Topic 27: clade vertebrata

Question 1

Ancestral chordates may have resembled

Answer 1

lancelets

Question 2

The same ___ genes that regulate vertebrate brain development are expressed during the development of
lancelet’s simple nerve cord tip

Answer 2

Hox

Question 3

chordates evolved into invertebrates during the:

Answer 3

Cambrian period

Question 4

Vertebrates

Answer 4

chordates that have a backbone

Question 5

_______ allowed vertebrates to become more efficient at capturing food and evading predators

Answer 5

A skeletal system and complex nervous system

Question 6

Vertebrate shared, derived traits

Answer 6

1. Vertebrates have a vertebral column (backbone)
2. Elaborate braincase enclosing brain
3. two or more sets of Hox genes
4. Neural crest cells
5. Dorsal, ventral, and anal fins stiffened by fin rays
6. Modified circulatory system

Question 7

what protects nerve cord

Answer 7

Skeletal elements (cartilage or bone) enclose and protect the nerve cord

Question 8

___ replaces the notochord

Answer 8

vertebral column

Question 9

Vertebrate brain enclosing included

Answer 9

Head consists of a brain, sense organs, including paired eyes, and a cranium (skull) without jaws

Question 10

A cranium allowed for

Answer 10

evolution of more complex nervous system to coordinate more complex movement and feeding behaviours

Question 11

vertebrate Hox genomes arose due to

Answer 11

whole-genome duplication

Question 12

Hox genes control

Answer 12

the body plan of an embryo along the head-tail axis; determine the type of segment structures that will form

Question 13

Benefit of neural crest cells

Answer 13

Neural crest cells develop along the edge of the neural tube of vertebrate embryos and eventually forming various structures, e.g. teeth, some bones/cartilage of the skull, several types of neurons (nerves)

Question 14

Fins

Answer 14

• are membrane extensions supported by cartilaginous or bony spines (rays)
• provide balance and propulsion while swimming

Question 15

Modification to the circulatory system in vertebrates

Answer 15

• closed circulatory
• heart with at least two chambers
• hemoglobin in red blood cells
• kidneys

Question 16

hagfishes and lampreys lack

Answer 16

backbone and jaw

Question 17

Chordates evolved into the

Answer 17

vertebrates

Question 18

earliest vertebrates

Answer 18

Conodonts

Question 19

vertebrates that have jaws are called

Answer 19

gnathostomes

Question 20

Shared, derived traits of gnathostomes

Answer 20

1. Opposing jaws that open/close the mouth forcefully to capture and process diverse foods
2. mineralization of the skeleton
3. two pairs of lateral appendages
4. gene duplication (incl HOX genes)
5. enlarged forebrain for smell and vision
6. lateral line system that is sensitive to vibrations

Question 21

Two pairs of _____ that had supported pharyngeal slits were modified to pump water over the gills by opening and
closing the mouth more effectively

Answer 21

skeletal rods

Question 22

Posterior pharyngeal rods evolved to

Answer 22

specialized supports for gas exchange (gill slits)

Question 23

Mineralization with calcium phosphate appears to have originated with ______

Answer 23

vertebrate mouthparts

Question 24

were first vertebrates with mineralized skeletal elements in their mouth and pharynx

Answer 24

Conodonts

Question 25

Natural selection for mineralization of mouthparts would have led to selection for ______

Answer 25

stronger and tougher mechanism for opening

and closing the mouth, i.e. true opposing jaws

Question 26

Two types of bones

Answer 26

1. Endoskeleton is derived from preformed cartilage

2. Dermal skeletons are bony structures derived from intramembranous ossification

Question 27

How gnathostomes get bony

Answer 27

cartilage becomes ossified (bony) with calcium phosphate as the embryo develops.

Question 28

Cartilage

Answer 28

a “flexible connective tissue with an abundance of collagenous fibers embedded in chondroitin sulfate”

Question 29

placoderms

Answer 29

an extinct lineage of armored vertebrate fish that are the earliest gnathostomes fossils

Question 30

Three lineages of extant gnathostomes

Answer 30

chondrichthyans, ray-finned fishes, and lobe-fins

Question 31

Chondrichthyans

Answer 31

cartilaginous fish (Endoskeleton of cartilage, but have bony teeth and bony placoid (pointed, tooth-shaped) scales)