Mammalian Senses Mammalogy (Spring 2014 Althoff - reference FDVM Chapter 8) LEC 09.
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Transcript of Mammalian Senses Mammalogy (Spring 2014 Althoff - reference FDVM Chapter 8) LEC 09.
Mammalian Senses
Mammalogy (Spring 2014 Althoff - reference FDVM Chapter 8)
LEC 09
Senses
• Well-developed compared to most all other classes (i.e., fishes, reptiles, etc.)
• Key to “_____________” resourcea) find prey (predators)b) find forage (prey) in form of seeds,
grasses, forbs• Key to being “had” by predator including
humans
Senses…con’t
• Sight: probably ____ superior to birds, specifically when compared to raptors
• Hearing: probably ____ superior to birds. (exception: echolocation)
• Touch: ______ superior to birds• Smell: _____ superior to birds
_____________vertebrate brain
forebrain midbrain hindbrain
embryonic vertebrate brain frog
human goosecerebellum
cerebrum
bird sheep
Items to note here: 1) ________ proportion of cerebellum to
cerebrum 2) ______—present (mammal) vs . absent
(bird)—in the cerebrum exterior
SOU
RCE:
Fis
hbec
k an
d Se
basti
ani (
2008
) Fig
. 12.
3
Types of Sensory Receptors
• _________________ (taste, smell)• _________________ (touch, hearing)• _________________ (sight)• _________________ (touch, pain)
Smell
• Acute • Development of turbinal bones (tubinates)
in nasal cavities (___________________ ________)
• Well developed olfactory bulbs(bulla) in insectivores, carnivores, &
rodents• Olfactory bulbs and lobes, great portion of
brain• Primates have reduced nasal capacity
• Some sensitivities up to 1 million trillion (1015) part of air
• Mammals…with very highly developed olfaction…aided by presence of ________: thin bone lined with olfactory epithelium
• vomeronasal organ(Jacobson’s
organ)
Olfactionmaxilloturbinates
GENERALIZED MAMMAL CONDITION
UNGULATE CONDITION
vomeronasal organ
Cutaway view of nasal chamber of Abert’s squirrel (Sciurus aberti)
presphenoidbone
frontal bone
frontal bonecribiform platemesethmoid
nasal
premaxillarymaxillarypalatine
Smell...con’t
• Smell accomplished throughchemoreceptors (broad range of these):
a) humans: ____ millionb) dog: ____ million
• Receptors detect food, predators, prey, and status of conspecifics
Smell...con’t
• Olfactory “hairs” (dendrites) connect to olfactory receptors which connect to olfactory bulb
• Receptor cells actually in ___________ ___________
To __________lobe in brain
olfactoryepithelium
olfactory ciliaof olfactory cell
“non-sensory”part
Smell...con’t
• Evidence for rodents (& mammals in general likely) to detect:a) sex of conspecificb) maturity of conspecificc) _________________ heritaged) _______________e) “social” status
• Important in _________________
Hearing• Well developed in most species (as
indicated by _____ of auditory bulla)
• ___________ of vertebrate animals to have this much dependency on
sense of hearing• Only class with ______________
(pinna) to funnel sound
Hearing...con’t• External auditory meatus--tube
leading from pinna to tympanicmembrane--is usually long in mammals
• Middle ear is air-filled chamber that houses three ossicles (hammer anvil stirrup)
(malleus incus stapes)
FDVMK Fig. 8.2 p146
Hearing...con’t
• Size of auditory bulla can reflect animals ability to pick-up low frequency (1-3 MHz) sounds
• Ex: Kangaroo rata) ___________________b) ____________________ ____________________
FDVMK Fig. 18.10 p354
Kangaroo rat (Dipodomys)
Auditory bulla is, on the average, larger in _____________________. Sound is known to be absorbed to different degrees under different temperature and humidity conditions. An enlarged bullae may _______________ for poor sound-carrying qualities of warm, dry, desert air
Echolocation
• _____ of all mammals use _____________ orientation forsensing surroundings (bats,shrews, cetaceans)
• Bats have overcome “darkness” with development of echolocation
Echolocation...con’t
• Microchiropterans pretty much have abandoned vision in favor of echolocation
