Chapter 7: Part 2 Flashcards
1
Q
Opsins
A
- photoreceptor protein
- protein required for color vision
2
Q
Retinal
A
- photoreceptor protein
- When the retinal molecule absorbs a photon of the appropriate wavelength, the molecule changes shape, contributing to a nervous impulse by the photoreceptor cell
3
Q
Opsin and Retinal
A
- Variations in the specific amino acids that hold on to the retinal molecule within the opsin produce differences in the wavelengths absorbed by the pigment in different photoreceptor cells
4
Q
rods
A
- respond to light intensity
- no color
-black and white
5
Q
How many types of cones do birds have?
A
4
- UV/violet cones (UV/ short WL sensitive)
- blue cone (short wavelength sens.)
- green cone (middle wavelength sens.)
- red cone (long wavelength sens.)
- ^^double cone of this (long-wavelength sens.)
6
Q
How do avian cones compare to mammal cones?
A
- the UV/violet cone is unique to birds!
- humans only have 3
7
Q
What is the function of oil droplets in the cone cells?
A
-carotenoid filled organelle, filters light
- filters before reaching visual pigments, enhances color
- refine the spectral sensitivities of the (A) violet-type and (B) ultraviolet-type avian visual systems
8
Q
External acoustic meatus/ External ear
A
- short external passage, covered by feathers
- often surrounded by muscle to partially or fully close the ear
9
Q
auricular feathers
A
- around ear opening
- protect when diving sound of wind
10
Q
Middle ear
A
- includes tympanic membrane and collumella
11
Q
Tympanic membrane
A
- carries sound waves into the ear, into the middle ear cavity
travel: - stapes»_space; oval window»_space; tectorial membrane»_space;basilar membrane»_space; cochlea»_space; round window
12
Q
Columella
A
- aka stapes
-the middle ear - connects tympanic membrane to the pressure sensitive fluid system of the inner ear
13
Q
Inner ear
A
- includes the cochlea
- organ of corti
14
Q
Cochlea
A
- fluid filled coiled section of the inner ear that is the base of the hearing organ
- includes lagena and organ of corti
15
Q
organ of corti
A
- a structure in the cochlea of the inner ear which produces nerve impulses in response to sound vibrations
- fluid vibrations has membrane move in turn to hair cells
16
Q
How do birds compare to mammals in regards to hearing ability?
A
- most birds can detect sounds within a range similar to humans
17
Q
How are owls special in hearing abilities?
A
- owls can hear in a really low register
- have adaptations for hearing in the dark (facial disk with facial ruff of feathers that reflect sounds into the ears)
- Assymetrical ears
- two coordinate system
18
Q
asymmetrical ears of owls
A
- with one being higher on the head than the other, and one ear canal aimed upward and the other downward
- This arrangement enables these owls to localize sounds in the vertical dimension as well as from side to side, resulting in a very sophisticated auditory map
19
Q
Two coordinate system
A
- detects both the elevation of the sound (the vertical dimension, how high or low it is) and its azimuth (the horizontal dimension, how far to the left or right)
20
Q
Echolocation
A
- Occurs in 2 families of birds: Steatornidae (oilbirds) and Apodidae (cave swiftlets)
- Used for orientation in dark caves
- Echolocate by producing clicking sounds and then receiving and interpreting the resulting echo
21
Q
How do the semicircular canals function and what kind of motion do they detect?
A
- work together to sense rotational and angular movements of the head
- they sense motion via the ampulla, a bulb-shaped structure, has hair cells
- have canal for anterior, posterior, and horizontal
- has pressure exerted by stationary fluid on the cupula in the middle of the semicircular duct, causing rotation of head
22
Q
Herbst corpuscle
A
- layer of “squishy” tissue
- The most elaborate of avian tactile sensors, it consists of as many as 12 onion-like layers of external lamellae that transfer slight pressure changes to the elaborate nerve ending of the receptor axon in the center
- Also found in feather follicles, joints
23
Q
How are herbst corpuscles used to detect hidden/buried prey items?
A
- The pressure gradient created in the mud by the insertion of bird’s beak (red) is distorted locally by a solid object, like a mollusk shell
- The variation in pressure induced by the shell (blue) is detectable as a difference between the two side of the tip of the beak by the Herbst corpuscles under the ramphotheca
- example: kiwis, red knot
24
Q
How do birds compare to mammals in terms of the number of taste receptors?
A
- Most birds have about 300 taste buds, the majority of which occur on the roof of the mouth or deep within the oral cavity
- Compared with mammals, birds have few or no taste buds on the tongue
- humans have 10,000 taste buds on tongue
25
Understand how hummingbirds have evolved a modified umami receptor (T1R3) to be able to
detect sweet tastes
- Umami (savory): sensed by taste buds with a combination of T1R1 and T1R3 proteins
- All living birds lack the T1R2 gene – have no sweet receptors
- hummingbirds evolved specific amino acid changes to the binding domain of T1R3 to enable it bind sugars
26
Where is the olfactory epithelium located
- in turbinates(conchae) of birds, aka "nose"
-various levels of smell
27
What is the relationship between oflactory bulb size and foraging
- the larger the bulb, the higher detection threshold for foraging
28
How do seabirds (like albatrosses) search for food? What chemical cues do they use?
- tend to fly crosswind, optimizing the likelihood of encountering an odor plume of prey.
- Once detected, these birds use a zigzag flight pattern to approach their prey, beginning their decent about 2.5 kilometers downwind of the capture site.
29
How do kiwis search for food?
- using herbst corpuscles!
30
