Chapter 53

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Published on 13 May 2011
School
UTSC
Department
Biological Sciences
Course
BIOA02H3
Chapter 53 Behaviour & Behavioural Ecology
- A POPULATION OF JAPANESE MACAQUES LEARNED AND TRANSMITTED A SET OF BEHAVIOURS THAT INCLUDED WASHING
FOOD; A NEW CULTURE OF WATER-RELATED BEHAVIOURS. HOWEVER, FEMALES WERE MORE LIKELY THAN MALES TO FOLLOW
THIS ACTION.
- SPIDERS ARE BORN WEB DESIGNERS; THEY ARE BORN WITH THE ABILITY TO SPIN WEBS AND THERE HAVE NO NEED TO
LEARN FROM EXPERIENCE OR TO MODEL THEIR MOVEMENTS AFTER THOSE OF A PARENT.
53.1 What Questions Do Biologists Ask About Behaviour?
- SOME QUESTIONS ADDRESS PROXIMATE MECHANISMS THAT UNDERLIE BEHAVIOUR THE NEURONAL, HORMONAL, AND
ANATOMICAL MECHANISMS.
- OTHER QUESTIONS LOOK AT HOW GENES AND EXPERIENCES ARE RELATED TO SPECIFIC BEHAVIOURS.
- MOST BEHAVIOUR IS THE RESULT OF THE PROXIMATE MECHANISMS AND EXPERIENCE COMBINED.
- OTHER QUESTIONS CONCERN THE ULTIMATE CAUSES OF BEHAVIOUR THE SELECTION PRESSURES THAT SHAPED ITS
EVOLUTION.
- STEREOTYPIC BEHAVIOUR (EX. ALWAYS THE SAME THING/WAY) IS SPECIES-SPECIFIC.
53.2 How Do Genes and Environment Interact to Shape Behaviour?
- THE OBSERVATION THAT A GIVEN BEHAVIOUR IS STEREOTYPIC AND REQUIRES LITTLE OR NO LEARNING TELLS BIOLOGISTS
LITTLE ABOUT THE RELATIVE ROLES OF GENES AND EXPERIENCE IN THE DEVELOPMENT OF THAT BEHAVIOUR; AN ANIMAL
MAY FAIL TO PERFORM EVEN A GENETICALLY CONTROLLED BEHAVIOUR IF THE ENVIRONMENTAL CONDITIONS NEEDED TO
STIMULATE IT ARE ABSENT. ON THE OTHER HAND, INDIVIDUALS MAY ALL ACT IN THE SAME WAY, NOT DUE TO GENES, BUT
BECAUSE THEY ALL IMITATED THE SAME TEACHER.
- GENES DO NOT ENCODE BEHAVIOUR; GENE PRODUCTS (EX. ENZYMES) CAN AFFECT BEHAVIOUR BY CAUSING A SERIES OF
GENE-ENVIRONMENT INTERACTIONS THAT UNDERLIE THE DEVELOPMENT OF PROXIMATE MECHANISMS THAT ENABLE
INDIVIDUALS TO MAKE CERTAIN BEHAVIOURAL RESPONSES.
- EXPERIMENTS CAN DISTINGUISH B/W GENETIC AND ENVIRONMENTAL INFLUENCES ON BEHAVIOUR; THERE ARE 2
EXPERIMENTAL APPROACHES TO SEE HOW GENES AND EXPERIENCE INTERACT TO SHAPE BEHAVIOURS:
(1) DEPRIVATION EXPERIMENT ANIMAL RAISED W/O EXPERIENCE RELEVANT TO THE BEHAVIOUR UNDER STUDY. EX.
SQUIRREL RAISED IN A CAGE AND NO SOIL AND WAS GIVEN, IT DUG THE IMAGINARY SOIL AND MADE AND REFILLED A WHOLE
THAT DIDNT EXIST, BUT ONLY WHEN GIVEN THE NUT (=STIMULUS) WAS PRESENTED, PROVING THAT THE STEREOTYPIC
BEHAVIOUR OF THE SQUIRREL BURYING A NUT IS DUE TO HEREDITY.
