Outline. A fossil timeline 11/22/2015. Reticulated (network) evolution, landscape and agency what the new fossils tell us

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1 Outline Reticulated (network) evolution, landscape and agency what the new fossils tell us Isabelle Winder 1. A brief history of hominin fossils 2. Putting evolution in context: the potential role of landscapes 3. From trees to bushes: diversity, mosaic evolution and reticulation 4. From heroic models to complex ones understanding our relatives roles in their own histories Neanderthal 1, Germany Engis, Belgium (1830) neanderthalensis named by William King Forbes Quarry, Gibraltar (1848) Cro Magnon, France Neanderthals, including from Spy, Belgium Java, Indonesia Mauer, Heidelberg, Germany Taung, South Africa Piltdown, England 1

2 Evolutionary contexts Piltdown disproven (1953) transvaalensis erectus sapiens Australopiths Early Earliest hominins 1856 Later 2015 Lewin (2005) An Illustrated Guide to Human Evolution; Gibbons (2009) Nature; DeMenocal (2004) Earth and Planetary Science Letters. The savannah hypothesis Forest hypotheses Raymond Dart For the production of man a different apprenticeship was needed. In my opinion, Southern Africa, by providing a vast open country with occasional wooded belts and a relative scarcity of water, together with fierce and bitter mammalian competition, furnished a laboratory such as was essential to this penultimate phase of human evolution Dart (1925, p.199) Nature The aquatic ape Variability hypotheses DeMenocal (2004) Earth and Planetary Science Letters; Potts (1998) Evolutionary Anthropology; Vrba (1992) Journal of Mammalogy 2

3 11/22/2015 A brief summary A key challenge... What s missing? Complex landscapes Winder et al. (2013) Antiquity King and Bailey (2006) Antiquity; Bailey and (2011) JHE Winder et al. (inking press) Antiquity. Moving into complex landscapes Humans and complex landscapes Brown and Yalden (1973) Mammal Review 3

4 Putting it all together: scrambler man? Putting it all together: scrambler man? Winder et al. 2013) Antiquity Hominin diversity Diversity within groups: Dmanisi Fossil diversity has increased in two ways: 1. With the recognition and description of new species (often based on small samples) and with the discovery of increasing diversity within species, including both morphological, ecological and genetic variation Overlaps between groups: genus Genetic evidence 1 4% of the non African A further 4 6% of the human genome may derive Melanesian genome may from Neanderthals derive from the Denisova There are several possible hominins explanations 4

5 Fossil evidence: hybrids? Fossil evidence: mosaics Duarte et al. (2011) PNAS; Soficaru et al. (2006) PNAS. Fossil evidence: mosaics Is this evidence for a new model of evolution? HIERARCHICAL EVOLUTION HETERARCHICAL OR RETICULATE EVOLUTION primates: the Papionins primates: Papio Lang (2006a, b) Primate Factsheets Gilbert (2011) AJPA Zinner et al. (2009) BMC Evolutionary Biology 5

6 primates: Rungwecebus primates: apes Jones et al. (2005) Science; Burrell et al. (2009) Molecular Phylogenetics and Evolution Wolkin and Myers (1980) Science Agency and non adaptive evolution What precisely is an adaptation? An adaptation is: Heritable Functional (i.e. actually capable of performing a function) Adaptive (i.e. contributing to fitness for those individuals that have it) Currently used for the function for which it was originally selected An example: feathers as an adaptation for flight Are key human traits adaptive? Alternatives to adaptation Adaptation Exaptation Something else A structure shaped by natural selection for its current use A structure that performs a function but which was not shaped for that purpose Spandrels, survivable non adaptations, neutral/random traits... 6

7 What if we aren t adapted? The vulnerable (compassionate!) ape Humans also produce a relatively large number of disabled (or differently abled) individuals Some high functioning disabilities may have benefits to the group, but many cannot be explained this way Must we really argue that our ancestors, as hairless, weak jawed, straight footed apes with congenitally encephalised offspring were somehow fitter than other apes? Conclusions The rapid growth of the fossil record gives us ever more insight into human evolution, and, together with theoretical developments, is helping generate brand new theories Just three examples come from our new understanding of hominins preferences for complex, heterogeneous landscapes, the role(s) of mosaics and reticulation, and the potential significance of agency and compassion... 7