Exploring the Complicated Role of Evolutionary Modeling Signatures 2

Signatures in the frequency spectrum Signatures in the frequency spectrum • Using only DNA polymorphism data we can detect a signature of selection Signatures in the frequency spectrum • Using only DNA polymorphism data we can detect a signature of selection • But the D statistic also depends the neutral parameter: 4Neµ Signatures in the frequency spectrum • Using only DNA polymorphism data we can detect a signature of selection • But the D statistic also depends the neutral parameter: 4Neµ ‣ Artifactual signature of positive selection can be produced by population size decrease Signatures in the frequency spectrum • Using only DNA polymorphism data we can detect a signature of selection • But the D statistic also depends the neutral parameter: 4Neµ ‣ Artifactual signature of positive selection can be produced by population size decrease ‣ Artifactual signature of purifying selection can be produced by population size increase Signatures in the frequency spectrum Signatures in the frequency spectrum • There is a persistent challenge: estimating or constraining the demographic parameters Signatures in the frequency spectrum • There is a persistent challenge: estimating or constraining the demographic parameters ‣ Demographic fluctuations affect the whole genome whereas selection targets specific genes Signatures in the frequency spectrum • There is a persistent challenge: estimating or constraining the demographic parameters ‣ Demographic fluctuations affect the whole genome whereas selection targets specific genes ‣ Functional information about the genes under consideration can help constrain the sequence evolution model 2. Models of cooperation 2. Models of cooperation • How do strategic social interactions figure into the evolution of human cognitive complexity? 2. Models of cooperation • How do strategic social interactions figure into the evolution of human cognitive complexity? • Social intelligence hypotheses: e.g., the demands of larger social groups or the Machiavellian arms race between cheating and detection 2. Models of cooperation • How do strategic social interactions figure into the evolution of human cognitive complexity? • Social intelligence hypotheses: e.g., the demands of larger social groups or the Machiavellian arms race between cheating and detection • Recent emphasis on cooperation and collaboration (Sterelny 2012; Tomasello et al 2012) Cooperation as the key? Cooperation as the key? • Ecological cooperation (or collaboration) in small groups as the easy first step Cooperation as the key? • Ecological cooperation (or collaboration) in small groups as the easy first step • Tomasello: cooperation becomes obligate, leads to “group-mindedness” that facilitates complex coordinated activity Cooperation as the key? • Ecological cooperation (or collaboration) in small groups as the easy first step • Tomasello: cooperation becomes obligate, leads to “group-mindedness” that facilitates complex coordinated activity • Sterelny: information pooling facilitates the productivity of cooperation, leads to adaptations for “high-fidelity cultural learning” Cooperation as the key? • • Ecological cooperation (or collaboration) in small groups as the easy first step • Tomasello: cooperation becomes obligate, leads to “group-mindedness” that facilitates complex coordinated activity • Sterelny: information pooling facilitates the productivity of cooperation, leads to adaptations for “high-fidelity cultural learning” Once cooperation becomes entrenched punishment and partner choice help enforce it