Chapter 29Overview: The Greening of EarthPowerPoint PresentationConcept 29.1: Land plants evolved from green algaeMorphological and Biochemical EvidenceSlide 6Genetic EvidenceLE 29-3Adaptations Enabling the Move to LandConcept 29.2: Land plants possess a set of derived terrestrial adaptationsDefining the Plant KingdomLE 29-4Derived Traits of PlantsLE 29-5aLE 29-5bLE 29-5cSlide 17The Origin and Diversification of PlantsLE 29-6Slide 20Slide 21LE 29-7Concept 29.3: The life cycles of mosses and other bryophytes are dominated by the gametophyte stageSlide 24Bryophyte GametophytesLE 29-8Slide 27Bryophyte SporophytesLE 29-9aLE 29-9bLE 29-9cLE 29-9dEcological and Economic Importance of MossesLE 29-10Concept 29.4: Ferns and other seedless vascular plants formed the first forestsOrigins and Traits of Vascular PlantsSlide 37Life Cycles with Dominant SporophytesLE 29-12Transport in Xylem and PhloemEvolution of RootsEvolution of LeavesSlide 43LE 29-13Sporophylls and Spore VariationsSlide 46Classification of Seedless Vascular PlantsLE 29-14aLE 29-14bLE 29-14cLE 29-14dLE 29-14eLE 29-14fPhylum Lycophyta: Club Mosses, Spike Mosses, and QuillwortsPhylum Pterophyta: Ferns, Horsetails, and Whisk Ferns and RelativesThe Significance of Seedless Vascular PlantsSlide 57Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsPowerPoint Lectures for Biology, Seventh EditionNeil Campbell and Jane ReeceLectures by Chris RomeroChapter 29Chapter 29Plant Diversity IHow Plants Colonized LandCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsOverview: The Greening of Earth•Looking at a lush landscape, it is difficult to imagine the land without any plants or other organisms•For more than the first 3 billion years of Earth’s history, the terrestrial surface was lifeless•Since colonizing land, plants have diversified into roughly 290,000 living speciesCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsConcept 29.1: Land plants evolved from green algae•Green algae called charophyceans are the closest relatives of land plantsCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsMorphological and Biochemical Evidence•Many characteristics of land plants also appear in a variety of algal clades, mainly algae•However, land plants share four key traits only with charophyceans:–Rose-shaped complexes for cellulose synthesis–Peroxisome enzymes–Structure of flagellated sperm–Formation of a phragmoplastCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsGenetic Evidence•Comparisons of both nuclear and chloroplast genes point to charophyceans as the closest living relatives of land plantsLE 29-3LE 29-310 mm40 µmChara,a pondorganism(LM).Coleochaete orbicularis, a disk-shaped charophycean (LM).Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsAdaptations Enabling the Move to Land•In charophyceans a layer of a durable polymer called sporopollenin prevents exposed zygotes from drying out•The accumulation of traits that facilitated survival on land may have opened the way to its colonization by plantsCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsConcept 29.2: Land plants possess a set of derived terrestrial adaptations•Many adaptations emerged after land plants diverged from their charophycean relativesCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsDefining the Plant Kingdom•Systematists are currently debating the boundaries of the plant kingdom•Some biologists think the plant kingdom should be expanded to include some or all green algae•Until this debate is resolved, we will retain the embryophyte definition of kingdom PlantaeLE 29-4LE 29-4ViridiplantaeStreptophytaPlantaeRed algaeChlorophytesCharophyceansEmbryophytesAncestral algaCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsDerived Traits of Plants•Five key traits appear in nearly all land plants but are absent in the charophyceans:–Apical meristems–Alternation of generations–Walled spores produced in sporangia–Multicellular gametangia–Multicellular dependent embryosLE 29-5aLE 29-5aApicalMeristemof shootDevelopingleavesShootRootApical meristem100 µm 100 µmApical MeristemsLE 29-5bLE 29-5bMitosisAlternation of GenerationsSporesMitosisMitosisZygoteGametesHaploid multicellularorganism (gametophyte)Diploid multicellularorganism (sporophyte)MEIOSISFERTILIZATIONLE 29-5cLE 29-5cWalled SporesProduced in SporangiaMulticellularGametangiaMulticellular,Dependent EmbryosLongitudinal section ofSphagnum sporangium (LM)SporesSporangiumSporophyteGametophyteSporophyte and sporangiumof Sphagnum (a moss)Archegonia and antheridiaof Marchantia (a liverwort)Male gametophyteAntheridiumwith spermFemale gametophyteArchegoniumwith eggMaternaltissueEmbryo2 µm10 µmWallingrowthsPlacentaltransfercellCopyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings•Additional derived traits such as a cuticle and secondary compounds evolved in many plant speciesCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsThe Origin and Diversification of Plants•Fossil evidence indicates that plants were on land at least 475 million years ago•Fossilized spores and tissues have been extracted from 475-million-year-old rocksLE 29-6LE 29-6Fossilized spores. Unlike the spores of most living plants, which are single grains, these spores found in Oman are in groups of four (left; one hidden) and two (right).Fossilized sporophyte tissue. The spores were embedded in tissue that appears to be from plants.Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings•Those ancestral species gave rise to a vast diversity of modern plants•Land plants can be informally grouped based on the presence or absence of vascular tissueCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsLE 29-7LE 29-7Ancestralgreen algaOrigin of land plants(about 475 mya)Origin of vascular plants(about 420 mya)Origin of seed plants(about 360 mya)Land plantsVascular plantsSeed plantsSeedless vascular plantsBryophytesLiverwortsHornwortsMossesLycophytesPterophytesGymno-spermsAngio-spermsCharophyceansCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsConcept 29.3: The life