How is behavior defined? Why are they subject to natural selection?
-behavior- an action carried out by muscles under control of the nervous system in response to a
stimulus
-based on physiological systems and processes
-collectively the change of an animal's responses to external and internal stimuli
-ex. animal using muscles to sing, releasing a scent to mark its territory
-essential to acquiring nutrients and finding a partner for sexual reproduction
-contributes to homeostasis
-subject to natural selection (ex. how big a crab's claw is, positioning of eyes on stalks)
Fixed action pattern example
-a sequence of unlearned acts directly linked to a simple stimulus
-essentially once unchangeable once initiated, usually carried to completion
-red color of male stickleback's belly-> cause of attack behavior
-won't attack fish w/o red, but will attack anything else that's red, even if not fish-shape
sign stimulus
-external sensory cue that triggers a fixed action pattern by an animal
migration
-a regular, long distance change in location
-pigeons sense their position rel to Earth's magnetic field-> navigate w/o solar or celestial cues
-circannual rhythms (periods of light/darkness)
circadian clock
-an internal mechanism that maintains a 24 hour activity rhythm or cicle (ex. migrating birds orient
diff to the sun at distinct times of the day)
circadian rhythm
-a daily cycle of rest and activity-> normally synchronized w/ light and dark cycles of the environment
signal
-a stimulus transmitted from 1 org to another
communication
-the transmission and reception of signals b/w animals-> role in proximate causation of behavior
-fruit fly stimulus-response chain
European honeybees communication
-"dance language" to show distance, location/angle of food
-waggle dance
Fruit Fly stimulus response chain
-fixed set of behaviors
-male visually recognizes female-> female releases chemicals detected by male's sense of smell->
male taps female's abdomen w/ foreleg-> male extends and vibrates wing, producing courtship song