KEY AP BIOLOGY – PARADE THROUGH THE PLANTS Complete the questions using the chapters of your textbook. CHAPTERS 29 & 30 – Plant Diversity 1. Chart the four phyla of the plant kingdom. Include the common names of each, the approximate number of extant species, and the major characteristics. a). BRYOPHYTES- SEEDLESS NON VASCULAR PLANTS - about 7% of total plant species Dominant gametophyte; Dependent sporophyte stays attached to parental sporophyte: Flagellated sperm require water; No seeds Liverworts – 9,000 extant (living) Hornworts – 100 species Mosses – 15, 000 species b). SEEDLESS VASCULAR PLANTS Dominant sporophyte; small independent gametophyte; No seeds; Flagellated sperm produced by antheridia require water to travel to eggs in archegonia. Presence of vascular tissue allowed these organisms to dominate the Carboniferous ecosystem; Lycophytes- clubmosses and relatives 1,200 species Pterophytes- ferns and relatives 12,000 species c). GYMNOSPERMS (NAKED SEED PLANTS) Dominant sporophyte (tree); dependent gametophytes (in cones) are mostly microscopic/develop from spores retained within sporangia of parental sporophyte; Ovule in ovule cones contain microscopic female gametophyte; Pollen in pollen cones contain male gametophyte: Allow pollination without water/over greater distances; Ginkos, 1 ; Cycads 130; Gnetophytes 75; Conifers 600 species d). ANGIOSPERMS (FLOWERING PLANTS)- (VASCULAR & SEEDS) - Largest plant group Dominant sporophyte; dependent microscopic gametophyte (pollen & ovule); Flowers and seeds; Seeds (mature ovules) enclosed in enclosed in ripened ovary = fruit Fruit aids in protection and dispersal; Many involved other organisms to help with pollination Double fertilization: one sperm fertilizes egg to becomes sporophyte embryo; 2nd sperm fuses with 2 nuclei in central cell of female gametophyte and divides to become endosperm (food reserves in seed) Vascular tissue present (xylem & phloem) Includes all flowering plants- 250,000 species 2. Why are Charophyceans (green algae) thought to be ancestors of land plants? 1. Rosette-shaped cellulose synthesis complexes- others have linear 2. Presence of peroxisome enzymes- not seen in peroxisomes of other algae 3. Flagellated sperm- structure of flagellated sperm in both resemble each other 4. phragmoplast- Alignment of cytoskeleton and Golgi vesicles in dividing cells similar 5. DNA evidence- both nuclear and chloroplast DNA show relatedness 3. List several adaptations of land plants significant for terrestrial survival. 1 SHOOTS and ROOTS- specialization for subterranean and aerial organs 2. ALTERNATION OF GENERATIONS- (not in charophycean ancestors)MULTICELLULAR BODY forms (sporophyte & gametophyte) alternate 3. XYLEM and PHLOEM- vascular tissue for transport of water & nutrients 4. SEEDS- protect embryo, provide food; aid in wider dispersal 5. WAXY CUTITLE- prevents drying out 6. STOMATES- gas exchange through cuticle 4. Label the generic diagram to explain Alternation of Generations 5. Describe a few features common to Bryophytes. (Liverworts, hornworts, mosses) NONVASCULAR- no xylem or phloem NO seeds Flagellated sperm require water to reproduce Dominant gametophyte; Sporophyte stays attached to parental gametophyte 6. What is the dominant phase of the moss life cycle? The male and female gametophytes are free living and the dominant phase of the life cycle. The sporophyte is small and dependent on gametophyte 7. List a couple of adaptations of Pteridophytes (ferns) not seen in Bryophytes. XYLEM (tracheids-dead tube shaped cells that carry water & minerals) with LIGNIN for strength and PHLOEM (living cells that carry sugar, organic molecules) ROOTS –anchor plant and absorb water and nutrients from soil LEAVES- increase surface area for photosynthesis SPOROPHYLLS- modified leaves that bear sporangia that make spores 8. What is the dominant phase of the fern life cycle? The sporophyte is the dominant phase in fern life and other vascular plants. Gametophyte is reduced in size, photosynthetic, and independent of sporophyte; flagellated sperm still require moisture to swim. 9. How is the reduced gametophyte an adaptation for seeded plants? Allows tiny gametophytes to develop from spores retained within sporangia of parental sporophyte. Protects female (egg containing gametophyte) from environment. Enables gametophyte to obtain nutrients from sporophyte. 10. What is the significance of the seed? Seed = embryo with food supply packaged within protective coat Allowed plants to better resist harsh environments and to disperse offspring more widely 11. What is the advantage of pollen? Eliminates need for water to fertilize egg 12. List the four phyla of gymnosperms. Which is the most common? 