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  • Figure 30.3 From ovule to seed in a gymnosperm
  • Figure 30.6 The life cycle of a pine
  • Figure 30.6 The life cycle of a pine
  • Figure 30.6 The life cycle of a pine
  • Figure 30.6 The life cycle of a pine
  • Figure 30.6 The life cycle of a pine
  • Figure 30.10 The life cycle of an angiosperm
  • Figure 30.10 The life cycle of an angiosperm
  • Figure 30.10 The life cycle of an angiosperm
  • Figure 30.10 The life cycle of an angiosperm
  • Figure 30.10 The life cycle of an angiosperm

biodiversity of plants biodiversity of plants Presentation Transcript

  • UNIT 3:BIODIVERSITYOF PLANTSCampbell & Reece (2010);Chapter 29 and 30http://en.wikipedia.org/wiki/File:Diversity_of_plants_image_version_2.png
  • 290, 000 known plant speciesLand plants enabled survival of other lifeforms on land – including animalsRoots provide habitats, stabilize landscapesOxygen supplyUltimate provider of food eaten by terrestrialanimals
  • Common (derived) traits of land plants –separate them from ancestral plants (algalrelatives):Alteration of generations & multicellular,dependent embryo’sWalled spores produced in sporangiaMulticellular gametangiaApical meristems
  • Alteration of GenerationsThe life cycle includes bothmulticellular haploid (n) &multicellular diploid (2n)organisms
  • Multicellular, Dependent EmbryosAfter fertilization zygote develops intoa multicellular embryo within maternalstructures.Maternal tissues provide nutrients.Embryo is dependentLand plant called embryophytes.
  • Walled Spores Produced in SporangiaSporophyte produces spores in organs calledsporangiaDiploid cells called sporocytes undergomeiosis – generate (n) sporesSpore walls containsporopollenin:resistant to harshenvironments
  • Multicellular GametangiaGametes produced in multicellular organs – gametangia.Female gametangia – archegonia – produce single eggMale gametangia – antheridia - produce & release sperm– fertilize egg internallywithin the archegonium
  • Apical MeristemsPlants sustain continual growth inapical meristemsCells from apical meristems differentiate into varioustissues1) Elongation of the rootsNutrients & water from soil2) Growth of stems & leavesMore area for photosynthesis
  • GROUPING OF LAND PLANTS• Ancestral species gave rise to a vast diversity ofmodern plants• Land plants informally grouped based onpresence or absence of vascular tissue• Most plants have vascular tissue; theseconstitute the vascular plants• Nonvascular plants are commonly calledbryophytessites.google.com
  • GROUPING OF LAND PLANTS• Seedless vascular plants can be divided:– Lycophytes (club mosses and their relatives)– Pterophytes (ferns and their relatives)contrib.andrew.cmu.eduquizlet.comen.wikipedia.orgbiology.iastate.edu
  • GROUPING OF LAND PLANTS• Seed plants• A seed is an embryo and nutrients surrounded bya protective coat• Seed plants can be divided into:– Gymnosperms, the “naked seed” plants, includingthe conifers– Angiosperms, the flowering plants
  • GYMNOSPERMS ANGIOSPERMSvisual.merriam-webster.combluebellnursery.com• Conifers (seeds not enclosed)• “Naked seed”• All flowering plants• 90% of living plant species• Seeds develop in ovaries –originate within flowers & matureinto fruitsbiology.iastate.eduucadia.com