(2) GENETIC EXPERIMENT INVESTIGATORS ALTER GENOME OF ORGANISM BY:
- INTERBREEDING CLOSELY RELATED SPECIES (=INBREEDING)
- COMPARING INDIVIDUALS THAT DIFFER IN ONLY ONE OR A FEW A GENES
- BY KNOCKING OUT OR INSERTING SPECIFIC GENES TO DETERMINE HOW THE CHANGES AFFECT BEHAVIOUR
(I) SELECTIVE BREEDING = ARTIFICIAL SELECTION (EX. DOGS).
(II ) INTERBREEDING = HYBRIDIZATION = the act of mixing different species or varieties of animals or plants
and thus to produce hybrids. Ex. Kondrad Lorenz interbred ducks and found that the courtship displays
are inherited.
(iii) Gene knockout behaviour = gene mutations that affect behaviour.
GENETIC CONTROL OF BEHAVIOUR IS ADAPTIVE UNDER MANY CONDITIONS
- BEHAVIOUR TO AVOID PREDATORS AND CAPTURE PREY IS ADAPTIVE UNDER GENETIC CONTROL.
- BEHAVIOURS THAT ARE UNDER GENETIC CONTROL ARE STILL NOT HARDWIRED AND MAY NOT SHOW UP IN DEPRIVATION
EXPERIMENTS BECAUSE THE RELEASER (=AN OBJECT, EVENT, OR CONDITION REQUIRED TO ELICIT A BEHAVIOUR) IS NOT
PRESENTED. I N THE SQUIRREL EXAMPLE, THE NUT IS THE RELEASED.
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- EX OF MALE ROBINS, EVEN WHEN RED FEATHERS ARE PLACED ON A STICK, AGGRESSIVE BEHAVIOUR IS STILL SEEN IN THE
MALE AS A RESPONSE EVEN THOUGH IT LOOKS NOTHING LIKE THE REAL ROBIN.
- COMPLETE STEREOTYPY MAY NOT BE UNDER GENETIC CONTROL. EX: SPIDERS ADJUST SOME DETAILS OF THEIR WEBS TO
ACCOMMODATE THE GEOMETRY OF THE STRUCTURES TO WHICH THEY ANCHOR THEIR WEBS. THE GENES THAT GOVERN
DEVELOPMENT OFTEN ALLOW ORGANISMS TO ADJUST THEIR FORMS AND BEHAVIOUR TO THE PARTICULAR ENVIRONMENT IN
WHICH THEY DEVELOP. FOR EXAMPLE, ANIMALS SELECT NESTING SITES WITH SPECIFIC FEATURES, BUT NO TWO SITES ARE
IDENTICAL.
IMPRINTING TAKES PLACE AT A SPECIFIC POINT IN DEVELOPMENT
- IMPRINTING MUST TAKE PLACE DURING CRITICAL PERIOD. EX: EMPEROR PENGUIN FATHERS RECOGNIZE THE CALLS OF
THEIR YOUNG BEFORE LEAVING TO FEED FOR WEEKS.
- THE CRITICAL PERIOD OF IMPRINTING MAY BE DETERMINED BY A BRIEF DEVELOPMENTAL OR HORMONAL STATE. THE
HIGH LEVELS OF OXYTOCIN IN THE MOTHERS CIRCULATORY SYSTEM AT THE TIME SHE GIVES BIRTH AND OLFACTORY CUES
FROM THE NEWBORN DETERMINE THE CRITICAL PERIOD. EX: MOTHER GOAT MUST NUZZLE AND LICK HER NEWBORN IN THE
FIRST 10 MINUTES AFTER BIRTH TO LATER RECOGNIZE IT AS HER CHILD.
SOME BEHAVIOURS RESULT FROM INTRICATE INTERACTIONS BETWEEN INHERITANCE AND LEARNING
- MALE SONGBIRDS USE A SPECIES-SPECIFIC SONG IN TERRITORIAL DISPLAYS AND COURTSHIP.
