteristics of Phylum Chordata, Subphylum Vertebrata=Craniata?

Answer 21

• Vertebral Column
• Cranium
• Endoskeleton
• Neural Crest

Question 22

What is the vertebral column in Phylum Chordata, Subphylum Vertebrata=Craniata?

Answer 22

notochord is replaced by column of interlocking vertebrae

Question 23

What is the cranium in Phylum Chordata, Subphylum Vertebrata=Craniata?

Answer 23

Protective housing around brain

Question 24

What is the endoskeleton of Phylum Chordata, Subphylum Vertebrata=Craniata?

Answer 24

Grows with body; First cartilage then bone

Question 25

What is the neural crest of Phylum Chordata, Subphylum Vertebrata=Craniata?

Answer 25

Embryonic cells, contribute to development of the cranium

Question 26

What are the five extant classes of the paraphyletic group of fish in Phylum Chordata, Subphylum Vertebrata=Craniata?

Answer 26

1) Myxini - hagfishes 2) Petromyzontida - lampreys 3) Chondrichthyes - sharks, skates, rays 4) Actinopterygii - ray-finned fishes 5) Sarcopterygii - lobe-finned fishes

Question 27

What is the evolutionary progression of the endoskeleton in fishes?

Answer 27

Notochord to vertebral column | -cartilage to bone

Question 28

What is the evolutionary progression of the Pharynx in fishes?

Answer 28

Pharyngeal gill slits to gills | -greater respiratory capacity

Question 29

What is the evolutionary progression of the Nervous System in fishes?

Answer 29

greater development of senses and brain

Question 30

What is the evolutionary progression of the Appendages in fishes?

Answer 30

greater development of paired pectoral and pelvic fins

Question 31

What is the evolutionary progression of the Jaws in fishes?

Answer 31

modified cartilaginous gill arches derived from neural crest cells with jaw muscles from gills

Question 32

How did gill arches in primitive jawless fish evolve in early jawed fishes to result in modern jawed fish?

Answer 32

From 9 gill arches in primitive jawless fish to Gill arches 1 and 2 lost and gill arch 3 modified to form hinged jaw in earlier extinct jawed fishes Gill arch 4 modified to form heavier more efficient jaw in modern jawed fishes

Question 33

What are the characteristics of the Phylum Chordata, Subphylum Vertebrata, Class Myxini (hagfish)?

Answer 33

Lack JAWS, scales, paired fins, bone Scavengers Keratin teeth on tongue used for rasping food Slime glands make sheet of mucus

Question 34

What are the characteristics of the Phylum Chordata, Subphylum Vertebrata, Class Petromyzontida (lampreys)?

Answer 34

Lack JAWS, scales, paired fins, bone Keratin teeth around sucker-like mouth may be used to parasatize -not all are parasites Life cycle involves ammocoetes larva that filter-feeds like cephalochordate but respire with gills

Question 35

What are the characteristics of the Phylum Chordata, Subphylum Vertebrata, Class Chondrichthyes (sharks, skates, rays)?

Answer 35

Has JAWS, paired pelvic and pectoral FINS, PLACOID SCALES adapted to form teeth Cartilaginous skeleton - lighter than bone to maintain position in water Osmoregulation requires copulation and shelled eggs No swim bladder, exposed gills, and heterocercal caudal fin

Question 36

What are the characteristics of the Phylum Chordata, Subphylum Vertebrata, Class Actinopterygii (ray-finned fish)?

Answer 36

Has JAWS, paired pelvic and pectoral FINS, lightweight cycloid, ctenoid or ganoid scales Bony skeleton, gills covered by bony operculum, and homocercal caudal fin Swim bladder may be present Osmoregulation permits free-spawning and planktonic development

Question 37

What are the characteristics of the Phylum Chordata, Subphylum Vertebrata, Class Sarcopterygii (lobe-finned fish)?

Answer 37

Has JAWS, paired pelvic and pectoral fins, heavy enameled scales Bony skeleton, gills covered by bony operculum, Diphycercal caudal fin Swim bladder acts as a lung in lungfish Strong, fleshy lobed-fins = lineage gave rise to tetrapod All predatory

Question 38

What fish is a ''living fossil''?

Answer 38

Coelocanth, a mesozoic relect belongs to class sarcopterygii