1. Cycadophyta- large cones, palm-like leaves; few species today; “Age of cycads” = “Age of dinosaurs” 2. Ginkgophyta- 1 living species; ornamental tree tolerates pollution 3. Gnetophyta- only 3 genera; Ephedra- makes ephedrine 4. Coniferophyta- MOST COMMON = conifers “carry cones” = evergreens 13. Identify five differences between monocots and dicots. MONOCOTS One cotyledon Veins usually parallel Vascular tissue scattered Fibrous roots (no main root) Pollen grain has one opening Floral organs in multiples of 3 Ex: Orchid, palm, grasses, corn, wheat, rice DICOTS Two cotyledons Veins usually netlike Vascular tissue in ring Taproot (main root) Pollen grain with three openings Floral organs in multiples of 4 or 5 Ex: Oak, rose, pea, zucchini, sunflower, maple 14. What is the adaptive value of the flower to plants? Sexual reproduction; Seed protected; Allows other organisms to participate in pollination and spread seeds to greater distances & by means other than wind 15. Describe the role of ovaries and ovules in the flowering plants. Ovary-Portion of carpel in which egg-containing ovules develop Ovule- Structure within ovary that contains the female gametophyte; if fertilized it develops into a seed; 16. List several features of angiosperms that aid in seed dispersal. Carried by wind- maple tree, dandelion Carried by water- coconut Carried by animals- burrs; edible fruits CHAPTER 35- Plant Structure and Growth 1. List the basic plant organs with their functions. Roots-anchor; absorb water/minerals; stores organic nutrients Stems- photosynthesis, growth; (modified stems = stolons, rhizomes, tubers, bulbs = storage, asexual reproduction) Leaves- photosynthesis 2. What is the adaptive value of root hairs? Increase surface area for greater absorption 3. List several types of leaves and examples of their functions. Tendrils- coils for support/attachment Spines- protection Storage leaves- Ex: succulents store water Bracts- attract pollinators Reproductive leaves- adventitious plantlets 4. List and indicate functions of several organelles unique to plant tissues. Chloroplasts-photosynthesis 5. Give a brief description and example of the following plant tissues. a. Xylem – tracheids-long thin cells with tapered ends; 2° walls have lignin to prevent collapse vessel elements- wider, shorter, thinner walled Dead at maturity; protoplast disintegrates thickened cell wall remains for water transport; Pits allow water to flow laterally b. Phloem – sieve cells (seedless vascular plants & gymnosperms) OR sieve tube (angiosperms) Alive at maturity, but lack organelles to allow nutrients to pass through; sieve plates with holes allow flow from cell to cell; companion cells help load sugar c. Parenchyma – Thin, flexible 1° walls; most lack 2° walls; “Typical cell”; carries out metabolic functions; Ex; photosynthesis happens here; makes up fleshy fruit tissue; d. Collenchyma – strands or cylinders help support young parts of shoot 1° walls unevenly thicker than parenchyma; lack 2° walls and lignin; Living at maturity; Flexible support without restraining growth e. Sclerenchyma – Thick walls with lignin; Can’t elongate when mature; specialized for support: 2° walls strengthened before protoplast dies; rigid walls act as “skeleton; Sclerids-shorter, irregular shape; very thick walls (nutshells & seed coats; pear grit) Fibers- long, slender, tapered (hemp fibers) f. Epidermis/Protective- outside layer of cells; tightly packed 6. List and describe the three primary growth tissues. Dermal- covers entire body of plant Vascular- Xylem (transports water & dissolved minerals) Phloem- transports organic nutrients from where made to where needed Ground- Pith-internal to vascular tissue Cortex- external to vascular tissue 7. Label the diagrams of the stems and indicate the functions of the tissues. Leaf DERMAL TISSUEprotection against physical damage and pathogens Stem Root VASCULAR TISSUE- long distance transport of water & materials GROUND TISSUE-responsible for most metabolic functions variety of cells for storage, photosynthesis, and support 8. Label the Diagram of the leaf and indicate the function of the tissues. Dermal tissues- epidermis (tightly packed surface layer) guard cells (open and close stomata) Vascular tissues- Xylem & Phloem (transport) Ground tissues- spongy mesophyll – Loosely arranged photosynthetic cells Palisade mesophyll- Layer(s) of elongated photosynthetic cells 9. What is the role of the stomata? (singular- stoma) Microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plant 10. Label the diagram of a cross section through a woody stem and indicate the functions of the tissues. CHAPTER 36- Transport in Plants 1. What is the role of each of the following in plant transport? a. Transpiration b. Xylem c. Phloem 2. What is the trend in atmospheric CO2 seasonally and over the past 50 years? 