  • Bryophyta (non-vascular plants)(p. 606 – 609)• Phylum includes all mosses (Bryophyta)• Bryophytes: all non-vascular plants– Include liverworts, hornworts & mosses• Mosses show alternation of generations– i.e. have sporophyte & gametophyte generationtolweb.orgflickrhivemind.netbryophytes.plant.siu.edu anbg.gov.au forums.gardenweb.com
  • Bryophyta• In all bryophytes gametophytes are dominantin life cycle• Larger & longer living than sporophytetolweb.orgflickrhivemind.netbryophytes.plant.siu.edu forums.gardenweb.combotany.hawaii.edu
  • KeyHaploid (n)Diploid (2n)Protonemata(n)“Bud”“Bud”Malegametophyte(n)Femalegametophyte (n)GametophoreRhizoidSporesSporedispersalPeristomeSporangiumMEIOSIS SetaCapsule(sporangium)FootMaturesporophytesCapsule withperistome (SEM)Femalegametophytes2mmRaindropSpermAntheridiaEggArchegoniaFERTILIZATION(within archegonium)Zygote(2n)EmbryoArchegoniumYoungsporophyte(2n)THE MOSS LIFE CYCLED:Chapter_29A_PowerPoint_Lectures29_Lecture_Presentation29_08MossLifeCycle_A.html
  • KeyHaploid (n)Diploid (2n)Protonemata(n)“Bud”“Bud”Malegametophyte(n)Femalegametophyte (n)GametophoreRhizoidSporesSporedispersalPeristomeSporangiumMEIOSIS SetaCapsule(sporangium)FootMaturesporophytesCapsule withperistome (SEM)Femalegametophytes2mmTHE MOSS LIFE CYCLE
  • KeyHaploid (n)Diploid (2n)Protonemata(n)“Bud”“Bud”Malegametophyte(n)Femalegametophyte (n)GametophoreRhizoidSporesSporedispersalPeristomeSporangiumMEIOSIS SetaCapsule(sporangium)FootMaturesporophytesCapsule withperistome (SEM)Femalegametophytes2mmRaindropSpermAntheridiaEggArchegoniaFERTILIZATION(within archegonium)THE MOSS LIFE CYCLE
  • KeyHaploid (n)Diploid (2n)Protonemata(n)“Bud”“Bud”Malegametophyte(n)Femalegametophyte (n)GametophoreRhizoidSporesSporedispersalPeristomeSporangiumMEIOSIS SetaCapsule(sporangium)FootMaturesporophytesCapsule withperistome (SEM)Femalegametophytes2mmRaindropSpermAntheridiaEggArchegoniaFERTILIZATION(within archegonium)Zygote(2n)EmbryoArchegoniumYoungsporophyte(2n)THE MOSS LIFE CYCLED:Chapter_29A_PowerPoint_Lectures29_Lecture_Presentation29_13FernLifeCycle_A.html
  • VASCULAR PLANTSLIVING VASCULAR PLANTS CHARACTERISED BY:• Life cycles with dominant sporophytes– Fern life cycle• Transport in vascular tissues– Xylem and phloem• Well-developed roots and leaves– Including spore bearing leaves called sporophylls
  • Pterophyta(p. 610 – 615)• Phylum includes all ferns, horsetails & whisk ferns• Vascular seedless plants– Vascular means plants could grow taller than bryophytes• Ferns show alternation of generations (dominantsporophyte)• Sperm flagellated – must swim through water to reach eggsi.e. found in damp environmentstolweb.orgflickrhivemind.netbryophytes.plant.siu.edu forums.gardenweb.combotany.hawaii.edu
  • KeyHaploid (n)Diploid (2n)MEIOSISSporedispersalSporangiumSporangiumMaturesporophyte(2n)SorusFiddleheadSpore(n)YounggametophyteMaturegametophyte(n) ArchegoniumEggAntheridiumSpermFERTILIZATIONNewsporophyteGametophyteZygote(2n)THE FERN LIFE CYCLED:Chapter_29A_PowerPoint_Lectures29_Lecture_Presentation29_13FernLifeCycle_A.html
  • KeyHaploid (n)Diploid (2n)MEIOSISSporedispersalSporangiumSporangiumMaturesporophyte(2n)SorusFiddleheadTHE FERN LIFE CYCLE
