Angiosperms or Flowering Plants the phylum Magnoliophyta Land Plant Evolution Algae to Angiosperms The greatest adaptive radiation is the largest radiation of plants involves series of dramatic adaptations to the problem of life on land and being nonmotile exhibits successive rounds of speciation and subsequent extinction sets the stage for the development of a land based ecosystem with fungi and animals Angiosperms Flowering Plants Angiosperms focus of the course comprise the phylum Magnoliophyta vast majority of plant diversity Fungi Fungi collectively are not a natural group More closely related to animals than to plants What are the non angiosperm land plants DNA evidence has clarified much but not all of the relatioships of other phyla divisions See first pages of Chpts 1 3 for more detail Plant Systematics 1 Fungi Fungi Turning the Crown Upside Down Gene Tree Parsimony Roots the Eukaryotic Tree of Life Traditional view of eukaryotic relationships Fungi are here Green Plants are here Charales stoneworts Green algal lineage Closest relatives to land plants Katz et al 2012 Systematic Biology Extinct Land Plants the first plants Ordovician Period 505 440 mya First evidence of land life at 460 mya Microfossils of spores with sporopollenin degradation resistant material like lignin and similar to modern day bryophytes such as liverworts Found worldwide in shales that were deposited at the marine terrestrial interface 2 bryophytes bryophytes earliest land plants non vascular gametophyte dominant 16000 species 3 lineages they are not a natural group hornworts mosses mosses Liverworts Marchantiophyta Mosses Bryophyta liverworts liverworts Extinct Land Plants first vascular plants Early Devonian Period 410 390 mya Rhynia seen in the early Devonian Rhynie Chert fossil is one of first vascular plants Hornworts Anthoceratophyta Lycopodiophyta club mosses 3 families 1150 species sporophyte dominant vascular free sporing they are sister to all other vascular plants 20 cm tall no roots no leaves primitive vascular tissue Lycopodium club mosses Isoetes quillworts Selaginella spike mosses 3 Extinct Land Plants the first ferns Late Devonian Period 390 360 mya Polypodiophyta ferns 11000 species immense variation in habit and habitat spores produced in specialized sporangia need a lot of systematic work tropics First true ferns Protopteridium free sporing with complex sporangia megaphylls Polypodiophyta ferns includes the horsetails as unusual ferns 15 species in Equisetum vascular plants reduced leaves terminal sporangia Polypodiophyta ferns includes the strange whish ferns 6 species in 2 genera vascular plants leafless green stemmed lateral sporangia Psilotum habit Psilotum branch Psilotum sporangia 4 Extinct Land Plants the seed plants Extinct Land Plants first gymnosperms Late Devonian Period 390 360 mya Permian Period 286 245 mya First seeds seed ferns Archaeosperma Plants fern like with dissected compound leaves but produce naked seeds embryo within protective coverings Big trees with net veined leaves Seed bearing derived from female gametophyte and pollen forming from male gametophyte Pinophyta gymnosperms 870 species seed plants but seeds naked often divided into 4 phyla is one closer to angiosperms conifers Pinophyta gymnosperms 870 species seed plants but seeds naked often divided into 4 phyla is one closer to angiosperms cycads pine spruce juniper male strobilus female strobili 5 Pinophyta gymnosperms 870 species seed plants but seeds naked often divided into 4 phyla is one closer to angiosperms Pinophyta gymnosperms 870 species seed plants but seeds naked often divided into 4 phyla is one closer to angiosperms gnetophytes mature seeds Gnetum ginkgo Ephedra male strobili Extinct Land Plants first flowering plants Welwitschia mirabilis Magnoliophyta angiosperms Cretaceous Period 146 65 mya Near the Jurassic Cretaceous border the first Angiosperms are seen 275 000 species seed plants with seeds encased in ovary flowers a key innovation Triassic Archaefructus 6 Angiosperms Flowering Plants tremendous adaptive radiation on land and back into water Angiosperms Flowering Plants tremendous adaptive radiation on land and back into water Eucalyptus regnans Myrtaceae over 100m tall and 19m dbh Eucalyptus regnans Myrtaceae Tasmania Angiosperms Flowering Plants tremendous adaptive radiation on land and back into water Angiosperms Flowering Plants tremendous adaptive radiation on land and back into water Wolffia microscopica Araceae less than 1mm long Rafflesia arnoldii Rafflesiaceae from New Guinea up to 1m across and 20lbs 0 1 mm 7 Angiosperms Flowering Plants tremendous adaptive radiation on land and back into water largest inflorescence Amorphophallus titanum Araceae Angiosperms Flowering Plants Angiosperms Flowering Plants tremendous adaptive radiation on land and back into water largest numbers of flowers Corypha palm The Flower Why Important The Flower most significant feature of angiosperms Magnoliophyta classification previously divided into two classes dicots and monocots artificial we will use Angiosperm Phylogeny Group APG III classification system of 2009 1 unlike anything else in other plants extremely variable co evolved with animals 2 floral features used in describing and id ing 3 plant specimens herbarium must include flowers or derived features 4 classification of angiosperms relies on flowers Calochortus fairy lanterns mariposas images T Givnish 8 The Flower What is it specialized shoot stem leaves folia shoot is highly modified and determinate ceased to grow The Flower What is it foliar theory of flower J W von Goethe in Attempt to Interpret the Metamorphosis of Plants 1790 from Schleiden 1855 The Flower What is it developmental evolutionary origin of the flower still debated 1 Euanthial theory foliar theory single shoot anthers The Flower What is it thus a flower is a specialized shoot that 1 is determinate vs indeterminate 2 has a modified stem with compressed internodes ovules 2 Pseudanthial theory compound shoot or cone 3 possesses modified leaves with various functions these determined by gene arrays e g ABC model 9 The Flower What is it The Flower What is it The ABC model of floral part identity The ABC model of floral part identity The Plant Cell 2010 B A C sepals petals stamens carpels The Flower What is it thus a flower is a specialized shoot that The Flower read chpt 9 in Plant Systematics 1 is determinate vs indeterminate 1st half deals with vegetative features