Chapter 1

Question 1

Chordates have a fluid-filled internal body cavity termed a ———-

Answer 1

coelom

Question 2

Among these coelomate animals, 2 apparently distinct and independent evolutionary lines are present. what are these two lines and how do they differ?

Answer 2

1. Protosomes:a multicellular organism whose mouth develops from a primary embryonic opening this includes mollusks, annelids and arthropods.
2. Deuterostomes: includes echinoderms, hemichordates and chordates and this means the mouth forms opposite to the blastopore.

Question 3

2 of the 3 chordate sub-phyla are technically ————

Answer 3

invertebrates (cephalochordata and urochordata)

Question 4

what are the 3 subtaxas in chordates?

Answer 4

1. cephalachordata
2. urochordata
3. vertebrata

Question 5

Most vertebrates have an endoskeleton which is defined as….

Answer 5

a system of rigid internal elements of bone or cartilage beneath the skin. It helps in locomotion, support and protection of delicate organs.

Question 6

are any cephalochordates or urochordates terrestrial?

Answer 6

NO, all marine!

Question 7

how do most cephalochordates and urochordates eat?

Answer 7

usually suspension feeders, using a sticky sheet of mucus to collect food from streams of water passing over a filtering apparatus.

Question 8

what are the 5 characteristis that help diagnose chordates?

Answer 8

1. Notochord
2. Endostyle or thyroid gland
3. Postanal tail
4. Dorsal and tubular nerve cord
5. Pharyngeal slits

Question 9

the pharynx is part of what?

Answer 9

the digestive tract

Question 10

The pharyngeal slits allowed what for the flow of water?

Answer 10

they allowed the one way flow of a water current: in at the mouth and out through the pharyngeal slits.

Question 11

when the pharyngeal slits became associated with gills, they not only aided with food but what?

Answer 11

the passing stream of water also participated in respiratory exchange with the blood circulating in the capillary beds of these gills.

Question 12

The current of water can thus simultaneously support ——- and ——— activities

Answer 12

feeding and respiratory

Question 13

In primitive chordates, the pharynx itself is often expanded into what?

Answer 13

a pharyngeal or branchial basket. This can increase the surface area exposed to the passing current of water.

Question 14

Suspension feedrs use a combination of what two things to effectively gather food?

Answer 14

cilia and mucus. The cilia gather the food-laden mucus and pass it into the esophagus.

Question 15

Notochord:

Answer 15

is a slender rod that lies dorsal to the coelom but beneath and parallel with the central nervous system. It prevents longitudinal collapse of the body during locomotion

Question 16

Thyroid and endostyle is involved in what?

Answer 16

iodine metabolism

Question 17

the —— is the predescessor to the ———

Answer 17

endostyle/ thyroid

Question 18

Dorsal and tubular nerve cord:

Answer 18

the nerve cord in chordates lies above the gut and is hollow along its entire length.

Question 19

the major nerve cord in most invertebrates is where?

Answer 19

ventral in position, below the gut and solid

Question 20

a postanal tail provides what for a chordate?

Answer 20

an increased surface area important for thrust and maneuverability in an aquatic environment

Question 21

chordates have what kind of symmetry?

Answer 21

bilateral