  • KeyHaploid (n)Diploid (2n)MEIOSISSporedispersalSporangiumSporangiumMaturesporophyte(2n)SorusFiddleheadSpore(n)YounggametophyteMaturegametophyte(n) ArchegoniumEggAntheridiumSpermFERTILIZATIONTHE FERN LIFE CYCLE
  • KeyHaploid (n)Diploid (2n)MEIOSISSporedispersalSporangiumSporangiumMaturesporophyte(2n)SorusFiddleheadSpore(n)YounggametophyteMaturegametophyte(n) ArchegoniumEggAntheridiumSpermFERTILIZATIONNewsporophyteGametophyteZygote(2n)THE FERN LIFE CYCLED:Chapter_29A_PowerPoint_Lectures29_Lecture_Presentation29_13FernLifeCycle_A.html
  • Transport in Vascular Tissues• Two types of vascular tissue:• Xylem and phloem• Xylem conducts water & minerals• Dead cells called tracheids• Phloem distributes sugars, amino acids, & other organicproducts• Consists of living cells• Water-conducting cells are strengthened by ligninand provide structural support
  • Evolution of Roots• Benefits of lignified vascular tissue belowground• Instead of rhizoids, roots evolved– May have evolve from subterranean stems• Roots: organs to absorb water & nutrientsfrom soil• Also anchor vascular plants
  • Evolution of Leaves• Leaves increase surface area of plant body• Main photosynthetic organ of vascular plants• Classified as:– Microphylls (only lycophytes) – leaves with asingle vein– Megaphylls (all vascular plants) – highly branchedvascular system• Greater photosynthetic productivity
  • Sporophylls and Spore Variations• Sporophylls are modified leaves withsporangia• Sori are clusters of sporangia on theundersides of sporophylls• Strobili are cone-like structuresformed from groups of sporophylls
  • • Most seedless vascular plants are homosporous• Produce one type of spore that develops into a bisexualgametophyte• All seed plants (and some seedless vascular plants)are heterosporous• Produce megaspores that give rise to femalegametophytes• And microspores that give rise to male gametophytesSporophylls and Spore Variations
  • SEED PLANTS• Seeds changed the course of plant evolution– Plants with seeds would become dominantproducers in most terrestrial ecosystems• Living seed plants can be divided into two:– Gymnosperms– Angiosperms• A seed consists of an embryo and nutrientssurrounded by a protective coat
  • SEED PLANTS5 DERIVED TRAITS: (COMMON TO ALL SEED PLANTS)1. Reduced gametophytes– Develop in walls of spores that are retained in tissues ofparent sporophyte2. Heterospory– Megasporangia produce megaspores (femalegametophytes)– Microsporangia produce microspores (malegametophytes)
  • SEED PLANTS3. Ovules– An ovule consists of a megasporangium, megaspore, andone or more protective integuments• Gymnosperm megaspores have one integument• Angiosperm megaspores usually have two integuments
  • SEED PLANTS4. Pollen– Microspores develop into pollen grains – contain malegametophytes– Pollination is the transfer of pollen to the part of a seedplant containing the ovules Pollen eliminates need for film of water Can be dispersed great distances by air or animals If a pollen grain germinates, it gives rise to a pollen tubethat discharges two sperm into the female gametophytewithin the ovule
  • SEED PLANTS5. Seeds• Evolutionaryadvantages overspores:– May remain dormantfor days to years, untilconditions are favorablefor germination– Transported longdistances by wind oranimals
