Innovation and Diversity. Douglas H. Erwin National Museum of Natural History Smithsonian Institution Washington, DC USA

Transcription

1 Innovation and Diversity Douglas H. Erwin National Museum of Natural History Smithsonian Institution Washington, DC USA

2 Questions What factors drive innovation, whether in biological, cultural or technological systems? Similar processes of variation, inheritance and selection and drift occur in all systems Understanding processes in one may shed light on the others Goal is to build models of innovation that span different systems

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4 Hawaiian Silverswords

5 Adaptive Radiation of Hawaiian Silverswords Carlquistia California Argyroxiphium sandwicense ssp. macrocephalum Dubautia reticulata Dubautia waialealae Dubautia latifola All photos from Hawaiian Silversword Alliance website

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9 THE CAMBRIAN EXPLOSION REPRESENTS THE CONSTRUCTION OF A DESIGN SPACE

10 THE CAMBRIAN EXPLOSION REPRESENTS THE CONSTRUCTION OF A DESIGN SPACE But how is this space constructed? Genes? Developmental Interactions? Ecological processes?

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

12 Burgess Shale Small Shelly Fauna Chengjiang Fauna Nama Doushantuo Embryos Avalon White Sea Ediacaran Ediacaran Assemblages Trezona

13 Laflamme in prep.

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16 Hurdia victoria Daley et al Science 2009

17 Anomalocaris

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19 Aysheaia

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22 Erwin and Valentine, The Cambrian Explosion, 2013

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

24 Maximal Early Disparity Diversity diversity Disparity disparity Rapid early increase in disparity Proterozoic/Cambrian acritarchs Paleozoic gastropods Paleozoic rostroconchs Ordovician bryozoans Crinoids Paleozoic blastozoans Ordovician trilobites Marine arthropods Insects Angiosperm pollen time

25 IMPORTANCE OF GENOMIC AND DEVELOPMENTAL COMPLEXITY

26 Tree diagram of the birth, transfer, duplication and loss of key genes in the redox and electron transport pathways, in a founding burst of gene evolution between 3.3 and 2.7 billion years ago (David and Alm 2010).

27 Genomic Complexity genome size (Mb) Monosiga Amphimedon Trichoplax Nematostella Drosophila # genes 9,100? 11,514 18,000 14,601 # cell types # T.F. s? min. 87 min. 87 # T.F. families 5 6? microrna (Erwin, 2009; Erwin & Valentine 2013)"

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30 Erwin and Valentine, The Cambrian Explosion, 2013

31 Hypothetical Urbilaterian After Carroll et al 2001

32 Erwin and Valentine, The Cambrian Explosion, 2013

33 Molecular Clock Analysis Concatenated sequences: 7 different housekeeping genes (2055 aa) (Peterson et al. 2004) 118 taxa representing all major metazoan clades 24 calibration points: vertebrate + invertebrate Relaxed molecular clock analyses: CIR clock model in Phylobayes All estimates tested under various sensitivity analyses; all appear robust

34 Cryogenian" Ediacaran" Cambrian"

35 last common" ancestor (LCA) of all living animals" ~ 800 Ma" ( Ma)"

36 LCA of cnidarians & bilaterians" ~ 700 Ma" ( Ma)"

37 LCA of bilaterians" ~ 668 Ma" ( )"

38 last common" ancestor of all " living members" of the phylum"

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40 Sea Urchin dgrn Biotapestry.org

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42 Strongylocentrotus

43 Sea Urchin dgrn Biotapestry.org

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

45 Nature of Kernels Recursively wired regulatory genes Specify the spatial domain of a part of the developing embryo, often a regional pattern The kernels are dedicated to development and are not re-used elsewhere Interference with the function of any gene will destroy kernel function This forces subsequent evolutionary change either upstream or downstream of the kernel

46 Implications There is a structure to the network of developmental regulatory interactions Changes in some parts of regulatory networks are easier than in others Some types of changes, particularly the establishment of kernels, appears to have been easier early in metazoan evolution; these kernels are now highly refractory to modification

47 BUT GENES ALONE ARE NOT SUFFICIENT: THE ROLE OF ECOLOGY

48 Cambrian Predators Ottoia Anomalocaris Pikaia

49 Vertebrates ~ 515 Ma Nemerteans ~ 546 Ma Chaetognaths ~ 540 Ma

50 Fedonkin et al The Rise of Animals, 2007

51 Crassostrea virginica Image: WHOI

52 Ecosystem Engineering From Eric Heupel UConn.mp

53 Ecosystem Engineering Species 1" Gene pool" Natural selection Ecological" Spillover" Et! Natural selection Species 2" Gene pool" Genetic inheritance" Ecological inheritance" Genetic inheritance" Gene pool" Natural selection Ecological" Spillover Et+1! Natural selection Gene pool"

54 Types of Ecosystem Engineering Physical Engineering: Construction of physical structures (reefs, ) Chemical Engineering: Modification of the geochemical environment redox.

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

56 IMPORTANCE OF MACROEVOLUTIONARY LAGS

57 Increase in mirna families; complexity of dgrn interactions Origin of Developmental Toolkit Origin of Eumetazoa Most signalling pathways present

58 Grassland Evolution

59 Grass Phylogeny Kellogg, 2001, Plant Physiology

60 Macroevolutionary Lags

61 Invention & Innovation Invention is the creation of something new and distinct (contrast with variation on established themes) Innovation occurs when inventions become economically or ecologically significant Joseph Schumpeter (

62 FLICKERING OF INNOVATION IN EARLY HOMO SAPIENS If at first you don t succeed..

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64 Chauvet Cave, France, 32,000 years old

65 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

66 Simpson t Adaptive Zones

67 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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