chordates

Question 1

tow character states chordates have that are nit synapomorphies are?

Answer 1

bilateral symmetry and segmentation

Question 2

the phylum chordata has four synapomorphies (shared derived characteristics), what are they?

Answer 2

1. notochords
2. dorsal, hollow nerve cord
3. pharyngeal clefts
4. muscular, post-anal tail

Question 3

what is the notochord?

Answer 3

a flexible rod located dorsally between the digestive tube and the nerve cord that provides structural support and allows for muscle attachment

Question 4

what is a chordata’s notochord made out of?

Answer 4

cartilage

Question 5

how does the hollow nerve cord develop?

Answer 5

from the neural plate of the ectoderm

Question 6

what does the chordates nerve cord turn into among vertebrates?

Answer 6

brain tissue, nervous tissue and spinal cord

Question 7

in most chordates, the pharyngeal clefts turn into?

Answer 7

pharyngeal slits

Question 8

what purpose does the pharyngeal cleft serve?

Answer 8

allows water entering the mouth to exit without continuing through the entire digestive tract

Question 9

what do the chordates pharyngeal slits turn into for vertebrates?

Answer 9

gas exchange/breathing

Question 10

in terrestrial vertebrates, the pharyngeal cleft does not turn into slits! what does it turn into?

Answer 10

jaw support and parts of the ear

Question 11

what is the function of chordates having a post-anal tail?

Answer 11

provides propulsive forces in swimming and for balance as a rudder

Question 12

the first group to diverge from the chordates is called the?

Answer 12

cephalochordata (lancelets)

Question 13

what are some characteristics of landcelets?

Answer 13

segmented
minimal cephalization
sedentary suspension feeders
breathe through the surface of their body wall

Question 14

what are hox genes?

Answer 14

a highly conserved (relatively unchanged) nucleotide sequence to has regulatory genes!

Question 15

what are regulatory genes?

Answer 15

proteins that turn other genes on or off; they determine what genes to express

Question 16

what did lancelets help scientists discover?

Answer 16

lancelets do not have a well-developed brain, but they have the same genes you would see in the brain of a well-developed vertebrate, meaning that the brain evolved from something similar to a lancelets simple notochord

Question 17

following cephalochordata came..?

Answer 17

urochordata (tunicates)

Question 18

in urochordata’s larval stage, they possess?

Answer 18

all four synapomorphies

Question 19

tunicates undergo metamorphosis, meaning?

Answer 19

chordate characters begin to disappear

Question 20

tunicates notochord is a ______________ characteristic?

Answer 20

homologous

Question 21

chordates subphylum vertebrata posses what new structure?

Answer 21

vertebral column (backbone)

Question 22

what is the vertebrata’s backbone replacing?

Answer 22

the function of the notochord

Question 23

what does the backbone provide vertebrates with?

Answer 23

rigidity and attachment site for muscles and other skeletal elements, can grow against gravity, strength

Question 24

chordates subphylum vertebrata also has hox gene duplication. what does this allow chordates to have?

Answer 24

more complex body structures

Question 25

how many sets of hox genes are in hox gene duplication?

Answer 25

two or more

Question 26

what two groups make up our jawless vertebrates?

Answer 26

hagfish and lampreys

Question 27

what are some characteristics of the class myxini (hagfish)?

Answer 27

1. skull and cranium composed of cartilage
2. notochord
3. tiny eyes that lack lenses
4. protection by exuding slime from glands on the sides of their bodies. when it interacts with water, it expands

Question 28

what are some characteristics of the class petromyzontida (lampreys)

Answer 28

1. sucker like mouth with hooks
2. single lens eyes
3. skeleton is made of cartilage that is not mineralized
4. skulls are incomplete but made of cartilage
5. notochord is surrounded by a cartilaginous tube that partially encloses the nerve chord

Question 29

what phylum includes fish with jaws?

Answer 29

gnathostomes

Question 30

gnathostomes have two pairs of?

Answer 30

limbs or fins

Question 31

gnathostomes had further duplication of ___ ______ which added?

Answer 31

hox genes which added genetic diversity

Question 32

what traits did the duplication of hox genes allow in gnathostomes?

Answer 32

sensory characteristics, larger brains, jaws, vision, smell

Question 33

how did jaws evolve?

Answer 33

modifications of two pairs of skeletal rods that had supported pharyngeal slits (skeletal rods began to move forward which allowed them to become larger and form into the jaw)

Question 34

what did gnathostomes have some of their posterior slits specialized for?

Answer 34

gas exchange (gill slits)

Question 35

the class chondrichthyes were some of the first early jawed fish; this included animals such as?

Answer 35

sharks, rays and chimeras

Question 36

chondrichthyes had an ___________ made of cartilage and ____ teeth

Answer 36

endoskeleton, bony

Question 37

chondrichthyes cartilaginous skeleton what what kind of character state?

Answer 37

derived!

Question 38

development of most vertebrates occurs when..?

Answer 38

the skeleton is first cartilaginous and then becomes ossified (bony)

Question 39

does all cartilage in chondrichthyes become ossified?

Answer 39

no!

Question 40

what is the function of sharks, rays and chimeras nostrils?

Answer 40

only for smelling and capturing scent, not breathing

Question 41

through chonrichthyes pores around their head, they are able to detect?

Answer 41

electrical signals emitted by their surroundings that are generated by muscular movement of other animals

Question 42

sharks, rays and chimeras are able to detect vibrations in the water due to their?

Answer 42

lateral line

Question 43

how do sharks reproduce?

Answer 43

sperm transfers through copulation (internal fertilization)