HORMONES INFLUENCE BEHAVIOUR AT GENETICALLY DETERMINED TIMES
- IN MULTICELLULAR ORGANISMS, ALL BEHAVIOUR DEPENDS ON THE SYSTEM FOR INITIATION, COORDINATION, AND
EXECUTION.
- HORMONES FROM ENDOCRINE SYSTEM DETERMINE WHEN A PARTICULAR BEHAVIOUR IS PERFORMED, AS WELL AS WHEN
CERTAIN BEHAVIOURS CAN BE LEARNED.
- EX 1: AS SPRING APPROACHES AND THE DAYS BECOME LONG, THE YOUNG MALES TESTES BEGIN TO GROW AND MATURE.
AS TESTOSTERONE , THE SONG REGION OF THE BRAIN DEVELOPS, AND NEURONS IN THAT REGION OF THE BRAIN
INCREASE IN SIZE AND GROW LONGER EXTENSIONS, AND THE NUMBER OF NEURONS IN THOSE REGIONS INCREASES. HE
BEGINS TO SING, MATCHING HIS OWN VOCALIZATIONS TO HIS IMPRINTED MEMORY OF HIS FATHERS SONG.
- EX 2: TO SEE WHY FEMALE SONGBIRDS DONT SING, EXPERIMENTERS INJECTED THEM WITH TESTOSTERONE AND THEY
SANG THEIR SPECIES-SPECIFIC SONG. FEMALES FORM A MEMORY OF THEIR SPECIES-SPECIFIC SONG WHEN THEY ARE
NESTLINGS AND HAVE THE CAPABILITY TO EXPRESS IT, BUT THEY NORMALLY LACK THE HORMONAL STIMULATION.
53.3 How Do Behavioural Responses to the Environment Influence Fitness?
CHOOSING WHERE TO LIVE INFLUENCES SURVIVAL & REPRODUCTIVE SUCCESS
- ONCE A HABITAT IS CHOSEN, AN ANIMAL SEEKS IT FOOD, RESTING PLACES, NEST SITES, AND ESCAPE ROUTES WITHIN THAT
HABITAT.
- THE CUES MOST ORGANISMS USE TO FIND A GOOD HABITAT ARE GOOD PREDICTORS OF CONDITIONS SUITABLE FOR FUTURE
SURVIVAL AND REPRODUCTION.
- EX: RED ABALONE (A MARINE MULLOSK) LIVES ON ROCKS WITH CORALLINE ALGAE, ITS MAJOR FOOD SOURCE. THEY
RECOGNIZE THE ALGAE BY A CHEMICAL THE ALGAE PRODUCES. IN LABS, THE CHEMICAL IS PRODUCED AND PLACED IN
AREAS WHERE THE ALGAE IS NOT PRESENT AND THE ANIMAL ALWAYS MAKES THAT PLACE STILL MAKES THAT PLACE ITS
HABITAT FOOD SUPPLY.
- VISUAL INFO IS ALSO A USEFUL CUE ABOUT THE QUALITY OF A HABITAT MANY INDIVIDUALS = FOOD ABUNDANCE = GOOD
HABITAT.
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Document Summary

A populat ion of japanese macaques learned and transm itted a set of behaviours that included wash ing. H owever, females were more l ikely t han males to follow. Spiders are born web designers; t hey are born with the abil i ty to spin webs and there have no need to. Learn from experience or to model t he ir movements after those of a parent. Some questions address proximate mechanisms that underl ie behaviour the neuronal, hormonal, and. Ot her questions look at how genes and experiences are related to specif ic behaviours. M ost behaviour is the result of t he proximate mechanisms and experience comb ined. Ot her questions concern the ult imate causes of behaviour t he selection pressures t hat shaped i ts. Always t he same t h ing/way) is species-specif ic. T he observation that a given behaviour is stereotyp ic and requires l ittle or no learning tells biologists.