Lee Alan Dugatkin Principles of Animal Behavior Alan Dugatkin Principles of Animal Behavior THIRD...
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Transcript of Lee Alan Dugatkin Principles of Animal Behavior Alan Dugatkin Principles of Animal Behavior THIRD...
9/14/15
1
Chapter 1 Principles of Animal Behavior
© 2014 W. W. Norton & Company, Inc.
Lee Alan Dugatkin
Principles of Animal Behavior
THIRD EDITION
• We are surrounded by animals and many humans like to know them"
• Early human art depicts animal behaviour"• Earliest humans depended on animals"• Ethology: the scientific study of animal
behaviour"
Animals and Humans!
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• Ethologists pose 4 distinct types of research questions in the scientific study of animal behaviour"
• Animal behaviour classic paper
Niko Tinbergen (1963) On the aims and methods of ethology. Zeitschrift fur Tierpsychologie 20:410-440"
Scientific Questions & Levels of Analysis! Niko Tinbergenʼs 4 Questions!
• Behaviour: the internally coordinated, externally visible response of whole living organisms to internal and/or external stimuli"
• Externally visible = can be observed & measured"• e.g. ectotherms, move to cooler locations as their
body temperature rises"
Definition!
• In 1859, Charles Darwin published his classic book “On The Origin of Species”"
• Arguments were laid for how evolutionary change has shaped the diversity of life through the process of natural selection!
• Natural selection: the process whereby traits that are heritable and confer the highest relative reproductive success increase in frequency over many generations"
• Studied from ultimate & proximate prospectives"
Evolution & Natural Selection!
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• Marlene Zuk, evolutionarybiologistUniversity of California, Riverside"
• Hawaiian field cricketsTeleogryllus oceanicus"
• Males sing to attract females"• Both benefits and costs to song"• Benefit: attracts females for mating"• Cost: attracts parasitoid flies (Ormia ochracea)"
Natural Selection in Field Crickets!
• Kauai male field crickets had modified wings (flat wings) thatcould not produce much song"
• Survival advantage for flat wing males, but how do they mate?"
• Satellite male mating strategy"• Experiment: flatwing wings were more strongly
attracted to playbacks of normal male song, suggesting the evolution of new mating strategy"
Natural Selection in Field Crickets!
• Andrew Spinks, evolutionarybiologistUniversity of Cape Town, South Africa"
• Xenophobia in the common mole rat,Cryptomys hottentotus"
• Xenophobia: fear of strangers"• Hypothesized xenophobia will be strong when
resources are scarce b/c of intense competition"• Aggression trials in 2 populations from arid (dry)
& mesic (moist) environments"
Natural Selection in Common Mole Rats!
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• Individual learning: a process that can alter the frequency of behaviours displayed within the lifetime of an individual organism"
• Proximate perspective: how learning affects behaviour over the lifetime of an organism"
• Ultimate perspective: how natural selection affects the learning abilities of an organism!
Individual Learning!
Learning & Natural Selection in Grasshoppers!
• Reuven Dukas, animal cognition & behavioural ecologyMcMaster University, Hamilton, ON (Reuven Dukas & Elizabeth Bernay)"
• Studied learning-related benefitsof foraging in the American grasshopper,Schistocerca americana"
• Laboratory feeding trials using “balanced” & “deficient” diets"
• Diets paired with flavour (odor) & colored cards (i.e. cues providing learning opportunities)"
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• A process that can alter type and frequency of behaviours displayed by an organism"
• Refers to situations where animals learn something by copying the behaviour of others"
• AKA: social learning!• Proximate perspective: how social learning
affects behaviour over the lifetime"• Ultimate perspective: how natural selection
affects social learning abilities over generations!
Cultural Transmission!
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Social Learning in Norway Rats!
• Jeff Galef, animal cognition & one of the “fathers” of social learning McMaster University, Hamilton, ON"
• Social learning & foraging in the Norway / common / brown / sewer rat,Rattus norvegicus"
• Scavenging foraging has costs (danger) & benefits (bounty)"
• Information-center hypothesis: foragers learn critical information about location/identity of foods by interacting with recent foragers"
Social Learning in Norway Rats!
• Information-center hypothesis: foragers learn critical information about location/identity of foods by interacting with recent foragers"
• Rats were divided into 2 groups: observers & demonstrators (tutors)"
• Question: can observer rats learn about novel foods by interacting with demonstrators (tutors)?"
• Observers & demonstrators housed together. Then tutors isolated and fed novel diet with distinct flavor/odor"
• Tutors returned to home cage, interact with observers for 15 min"
• Observers isolated & tested for food preferences 48 hrs"
Social Learning Across Generations!
• Unlike individual learning, social learning can occur both within and between (across) multiple generations"
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Social Learning Across Generations!
• Unlike individual learning, social learning can occur both within and between (i.e. across) multiple generations"
• Natural selection can act on the tendency to copy the behaviour of others (e.g. conspecifics)"
Conceptual, Theoretical & Empirical Approaches!
Conceptual Approaches!
• Conceptual approaches involve formulating & integrating unconnected ideas in new ways and can lead to new experimental work"
• Example: kin selection (William D. Hamilton)""Considered to be one of THE most important conceptual breakthroughs in animal behaviour"
Kin Selection (W. D. Hamilton, 1964)!
• Kin selection: natural selection favours behaviours that increase the reproductive success of individuals that express the behaviour AND the close genetic relatives (i.e. kin) that also express the behaviour"
• Fitness consists of direct & indirect components"• Direct fitness: # viable offspring produced by IND + any
effects IND has on direct descendents of its own offspring"• Indirect fitness: increased reproductive success of INDʼs
genetic relatives (excluding offspring & direct descendants of own offspring) due to the behaviour of IND"
• Inclusive fitness: direct fitness + indirect fitness"
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Theoretical Approaches!
• Theorectical approaches involve formulating explicit mathematical models of the world"
• Example: optimal foraging theory (Stevens and Krebs, 1986)"
• Optimality theory: searches for best (optimal) solution to a problem given certain constraints"
• Solving for different parameter values in a model leads to testable (and often counterintuitive) predictions in animal behaviour"
• Goal: obtain a model that distils complex behaviour to general essentials with clear, testable predictions (models are not meant to mimic natural world)"
Empirical Approaches!
• Empirical approaches involve gathering data about the world and drawing conclusions from that evidence"
• Consists of 2 basic types of research:"• Observational studies: watching and recording
without attempting to manipulate system; used to infer correlation but not causation"
• Experimental studies: manipulating a system by changing one variable and holding all others constant; can be used to examine causality"
Scientific Method!
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Scientific Method!
• Formulate a research question based on observations or literature review"
• Generate a research hypothesis based on observations/what is known from literature"
• Make new observational studies, or better yet"• Design an experiment using a paradigm and
research methods appropriate for the question
Be sure to include carefully designed control conditions in your experiments!!