Lecture 4

Question 1

neural crest cells

Answer 1

a group of cells that split from the nerve cord

Question 2

neural crest cells are ectodermal, meaning

Answer 2

they come from the outermost layer of the developing embryo

Question 3

neural crest cells spread all over and give rise to

Answer 3

give rise to cranial nerves, meninges of the brain, the braincase, and gill bars (and in vertebrates the membrane bones of the skull, jaws, and body armor as well as the odontoblasts that form dentine teeth)

Question 4

sensory placodes

Answer 4

the unique tissue to craniates that forms the lens of the eye, nose, and lateral line in fish and larval amphibians

Question 5

forebrain

Answer 5

integrates olfactory info

Question 6

midbrain

Answer 6

processes visual info

Question 7

hindbrain

Answer 7

related to hearing and the lateral line pressure sensing system

Question 8

craniates introduced a closed

Answer 8

circulatory system

Question 9

braincase

Answer 9

protective cranium of cartilage (and later bone)

Question 10

pharyngeal bars evolve into ___________ in craniates

Answer 10

gills

Question 11

gills are made up of

Answer 11

cartilage

Question 12

craniates also developed gut tube

Answer 12

muscularization

Question 13

craniates introduce true

Answer 13

blood with hemoglobin (respiratory pigment)

Question 14

coelom

Answer 14

cuts down abrasion

Question 15

primitively there was the

Answer 15

pericardial cavity for the heart and the peritoneal cavity for digestive organs

Question 16

typical vertebrate consists of

Answer 16

centrum, dorsal neural arch, ventral hemal (= haemal) arch

Question 17

the first vertebrate only consisted of

Answer 17

arch elements

Question 18

arch elements provided

Answer 18

muscle attachment sites and protection for the spinal cord and caudal blood vessels

Question 19

vertebrates have two or more

Answer 19

circular canals

Question 20

circular canals are important for

Answer 20

roll, pitch, and yaw

Question 21

vertebrates got radial

Answer 21

fin muscles for better control of fin movements

Question 22

vertebrates appeared about

Answer 22

544 million years ago

Question 23

the first vertebrates were all

Answer 23

equatorial and marine

Question 24

first vertebrates were _______ sized

Answer 24

minnow

Question 25

first vertebrates had bony

Answer 25

cosmoid armor

Question 26

Cosmoid armor was four-layered,

Answer 26

enameloid, over dentine, over aceullular-cancellous bone, over acellular-avascular bone

Question 27

acellular bone cannot be

Answer 27

remodeled internally (so it cannot repair injury, release minerals, or change shape)

Question 28

vertebrates had small and often

Answer 28

hypocercal tails (horizontal instead of vertical tails

Question 29

when you see a hypocercal tail thing a creature that’s trying to

Answer 29

push itself to the bottom of the seafloor

Question 30

lampreys are from a

Answer 30

semi-derived lineage that gives us an idea of the soft tissue; their sister clade has small plates

Question 31

lampreys retained a

Answer 31

prominent notochord and a vertebra consisting of cartilaginous neural and hemal arches

Question 32

Osteostracans

Answer 32

first to show cellular bone in their armor, allowing for larger size and more pelagic habits

Question 33

osteostracans were the first vertebrates to get

Answer 33

lateral fins only in the pectoral region

Question 34

lateral fins of osteostracans were

Answer 34

NOT supported internally by bone

Question 35

osteostracans had an

Answer 35

upturned heterocercal tail (they were swimming around)

Question 36

ostestracans mouths were lined with

Answer 36

tiny armor plates that served as a precursor to teeth

Question 37

Gnathostomes had the first

Answer 37

pelvic fins supported by internal cartilaginous skeleton

Question 38

gnathostomes got to have three

Answer 38

semicircular canals

Question 39

at the point of gnathostomes, vertebrates become

Answer 39

primary predators of their environment

Question 40

Gnathostomes were the first to develop

Answer 40

jaws which let them eat large prey

Question 41

jaws originate from an

Answer 41

anterior visceral ‘gill’ arch

Question 42

elasmobranchomorpha

Answer 42

the first major clade of gnathostomes

Question 43

Chondrichthyes have

Answer 43

fin rays called ceratotrichia

Question 44

Chondrichthyes also have unique

Answer 44

placoid scales that are usually pointed or conical