Download
1 / 47
520 likes | 1.24k Views
Ethology: The Study of Instincts. Konrad Lorenz. Karl von Frisch. Niko Tinbergen. Nobel Laureates, 1973. Instinctive Motor Behavior. Infant primates hold onto their mothers' hair so as not fall off when she moves briskly. .
E N D
Ethology: The Study of Instincts Konrad Lorenz Karl von Frisch Niko Tinbergen Nobel Laureates, 1973
Instinctive Motor Behavior Infant primates hold onto their mothers' hair so as not fall off when she moves briskly.
A cardinal feeds minnows, which rose to the surface looking for food. During several weeks the bird fed them, probably because his nest had been destroyed.
Etymology Of ‘Instinct’ The term instinct derives from Indo European, Greek, and Latin roots meaning “stick” “to goad,” e.g., Latin stiguere -- to goad, excite, or incite; instiguere -- to incite, to instigate. Greek: stigma -- a pricked mark, a brand.
Umwelt:sensory world of the animal Merkwelt:our perception of the environment(Von Uexkull) Example: A pond is perceived differently by a: tadpole fish paramecia hawk duck fisherman
Examples Of Instinctive Behavior • Loggerhead turtles (found off east coast of Florida) Females deposit about 50-100 eggs in small holes they dig on sandy beach. Eggs hatch in approximately 50 days. After 3-5 days in the nest infant turtles crawl out, head for sea and swim out. Conclusion: Loggerhead turtle has an instinct to go to sea. • Imprinting: Young goslings follow their mother (or Lorenz; whichever comes first) wherever she moves. Conclusion: Young goslings follow their mother instinctively (imprinting is an instinctive reaction). • Crows that live in western part of North America migrate each fall from Alberta Canada to the south. The following spring they head north again. Conclusion: Crows have an instinct to migrate. • Pregnant female rats build nests of laboratory shavings. After giving birth to her litter, mother rat looks after her young, suckles them, retrieves them when they stray from nest, etc. Conclusions: This is the result of a maternal instinct.
Critical Period for Following Response LORENZ: BASIC CONCEPTS • Sign Stimuli key to a lock • Fixed Action Pattern Response of whole organism, not a reflex • Innate Releasing Mechanism(IRM) leads to consummatory event • Vacuum Activity IRM released in absence of sign stimulus
SUPERNORMAL STIMULUS A supernormal egg that is unusual only in the size of its spots (left) is preferred by the ringed plover (Charadruis hiaticula) to a normal egg (right).
Orienting Responses • TAXES: Movement towards or away from some feature of the environment. -Positive (e.g., Positive geotropism). -Negative (e.g., Negative phototropism). • KINESES: Rate of movement (but not direction) is determined by some feature of the environment. -Orthokinesis: Rate of movement (in any direction) is a function of environmental conditions. -Klino-kinesis: Rate of turning (but not velocity) is a function of environmental conditions.
Proportion Of Woodlice Inactive For 30 Seconds As A Function Of Humidity
Do Drivers Like Traffic Jams? Area Rural Urban Rural Speed (mph) 40 10 40 Distance (miles) 10 20 30 Time covered by 15’ 60’ 15’ each car (min.) No. of cars 25 100 25
How Bees Communicate About Food • After a foraging bee returns to hive, other bees leave for food. • Forager dance in circle; other bees follow. • The richer the source of food, the longer the dance. • Many followers leave before forager finishes. • If foraging bee is detained, other bees still fly out to seek food. • “Location” scents released as guides to particular patches of flowers.
Key Phases Of Blowfly Eating Cycle: • pumping reflex of proboscis • sensory adaptation of sugar receptors • sugar concentration of food • state of crop • state of gut (blood sugar level)
Foraging Cycle Of Blowfly - Gut is empty at beginning of cycle. - Flight is guided by kineses (e.g., temperature, light level, time of day, odor of fermenting sugars in plants). - Taxes guide approach to specific stimuli. - Blowfly lands on leaf. - Sugar receptors on hairs of legs are stimulated. - Proboscis uncoils reflexively.
-Rate of pumping from proboscis to crop is a function of sweetness and adaptation level of sugar receptors. Sweetness steadily decreases.-Sweetness eventually falls below some critical value; pumping resumes.-Intake is not a simple cyclic function of adaptation of sugar sensors.-The digestive tract regulates the value of threshold for sweetness.-Crop stores food and then transfers it to main gut and to bloodstream. Foraging Cycle of Blowfly, cont’d
Three Phases Of Motivated Activity(as illustrated by feeding cycle of blowfly) • DRIVE • Some state of a regulator produces or makes probable (e.g., empty crop). • APPETITIVE BEHAVIOR • responses to stimuli, which contribute to a consummatory event, (e.g., ingesting sugar). • CONSUMMATORY EVENT • a shift in the regulator away from its initial drive state (e.g., transferring food from crop to gut).
Development Of Chaffinch Song • Chaffinch is born in the spring. • It sings its mature song 1 year later (at which time it also nests for the first time). • During the first few weeks after hatching, it only emits food begging calls. • During the summer and fall it produces asubsong,bits of the full song that are not integrated into correct sequence and that are not sung as loudly as full song. • There is very little singing of any kind during the winter. • During the following spring it resumes singing the subsong which, over a period of a few weeks, blends smoothly into full song. • The transitional song is called plastic song (because it is more variable than full song). • A permanent crystallized song finally appears about second month of the second spring. The crystallized song is sung every spring for the rest of the chaffinch’s life- approximately five years.
What A Chaffinch Sings • First-year chaffinches, raised by themselves, or deafened, will sing abnormal songs during the following spring. • If they hear (but not see) a normal adult male, they will get it right during the second spring. • If, however, the chaffinch sings the wrong song during the second spring (by virtue of socializing with a different kind of finch) it will never get it right. • Depending upon how much of the adult song the young chaffinch hears (and the quality of that song) it picks the best components to copy. • If deafening occurs after the second spring, normal song is still produced.
Key Phases Of Blowfly Eating Cycle: • pumping reflex of proboscis • sensory adaptation of sugar receptors • sugar concentration of food • state of crop • state of gut (blood sugar level)
Critical Periods for Development of Behavior White crown sparrow’s song: 10-50 days Gosling’s following behavior: 4-17 days
Imprinting Apparatus Test: Will gosling follow duck that moved during training? Test: Will gosling overcome obstacles to follow duck?
