Presentation on theme: "Ch. 38 Angiosperm Reproduction and Biotechnology"— Presentation transcript:
1Ch. 38 Angiosperm Reproduction and Biotechnology Objectives:L.O The student can connect concepts in and across domains to show that timing and coordination of specific events are necessary for normal development in an organism and that these events are regulated by multiple mechanisms.L.O TSIAT use a graph or diagram to analyze situations or solve problems (quantitatively or qualitatively) that involve timing and coordination of events necessary for normal development in an organism.L.O TSIAT justify scientific claims with scientific evidence to show that timing and coordination of several events are necessary for normal development in an organism and that these events are regulated by multiple mechanisms.L.O TSIAT describe the role of programmed cell death in development and differentiation, the reuse of molecules, and the maintenance of dynamic homeostasis.L.O TSIAT design a plan for collecting data to support the scientific claim that the timing and coordination of physiological events involve regulation.L.O TSIAT justify scientific claims with evidence to show how timing and coordination of physiological events involve regulation.L.O TSIAT connect concepts that describe mechanisms that regulate the timing and coordination of physiological events.
2Alteration of generations 38.1 Flowers, Double Fertilization, and Fruits are Unique Features of the Angiosperm Life CycleAlteration of generationsMulticellular haploid (n) gametophyte and diploid (2n) generations sporophyte.KeyHaploid (n)Diploid (2n)GametesMEIOSISFERTILIZATIONZygoteMitosisDiploid multicellular organism(a) Animalsn2nSporesHaploid multi- cellular organism (gametophyte)Diploid multicellular organism (sporophyte)(b) Plants and some algae
3Flower Structure and Function Flowers are angiosperm’s reproductive organ system.Flowers’ size, shape, color, odor, organ arrangement, and time of opening are largely influenced by the type of pollinator.StamenAntherFilamentPetalReceptacleStigmaStyleOvaryCarpelSepal(a)Structure of an idealized flowerSimplified angiosperm life cycle(b)KeyHaploid (n)Diploid (2n)Pollen tubeGerminated pollen grain (n) (male gametophyte)OvuleEmbryo sac (n) (female gametophyte)Egg (n)Sperm (n)FERTILIZATIONZygote (2n)Mature sporophyte plant (2n)Germinating seedSeedSimple fruitEmbryo (2n) (sporophyte)
5Pollination Transfer of pollen from an anther to a stigma. Wind (grasses and trees)Water (aquatic plants)Animals; insects, birds, etc.Abiotic Pollination by WindPollination by BeesHazel staminate flowers (stamens only)Hazel carpellate flower (carpels only)Common dandelion under normal lightCommon dandelion underultraviolet lightPollination by Moths and ButterfliesBlowfly on carrion flowerPollination by FliesPollination by BatsMoth on yucca flowerLong-nosed bat feeding on cactus flower at nightHummingbird drinking nectar of columbine flowerPollination by BirdsStigmaAntherMothFly egg
8CoevolutionThe evolution of interacting species in response to changes in each otherMany flowering plants have coevolved with specific pollinatorsThe shapes and sizes of flowers often correspond to the pollen transporting parts of their animal pollinatorsEx: Darwin correctly predicted a moth with a 28 cm long tongue based on the morphology of a particular flower
9Development of Male Gametophytes in Pollen Grains Each anther has 4 microsporangia (pollen sacs)Within this are microsporocytes (2n similar to animal follicle)These undergo meiosis producing microspores.These undergo mitosis producing 2 cells (pollen):Generative: forms 2 spermTube: used to transfer sperm to ovuleMicrosporangium (pollen sac)MicrosporocyteMicrospores (4)Each of 4 microsporesGenerative cell (will form 2 sperm)(LM)75 m20 mMEIOSISMITOSISMale gametophyte (in pollen grain)Nucleus of tube cellRagweed pollen grain (colorized SEM)Key to labelsHaploid (n)Diploid (2n)
10Development of Female Gametophytes (embryo sac) Development of a female gametophyte (embryo sac)100 mMEIOSISMITOSISKey to labelsHaploid (n)Diploid (2n)(LM)Embryo sacOvuleMegasporangiumMegasporocyteIntegumentsMicropyleSurviving megasporeAntipodal cells (3)Polar nuclei (2)Egg (1)Synergids (2)Female gametophyte (embryo sac)Occurs within the megasporangium.The megasporocyte undergoes meiosis making megaspores.This undergoes mitosis (w/o cytokinesis) making a large cell with 8 nuclei. This is the embryo sac.
11Double FertilizationWhen pollen reaches the stigma, the tube forms, grow down the style to the micropyle (hole in the underside of the embryo sac).Each sperm has a job:Fertilizes the eggCombines with polar bodies making a triploid nucleus in a large cell endosperm (food storing tissue for seed)StigmaPollen tube2312 spermStyleOvaryOvuleMicropylePollen grainPolar nucleiEggSynergidEndosperm nucleus (3n) (2 polar nuclei plus sperm)Zygote (2n)
13Seed Development, Form, and Function Endosperm develops as a food source (carbohydrates storage)The embryo divides into a basal cell (anchor) and terminal cell (embryo) and cotyledon forms (another food supply)Seed dehydrates entering dormancy.This is an adaptation for when environmental conditions are right for imbibition (uptake of water to start germination)..OvuleEndosperm nucleusIntegumentsZygoteTerminal cellBasal cellProembryoSuspensorCotyledonsShoot apexRoot apexSeed coatEndosperm
14Fruit Form and Function Fruit is the ovary of the flower which protects and aids in dispersal of the seed.Types of fruit:StamenOvaryStigmaOvulePea flowerSeedPea fruit(a) Simple fruit: 1 carpel(b) Aggregate fruit:many carpels(c) Multiple fruit:Many flowers(d) Accessory fruit: carpel is the core,The flesh is the receptable.CarpelsRaspberry flowerCarpel (fruitlet)Raspberry fruitFlowerPineapple inflorescenceEach segment develops from the carpel of one flowerPineapple fruitPetalStyleSepalOvary (in receptacle)Apple flowerRemains of stamens and stylesSepalsReceptacleApple fruit
15Seed Dispersal Dispersal by Wind Dispersal by Water Dandelion fruit Dandelion “seeds” (actually one-seeded fruits)Winged fruit of a mapleDandelion fruitTumbleweedDispersal by WaterWinged seed of the tropical Asian climbing gourd Alsomitra macrocarpaCoconut seed embryo, endosperm, and endocarp inside buoyant husk
16Seed Dispersal Dispersal by Animals Fruit of puncture vine (Tribulus terrestris)Squirrel hoarding seeds or fruits undergroundAnt carrying seed with nutritious “food body” to its nestSeeds dispersed in black bear feces