Presentation on theme: "Plant Diversity & Structure"— Presentation transcript:
1 Plant Diversity & Structure General CharacteristicsMajor Plant GroupsPlant Evolution
2 General Plant Characteristics MulticellularEukaryoticCell walls made of celluloseAutotrophs (photosynthesis)Use chlorophyll a and chlorophyll bLife cycle is characterized by alternation of generations
3 Plant Groups Flowering plants Cone-bearing plants Ferns and their relativesMosses and their relativesGreen algae ancestorFlowers; Seeds Enclosed in FruitSeedsWater-Conducting (Vascular) TissueGreen algae are thought to be the ancestors of plantssimilar size, color, and appearanceSimilar reproductive cyclesIdentical cell walls and pigments used for photosynthesis
4 There are two major groups of land plants which are separated based on their adaptations that enable them to survive on land:Non-Vascular Plants: Water enters plant directly through surface. They do not have roots. Rhizoids anchor plant.Example: mossRhizoidCapsuleStalkSporophyteGametophyteStemlike structureLeaflike structureVascular Plants: have vascular tissue - internal tubes for transporting water and minerals from the ground. Examples: fern, oak trees, roses, grasses, etc.Cuticle: a waxy waterproof layer that prevents water being evaporated from plant.Thought Question:Which group of plants is more limited in terms of how large the individual plant can grow?
5 The Diversity of Plants Cone-bearing plants 760 speciesFlowering plants 235,000 speciesFerns and their relatives 11,000 speciesMosses and their relatives 15,600 speciesHow has this diagram changed over the last200 million years?
6 Comparing Features of Seed Plants GYMNOSPERMS - (gymn = naked, sperm = seed) Male cones produce pollen that travel to the female cones which contain ovules. Seeds develop uncovered on scales within the female cones.ANGIOSPERMS - (angio = vessel, sperm - seed) Flowering plants produce their seeds using flowers. Many flowers have male and female organs. Seeds develop inside a protective, fleshy tissue called fruit. Many flowering plants rely on animals to pollinate them and some use wind pollination.Comparing Features of Seed PlantsFeatureSeedsReproductionExamplesGymnospermsAngiospermsBear their seeds on conesCan reproduce without water; male gametophytes are contained in pollen grains; fertilization occurs by pollinationConifers, cycads, and ginkgoesBear their seeds within flowersGrasses, flowering trees and shrubs, wildflowers, cultivated flowers
7 The Structure of a Flower The reproductive structures of angiosperms are flowers. These structures all evolved as modifications of leaves.FilamentAntherStigmaStyleOvaryCarpelPetalSepalOvuleStamenSepal - a whorl of modified leaves that protects the flower bud before it opens.Petal - generally more brightly colored than sepals, advertise the flower to pollinators.Stamen - The pollen producing male reproductive organ of a flower, consisting of an anther & a filament.Carpel - The female reproductive organ of a flower, consisting of a stigma, style, & ovary.
8 Compare/Contrast Table Comparing Wind-pollinated and Animal-pollinated PlantsCharacteristicsPollination methodRelative efficiency of pollination methodPlant typesReproductive organsAdaptations that promote pollinationWind-pollinated PlantsWind pollinationmore pollen produced/ wasted, less decorationgymnosperms and angiospermsCones or Simple FlowersPollination dropAnimal-pollinated PlantsVector pollinationless pollen produced/ wasted, more decorationAngiospermsFlowersBright colors, sweet nectarWhich pattern of macroevolution is demonstrated by this table? Why?
9 Generalized Plant Life Cycle What cellular process is illustrated here?HaploidDiploid???????The generalized plant life cycle is described as alternation of generations. This is a life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte.The gametophyte produces gametes.The sporophyte produces spores.Spores (N)Gametophyte Plant (N)Sporophyte Plant (2N)Sperm (N)Eggs (N)FERTILIZATION
10 Evolution of the Gametophyte and the Sporophyte Gametophyte (N)Sporophyte (2N)BryophytesFernsSeed plants
11 Review of Plant Evolution Flowering plantsCone-bearing plantsFerns and their relativesMosses and their relativesGreen algae ancestorFlowers; Seeds Enclosed in FruitSeedsWater-Conducting (Vascular) TissueThought Question: What is the evolutionary advantage associated with each of the derived characters shown in the cladogram below?