3. How does chemiosmosis bring the following into the plant cell? a. Cations b. Anions c. Sucrose 4. What is the mechanism that creates the gradient in chemiosmosis? 5. What is believed to be responsible for the rapid water exchange in plant cells? 6. Define the following methods of lateral transport. a. Transmembrane b. Symplastic c. Apoplastic 7. What is the role of the epidermis in the root? 8. How do mycorrhizae help plants? 9. Describe the mechanisms of water transport. a. Transpiration b. Cohesion and Adhesion c. Root pressure 10. What mechanism causes the stoma to open when the guard cells are in “good conditions”? 11. Describe the pressure flow mechanism of sugar transport. CHAPTER 37- Plant Nutrition 1. How do nutrients enter plants? 2. What is the difference between macronutrients and micronutrients? 3. Why is magnesium important to plants? 4. How do plants absorb cations from the soil? 5. Why are root hairs important to plants? 6. Describe the path of nitrogen from the atmosphere to plant protein. Include the role of each of the following. a. Nitrogen-fixing bacteria b. Ammonifying bacteria c. Nitrifying bacteria d. Denitrifying bacteria 7. Describe the following unique nutritional relationships a. Rhizobium bacteria and legumes b. Mycorrhizae c. Parasitic plants d. Carnivorous plants CHAPTER 38 Plant Reproduction 1. When does the sporophyte and gametophyte generation begin in the typical angiosperm? 2. Identify the general function of the parts of a complete flower. a. Sepal b. Petals c. Stamen d. Carpel 3. Describe the two processes that produce the angiosperm’s gametophyte. a. Male b. Female 4. What is meant by double fertilization? 5. How is the seed embryo nourished? Cotyledons absorb nutrients from endosperm 6. Sketch and label a dicot and monocot seed. Include the functions. Ex: Beans Seed coat- hard protective coat Endosperm- stores nutrients for embryo Cotyledons-absorb food from endosperm Epicotyl- embryo above cotyledon attachment Hypocotyl- embryo below cotyledon attachment Radicle- embryonic root EX; Corn, grasses Pericarp- protective coat Scutellum-absorbs nutrients from endosperm Endosperm- stores nutrients for embryo Coleoptile- covers young shoot Coleorhiza-covers young root 7. What does a seed need to germinate? Uptake of water (imbibition) causes seed to expand and rupture coat, triggering metabolic changes 8. Identify some asexual mechanisms for plant reproduction. Vegetative reproduction- cloning of plants by asexual means Fragmentation- offspring grows from piece of parent plant; Ex: root gives rise to adventitious roots Apomixis- (dandelions) no joining of sperm/egg. Diploid cell in ovule gives rise to embryo and ovules mature into seeds (clones with advantage of seed dispersal) 9. Label the diagram of an idealized flower. CHAPTER 39- Control Systems in Plants 1. How does light influence sprouting plants? 2. Describe the steps of the signal transduction pathway. a. Reception b. Transduction c. Response 3. What did early experiments on photoperiodism demonstrate? 4. What does auxin do in plant cells that causes elongation? 5. Define apical dominance. 6. Identify the two functions of gibberellins. Stem elongation- stimulate growth of leaves and stems; little effect on roots Stimulates cell elongation and cell division Fruit growth- Auxins and gibberellins must be present for fruit to set; Germination- After imbibition, release of gibberellins from embryo signals seeds to break dormancy and germinate 7. Identify a few plant responses to ethylene Promotes fruit ripening Triple response- allows plant to grow round an object when sprouting; Apoptosis- leaf abscission (fall leaves) 8. Are all wavelengths of light equal when it comes to phototropism? Explain. 9. What are the two forms of phytochrome and how are they switched? 10. When do short day plants flower? 11. What happens when short day plants receive flashes of light? 12. When do long day plants flower? 13. What happens when long-day plants receive flashes of light? 14. What may be a cause of root gravitropism? 15. What is the mechanism that causes Mimosa leaves to close?