Unit 5: Plant Science. Mr. Nagel Meade High School

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1 Unit 5: Plant Science Mr. Nagel Meade High School

2 Warm Up What significant roles do plants perform on Earth? How do you know? Name two modern issues that could be interrelated with plants.

3 IB Syllabus Statements Draw and label plan diagrams to show the distribution of tissues in the stem and leaf of a dicotyledonous plant. Outline three differences between the structures of dicotyledonous and monocotyledonous plants. Explain the relationship between the distribution of tissues in the leaf and the functions of these tissues. Identify modifications of roots, stems and leaves for different functions: bulbs, stem tubers, storage roots and tendrils. Damon, Alan, et al. Pearson Baccalaureate: HL Biology. Pearson, Print.

4 Hierarchy Organize and describe the following terms: Level 1 Non-vascular land plants Seedless Vascular Plants Seeded Vascular Plants Level 2 Gymnosperms Angiosperms Level 3 Dermal Tissue Ground Tissue Vascular Tissue

5 Hierarchy Level 1 Non-vascular land plants No conducting tissue; small and grow close to the ground» Ex: Mosses, Liverworts, and Hornworts Seedless Vascular Plants Well-developed vascular tissue; no seed production» Ex: Horsetails, Ferns, Club Mosses, and Whisk Ferns Seeded Vascular Plants Most living plants are in this group; extensive vascular system Level 2 Gymnosperms Have seeds that do not develop within an enclosed structure Angiosperms Have seeds that develop within a protective structure Level 3 Dermal Tissue Outer protective covering protects against physical agents and pathogenic organisms; prevents water loss and may be specialized for various purposes Ground Tissue Thin-walled cells that function in storage, photosynthesis, support and secretion Vascular Tissue Xylem and Phloem carry out long-distance conduction of water, minerals, and nutrients within the plant, while providing support.

6 Plan Diagrams Root Tissue Stem Tissue Leaf Tissue

7 Mono vs. Di Monocots Dicots Embryo One cotyledon Two cotyledons Veins Flowers Vascular System Root System Pollen Parallel venation in leaves 3 flower parts or multiples Vascular bundles arranged throughout stem Mainly fibrous One opening on pollen grain Netlike venation in leaves 4 or 5 flower parts or multiples Vascular bundles arranged as a ring in the stem Taproot (main root) with surrounding fibers Three openings on pollen grain Cotyledon: Leaf that emerges from a seed.

8 Homework Consider the LEAVES, ROOTS, and STEMS of various plants. Consider the variation that exists in these structures as you go from plant to plant. Identify FOUR observed differences in each organ, with examples to support your observations. Produce a simple bubble map to organize your thoughts.

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10 Warm Up Compare and contrast Monocots with Dicots on three characteristics. Identify the three main groupings that all plants fall into. Provide an example of each. What roles do the xylem and phloem play in the plant?

11 IB Syllabus Statements Identify modifications of roots, stems and leaves for different functions: bulbs, stem tubers, storage roots and tendrils. State that dicotyledonous plants have apical and lateral meristems. Compare growth due to apical and lateral meristems in dicotyledonous plants. Explain the role of auxin in phototropism as an example of the control of plant growth. Damon, Alan, et al. Pearson Baccalaureate: HL Biology. Pearson, Print.

12 Plant Organ Mods - Roots Roots Prop roots Thick adventitious roots that grow from the lower part of the stem to brace the plant. Ex: Corn Storage roots Specialized cells within the root store large quantities of carbohydrates and water. Ex: Carrot, Beet Air roots (pneumatophores) Produced by plants that live in wet places, these roots extend above the soil or water surface and facilitate oxygen uptake. Ex: Mangrove, Cyprus tree Buttress roots Large roots that develop near the bottom of trees to provide stability. Ex: Fig tree

13 Plant Organ Mods - Stems Stems Bulbs Vertical, underground stems consisting of enlarged bases of leaves that store food. Ex: Onion Tubers Horizontally growing stems below ground that are modified as carbohydrate-storage structures. Ex: Potatoes Rhizomes Horizontal stems that grow just below the surface to allow plant spreading. Ex: Ginger Stolons Horizontal stems growing above ground that allow plant to reproduce asexually. Ex: Strawberry plants

14 Plant Organ Mods Leaves Leaves Tendrils Structures that coil around objects to aid in support and climbing (sometimes modified stems). Ex: Pea plants produce tendrils from leaves Reproductive leaves Produce tiny plants along the leaf margins that fall to the ground and take root in the soil. Ex: Kalanchoe plants Floral leaves / bracts Colored modified leaves that surround flowers and attract insects for pollination. Ex: Poinsettia Spines Reduce water loss, may be associated with modified stems that carry out photosynthesis. Ex: Cacti

15 Meristems What are they? What type of cells are similar in animals? What is different about a meristem as compared to these animal cells?

16 Meristems Two types Apical Primary growth Root tips and stems (length) Herbaceous, non-woody stems and roots Lateral Secondary growth Increased thickness of plants (width) Woody plants (shrubs, trees) Vascular cambium secondary vascular tissue produces secondary xylem on the inside (wood component) and secondary phloem on the outside Cork cambium bark produces cork cells of outer bark

17 Phototropism Define phototropism. What hormone is responsible for this behavior? What parts of the plant exhibit high levels of this hormone? Is the hormone produced in greater quantities or redistributed within the plant? How do high concentrations of this hormone facilitate growth TOWARD a light source?

18 HW Questions Why would girdling (the removal of bark and vascular cambium in a narrow ring all the way around a tree) result in the death of the tree? If you remove the apical meristem from a dicotyledonous plant, what would be the effect on further plant growth? Of what value are tubers, a type of stem modification, to the survival of the plant species?

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20 Transpiration sc/webfeat/vis2005/show/transpiration.swf

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22 Warm Up Name three environmental factors that will increase the rate of transpiration. What plant part/feature has the most direct influence on the rate of transpiration? What is the purpose of root hairs?

23 Damon, Alan, et al. Pearson Baccalaureate: HL Biology. Pearson, Print. IB Syllabus Statements Draw and label a diagram showing the structure of a dicotyledonous animalpollinated flower. Distinguish between pollination, fertilization and seed dispersal. Draw and label a diagram showing the external and internal structure of a named dicotyledonous seed. Explain the conditions needed for the germination of a typical seed. Outline the metabolic processes during germination of a starchy seed. Explain how flowering is controlled in long-day and short-day plants, including the role of phytochrome.

24 Anatomy of a Flower Sepals Petals Anther Filament Stigma Style Ovary

25 Anatomy of a Flower Sepals Protect developing flower while in the bud Petals Colorful to attract pollinators Anther Part of stamen which produces male pollen Filament Stalk of stamen that holds up anther Stigma Sticky top of carpel (pistil) where pollen lands Style Part of carpel that supports Ovary Base of carpel where female sex cells develop

26 Birds and the Bees Pollination Process of pollen being placed on the female stigma Leads to Fertilization Male and female sex cells unite to form a diploid zygote Leads to Seeds! (inside juicy fruit)

27 Seeds Require oxygen, water, and appropriate temperature

28 Light-sensitive Plants Plant Type Flowering and light Examples Long-day Radishes, spinach, and lettuce Short-day Day-neutral Poinsettias, chrysanthemums, and asters Roses, dandelions, and tomatoes