Paleo-Biogeography - Lecture Slides | BOTANY 422, Study notes of Geography

Download Paleo-Biogeography - Lecture Slides | BOTANY 422 and more Study notes Geography in PDF only on Docsity! 1 Paleo-biogeography Paleo-biogeography Paleobiogeography is an exciting (and re-emerging) field that involves knowledge of paleo-geology, paleo- climates, paleo-vegetation, and paleo-floras We will examine the rise of land vegetation and floras and specifically in N. America and the Great Lakes region by using information from paleobiogeography • paleo floras - plants moving onto land over 400 mya and becoming the dominant set of terrestrial organisms • modern floras - diversification of land plants and especially flowering plants over the last 100 my • ice age events (Pleistocene - last 2.5 my) and the assembly of vegetation and flora in Great Lakes region during recent times (Holocene) Paleo-biogeography Extant Land Plants Green Plants are here The story of paleo- biogeography on earth involves “land plants” and so we will exclude green algae from our review of extant land plants 2 Extant Land Plants Bryophyta - bryophytes • 16,000 species • nonvascular plants, most primitive land plants • comprising 3 main groups (now 3 phyla) liverworts mosses hornworts Extant Land Plants Bryophyta - bryophytes hornworts Extant Land Plants • hornworts are sister to all other land plants • liverworts are the first diverging land plants liverworts Lycopodiophyta - lycopods • 1,150 species • vascular plants, most primitive vascular plants • sporophyte dominant; free sporing • comprising 3 families spikemoss quillwort club moss Extant Land Plants 5 • 870 species • seed plants but seeds naked or exposed • often divided into 4 phyla ginkgo Extant Land Plants Pinophyta - gymnosperms • 870 species • seed plants but seeds naked or exposed • often divided into 4 phyla gnetophytes Extant Land Plants Pinophyta - gymnosperms Magnoliophyta - angiosperms, flowering plants • 275,000 species • tremendous adaptive radiation on land • seed plants with seeds encased in ovary Extant Land Plants Extant Land Plants Magnoliophyta - angiosperms, flowering plants • 275,000 species • tremendous adaptive radiation on land • seed plants with seeds encased in ovary • flowers a “key innovation” 6 Earth Time Age of the earth = 1 calendar year 4.6 billion years = 365 days Earth forms at 4.6 bya = January 1, 12:00 a.m. A different perspective before taking a look at the rise and fall of floras and faunas through time . . . First evidence of life - 3.8 bya Oldest fossils - 3.5 bya = late March (1/4 of earth time ) Age of the earth = 1 calendar year 4.6 billion years = 365 days Stromatolites - CaCO3 ppt by cyanobacteria = photosynthesis! Earth Time O2 accumulates in atmosphere - 2.0 bya = late July (>1/2 of earth time) Age of the earth = 1 calendar year 4.6 billion years = 365 days CO2 + H2O Starch + O2 reducing atmosphere oxidizing atmosphere anaerobe extinction aerobe evolution Earth Time First eukaryotes - 1.5 bya = early September (2/3 of earth time gone) Age of the earth = 1 calendar year 4.6 billion years = 365 days Earth Time 7 First abundant fossils in Cambrian “explosion” - 560 million ya Many phyla of animals = early November Age of the earth = 1 calendar year 4.6 billion years = 365 days Burgess Shale Earth Time First land life in Ordovician - 460 mya (a liverwort?) = November 15 (7/8ths of earth time gone!) Age of the earth = 1 calendar year 4.6 billion years = 365 days Spore Tetrad Earth Time First flowering plant - 135 mya = December 22 Age of the earth = 1 calendar year 4.6 billion years = 365 days Earth Time Earliest civilization of Homo sapiens and assembling of Great Lakes flora - 13,000 ya = December 31, 11:59 p.m. Age of the earth = 1 calendar year 4.6 billion years = 365 days Conifers enter Great Lakes region Earth Time 10 • 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! Extinct Land Plants - the Fossil Record Ordovician Period (505 - 440 mya) • Other evidence of land life Manitobia patula thallus from Canada - a terrestrial algae Extinct Land Plants - the Fossil Record Ordovician Period (505 - 440 mya) Silurian Period (440 - 410 mya) In earliest Silurian, the fossil Parka is first seen. Coleochate - charalean green alga Questions about its affinitiy are not answered; it resembles charalean green algae - a lineage that is now shown to be the closest to land plants Extinct Land Plants - the Fossil Record Cooksonia fossils are seen in the mid Silurian growing close to water