• Echolocation: ultrasonic pulses are emitted by bats, pulses reflected back objects
• Not confirmed until 1940’s
Echolocation...con’t
• For bats, not only is prey detected, but communication with conspecifics is achieved
• Vocalizations produced by larynx emittedthrough nose or mouth
FDVMK Fig. 13.8 p263
Echolocation: INFORMATION GAINED
of target
of the target
of the target
of the target
1
2
3
4
Echolocation...con’t
• Humans can hear _____ kHz(20,000 cycles per second)
• Bats emit _______ kHz pulses with very _____ wavelengths...this
range results in detect of prey closest to the size that a bat species can handle
Echolocation...con’t
• Different species of bats emit different ranges of pulses--able to __________________ now by recording pulse rate & duration
• ______ also, apparently, able todetect bat sounds to some degree…version of “___________________”
References on bat foraging & detection of different species:
Adam, M.D., M.J. Lacki, and T. G. Barnes. 1994.Foraging areas and habitat use of the Virginia big-eared bat in Kentucky. J. Wildlife Management 58:462-469.Krusic, R.A., M. Yamaski, C.D. Neefus, and P.J.
Pekins. 1996. Bat habitat use in WhiteMountain National Forest. J. Wildlife.
Management 60:625-631.
Sight: eye proportional differences(specifically in the _______)
FDVMK Fig. 8.1 p145
d = dorsal side of eyeball v = ventral side (bottom)n = nasal (nose) side of eyeball t = temporal (outer side)c = cornea l = lens (shaded-tan)
Sight
• Most mammals have well-developed ___________________ ...this is a reflective
structure within the choroid that improves night vision by reflecting light back to the retina
Sight...con’t
• Tapetum luciduma) results in “________”b) some species can have
different color of eye shine• _____ vs. ______ photoreceptors
Rods
• Very sensitive to _____ light• Contribute to “coarse” vision
--detection of movement by detecting changes in
light intensity--good night-time
vision • Contain molecules of ______________
Rods...con’t• Rhodopsin breaks down with light
absorption, result is _________ changes across the rod membrane which, in turn, influence neurons.
• _________ rods than cones in __________ species
CHOROID
To occipital lobe in brain
Conecell
Rodcell
Ro
d m
emb
ran
e
Lightrays
Cones
• Stimulated by _________ light levels• Densely packed in fovea where nerve
tissue is thinner• Contribute to “precise” _____________
between adjacent points in space
Cones...con’t
• Pigments in different cone cells aresensitive to wavelengths
corresponding to red, green, and blue colors
• More abundant in diurnal species, but--even for those--______ as much
as birds
Up to present day, only three mammalian groups again developed retinas dominated by cones:A) SCIURID RODENTS, B) TUPAIAS (tree shrews) and C) (DIURNAL) PRIMATE GROUPS
European Ground Squirrel
Citellus citellus
This stained semi-thin section shows the photoreceptor mosaic.A few rods are present but not well distinguishable atthis level of sectioning. In the ground squirrel retinas (also the Alpine marmot for example) they are a small minority (5%). Otherwise, apparently there are two types of cones.
A) subpopulation of larger darker staining cells are the short wavelength sensitive (Blue or S-) cones. They establish a regular sub-mosaic of ca. 10%.
(and they are apparently ________________)
B) Other cells are mostly (>80% )long wavelength sensitive or "Green" cones.
European Ground Squirrel
Citellus citellus
Regardless of number of cones and rods, object ____________ still can be _____________
___________ intypes of photoreceptors…including types of cones
1
2
What some mammals might see…
• http://premiumblend.net/2009/08/21/how-dogs-see-colors/
Human Dog
Sight...con’t
For the most part, then, most mammals probably “see” black-and-white” but there is a ________ _______________ for those with well-developed sight
(excludes microchiropterans, moles, shrews, etc.—who have really poor eyesight)