  • Seed coat(derived fromintegument)(c) Gymnosperm seedEmbryo (2n)(new sporophyte)Food supply(femalegametophytetissue) (n)(b) Fertilized ovule(a) Unfertilized ovuleIntegumentImmaturefemale coneSpore wallMegasporangium(2n)Male gametophyte(within a germinatedpollen grain) (n)Megaspore (n) Micropyle Pollen grain (n)Egg nucleus (n)Dischargedsperm nucleus (n)Femalegametophyte (n)
  • SUMMARY
  • Gymnosperms(p. 618 – 625)• Plants with ‘naked seeds’ not enclosed inovaries• Include conifers (pine tree) and cycads• Three key features of the gymnosperm life cycleare:1. Dominance of the sporophyte generation2. Development of seeds from fertilized ovules3. The transfer of sperm to ovules by pollen• The life cycle of a pine provides an exampletolweb.orgflickrhivemind.netbryophytes.plant.siu.edu forums.gardenweb.combotany.hawaii.edu
  • Microsporangium (2n)Microsporocytes(2n)Pollengrains (n)PollenconeMicrosporangiaMEIOSISMaturesporophyte(2n)Haploid (n)Diploid (2n)KeyMEIOSISSurvivingmegaspore (n)PollengrainMegasporocyte (2n)OvuleIntegumentOvulateconeFERTILIZATIONPollentubeFemalegametophyteSpermnucleus (n)Egg nucleus (n)ArchegoniumSeedlingSeedsSeed coat(2n)Foodreserves(n)Embryo(2n)Megasporangium(2n)THE PINE LIFE CYCLED:Chapter_30A_PowerPoint_Lectures30_Lecture_Presentation30_06PineLifeCycle_A.html
  • Microsporangium (2n)Microsporocytes(2n)Pollengrains (n)PollenconeMicrosporangiaMEIOSISMaturesporophyte(2n)Haploid (n)Diploid (2n)KeyOvulateconeTHE PINE LIFE CYCLE
  • Microsporangium (2n)Microsporocytes(2n)Pollengrains (n)PollenconeMicrosporangiaMEIOSISMaturesporophyte(2n)Haploid (n)Diploid (2n)KeyMEIOSISSurvivingmegaspore (n)PollengrainMegasporangium(2n)Megasporocyte (2n)OvuleIntegumentOvulateconeTHE PINE LIFE CYCLE
  • Microsporangium (2n)Microsporocytes(2n)Pollengrains (n)PollenconeMicrosporangiaMEIOSISMaturesporophyte(2n)Haploid (n)Diploid (2n)KeyMEIOSISSurvivingmegaspore (n)PollengrainMegasporocyte (2n)OvuleIntegumentOvulateconeFERTILIZATIONPollentubeFemalegametophyteSpermnucleus (n)Egg nucleus (n)ArchegoniumMegasporangium(2n)THE PINE LIFE CYCLE
  • Microsporangium (2n)Microsporocytes(2n)Pollengrains (n)PollenconeMicrosporangiaMEIOSISMaturesporophyte(2n)Haploid (n)Diploid (2n)KeyMEIOSISSurvivingmegaspore (n)PollengrainMegasporocyte (2n)OvuleIntegumentOvulateconeFERTILIZATIONPollentubeFemalegametophyteSpermnucleus (n)Egg nucleus (n)ArchegoniumSeedlingSeedsSeed coat(2n)Foodreserves(n)Embryo(2n)Megasporangium(2n)THE PINE LIFE CYCLED:Chapter_30A_PowerPoint_Lectures30_Lecture_Presentation30_06PineLifeCycle_A.html
  • Angiosperms(p. 625 – 634)• Most widespread and diverse of all plants• Are seed plants with reproductive structurescalled flowers and fruits• Characterised by enclosed seeds• The flower is an angiosperm structurespecialized for sexual reproduction• Pollinated by insects, animals or wind
  • Angiosperms(p. 625 – 634)• A flower is a specialized shoot with up to fourtypes of modified leaves:– Sepals, which enclose the flower– Petals, which are brightly colored and attractpollinators– Stamens, which produce pollen on their terminalanthers– Carpels, which produce ovules• A carpel consists of an ovary at the base and a styleleading up to a stigma, where pollen is received
