What is the PanspermiaHypothesis? Molecular phylogeneticsand other tree termsroot of a treecladogram vs phylogramalignment (nucleotide homology)gaps and substitutionstransition-transversion biasbase composition biasrate variation in DNAgenetic distancemaximum likelihood and use ofevolutionary modelsbootstrap analysisApiniMeliponiniBombiniEuglossiniAdvanced eusocialityPrimitive eusocialitySolitary to communalApiniMeliponiniBombiniEuglossiniMORPHOLOGYApiniMeliponiniBombiniEuglossiniDNAAre the taxa with highly eusocialcharacteristics monophyletic??Apis mel.Apis nigApis dor.EufrieseaExaereteEulaemaEuglossaBombus avi.Bombus pen.Bombus ter.MeliponaScaptotrigonaTetragonaTrigonaLestrimelittaMelissodesAnthophoraHabropodaXylocopaCentrisHoney beesOrchid beesBumble beesStingless beesOpsin + Cyt b + 28S + 16SApiniMeliponiniBombiniEuglossiniOutgroupApiniMeliponiniBombiniEuglossiniOutgroup+——++3 changes3 changes+Variation in Highly Social Traits Honey bees• swarming: old queen• progressively provision• recruit by dance• queen multiply mated• nest architecture Stingless bees• swarming : new queen• mass provision larvae• recruit by odor trails• queen singly mated• nest architecturewaxwax and resinTerms for how life beganribozymeTetrahymena thermophilapanspermia hypothesisMurchison meteoritecarbonaceous chondritesCHON S POparin-Haldane modelmontmorilloniteEvolution: What is it?“Descent with modification” (Darwin, Origin, 1859)Descent with modificationHow Did Life Begin?4 Billion Ma1. What was Earth’s environment like when life arose?2. How is life defined, and how did it arise from non-life?3. What were the characteristics of the very first cells?HARD QUESTIONSWhat is Life?• Ability to store and transmit information= having a genotype• Ability to express that information= having a phenotype• Ability to evolve= change over timeWhat came first? Protein DNARibozymeTetrahymena thermophila genotypephenotypeRNA evolution in a test tubeQ! RNA VirusTest tube evolution of RibozymeTetrahymenaTetrahymena ribozyme generation 1generation 9Formation rate of ribozyme phosoester bondsIncrease incatalyticactivityPanspermiaLife elsewhere in the Universe?Fossil Bacteria?Monomers of CHONStanleyMiller’sApparatus(1953)Glycine,AlanineOparin- Haldane ModelMurchison Meteoritealanine,glycineprolinevalineproteinsNucleotidesChain 10 bases long10-base nucleotides bind to clay20 bp11 bp(montmorillonite)Assemblage of biological polymersOldest known sedimentary rocksBanded iron formation, Akilia Island,Greenland-- 3.8 billion years oldCarbonaceous apatite crystalAkilia Island, Greenland3.8 billion years oldInclusion in crystal, perhaps produced by livingorganism (ratio 12C to 13 C)History of ImpactsEarthApex Chert Fossils of Western Australia3.5 billion yrs. Living1.5 billionLivingLivingLiving850 Ma950 MaCyanobacteriaJ. W. SchopfCr adle of Life ( 1999)2.1
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