Animal Behavior

John Alcock, The Triumph of Sociobiology , ch 2: Proximate vs ultimate 3. Contrast proximate mechanisms/causes and ultimate outcomes for a specific behavior. Consider psychological and physiological / anatomical mechanisms (proximate causes) and, separately, the reasons for their evolution. Example: Human desire to eat high fat, sweet foods: Ultimate causes: This evolved to increase genetic fitness, and genetic fitness does not involve long-term survival, at least, not very much. (Just how much is a subject of debate.) What are advantages of fat and sweet foods? Proximate causes: Taste effects on hunger & eating (IRMs); brain mechanisms, hormonal mechanisms, feeding reflexes & FAPs. Such advantages are what caused us to evolve innate preferences for them. 8 John Alcock, The Triumph of Sociobiology , ch 2: George C. Williams vs Wynne-Edwards 4. What was the thesis of Wynne-Edwards in his 1962 book, that was forcefully countered in 1966 by George C. Williams? Describe Williams’ counter thesis, which is a key for understanding modern sociobiology (since 1975). Wynne-Edwards’ book was very popular, and the views expressed there persisted in public perceptions. They persist even today. Wynne-Edwards VC (1962) Animal Dispersion in Relation to Social Behaviour. Williams GC (1966) Adaptation and Natural Selection. 9 George C. Williams vs Wynne-Edwards on how evolution works: Wynne-Edwards (’62), Animal Dispersion in Relation to Social Behavior. Interpreted almost every aspect of social behavior to be altruistic self-sacrifice that advances the welfare of the species ( Alcock, p 29 ) George C. Williams (’66), Adaptation and Natural Selection. “presented the counter thesis that evolved adaptations, including behavioral ones, were extremely unlikely to promote the long-term survival of entire populations or species at the expense of individual reproduction.” See p. 30: his thought experiment 10 • But what about the effects of overcrowding that result in population declines? – They are caused by physiological and behavioral effects of stress – Examples: overactive adrenal gland secretions, decreased immune-system function, increased social confict • These effects caused reduced fertility, which makes them constitute a “Darwinian puzzle” of interest to sociobiologists. • NOTE: E.O. Wilson (1975, 1980) discusses the issue of group selection extensively after citing G.C. Williams (1966). He evaluates conditions that favor inter-demic selection for genes promoting altruism. The issue is a complex one. • Since 1975, most sociobiological studies have not focused on such group selection. This has begun to change in the last few years 11

MIT9 | 20 | Animal Behavior | lecture notes | John Alcock  The Triumph of So

9.20 M.I.T. 2013 Lecture #16 Foraging Anti-predation behavior 1 Scott ch 6, “Foraging behavior” 1) Does the level of foraging or hunting activity depend on the amount of hunger? Could it be independent of hunger? Contrast the picture painted by Scott with what we learned earlier from Konrad Lorenz, Paul Leyhausen and John Flynn. 2 Scott ch 6, “Foraging behavior” 1. Does the level of foraging or hunting activity depend on the amount of hunger? Could it be independent of hunger? Contrast the picture painted by Scott with what we learned earlier from Konrad Lorenz, Paul Leyhausen and John Flynn. Scott’s textbook does not make it very clear that some innate foraging drives are separate from hunger. Remember our discussion of the studies of cats by Konrad Lorenz and Paul Leyhausen, and also the brain stimulation studies of John Flynn. Text p 120: Role of social cues and of learning. Why might an animal eat more when feeding with a group of conspecifics than it would eat if feeding alone? (Answered in the reading) 3 Scott ch 6, “Foraging behavior” 2. What is conditioned taste aversion (discovered in rats by John Garcia)? Is it really “a form of classical conditioning”? (p 121-122) Critique of Scott’s discussion of CTA (box, p 122) Examples in class discussion 4 Critique of Scott’s discussion of CTA (box, p 122) (Also called the “poisoned bait effect”—discovered by John Garcia) It’s properties do not fit the descriptions of classical conditioning because:  It is one-trial learning  The illness (the unconditioned response) does not have to occur immediately  The memory is unusually long-lasting. In humans it can last for many years. 5 • Why might Scott have written that "CTA is of course a form of classical conditioning..."? – Many learning theorists have tried to lump all learning into just a few categories. Many textbooks on learning are organized this way. – Many people, including scientists, also have believed that almost every behavior is learned (especially in America). K. Lorenz called CTA " an innate disposition for learning "-- i.e., it shows strong evidence of a built-in program for a particular kind of learning. (Very adaptive) 6 Scott ch 6, “Foraging behavior” 3. How (and why) would you expect neophobia in feeding behavior to change with (a) hunger level (b) age? See also p 123, which discusses a kind of social facilitation in capuchin monkeys faced with novel food. • Note that the monkeys being studied saw the others eating only familiar food, and yet they still ate more novel food in the presence of the other monkeys. decrease it Younger ones show more. Obvious in humans. 7

