BIOL 152 1st Edition Lecture 14 Outline of Last Lecture I. Plants respond to lighta. Discovery of plant hormonesi. Auxin-first one discovered1. Named by Fritz Went2. Produced by stem tip3. Influences plant growthII. Other plant hormonesa. Cytokinini. Stimulates cell divisionb. Gibberellini. Stimulates germinationii. Promotes fruit growthc. Abscisic Acidi. Induces dormancyd. Ethylenei. Causes senescence, ripeningIII. Other tropismsa. Gravitropismb. ThigmotropismPlant Defense Outline:I. Advantages and disadvantages of a plant’s defensesII. Pathogensa. Mode of entryb. Types of pathogensIII. Plant immune responses (basal and specific)a. Hypersensitive responseb. Acquired resistanceOutline of Current Lecture I. Diversity of land pantsa. Non-vascular land plants- Bryophytesi. Gametophytes dominantii. Liverworts1. Microscopic sporophyteThese 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.iii. Mosses1. Macroscopic sporophyte2. Sphagnum mossiv. Hornworts1. Photosynthetic sporophyteII. Spore-producing vascular plantsa. Lycophytes- first vascular plantsi. Extinct ancestors= treesii. Extant species= understory herbsiii. Leaves with single vascular traceb. Fernsi. Multiveined leaves ii. Diverse growth forms and habitatsc. Seed producing vascular plants i. Gymnosperms1. Naked seeds2. Junipers3. Redwoods4. Ginkgos5. Cycadsii. Angiosperms1. Fruits cover seeds 2. Highly diverse 3. Co-evolution with pollinatorsCurrent LectureWhat two hormones are most likely responsible for the change in plant morphology and why?Auxin and cytokinin, both responsible for growth factors of plant (whether increasing or decreasing)Types of defenses- Mechanical - Chemical - EcologicalMechanicalStructure-based defense- Thorns- SpinesChemicalPlants can release chemicals to repel predatorsWhat can trigger a chemical defense?- Physical damage- Can respond to sounds/vibrations in the environment- Detecting of attacker compoundsEcologicalEx. Symbiosis of ants and acacia- The plants house and feed the ants- The ants protect the plant by attacking any foreign predatorsWhat about the pollinators? How will they get to the plant if the ants attack them every time?- The plants produce a chemical to repel the ants during pollination periodsAdaptation in grasses (fig. 32.14)- They have low apical meristems allowing them to be mowed/grazed without dyingResources and defense (32.15)Constitutive vs. inducible defensesDiversity of land plantsNONVASCULAR:Liverworts (33.3 b)Moss- Obvious sporophyteo Sphagnum moss (33.5) Can reduce pH in water of it habitatHornworts- Macroscopic sporophyteso Persistently photosyntheticWhy are mosses more diverse?More physiological adaptions to stress than othersVASCULAR PLANTS:Lycophytes- Oldest- Xylem and phloem- Left fossils- Single veined leavesFerns- Multiveined leaves- Starts as croziers- Large leaves- Can thrive in many different environments- Epiphytes-capable of living on other plantsDiversity of gymnosperms- “Naked” seeds- no fruit covering- Embryo already insideo Surrounded by gametophyte (food)Seed- embryo sporophyte packed with a lot of nutrients and covered by a seed coat- Ex. o Junipers- common shrubso Redwoodso Gingkos- extinct in natureo Cycads- house plantsGymnosperms and Angiosperms= SEEDS AND POLLENAngiosperms- Flowering plants- Fruit= covering for the seedo Greater protection and ability for dispersal- All human food is from angiosperms- Very large- Origin unknown- Co-evolved with pollinatorso Rapid
View Full Document
Unlocking...