Extinct Land Plants - the Fossil Record Silurian Period (440 - 410 mya) 11 Cooksonia fossils are seen in the mid Silurian growing close to water • very simple, stick-like, leafless plants but sporophyte dominant • roots never seen • terminal sporangia (spore producing structures) • possibly non-vascular • first seen in Euramerica (tropical setting) and later in Australia Silurian Period (440 - 410 mya) Extinct Land Plants - the Fossil Record Euramerica In the late Silurian, the lycopsid (Lycopodiophyta) fossil Barawagnathia is seen in Australia- possibly the first vascular plant Lycopodiophyta is the first lineage to diverge within extant vascular plants Silurian Period (440 - 410 mya) Extinct Land Plants - the Fossil Record Primitive leaves - microphylls - are first seen in this fossil Derived from enations or outgrowths of the stem which are then vascularized Silurian Period (440 - 410 mya) Extinct Land Plants - the Fossil Record In the late Silurian, the lycopsid (Lycopodiophyta) fossil Barawagnathia is seen in Australia- possibly the first vascular plant Lycopodiophyta is the first lineage to diverge within extant vascular plants Extinct Land Plants - the Fossil Record Cooksonia Barawagnathia 12 Late Silurian is also the first occurrence of land animals - arachnids, centipedes Predators and thus indicate that there were unknown herbivores - community of plants, herbivores and carnivores! Silurian view Trigonotarbid Spider in chert Silurian Period (440 - 410 mya) Extinct Land Plants - the Fossil Record Early Devonian Period (410 - 390 mya) The ‘greening’ of the earth Extinct Land Plants - the Fossil Record Abundant and esquisite fossils known from chert fossil beds in Rhynie, northern Scotland (tropical Euramerica) Early Devonian Period (410 - 390 mya) Rhynia seen in the early Devonian (Rhynie Chert fossil) is more complex than Cooksonia (part of Rhyniophytes) 20 cm tall, no roots, no leaves, primitive vascular tissue Extinct Land Plants - the Fossil Record Similarity to present day whisk ferns (Psilotum) had given rise to the long-held idea that Psilotum was the first diverging lineage of vascular plants Now known that Psilotum is just a reduced fern Extinct Land Plants - the Fossil Record Early Devonian Period (410 - 390 mya) Rhynia seen in the early Devonian (Rhynie Chert fossil) is more complex than Cooksonia (part of Rhyniophytes) 20 cm tall, no roots, no leaves, primitive vascular tissue 15 Rhynia Extinct Land Plants - the Fossil Record The Early Devonian lasted some 30 million years after the first appearance in mid- Silurian of simple land plants During this interval the critical features of land plant survival evolved: Early Devonian Period (410 - 390 mya) • epidermis, cuticle, stomates • internal transport - vascular tissue • primitive leaves • underground (root) and above ground photosynthetic stem • rhizoids (water uptake) • support tissue - lignin • shift to sporophyte rather than gametophyte dominant • sporopollenin to cover spores for protection gametophyte sporophyte Extinct Land Plants - the Fossil Record The Early Devonian lasted some 30 million years after the first appearance in mid- Silurian of simple land plants During this interval the critical features of land plant survival evolved: Early Devonian Period (410 - 390 mya) • epidermis, cuticle, stomates • internal transport - vascular tissue • primitive leaves • underground (root) and above ground photosynthetic stem • rhizoids (water uptake) • embryo Extinct Land Plants - the Fossil Record Early Devonian Period (410 - 390 mya) The Early Devonian lasted some 30 million years after the first appearance in mid- Silurian of simple land plants During this interval the critical features of land plant survival evolved: • support tissue - lignin • shift to sporophyte rather than gametophyte dominant • sporopollenin to cover spores for protection • epidermis, cuticle, stomates • internal transport - vascular tissue • primitive leaves • underground (root) and above ground photosynthetic stem • rhizoids (water uptake) First “progymnosperms” - believed to be ancestors of seed plants Extinct Land Plants - the Fossil Record Late Devonian Period (390 - 360 mya) Archaeopteris 16 First “progymnosperms” - free sporing like ferns but trees like gymnosperms; first forests Archaeopteris Extinct Land Plants - the Fossil Record Late Devonian Period (390 - 360 mya) First complex leaves - megaphylls Archaeopteris Extinct Land Plants - the Fossil Record Late Devonian Period (390 - 360 mya) Extinct Land Plants - the Fossil Record Late Devonian Period (390 - 360 mya) Eospermatopteris trunks from New York recently connected to Wattieza fern like crown. 