12 Moss + relatives Fern + relatives Gymno-sperms Angio-sperms Characteristic FeaturesNo roots, stems, or leavesSpores produced by sporangia, have underground roots & stems, leaves above ground“gymn” - nakedSperm” – seedSeed is exposed“ang” – vessel“sperm” – seedSeed is covered by fruitFertilizationThin layer of water; sperm swims to egg (ovule)Some use swimming sperm, others use wind blown pollenSome use wind-blown pollen, others use animal vectorsDispersal of OffspringSpores blown by wind or carried by waterSeeds blown by wind or carried by waterSeeds blown by wind, carried by water or spread by animalsMethod of Getting Water and MineralsPoresRoots & vascular tissueHabitatWet, moistTolerates drier conditionsWidely adapted: Aquatic to desert
14 The Internal Structure of a Leaf CuticleThought Question: What materials enter the stoma? What materials leave it?VeinsEpidermisPalisade mesophyllXylemVeinPhloemSpongy mesophyllEpidermisStomaGuard cells
15 Function of Guard Cells Inner cell wallInner cell wallStomaStoma OpenStoma ClosedWhen water pressure is high, guard cells are forced into a curved shape and open the stomaWhen water pressure is low, the guard cells pull together and the stoma closesPhotosynthesis = carbon dioxide in and oxygen outCellular Respiration = oxygen in and carbon dioxide out
16 Water Cycle Condensation Precipitation Evaporation Transpiration RunoffSeepageRootUptake
17 TranspirationThought Question: How does water get “sucked-up” the plant? Does the plant have to work (use ATP) do this? Explain.ABEvaporation of water molecules out of leaves.Pull of water molecules upward from the roots.
18 Pulling It All Together 3. Transpiration – the movement of water out of the leaf, “pulls” water upward by osmosis2. Capillary action – the tendency of water to rise in a thin tubecohesion – attraction between like moleculesadhesion – attraction between different molecules1. Root pressure and active transport cause water to move from the soil into the rootWhat causes a plant to wilt?
23 ChlorophyllChlorophyll is the type of pigment found in plants (pigments are molecules that absorb light).Absorption of Light byChlorophyll a and Chlorophyll bThought Questions:How does the wavelength of light absorbed and reflected by leaves related to the change of leaf color in the autumn?Chlorophyll bChlorophyll aHow does this relate to the pigments found in different types of algae at different depths of water?VBGYOR
24 Photosynthesis:Chloroplasts - bacteria sized organelle used for photosynthesis.The light dependent reactions take place in granum.Granum - Stacks of thylakoids where the first half of photosynthesis takes place, (light-dependant reactions).Stroma - The space around the thylakoids where the second half of photosynthesis takes place. (The Calvin Cycle)
25 Light-Dependent Reactions Produce oxygen gas and convert ADP and NADP+ into energy carriers ATP and NADPH. These reactions take place within the thylakoid membranes of chloroplasts.HydrogenIon MovementPhotosystem IIChloroplastATP synthaseInnerThylakoidSpaceThylakoidMembraneStromaElectronTransport ChainPhotosystem IATP Formation
26 Calvin CycleUses ATP and NADPH from the light-dependant reactions to produce high-energy sugars. The Calvin Cycle takes place in the stroma of chloroplasts and does not require light.CO2 Enters the CycleEnergy InputChloropIast5-CarbonMoleculesRegeneratedFactors Affecting Photosynthesis- Both temperature and the availability of water can affect rates of photosynthesis.Can you explain why?6-Carbon SugarProducedSugars and other compounds
27 PhotosynthesisincludesLight-dependentreactionsCalvin cycletakes place inusesusetake place inThylakoidmembranesStromaNADPH & CO2ATPEnergy fromSunlight and Waterto produceofto produceATPNADPHO2ChloroplastsHigh-energysugarsThought Question:What factors will impact the rate of photosynthesis? What will cause the rate of photosynthesis to increase? Decrease?
28 Essays 1. a. Label letters A-J on the diagram of flower parts. b. Even though plants have to expend a lot of energy to make flowers, why is it still an evolutionary advantage to have flowers? Use the terms pollinators, pollination, fruit, seed dispersal, reproductive success, physical appearance in your response.2. The evolution of Plants and Animals on land are strongly linked, particularly when it comes to the evolution of insects. Explain how the evolution of the first plants 470 million years ago, and the first vascular plants 410 million years ago, is linked to a major change in animal evolution. Also, explain how the evolution of a new group of plants 150 million years ago (with an adaptive radiation starting 65 million years ago) has led to the types of plants and animals that are common today. Some key terms to incorporate include: open niches, mass extinction, coevolution, and mutualism.