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Published byNathan Norton Modified over 8 years ago
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Stem Arthropods AnomalocarisOpabiniaHurdia
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Erwin and Valentine, The Construction of Animal Biodiversity, 2013
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MonosigaAmphimedonTrichoplaxNematostellaDrosophila genome size (Mb) 41.616798450180 # genes 9,100?11,51418,00014,601 # cell types 11242050 # T.F.’s ?5735min. 87 # T.F. families 56?910 microRNA 08040152 Genomic Complexity (Erwin, 2009; Erwin & Valentine 2013)
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Erwin et al. 2011, Science
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Strongylocentrotus
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Sea Urchin dGRN Biotapestry.org
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Sea Urchin endomesoderm GRN
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Gene Regulatory Network Structure Erwin and Valentine, Forthcoming, 2012; after Davidson
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Davidson & Erwin, 2009
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Origin of Eumetazoa Origin of Developmental Toolkit Increase in miRNA families; complexity of dGRN interactions Most signalling pathways present
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Fedonkin et al The Rise of Animals, 2007
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Erwin and Valentine, Forthcoming, 2012
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Genetic inheritance EtEt E t+1 Natural selection Gene pool Ecological inheritance Natural selection Genetic inheritance Gene pool Natural selection Ecological Spillover Ecological Spillover Species 1 Species 2 Ecosystem Engineering
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Cambrian Ecosystem Engineering Archaeocyathid reefs (+) Sponges & other filter feeders (+) Burrowed sediments (+/-) Shelly substrates (+) Mesoozooplankton (+)
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Ecological Spillovers Sponges: sequestering carbon via filtration. Oxidation of oceans allow increased production of collagen. Burrowing: change in S isotopes, enhances primary productivity in seds, increases biodiversity
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P & P Definitions Innovation “improve on existing ways of doing things” (which sounds to a biologist like adaptation) Inventions “change the ways things are done”
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Invention is the creation of something new and distinct (contrast with variation on established themes) Innovation occurs when inventions become economically or ecologically significant Invention & Innovation Joseph Schumpeter (1883-1950
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Origin of Eumetazoa Origin of Developmental Toolkit Increase in miRNA families; complexity of dGRN interactions Most signalling pathways present
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Defining Novelty Are ‘novelty’ and ‘innovation’ synonymous? Character based: new construction elements of a body plan (not homologous to pre-existing structure) Process based: novelty should involve a transition between adaptive peaks and a breakdown of ancestral developmental constraints so that new sorts of variation are generated (Halgrimsson et a. 2012 J. Exp. Zool)
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Evolutionary novelty originates when part of the body acquires individuality and quasi- independence Involves origin of new character identity rather than character state (homology)
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How are new evolutionary spaces created? Potentiated by broader environmental setting (physical, genetic, ecologic) Actualized by genetic and developmental innovations leading to a new clade Refined by further developmental and ecological changes Realized as innovations by ecological expansion and evolutionary success
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Mechanisms of Organizational Genesis Transposition and refunctionality (var) Anchoring diversity (ecology) Incorporation and detachment (var) Migration and homology (niche const) Conflict displacement/dual inclusion (ETI) Purge and mass mobilization (ecology) Privatization and Business groups (ecol/ETI) Robust action and multivocality (?)
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Nature of Contingency Sampling error Unpredictability of the course of history Sensitivity to initial conditions (Beatty 2006) Sensitivity to external disturbance Macroevolutionary stochasticity
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Nature of Contingency Sampling error Unpredictability of the course of history Sensitivity to initial conditions (Beatty 2006) Sensitivity to external disturbance Macroevolutionary stochasticity And does the ‘topography’ of historical contingency change over time?
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Modern Synthesis Transmission Genetics Simple path from genotype to phenotype Primacy of genetic inheritance Selection within populations as primary driver of evolution Opportunistic Uniformitarian
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Emerging Perspectives No simple mapping from genotype to phenotype (evo-devo) Multiple forms of inheritance Multiple levels of selection Important roles for mutation and drift in addition to selection Macroevolutionary lags Non-uniformitarian
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Search Vs Construction Innovation is often described as search through a space of “the adjacent possible” (Kaufmann, Wagner)
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Grassland Evolution
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Grass Phylogeny Kellogg, 2001, Plant Physiology
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Macroevolutionary Lags
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How are new evolutionary spaces created? Potentiated by broader environmental setting (physical, genetic, ecologic)
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How are new evolutionary spaces created? Potentiated by broader environmental setting (physical, genetic, ecologic) Actualized by genetic and developmental innovations leading to a new clade
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