385 my old forests of at least 8m tall trees with primitive root systems. Extinct Land Plants - the Fossil Record Late Devonian Period (390 - 360 mya) 17 First true ferns - free sporing with complex sporangia & megaphylls Protopteridium Pteridium - Bracken fern Extinct Land Plants - the Fossil Record Late Devonian Period (390 - 360 mya) Rhacophyton and the rarer Gillespiea were understory ferns in the Archaeopteris forests. Rhacophtyon produced enough biomass, that the first records of forest fires are seen in the Catskill fossil sites Extinct Land Plants - the Fossil Record Late Devonian Period (390 - 360 mya) Rhacophyton Gillespiea First “seeds” - “seed fern” lineage Plants fern-like with dissected compound leaves, but produce naked seeds (embryo within protective coverings) Archaeosperma Extinct Land Plants - the Fossil Record Late Devonian Period (390 - 360 mya) • Great diversity of plants in warm, wet climate and no apparent provincialism yet seen - worldwide • Arthropods diversify and first amphibians seen by late Devonian Ichthyostega Hynerpeton Extinct Land Plants - the Fossil Record Late Devonian Period (390 - 360 mya) 20 Calamites was the dominant large tree-like horsetail (sphenopsid); but other smaller horsetails covered the ground Annularia Extinct Land Plants - the Fossil Record Carboniferous Period (360 - 286 mya) “Seed ferns” continue to diversify Extinct Land Plants - the Fossil Record Carboniferous Period (360 - 286 mya) First indication of insect pollination - insect movement of male pollen (microgametophyte) to egg in female gametophyte in Medullosa Medullosa Extinct Land Plants - the Fossil Record Carboniferous Period (360 - 286 mya) “Seed ferns” continue to diversify At the end of the Paleozoic, Pangaea begins to coalesce Tethys Sea forms and allows for provincial floras to develop Permian Period (286 - 245 mya) Extinct Land Plants - the Fossil Record 21 Herbivorous insects and reptiles diversify Lycopods and sphenopsids still dominate, but true ferns, “seed ferns”, ginkgophytes, cycadophytes, and cone bearing gymnosperms begin to replace them Extinct Land Plants - the Fossil Record Permian Period (286 - 245 mya) Cathaysia • Rich, rain-forest • Seed ferns, lycopsids, sphenopsids Continentality - mid continent aridity first seen Extinct Land Plants - the Fossil Record 3 provincial floras develop in response to continentality and still separated land masses Permian Period (286 - 245 mya) Angarar • Cordaites conifers • Northern hemisphere mainly Possible forerunners to modern conifers beginning to be seen with fossils such as Cordaites with cones Fossilized trunks common around Welwitschia sites in the Namib Desert region Extinct Land Plants - the Fossil Record Permian Period (286 - 245 mya) Gondwana • Glossopterids Extinct Land Plants - the Fossil Record Cathaysia • Rich, rain-forest • Seed ferns, lycopsids, sphenopsids Continentality - mid continent aridity first seen 3 provincial floras develop in response to continentality and still separated land masses Permian Period (286 - 245 mya) Angarar • Cordaites conifers • Northern hemisphere mainly 22 South of the tropical flora dominated by lycopsids, sphenopsids, and seed ferns existed the Glossopterid flora • Big trees with net-veined leaves • Seed bearing (derived from female gametophyte) and pollen forming (from male gametophyte) Biogeographically ties together flora of Gondwana “Gond” = site in India where Glossopterid fossils first seen “Gondwana” = “land of Gond” Extinct Land Plants - the Fossil Record Permian Period (286 - 245 mya) Remember! Wegener described both plant and animal fossil examples supporting his theory — he believed that this biogeographic data was the strongest evidence for his theory Glossopteris - Permian seed plants Mesosaurus - Permian freshwater reptile Cynognathus - Triassic land reptile Lystrosaurus - Triassic land reptile Extinct Land Plants - the Fossil Record Permian Period (286 - 245 mya) End of the Paleozoic Era (245 mya) By the end of Permian and the Paleozoic Era, land life had seen: • Charophycean green algae • Bryophytes • early non-vascular and vascular lineages • Lycopodiophyta • Pteridophytes (ferns and allies) • Progymnosperms (free sporing) • Early seed plants including Glossopterids, seed ferns, conifers, cycadophytes, ginkgophytes Extinct Land Plants - the Fossil Record