Lab Exam - Definitions

Question 1

Oral hood

Answer 1

Opening at the anterior end of the body for food (amphioxus)

Question 2

Tentacles (Amphioxus)

Answer 2

Cilia lining the opening of the oral hood

Question 3

Notochord

Answer 3

Cartilaginous rod running down the dorsal side of the body

Goes to the tip of the head in amphioxus

Question 4

Dorsal nerve cord

Answer 4

Runs dorsal to the notochord, is what will become the spinal cord in later taxa

Question 5

Pharyngeal bars

Answer 5

pharyngeal slits

Run along the lateral sides of the body (anterior portion)

Question 6

Gonad - amphioxus

Answer 6

Present as little “balls” below the pharyngeal slits

Question 7

Incurrent and excurrent siphons

Answer 7

Water enters through the incurrent siphon (closest to substrate) and moves through the gut, removing food. Water is then expelled through the excurrent siphon

Question 8

Anterior attachment gland

Answer 8

Urochordata

Is the location where the larva attaches to the substrate before undergoing metamorphosis into an adult

Question 9

Placoid scales

Answer 9

Tooth-like in structure

Pulp covered by dentine and reinforced with enamel at the tip

Question 10

Spiracle

Answer 10

Small opening behind the eye that opens to the mouth

Functions similarly to gills in basal vertebrates (i.e. no gill arches)

Question 11

Lateral line

Answer 11

Canals running under the skin that are lined with sensory cells; run down the sides of fish and in complicated patterns on head and snout

Connected to the surface through pores

Detect minute movements in the water

Question 12

Ampullae of Lorenzi

Answer 12

Pores on the head that are used to detect electromagnetic fields

Question 13

Heterocercal

Answer 13

One lobe on the tail is longer than the other

Asymmetrical caudal fin

Question 14

Homocercal

Answer 14

Both lobes on the tail are the same size

Symmetrical caudal fin

Question 15

Ctenoid scales

Answer 15

Rounded and serrated along the exposed edge

Question 16

Cycloid scales

Answer 16

Rounded and smooth along the exposed edge

Question 17

Costal grooves

Answer 17

“Ribbing” along the body

Each groove marks the position of an internal rib

Question 18

Naso-labial groove

Answer 18

Groove that runs from the nostril to the upper lip that is lined with glands

Enhances chemoreception

Question 19

Tympanum

Answer 19

Membrane that is stretched across a cartilaginous ring behind the eye

Question 20

Parotoid gland

Answer 20

Bean-shaped gland behind the eye and tympanum

Only present in toads

Question 21

Annuli

Answer 21

Ringlike folds/segments in the skin

Give a segmented, worm-like appearance

Each is associated with one vertebra

Question 22

Tentacles (caecilians)

Answer 22

Sensory organs that emerge from grooves on either side of the head; little nubs

Used to detect chemical cues

Question 23

Carapace

Answer 23

Upper shell

Consists of up to 50 bony plates
- Vertebrae, ribs, and limb girdles are all fused to these

Question 24

Plastron

Answer 24

Lower shell

Question 25

Bridge

Answer 25

Connects the carapace and plastron on each side of the body

Question 26

Scutes

Answer 26

Modified scales that cover the carapace and plastron Seams between scutes are offset from sutures between bones, increasing strength

Question 27

Dewlap

Answer 27

Colourful projection of skin under the chin

Question 28

Subdigital lamellae (scansors)

Answer 28

Pads on the feet that allow geckos to climb smooth surfaces

Question 29

Tubercles

Answer 29

Raised bumps, usually on the dorsal surface Used to assist in camouflage by breaking up the pattern on the lizard's back; defense against predators

Question 30

Loreal pits

Answer 30

Small depressions between the eyes and nostrils

Question 31

Antorbital fenestrae

Answer 31

Holes in front of the eye socket on each side of the snout

Question 32

Temporal fenestrae

Answer 32

Two holes on either side of the skull behind the eye Upper and lower temporal fenestrae on each side

Question 33

Nares

Answer 33

Holes at the end of the snout

Question 34

Secondary palate

Answer 34

If complete, the entire roof of the mouth is bony

Question 35

Palatal valve

Answer 35

Large fleshy flap on the back of the tongue and secondary palate Seals off the throat

Question 36

Osteoderms

Answer 36

Bony plates that are embedded within the dermal layer of skin in crocodylians

Question 37

Dome pressure receptors

Answer 37

Brownish dots along the jaws in crocodilians Detect pressure waves in water and allow for the detection of minute movements

Question 38

Tail walking

Answer 38

Starting from stationary, the crocodile used sinusoidal undulations of the tail to push itself out of the water

Question 39

Synsacrum

Answer 39

Fusion of the caudal vertebrae and pelvic girdle

Question 40

Pygostyle

Answer 40

Fusion of the terminal caudal vertebrae for the attachment of tail feathers

Question 41

Pneumatic bones

Answer 41

Bones that contain hollow cells full of air

Question 42

Rhamphotheca

Answer 42

Keratinized epidermis that covers the jaw bones of a bird

Question 43

Ansiodactyl

Answer 43

Reversed hallux Three forward toes Used for perching

Question 44

Zygodactyl

Answer 44

Reversed hallux and 4th toe Other two toes in front Used for climbing

Question 45

Totipalmate

Answer 45

All four toes face forward Webbing between all four toes Used for swimming

Question 46

Palmate

Answer 46

Reversed hallux Webbing between three forward-facing toes Used for swimming

Question 47

Raptorial

Answer 47

All four toes forward-facing Toes deeply cleft Talons Used for grasping

Question 48

Lobate

Answer 48

Reversed hallux Lateral lobes along three forward-facing toes Used for swimming

Question 49

Hemipenes

Answer 49

Two penises Groove transports sperm during copulation Often supported by hemibacula

Question 50

Hemibacula

Answer 50

penis bones