BIOL 1F90 Lecture Notes - Courtship Display, Haliotis Rufescens, Fosb

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Published on 25 Nov 2012
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
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
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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
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)
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