Land Plant Evolution Algae to Angiosperms a nearly 500 million year wait The greatest adaptive radiation a nearly 500 million year story is the largest radiation of plants involves series of dramatic adaptations to the problem of living on land and being nonmotile exhibits successive rounds of speciation and subsequent extinction sets the stage for the development of a landbased ecosystem with fungi and animals Land Plant Evolution Algae to Angiosperms The greatest adaptive radiation know the basic extant land plant lineages today understand the general not the details series of events and timing of the rise and fall of extinct land plant lineages know some of the adaptations for land plant life that arose from Ordovician to Devonian understand the basic arguments on the 4 phylogenetic issues relating to land plant evolution for the evolution of Hordeum and Humulus Ancestors of Land Plants land plants are in a larger lineage of green plants within Plantae a single endosymbiotic event gave rise to plastids land plants are derived from the green algae lineage Ancestors of land plants Base of land plants Base of vascular plants Green Plants are here Relationships among seed plants 1 Extant Land Plants Extant Land Plants hornworts club moss mosses quillwort liverworts Bryophyta bryophytes 16 000 species nonvascular plants primitive land plants gametophyte dominant comprising 3 main groups often 3 phyla Extant Land Plants Lycopodiophyta lycopods spikemoss 1 150 species vascular plants primitive vascular plants sporophyte dominant free sporing comprising 3 families Extant Land Plants Equisetophyta horsetails scouring rushes Psilophyta whisk ferns 15 species in Equisetum vascular plants reduced leaves terminal sporangia sporophyte dominant free sporing 6 species in two genera vascular plants leafless green stemmed lateral sporangia once considered most primitive extant land plant 2 Extant Land Plants Extant Land Plants Pinophyta gymnosperms 870 species seed plants but seeds naked or exposed often divided into 4 phyla ginkgo Polypodiophyta ferns 11 000 species diverse in habit and habitat spores produced in specialized sporangia Extant Land Plants Extant Land Plants Pinophyta gymnosperms Pinophyta gymnosperms 870 species seed plants but seeds naked or exposed often divided into 4 phyla 870 species seed plants but seeds naked or exposed often divided into 4 phyla conifers cycads 3 Extant Land Plants Extant Land Plants Pinophyta gymnosperms 870 species seed plants but seeds naked or exposed often divided into 4 phyla gnetophytes Magnoliophyta angiosperms flowering plants 275 000 species tremendous adaptive radiation on land seed plants with seeds encased in ovary flowers a key innovation innovation Earth Time Earth Time First evidence of life 3 8 bya Oldest fossils 3 5 bya late March 1 4 of earth time gone A different perspective before taking a look at the rise and fall of land plant lineages through time Earth forms at 4 6 bya January 1 12 00 a m Age of the earth 1 calendar year 4 6 billion years 365 days Age of the earth 1 calendar year 4 6 billion years 365 days Stromatolites CaCO 3 ppt by cyanobacteria photosynthesis 4 Earth Time Earth Time O2 accumulates in atmosphere 2 0 bya late July 1 2 of earth time gone CO2 Age of the earth 1 calendar year 4 6 billion years 365 days First eukaryotes 1 5 bya early September 2 3 of earth time gone Starch H2O O2 reducing atmosphere oxidizing atmosphere anaerobe extinction aerobe evolution Earth Time Age of the earth 1 calendar year 4 6 billion years 365 days Earth Time First abundant fossils in Cambrian explosion explosion 560 million years ago Many phyla of animals early November First land life in Ordovician 460 mya a liverwort November 15 7 8ths of earth time gone Spore Tetrad Age of the earth 1 calendar year 4 6 billion years 365 days Burgess Shale Age of the earth 1 calendar year 4 6 billion years 365 days 5 Earth Time Earth Time First angiosperm Jurassic Cretaceous 135 mya December 21 Age of the earth 1 calendar year 4 6 billion years 365 days First human civilization centered on beer production formation of Great Lakes flora vegetation December 31 11 59pm Age of the earth 1 calendar year 4 6 billion years 365 days Barley harvest Mesopotamia 7000ya Extinct Land Plants the Fossil Record Ordovician Period 505 440 mya 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 Extinct Land Plants the Fossil Record Ordovician Period 505 440 mya mya Other evidence of land life Glomales fungi seen in 460 my Wisconsin rock Glomales today form important arbuscular mycorrhizal associations with some liverworts and hornworts and many vascular plants Symbiosis 6 Extinct Land Plants the Fossil Record Extinct Land Plants the Fossil Record Ordovician Period 505 440 mya mya Silurian Period 440 410 mya mya Other evidence of land life Cooksonia fossils are seen in the mid Silurian growing close to water Manitobia patula thallus from Canada an aquatic charophyte algae Extinct Land Plants the Fossil Record Extinct Land Plants the Fossil Record Silurian Period 440 410 mya mya Silurian Period 440 410 mya mya Cooksonia fossils are seen in the mid Silurian growing close to water Late Silurian is also the first occurrence of land animals arachnids centipedes These are predators and thus indicate that there were unknown herbivores community of plants herbivores and carnivores very simple stick like leafless plants but sporophyte dominant no roots are seen terminal sporangia spore producing structures possibly non vascular Silurian view Spider in chert 7 Extinct Land Plants the Fossil Record Extinct Land Plants the Fossil Record Early Devonian Period 410 390 mya mya Early Devonian Period 410 390 mya mya Rhynia seen in the early Devonian Rhynie Rhynie Chert fossil is more complex than Cooksonia part of Rhyniophytes Rhyniophytes Rhynia seen in the early Devonian Rhynie Rhynie Chert fossil is more complex than Cooksonia part of Rhyniophytes Rhyniophytes 20 cm tall no roots no leaves primitive vascular tissue 20 cm tall no roots no leaves primitive vascular tissue Rhynia and other Rhynie Chert plants were infected with the fungus Paleomyces Paleomyces indicating extensive mycorrhizal relationships Extinct Land Plants the Fossil Record Early Devonian Period 410 390 mya