Sensory adaptations exotics

Question 1

Explain significance of infrared sensors in snakes

Answer 1

Enables snakes to see infrared
Detect prey
Pinpoint where to strike

Question 2

Vomeronasal (jacobson’s) organ structure

Answer 2

Found in nasal cavity
Responsible for detecting odors
Contains pair of small tubular structures lined with sensory epithelium
Sensory epithelium contains vomeronasal receptor neurons that detect and respond to pheromones

Question 3

Describe fish eye anatomy

Answer 3

Huge variation
Most can see color and some see UV light
Fish don’t have lacrimal glands and an immovable iris
Light is focused by changing position of lens in relation to retina

Question 4

Describe reptilian/avian eyelid

Answer 4

Have nictitating membrane (third eyelid) and a mobile lower lid

Question 5

What are scleral ossicles

Answer 5

Birds & reptiles
Bones within sclera
Protection & support
Aid function of ciliary muscles

Question 6

Describe fovea in reptiles

Answer 6

2 foveas
Allow for wide, binocular field of view and sharp vision

Question 7

Describe the avian eye

Answer 7

Large in relation to socket (exophthalmic)
No tapetum lucidum
Avascular retina (less light scatter from blood vessels, higher visual acuity)
Highly vascularised pecten (nutritive role)

Question 8

What are spectacles

Answer 8

Snakes & some lizards
Fused transparent eyelids
Shed during ecdysis (color change)

Question 9

Describe reptile ears

Answer 9

External ear absent/diminished in most species (except crocodiles)
Tympanum absent in some species

Question 10

Describe hearing in birds and reptiles

Answer 10

Much simpler
1 auditory ossicle
cochlea not coiled = poor hearing

Question 11

Describe hearing in snakes

Answer 11

No tympanic membrane
Quadrate bone for jaw flexibility and connects stapes to oval window of cochlea
Can hear low frequencies

Question 12

Describe avian ears

Answer 12

No pinna
Can have ear lobes
Some birds have operculum
2 tympanic membranes
Short external auditory meatus
1 auditory ossicle

Question 13

Describe fish hearing

Answer 13

Auditory system - otolithic inner ear
Mechanosensory system - lateral line (used to detect movement/vibration)

Question 14

What are the pineal gland and parietal eye

Answer 14

Pineal gland in vertebrates:
- endocrine gland in brain
- produces melatonin
- sleep/wake cycles - responds to light/dark

Parietal eye:
- on top of head
- Lizard & amphibian species
- produces & secretes melatonin
- light/dark, sleep cycles, hormone production, thermoregulation