Darwin’s AbominableMystery. . . origin of angiosperms . . .Great Mysteries to ZoologistsArchaeopteryxRise of the birds from a dinosaur lineageGreat Mysteries to ZoologistsEdmontosaurusDemise of the non-aviandinosaur lineageGreat Mysteries to ZoologistsEocene inKansasAdaptive radiation ofmammals after dinosaursKT eventGreatest Mystery to BotanistsOrigin and rise ofangiospermsAngiosperm DominanceAngiosperm DominanceAngiosperm DominanceAngiosperm DominanceAngiosperm DominanceGymnosperm DominanceGymnosperm DominanceAngiosperms have NOT always dominatedFossil Recordas seen by Charles Darwin• ferns, cycads, ginkos, conifers -the Triassic/Jurassic• flowering plants suddenly showup at start of Cretaceous• tree-like lycopods, horsetails,primitive gymnosperms - theCarboniferousFossil Record• by mid-Cretaceous, 50 familiesof angiosperms seen• including 5 monocot• including 4 ament/catkinbearingas seen by Charles DarwinFossil Record• by mid-Cretaceous, angiosperms also dominate the face ofthe earth (based on fossil diversity)as seen by Charles Darwin% of total fossilsthe Abominable Mystery “The rapid development, as far as we canjudge, of all the higher plants within recentgeological time is an abominable mystery”Director of the KewRoyal Botanic Gardenand good friend ofDarwin (the onlyacknowledged person inthe “Origin of Species”)Joseph Dalton Hooker(Darwin, 1879, in a letter toHooker)the Abominable Mystery(page 3, letter of 22 July 1879)- Continues with speculations onhow to answer the mystery• originated in alpineconditions• arose in response to riseof ‘flower-frequentinginsects’• originated in isolatedtropical islandthe 2012 Questions1. When did the Angiosperms arise?2. What were the first Angiosperms?3. Where did the Angiosperm arise?4. From what Gymnosperm cladedid the Angiosperms arise ?5. Why did they take over the world’s flora?2009 AJBvolumethe 2012 Evidence1. Modern fossil record2. Geographical distributions3. Morphological phylogenetics4. Evo-devo studies of flowers5. Molecular phylogenetics6. Molecular “clocks”• Pollen• Leaves• Flowers• FruitPollen Record• ubiquitous - preserves well due to exine layer• often diagnostic to specific gymnosperm or angiospermgroupsPollen Record• ubiquitous - preserves well due to exine layer• often diagnostic to specific gymnosperm or angiospermgroups• but different levels of production and fossilization• abundant pine pollen in lake sediments• little Senecio pollen in tropicsPollen Record• gymnosperm vs. early angiosperm pollen differentiationoften requires TEM vs. SEM visualization - both one poredPollen Record• all pre-Cretaceouspollen = gymnosperm• Barr.-Aptian (125mya)= oldest tricolpate pollen(eudicots)• Neocomian (130mya)= oldest angiospermsingle pored pollen(basal angiosperms)Jim Doyle - UC DavisPollen Record• magnoliids• monocots• cordate-leavedeudicots• aments - windpollinatedAlbian (110 mya)diversityUpper Cretaceous (100mya) - angiospermpollen dominatesPollen Record• pollen diversification continues through Upper Cretaceousinto Tertiary• family Asteraceaefirst seen in midEocene: 47mya• genus Fuchsia(Onagraceae) firstseen 30mya inOligoceneLeaf Record• consistent trends emerge with leaf fossils• Neocomian (130mya)Rogersia (basalangiosperm) simple,pinnately veined, entireLeaf Record• consistent trends emerge with leaf fossils• Aptian to Albian (120-110mya) = magnoliids(pinnate veins), cordates(palmate veins),monocots (parallelveins)• early Aptian (125mya)Archaefructus (basalangiosperm) palmatelycompoundLeaf Record• consistent trends emerge with leaf fossils• Aptian to Albian (120-110mya) = magnoliids(pinnate veins), cordates(palmate veins),monocots (parallelveins)• early Aptian (125mya)Archaefructus (basalangiosperm) palmatelycompoundgreat leaf diversity within 15myLeaf Record• consistent trends emerge with leaf fossils• by Upper Cretaceous(100mya) a variety ofprimitive eudicot leavesare seenPlatanoid - lobedSapindopsis - compoundLeaf Record• consistent trends emerge with leaf fossils• by Upper Cretaceous(100mya) a variety ofprimitive eudicot leavesare seenFlower Record• the “Magnolia = primitive” idea has biased the waypaleobotanists have looked at the fossil record1. bisexual flower2. ∞ spirally arranged stamens &carpels3. ∞ perianth parts4. cone-like receptacle5. beetle pollination• what does the fossil recordactually say?Flower Record• large flowered, insect-pollinated flowers are seen (such asthese 98-90 mya mid-late Cretaceous fossils) . . .Archaeanthus (Magnoliaceae) –from Kansas 98-95myaMagnoliaceae withstingless bee – 90myaFlower Record• large flowered, insect-pollinated flowers are seen (such asthese 95-85 mya late Cretaceous fossils) . . . . . . but the earliest and mostnumerous are small, bisexual orunisexual, wind or insect-pollinatedFlower Record• what are the earliest fossil flowers?1990 - Leo Hickey• 120 mya - Australia• small, unisexual flowers• placed into Piperales(pepper, wild ginger)Flower Record• what are the earliest fossil flowers?1996 - Chris Hill• Bevhalstia pebia• 130 mya - England• small, 25cm aquaticherb• dissected leavesFlower Record• what are the earliest fossil flowers?1998 - David Dilcher & Chinesecolleagues –read Sun et al.!• Archaefructus• 125 [135 1st] mya - China• small, dissected leaves• stamens and carpels on long axisFlower Record• what are the earliest fossil flowers?• morphology phylogenetic[some!] analyses place it beforeAmborellaFlower Record• what are the earliest fossil flowers?2011 - David Dilcher & Chinesecolleagues again• Leefructus• 122mya - China• first Eudicot• Ranunculaceae?Summary of AngiospermEvolution1. When did the Angiosperms arise?• Fossils - after boundary of Jurassic and Cretaceous -130mya• DNA - some molecular clocks suggest >200myaMagallón 2010Stem lineage• stem nodewith livinggymnosperms• crown nodeof livingangiosperms350mya225myaSummary of AngiospermEvolution1. When did the Angiosperms arise?• perhaps older but unseen (in fossil record) radiationof angiosperms• perhaps older radiation but we can’t tell them apartfrom ancestors (share features of gymnosperms andsome but not all of angiosperms)Summary of AngiospermEvolution2. What were the first Angiosperms?• “Magnolia = primitive” not justified• Amborella and water lilies are first extant taxa toseparateSummary of