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Stem Arthropods AnomalocarisOpabiniaHurdia Erwin and Valentine, The Construction of Animal Biodiversity, 2013.

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Presentation on theme: "Stem Arthropods AnomalocarisOpabiniaHurdia Erwin and Valentine, The Construction of Animal Biodiversity, 2013."— Presentation transcript:

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3 Stem Arthropods AnomalocarisOpabiniaHurdia

4 Erwin and Valentine, The Construction of Animal Biodiversity, 2013

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7 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)

8 Erwin et al. 2011, Science

9 Strongylocentrotus

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11 Sea Urchin dGRN Biotapestry.org

12 Sea Urchin endomesoderm GRN

13 Gene Regulatory Network Structure Erwin and Valentine, Forthcoming, 2012; after Davidson

14 Davidson & Erwin, 2009

15 Origin of Eumetazoa Origin of Developmental Toolkit Increase in miRNA families; complexity of dGRN interactions Most signalling pathways present

16 Fedonkin et al The Rise of Animals, 2007

17 Erwin and Valentine, Forthcoming, 2012

18 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

19 Cambrian Ecosystem Engineering Archaeocyathid reefs (+) Sponges & other filter feeders (+) Burrowed sediments (+/-) Shelly substrates (+) Mesoozooplankton (+)

20 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

21 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”

22 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

23 Origin of Eumetazoa Origin of Developmental Toolkit Increase in miRNA families; complexity of dGRN interactions Most signalling pathways present

24 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)

25 Evolutionary novelty originates when part of the body acquires individuality and quasi- independence Involves origin of new character identity rather than character state (homology)

26 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

27 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 (?)

28 Nature of Contingency Sampling error Unpredictability of the course of history Sensitivity to initial conditions (Beatty 2006) Sensitivity to external disturbance Macroevolutionary stochasticity

29 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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31 Modern Synthesis Transmission Genetics Simple path from genotype to phenotype Primacy of genetic inheritance Selection within populations as primary driver of evolution Opportunistic Uniformitarian

32 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

33 Search Vs Construction Innovation is often described as search through a space of “the adjacent possible” (Kaufmann, Wagner)

34 Grassland Evolution

35 Grass Phylogeny Kellogg, 2001, Plant Physiology

36 Macroevolutionary Lags

37 How are new evolutionary spaces created? Potentiated by broader environmental setting (physical, genetic, ecologic)

38 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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