Innovation and Diversity
Douglas H. Erwin National Museum of Natural History Smithsonian Institution Washington, DC USA 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
Hawaiian Silverswords Adaptive Radiation of Hawaiian Silverswords
Carlquistia California
Argyroxiphium Dubautia sandwicense reticulata ssp. macrocephalum
Dubautia waialealae Dubautia latifola All photos from Hawaiian Silversword Alliance website
THE CAMBRIAN EXPLOSION REPRESENTS THE CONSTRUCTION OF A DESIGN SPACE THE CAMBRIAN EXPLOSION REPRESENTS THE CONSTRUCTION OF A DESIGN SPACE
But how is this space constructed? Genes? Developmental Interactions? Ecological processes? Erwin and Valentine, The Construction of Animal Biodiversity, 2013 Burgess Shale
Chengjiang Small Shelly Fauna Fauna
Nama
White Sea – Ediacaran Avalon Doushantuo Embryos Ediacaran Assemblages
Trezona Laflamme in prep.
Hurdia victoria
Daley et al Science 2009 Anomalocaris
Aysheaia
Erwin and Valentine, The Cambrian Explosion, 2013 Erwin and Valentine, The Construction of Animal Biodiversity, 2013 Maximal Early Disparity
Rapid early increase in disparity – Proterozoic/Cambrian acritarchs – Paleozoic gastropods – Paleozoic rostroconchs – Ordovician bryozoans – Crinoids – Paleozoic blastozoans – Ordovician trilobites – Marine arthropods Diversitydiversity – Insects Disparity – Angiosperm pollen disparity
time IMPORTANCE OF GENOMIC AND DEVELOPMENTAL COMPLEXITY 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). Genomic Complexity
Monosiga Amphimedon Trichoplax Nematostella Drosophila genome 41.6 167 98 450 180 size (Mb) # genes 9,100 ? 11,514 18,000 14,601 # cell types 1 12 4 20 50 # T.F.’s ? 57 35 min. 87 min. 87 # T.F. 5 6? 9 10 10 families microRNA 0 8 0 40 152
(Erwin, 2009; Erwin & Valentine 2013)
Erwin and Valentine, The Cambrian Explosion, 2013 Hypothetical Urbilaterian
After Carroll et al 2001 Erwin and Valentine, The Cambrian Explosion, 2013 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 Cryogenian Ediacaran Cambrian last common ancestor (LCA) of all living animals