Adaptiveness of Behavior

1. Adaptiveness of Behavior Chapter 43

2. What are the Causes of Behavior? • two levels of causation • proximate causation • immediate basis of behavior (“how”) • includes learned behaviors; anatomy and physiology • ultimate causation • evolutionary basis of behavior (“why”) • includes innate and instinctive behaviors • behavioral ecology • impact of behavior on an organism’s life • uses both kinds of causation and many variables are involved • habitat selection • why do animals live where they do? • how is habitat chosen – genetics or learning? • foraging behavior • why do animals forage where they do? • generalists vs. specialists • opportunists vs. extreme specialists • efficiency of foraging • maximize gain and minimize expenditure

3. Fig. 43.13 Foraging for food

4. Biological Clocks • innate mechanisms that allow an org. to perceive lapse & flow of time • biorhythms (cycles) • behaviors associated with biol. clocks • annual • yearly cycles, usually based on the seasons • most fundamental life activities are annual cycles • lunar • based on phases of moon causing the tides • Important for intertidalorganisms • circadian • daily, day-night cycles • diurnal vs. nocturnal vs. crepuscular • can be influenced by photoperiod (day-length) • organ, physiological, hormonal, cellular cycles • Orientation and Navigation • navigation • directional sense that allows orgs. to make way back to territory • compass sense (general direction) vs. map sense (specific location) • often coupled to biol. clocks  time-direction mechanism • orientation • navigation around env. obstacles

5. migration • seasonal movement of a sp. from one geographic location to another • vast distances • between breeding & non-breeding (wintering) grounds • high E and risk • occurs in many species • some sp. only migrate if conditions are very harsh • navigation cues • sun (day migrators) • stars (night migrators) • earth's magnetic field • geographical cues (mountains, rivers, etc.) • memory, experience (learning), biorhythms • group cohesion (ind. working together) • migration is triggered by: • physiological cues (esp., changing hormone levels) • changing photoperiod and env. temperature • migratory sp. get “restless” just prior to migration • combination of genetics and experience General Cues Specific Cues

6. Fig. 43.6 Starling migratory experiment, showing the combined effect of genetics and learning

7. Animal Communication • any behavior produced by one org. and received by another  response • enhances survival and reproduction reproductive enabling device • direct vs. indirect • enhancing one’s own reproductive success vs. enhancing success of offspring • modes of communication • each has advantages and disadvantages • visual • color, posture, shape, movement • graded displays Fig. 43.10 Fireflies using visual communication. Each number represents the male flash pattern of a different species. The patterns are a behavioral reproductive isolating mechanism. Fig. 43.9 Male baboon displaying a full visual threat display.

8. vocal • frequency, amplitude, duration • seismic communication • produced in some way other than vocal apparatus • vocal repertoire • sp. full range of vocal comm. Fig. 43.8 Vocal communication in vervet monkeys. The monkeys give different alarm calls according to whether a troop member sights an eagle or leopard. The repertoire of a songbird

9. chemical • pheromones • most basic of all comm. forms • can produce stereotyped behaviors • always performed in same way • tactile • touch or very close proximity • Social Behavior • behavior of orgs. in groups • agonistic behavior • behaviors used to resolve conflict • intraspecific vs. interspecific • territoriality • behaviors associated with defending territory • fighting • usually ritualized • not to death Fig. 43.7 Chemical communication with a pheromone. A male cheetah spraying urine to mark his territory. Fig. 43.15 Ritualized competition among elk

10. cooperation • species or individuals work together for mutual benefit • mating behavior • may include sexual dimorphism • visual and/or behavioral differences between males and females • often involves species-specific courtship rituals and displays • males advertise/display for females  females choose mates • female-choice Fig. 43.14 Sexual dimorphism in Hamadryas baboons. The male is silver-white and twice the size of the brown females.

11. Female warblers prefer males with large song repertoires.

12. several modes of communication used • social dominance hierarchies often play a role • males compete among themselves for dominance and position • winners have greatest access to females  mate with females • male competition Female choice and male dominance among baboons.

13. symbiosis • two or more species living closely together • mutualism • both organisms benefit from relationship • commensalism • one organism benefits, the other is unaffected • parasitism • one organism benefits, the other is harmed • host vs. parasite • endoparasites vs. ectoparasites • altruism • any action that benefits another individual at one’s own expense • kin selection • tendency to help relatives at one’s own expense • reciprocal altruism • “I’ll scratch your back, if you scratch mine” • Sociobiology (E.O. Wilson) • applies evolutionary principles to study of social behavior • adaptive basis for animals to live together in groups • group foraging • group protection (“selfish herd” effect) • increased vigilance • reproductive coordination