Tinbergen's Four Questions: Behavioural Ecology PDF

Behavioural Ecology: Tinbergen’s Four Questions Presentation #2 Alex Mills 1 Tinbergen’s Lasting contribution: the Four questions of Ethology Question #1 What is it for? OR: How have...

Behavioural Ecology: Tinbergen’s Four Questions Presentation #2 Alex Mills 1 Tinbergen’s Lasting contribution: the Four questions of Ethology Question #1 What is it for? OR: How have variations in the trait interacted with the environment to influence fitness in ways that help explain the trait’s form? Question #2 How did it develop? OR: How does the trait develop in individuals Question #3 How did it evolve? OR: What is the phylogenetic history of the trait? Question #4 How does it work? OR: What about the structure or composition of the trait allows it to fulfil its function?  Static Dynamic Proximate focus Ultimate focus  Static Dynamic Proximate focus Mechanism (causation) Ontogeny (development) Ultimate focus Function (adaptation) Phylogeny (evolutionary history)  Static Dynamic Proximate focus Mechanism (causation) Ontogeny (development) Stimulus and response that relies primarily on the sensory-motor apparatus for expression of the behaviour Ultimate focus Function (adaptation) Phylogeny (evolutionary history)  Static Dynamic Proximate focus Mechanism (causation) Ontogeny (development) Stimulus and response that relies How the behaviour develops: primarily on the sensory-motor instinct? Imprinting? Operant apparatus for expression of the learning? The role of genes? behaviour Ultimate focus Function (adaptation) Phylogeny (evolutionary history)  Static Dynamic Proximate focus Mechanism (causation) Ontogeny (development) Stimulus and response that relies How the behaviour develops: primarily on the sensory-motor instinct? Imprinting? Operant apparatus for expression of the learning? The role of genes? behaviour Ultimate focus Function (adaptation) Phylogeny (evolutionary history) How the behaviour advances fitness, either through survival, or through reproduction  Static Dynamic Proximate focus Mechanism (causation) Ontogeny (development) Stimulus and response that relies How the behaviour develops: primarily on the sensory-motor instinct? Imprinting? Operant apparatus for expression of the learning? The role of genes? behaviour Ultimate focus Function (adaptation) Phylogeny (evolutionary history) How the behaviour advances Is it a derived behaviour that’s fitness, either through survival, or being selected for? Is it a carry- through reproduction over from a common ancestor? Is it an exaptation? Example: Function bird song Mechanism Ontogeny Phylogeny (A) Mechanism Much research on song learning and production … central to which is ‘the song system’, a well-mapped neural circuitry of brain nuclei and their projections within the songbird brain (B) Current utility Much research on song context and function Birds sing primarily to advertise their quality, with songs functioning as signals both to warn off rivals and attract mates (C) Development Most songbirds learn songs early in life (from isolation experiments) Song is learned during a sensitive period, when birds are predisposed to learn the songs of conspecifics. The image shows sonograms of a typical wild chaffinch song and of the song of a chaffinch reared in isolation.  (D) Evolution Comparative analyses have established that song features vary along phylogenetic lines Researchers have also documented how songs in many contemporary songbird populations change through a cultural evolution process in which song elements are differentially transmitted “Despite Tinbergen’s emphasis on the need for an integrated understanding, in few study systems have all four of Tinbergen’s questions been addressed.”