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Lecture

SOC101Y1 Lecture Notes - Phloem, Waggle Dance, Electric Field


Department
Sociology
Course Code
SOC101Y1
Professor
S

Page:
of 7
53.1
culture: set of behaviours shared by members of a population, transmitted through learning
when generations do not overlap, parental guidance is not factor is acquisition of behaviour
stereotypic: performed almost exactly the same way each time (ex spider spinning web)
ostereotypic behaviour is often species-specific: individuals of given species perform it
in same way
ethology: the study of animal behaviour from an evolutionary perspective
oaddresses behaviour patters, how and when to perform them
oproximate mechanisms that underlie behaviour: neuronal, hormonal, anatomical
oultimate causes of behaviour: selection pressure that shaped evolution
most behaviours result from interactions btwn inherited anatomical and physiological
mechanisms and the ability to modify behaviour as a result of experience
many animals’ behaviour is unlearned and highly stereotypic
53.2
stereotypic behaviour tells biologists little about genes and experience in development
animal may fail to perform behaviour if the environmental conditions needed to stimulate it
are absent; may perform behaviour if they imitate the same teacher
genes do NOT encode behaviours; gene products (enzymes) set in motion a series of gene-
environment interactions that underlie development of proximate mechanisms that enable individuals
to make certain behavioural responses
experiments help distinguish btwn genetic and environmental influences
deprivation experiment: rears a young animal so its deprived of all experience relevant to
behaviour; if it exhibits behaviour, it can be developed without learning
oheredity underlies food-storing behaviour of tree squirrel species, but behaviour was
expressed only when environment provided situations that stimulated behaviour
genetic experiments: alters genomes by
ointerbreeding closely related species
selective breeding: means of genetic manipulating; used to select for both
anatomical traits and behaviours; approach is applied and not theoretical, but does provide insight
about effect genes have on behaviour
ocomparing individuals that differ in few genes
interbreedingwhen Lorenz crossbred ducks, hybrid offspring had some
elements of each parents courtship display in new combinations. Hybrids exhibited display elements
characteristic of other species; motor patterns of courtship displays are inherited; sexual selection has
shaped these genetically determined behaviours
oby knocking out/inserting gene sequences
fosB is involved in stimulating neural changes in hypothalamus of mother’s
brain, possibly odor clues upon initial inspection of pups. It plays a part in motivating mother to
retrieve and care for pups; neural changes do not occur if fosB gene is inactivated
without role models and opportunities for learning, individuals might fail to acquire
appropriate behaviour, if genes didnt exert strong influences on development of behaviour
inherited behaviour is also adaptive when mistakes are costly or dangerous
patterns used to avoid predators is adaptive
some behaviours are expressed only under certain conditions (Red feathers of Robins)
oreleaser: object, event, condition required to elicit behaviour
complete stereotypy may not be adaptive (spiders adjust details of web for objects)
critical period: learning takes place only at specific time
imprinting: an animal learns a set of stimuli during a limited critical period; requires only
brief exposure but its effects are strong and can last a lifetime (ex recognizing call of chicks)
ocritical period may be determined by brief developmental or hormonal state (ex at
birth, mother goat must lick newborns neck to recognize it later on)
species-specific song in territorial displays and courtship is learned (birds hear it as nestlings,
form a song memory in nervous system; matches his stored song memory when mature. If he is
deafened after he sings SSS, he can sing it normally but if deafened before he sings before he learns
it, he will not develop SSS2 critical stages: nestling, approaching sexual maturity)
deprivations experiments demonstrate that young male sparrows do not learn songs of other
species, but exposure to few songs of their own is enough for imprinting
ogenes make it difficult to learn songs of other species
in multicellular organisms, all behaviour depends on nervous system for initiation,
coordination, execution
ohormones of endocrine system determine when behaviour is performed and when
they can be learned
male birds use song to claim and advertise breeding territory, compete with other males, and
declare dominance, attract females (females recognize song of species)
female birds injected with testosterone develop SSF just as males did. Females form SSS
memory when nestling, but lack hormonal stimulation to express it
increase in testosterone causes certain parts of males brain for learning song to grow larger
hormones can control behaviour by changing brain structure and function, developmentally
and seasonally
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
ocan determine rate at which an animal would obtain energy given foraging strategy
oanimal 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
ob/c sperm are small and cheap to make, very large # of offspring, males can increase
reproductive success by mating with females
ob/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