MIT9 | 20 | Animal Behavior | lecture notes | 9.20 M.I.T. 2013 Lecture #16 F

MIT9_20F13_Lec9.pdf-M.I.T. 2013 Lecture #9 Key concepts

9.20 M.I.T. 2013 Lecture #8 More about innate behavior & motivation Key concepts from Lorenz on fundamentals of ethology: The “fixed action pattern” 1 Why do animals sleep? A question with multiple levels of meaning: • Adaptive pressures (the functions that have increased survival to the age of reproduction) • Sleep instinct (Fixed Action Pattern) • Action of neuromodulator systems in the CNS 2 Adaptive pressures: why it evolved • Need for rest and recuperation • Need to conserve energy stores • Need to avoid predators • Role in the ontogeny of neural circuits: promoted by organized activity during dream sleep • Memory consolidation; memory editing 3 Why do animals sleep? A question with multiple levels of meaning: • Adaptive pressures • Sleep instinct (FAP) triggered by a biological clock entrained by the light-dark cycle • Action of neuromodulator systems: – Axons with widespread axonal connections: serotonin, norepinephrine, acetylcholine – Chemicals in the cerebrospinal fluid (another type of neuromodulator) 4 Addendum: Sleep schedules • Biphasic sleep in humans – Before electric lights: the frequent practice of “first sleep” and “second sleep” – More common when daylight is < 10 hr – More common in absence of electric lighting • Polyphasic sleep – “Siesta” in humans (which may be another biphasic sleep pattern) – Very common in animals • In hamsters: Shorter cycles of activity are superimposed on a daily schedule of overall intensity of activity divided into active and inactive portions. • During inactive periods, the animals are not always sleeping. 5 Addendum: Sleep schedules (continued) Arctic animals : reindeer in northern Norway (70 degrees N) and in the high arctic archipelago of Svalbard (78 degrees N) “Circadian organization in reindeer”, Science 2005 (6 authors) Daily rhythms abandoned in summer (continuous light) for both groups; abandoned also in winter (continuous dark) by the Svalbard group. Goldfish: variability & complexity  Activity rhythms and feeding rhythms can be out of phase under normal day-night lighting  Activity is higher during daytime, and feeding higher during nighttime,  or vice-versa in some cases  Activity of some fish may be more diurnal, others more nocturnal  Free-running rhythms under constant lighting conditions can have different periods for locomotor activity and for feeding. 6 Addendum: Sleep schedules (continued) • Various studies of total sleep need in humans (of interest to military organizations and others) – Experiments on increasing efficiency of activities – Greatly varying results, many failures – One thing is certain: Individuals vary greatly in sleep patterns and sleep needs • However, they all have a biological clock – actually, more than one. 7

MIT9 | 20 | Animal Behavior | lecture notes | 9.20 M.I.T. 2013 Lecture #8 Mo

MIT9_20F13_Lec12.pdf-M.I.T. 2013 Lecture #12 Early evolution

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