53.3
• old animals made decisions thru life as it matured (settle, eat, associate)
• all decisions made in environment that varies in space and time
• habitat: environment in which an organism lives; seeks food, rest, nest sites, escape routes
in habitat
• suitable habitats: good predictors of conditions suitable for future survival+reproduction
• chemosensory cue of red abalone larvae settles on surface that has potential of supplying
food for future survival and reproductive success
• visual info provides useful cues; presence of already settled individuals is indication
• flycatchers assess quality of habitat by seeing how well neighbours are doing; (settle in
areas where broods (abundant food) artificially enlarged)
• some highly social animals vote on quality of habitats (worker bees dance to communicate
location, site that excites most workers is chosen)
• animals compete for high-quality habitats; may improve its fitness by establishing
exclusive use of habitat
• may do this by establishing territory which excludes conspecifics (same species) by
advertising it owns area and chasing others away (but advertising and chasing takes energy)
• cost-benefit approach: assumes an animal has only a limited amt of time and energy to
devote to activities; [costs must not outweigh benefits]; ecologists can make predictions, design
experiments, and make observations explaining why patterns evolve the way they do
• benefits of behaviour are improvements in survival and reproductive success; 3 costs
• energetic cost: difference btwn energy at rest and energy used to perform behaviour
• risk cost: increased change of getting killed/injured when performing behaviour
• opportunity cost: sum of benefits the animal forfeits by not performing other behaviours
• Moore and Marler: male lizards with more testosterone spent more time patrolling
territories, doing advertising displays, used 1/3 more energy than control males. They had less time
to feed, got fewer insects, stored less energy, died at higher rate
• some animals defend all-purpose territories that include all resources (tigers, songbirds)
• food supplies cannot be defended if widely distributed or fluctuate a lot (ex oceans)
• some animals defend territory used only for mating (male grouse congregate on display
grounds, defending small area. Males often use so much energy that less tired males eventually
evict them)
• foraging theory: helps us understand survival (ultimate) value of feeding choices; benefits
= nutritional value, and costs similar to those for territorial defense
• more rapidly an animal captures food, more time+energy it will have for other things
• characterize each type of available food item in 2 ways: time it takes animal to pursue,
capture, and consume item; and by amt of energy an item contains
• most valuable food type is one that yields most energy per unit of time expended
o can determine rate at which an animal would obtain energy given foraging strategy
o animal gains most energy by taking only most valuable type and ignoring all others;
but as that type depletes, it adds less valuable types (ex fish would ignore small water fleas if there
are large ones) • for bluegills, only energy content of water fleas mattered; some animals travel great
distances for nutrients
• some ingest food for other reasons. Frogs get poisons from eating ants that have evolved
poisons as defense mechanisms b/c frogs are immune to poisons
• spices in food preparation protects ppl from contaminated food; most commonly used
spices inhibited growth of some food-borne bacteria; perhaps spices disguise taste/smell of spoiled
food. But eating spoiled food could be dangerous, and natural selection is not likely to have
favored ppl who ate rancid food, no matter how tasty
• most animals associate with others for mating partners and/or for resources it controls
• males initiate courtship, hardly reject receptive females, fight for females
• females seldom fight and often reject males
o b/c sperm are small and cheap to make, very large # of offspring, males can
increase reproductive success by mating with females
o b/c eggs larger and expensive than sperm, females cannot increase reproductive
output by increasing # of males she mates with, but by quality of genes received from mate,
resources he controls, and assistance; may cause evolution of traits
• males use tactics – courtship behaviour signals good health, good provider, controls
resources, good genotype
• circadian rhythms: persistence of daily cycles in absence of environmental time cues
suggests animals have internal clock; not exactly 24 hrs so must be p-a or p-d (below)
• period of rhythm=length of cycles; phase=any point on cycle; when 2 rhythms match=in
phase; if rhythm is shifted=phase-advanced or phase-delayed
• animal kept in constant conditions will be free-running: CR runs to natural period;
genetically controlled
• under natural conditions, environmental time cues entrain free-running rhythms to light-
dark cycle of environment
• nocturnal: active during night; depend on hearing, smell, tactile info (flying squirrels: rods)
• diurnal: active during day; tend to be highly visual (ground squirrels: cones in eye)
• most animals reproduce most successfully if reproductive behaviour coincides with most
favourable time of year for survival of offspring
• change in day length (photoperiod) is reliable indicator of seasonal changes to come
• hibernators and equatorial migrants have circannual rhythms, built in neural calendars that
keep track of time of year
• piloting: animals use this to find their way by knowing and remembering structure of
environment (Grey whales)
• homing: ability to return over long distances to nest site, burrow, location by piloting in a
known environment (pigeons)
• birds disappear and reappear seasonally – migration
• same birds and offspring often return to same breeding grounds year after year, and found
at non-breeding season at locations very far away from breeding grounds. 2 systems:
• distance-and-direction navigation: knowing what direction and how far away destination is
• bicooordinate navigation: ‘true navigation’ requires knowing latitude and longitude of both
current and destination position; animals capable of this o circadian clock gives albatross enough info about time and position of sun to
determine coordinates
o can determine direction from sun and stars’ position (birds)
• animals can orient by means of time-compensated solar compass
• stars offer 2 sources: moving constellations and a fixed point
o direction can be determined from constellation; one point that does not change
position in night is Polaris, always indicating north
o if star patters were rotated, young birds able to orient in planetarium
• animals c
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