BIOL 152 1st Edition Lecture 11 Outline of Last Lecture I. The green algae are the closest relatives of the land plantsa. Green algae and land plants share many featuresb. Green algae are NOT monophyleticc. The Caryophyceans are sister to the land plantsII. The colonization of Earth presents many challengesa. Consider the habitat(s) of the ancestors of land plantsb. Review the major challengesIII. A series of key innovations permit colonizing Eartha. Reflect upon the synapomorphies of land plantsb. Leaf morphology illustrates some of the solutions to desiccationc. Stoma (or stomates) regulate water loss in many plantsIV. One clade of land plants evolved complex vascular tissuesa. Xylem is a complex tissue that functions to transport waterb. Energy is not required to move waterc. Phloem is a complex tissue that functions to transport the product of photosynthesis d. Energy IS required for phloem to move sugars via bulk flow Outline of Current Lecture I. Summary of plant transport systemsa. Water/nutrientsb. Bulk flowII. The move to landa. Preventing desiccationb. Confronting gravityc. Exploring complex habitatsIII. Alteration of generationsa. Genericb. HumansIV. Diploid/haploid organismsV. Plant life cycle summarya. ExamplesVI. Gymnosperms a. Homosporyb. Heterospory These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Current LectureSummary of plant transport systems- Water and nutrients pulled up by xylemo Driven by transpiration- Bulk flow of photosynthesis from sucrose to sink through phloemo Driven by hydrostatic pressureThe move to land- Preventing desiccationo Sporopollenino Cuticle- Confronting gravityo Lignin; stiff cell walls (xylem)- Exploring complex habitatso Alteration of generationso Multicellular haploid/diploid phasesAlteration of generations2n (diploid) Meiosis (reduction division) n (haploid) Fertilization (fusion, sperm/egg)Humans:Ovary/testes-Meiosis (gametes are unicellular) sperm/egg Fertilization Mitosis (fetus) 2n (mitosis) Diploid/haploid organisms- Meiosis changes a diploid to a haploid- Fertilization changes a haploid to a diploid- Human diploid: complex and multicellular- Human haploid: unicellular, not really a “generation”In plants, both diploid and haploid generations are MULTICELLULAR.Diploid=sporophyte sporangia (by mitosis) meiosis spore Multicellular haploid (mitosis) sperm/egg FERTILIZATION zygote mitosis Plant Life Cycle Summary- Diploid generation= sporophyte - Haploid generation= gametophyteo Sporophyte mitosis sporangiao Sporangia mitosis sporeso Spores mitosis gametophyteso Gametophytes mitosis gameteso Gametes fertilization (egg/sperm) zygoteEx. Moss- Sporophyte multicellular- Sexual reproductiono Gametophytes maturation gametongial shootso Sperm swims in film of water to eggo Zygote (2n) mitosis sporophyte shoot’Ex. FernsDiploid/haploid generations that become independent plantsDiploid (2n) meiosis spores (dispersal of spores by wind) germination fertilization (sperm swims to egg, water required) gametophyte mature sporophyteGymnospermsGametophyte is now dependent on sporophyteHomospory vs. heterospory- Homosporous plants are ferns and mosso Sporophyte one sized spores (by meiosis) bisexual gametophyte (by mitosis) egg or sperm- Heterosporous plants are seed plantso Sporophyte megaspores or microspores (by meiosis) female gametophyte ormale gametophyte (by mitosis) egg or spermFemale cone vs. Male cone- Female cone- megaspore (ovule)- Male cone- microspore (pollen)o Pollen is dispersed by wind, pollination does not require
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