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Mammalogy (Fall 2013 Althoff - reference FDVM Chapter 8). LEC 09. Mammalian Senses. Senses. Well-developed compared to most all other classes (i.e., fishes, reptiles, etc.) - PowerPoint PPT Presentation

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MAMMALOGY AS A SCIENCE

Mammalian Senses

Mammalogy (Spring 2014 Althoff - reference FDVM Chapter 8)LEC 09SensesWell-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, forbsKey to being had by predator including humans2SensescontSight: probably ____ superior to birds, specifically when compared to raptorsHearing: probably ____ superior to birds. (exception: echolocation)Touch: ______ superior to birdsSmell: _____ superior to birds3

_____________vertebrate brainforebrainmidbrainhindbrain

embryonic vertebrate brainfroghumangoosecerebellumcerebrum

birdsheepItems to note here: 1) ________ proportion of cerebellum to cerebrum 2) ______present (mammal) vs . absent (bird)in the cerebrum exteriorSOURCE: Fishbeck and Sebastiani (2008) Fig. 12.3Types of Sensory Receptors_________________ (taste, smell)_________________ (touch, hearing)_________________ (sight)_________________ (touch, pain)7SmellAcute Development of turbinal bones (tubinates) in nasal cavities (___________________ ________)Well developed olfactory bulbs(bulla) in insectivores, carnivores, &rodentsOlfactory bulbs and lobes, great portion of brain Primates have reduced nasal capacity

8

Some sensitivities up to 1 million trillion (1015) part of airMammalswith very highly developed olfactionaided by presence of ________: thin bone lined with olfactory epitheliumvomeronasal organ(Jacobsons organ)OlfactionmaxilloturbinatesGENERALIZED MAMMAL CONDITIONUNGULATE CONDITIONvomeronasal organ

Cutaway view of nasal chamber of Aberts squirrel (Sciurus aberti)presphenoidbonefrontal bonefrontal bonecribiform platemesethmoidnasal premaxillarymaxillarypalatineSmell...cont Smell accomplished throughchemoreceptors (broad range of these):a) humans: ____ millionb) dog:____ million

Receptors detect food, predators, prey,and status of conspecifics12Smell...contOlfactory hairs (dendrites) connect to olfactory receptors which connect to olfactory bulb

Receptor cells actually in ___________ ___________13

To __________lobe in brainolfactoryepitheliumolfactory ciliaof olfactory cellnon-sensorypartSmell...contEvidence for rodents (& mammals in general likely) to detect:a) sex of conspecificb) maturity of conspecificc) _________________ heritaged) _______________e) social statusImportant in _________________16HearingWell developed in most species (as indicated by _____ of auditory bulla)___________ of vertebrate animals to have this much dependency onsense of hearingOnly class with ______________ (pinna) to funnel sound 17Hearing...contExternal auditory meatus--tube leading from pinna to tympanicmembrane--is usually long in mammalsMiddle ear is air-filled chamber that houses three ossicles (hammer anvil stirrup)(malleus incus stapes)18

FDVMK Fig. 8.2 p146 Hearing...contSize of auditory bulla can reflect animals ability to pick-up low frequency (1-3 MHz) soundsEx: Kangaroo rata) ___________________b) ____________________ ____________________21

FDVMK Fig. 18.10 p354Kangaroo 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 air23Echolocation_____ of all mammals use _____________ orientation forsensing surroundings (bats,shrews, cetaceans)Bats have overcome darkness with development of echolocation 24Echolocation...contMicrochiropterans pretty much have abandoned vision infavor of echolocationEcholocation: ultrasonic pulses are emitted by bats, pulses reflected back objects Not confirmed until 1940s25Echolocation...cont For bats, not only is prey detected, but communication with conspecifics is achieved Vocalizations produced by larynx emittedthrough nose or mouth26

FDVMK Fig. 13.8 p263Echolocation: INFORMATION GAINED of target of the target of the target of the target1234Echolocation...cont 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 handle29Echolocation...contDifferent species of bats emitdifferent ranges of pulses--able to __________________ now by recording pulse rate & duration______ also, apparently, able todetect bat sounds to some degreeversion of ___________________30References 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 60:625-631.31Sight: eye proportional differences(specifically in the _______)

FDVMK Fig. 8.1 p145d = dorsal side of eyeball v = ventral side (bottom)n = nasal (nose) side of eyeball t = temporal (outer side)c = cornea l = lens (shaded-tan) 32SightMost mammals have well-developed ___________________ ...this is a reflective structure within the choroid that improves night vision by reflecting light back to the retina33Sight...cont Tapetum luciduma) results in ________b) some species can have different color of eye shine _____ vs. ______ photoreceptors34

RodsVery sensitive to _____ lightContribute to coarse vision--detection of movement by detecting changes inlight intensity--good night-time vision Contain molecules of ______________ 36Rods...cont Rhodopsin breaks down with light absorption, result is _________ changes across the rod membrane which, in turn, influence neurons.

_________ rods than cones in __________ species37

CHOROIDTo occipital lobe in brain

ConecellRodcellRod membraneLightrays

ConesStimulated by _________ light levelsDensely packed in fovea where nerve tissue is thinnerContribute to precise _____________ between adjacent points in space40Cones...cont 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 asbirds41Up 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.

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 photoreceptorsincluding types of cones12What some mammals might seehttp://premiumblend.net/2009/08/21/how-dogs-see-colors/

HumanDogSight...contFor 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)46