  • Angiosperms(p. 625 – 634)• A fruit typically consistsof a mature ovary butcan also include otherflower parts• Fruits protect seeds andaid in their dispersal• Mature fruits can beeither fleshy or dry
  • Angiosperms(p. 625 – 634)• Various fruitadaptations helpdisperse seeds• Seeds can be carried bywind, water, or animalsto new locations
  • MEIOSISKeyMicrosporangiumMicrosporocytes (2n)Generative cellAntherTube cellPollengrainsMicrospore(n)Male gametophyte(in pollen grain)(n)Mature flower onsporophyte plant(2n)Haploid (n)Diploid (2n)MEIOSISOvule (2n)OvaryMegasporangium(2n)Megaspore(n)Female gametophyte(embryo sac)Antipodal cellsCentral cellSynergidsEgg (n)PollentubePollentubeStigmaSperm(n)Discharged sperm nuclei (n)FERTILIZATIONGerminatingseedEmbryo (2n)Endosperm (3n)Seed coat (2n)SeedNucleus ofdevelopingendosperm(3n)Zygote (2n)Eggnucleus (n)StyleSpermTHE ANGIOSPERM LIFE CYCLE
  • MEIOSISKeyMicrosporangiumMicrosporocytes (2n)Generative cellAntherTube cellPollengrainsMicrospore(n)Male gametophyte(in pollen grain)(n)Mature flower onsporophyte plant(2n)Haploid (n)Diploid (2n)THE ANGIOSPERM LIFE CYCLE
  • MEIOSISKeyMicrosporangiumMicrosporocytes (2n)Generative cellAntherTube cellPollengrainsMicrospore(n)Male gametophyte(in pollen grain)(n)Mature flower onsporophyte plant(2n)Haploid (n)Diploid (2n)MEIOSISOvule (2n)OvaryMegasporangium(2n)Megaspore(n)Female gametophyte(embryo sac)Antipodal cellsCentral cellSynergidsEgg (n)THE ANGIOSPERM LIFE CYCLE
  • MEIOSISKeyMicrosporangiumMicrosporocytes (2n)Generative cellAntherTube cellPollengrainsMicrospore(n)Male gametophyte(in pollen grain)(n)Mature flower onsporophyte plant(2n)Haploid (n)Diploid (2n)MEIOSISOvule (2n)OvaryMegasporangium(2n)Megaspore(n)Female gametophyte(embryo sac)Antipodal cellsCentral cellSynergidsEgg (n)PollentubePollentubeStigmaSperm(n)Discharged sperm nuclei (n)FERTILIZATIONEggnucleus (n)StyleSpermTHE ANGIOSPERM LIFE CYCLE
  • MEIOSISKeyMicrosporangiumMicrosporocytes (2n)Generative cellAntherTube cellPollengrainsMicrospore(n)Male gametophyte(in pollen grain)(n)Mature flower onsporophyte plant(2n)Haploid (n)Diploid (2n)MEIOSISOvule (2n)OvaryMegasporangium(2n)Megaspore(n)Female gametophyte(embryo sac)Antipodal cellsCentral cellSynergidsEgg (n)PollentubePollentubeStigmaSperm(n)Discharged sperm nuclei (n)FERTILIZATIONGerminatingseedEmbryo (2n)Endosperm (3n)Seed coat (2n)SeedNucleus ofdevelopingendosperm(3n)Zygote (2n)Eggnucleus (n)StyleSpermTHE ANGIOSPERM LIFE CYCLE
  • Angiosperm DiversityMonocots (one cotyledon)¼ of angiosperm speciesEudicots (“true” dicots)More than 2/3 angiospermspeciesTWO MAIN GROUPS OF ANGIOSPERMS
  • HUMAN WELFARE• No group of plants is more important tohuman survival than seed plants• Plants are key sources of food, fuel, woodproducts, and medicine• Our reliance on seed plants makespreservation of plant diversity critical
  • PRODUCTS FROM SEED PLANTS• Most of our food comes from angiosperms• Six crops (wheat, rice, maize, potatoes, cassava, andsweet potatoes) yield 80% of the calories consumedby humans• Modern crops are products of relatively recentgenetic change resulting from artificial selection• Many seed plants provide wood• Secondary compounds of seed plants are used inmedicines