Plants/The Importance Of Leaves

1. Plants/The Importance Of Leaves Chapters 6 & 19

2. Plant Classification • Plant features • Common traits in all plants: • All plants have chloroplasts • Contain chlorophyll: a chemical that gives plants their green color and traps light energy • Light energy is used in photosynthesis: the process in which plants use water, carbon dioxide, and energy from the sun to make food • Releases oxygen  • Occurs in the chloroplast • All plants contain a stiff cell wall

3. Plant Classification • Two groups of plants • Based on whether or not they have cells that make up tubes throughout the length of the plant • Vascular plants: plants that have tube like cells in their roots, stems, & leaves • like a straw • Like an elevator- these tube like cells carry things up and down the length of the plant • Carries: • *water and minerals • *food made by the leaves • Nonvascular plants: do not have tube like cells in their roots, stems, & leaves • Shorter & grow close to the ground • Use osmosis to take up water

4. Nonvascular Plants • Mosses & Liverworts • Moss: small, nonvascular plant that has both stems and leaves but no roots • Liverworts: found in small patches that appear wet and slippery

5. Nonvascular Plants • Mosses & Liverworts • Neither have roots • Hair like cells used to attach to the ground or tree trunk • Take up water • Only a few cm tall • Common in wet or damp areas • Mosses • Stems grow upright • Fine & soft • Stems that creep across the ground • Appear like longer, tangled, wavy hair

6. Nonvascular Plants • Mosses & Liverworts • Mosses cont. • Leaves= 1 or 2 cells thick • Easily dry out • Liverworts • Many don’t have roots, stems, or leaves • Body is flat slippery layer of green cells • Leaves grow in 2 or 3 flattened rows along the stem

7. Nonvascular Plants • Mosses & Liverworts • Uses • Food • Snails & worms • Help hold soil in place • Prevents soil from washing away • Some mosses that live on rocks-cause them to break down and form soil • Sphagnum moss used in hanging baskets or flowers • Aka peat moss • Increases the amount of water that can be held

8. Nonvascular Plants • Life cycle of a moss • ***Need constant source of water to survive*** • Used in sexual reproduction • Sexual Reproduction: the forming of a new organism by the union of two reproductive cells • Female reproductive cell: egg • Male reproductive cell: sperm • Fertilization: joining of the sperm and egg cell • Occurs in most plants and animals • Sperm & eggs of mosses form at the tips of the leafy stems

9. Nonvascular Plants • Life cycle of a moss

10. Vascular Plants • Majority of plants • Two types of tube like cells • Xylem: carry water and dissolved minerals from roots to the leaves • Phloem: carry food that is made in the leaves to all parts of the plant

11. Vascular Plants • Ferns: vascular plant that reproduces with spore • Can grow much taller than mosses or liverworts • In tropical forest can grow to 25 meters! • During part of its life ferns do not have a vascular system at all • Often grow in moist, shaded areas • Some can live in drier areas and some actually grow in water • 12,000+ species- most live in tropical forests

12. Vascular Plants • Fernscont. • Leaves grow from a horizontal stem that lies underground • Stem stores food and water • Roots • Anchor plant • Take up water and minerals from the soil • Fern leaves are divided into many leaflets • Many lose their leaves at the end of the growing season • New leaves form in the spring • Named by the shapes of their leaves • Reproduce with spores • Found on the underside of the leaves • Brown/orange “spots”- spore cases: hold the spores

13. Vascular Plants • Fernscont. • Leaves grow from a horizontal stem that lies underground • Stem stores food and water • Roots • Anchor plant • Take up water and minerals from the soil • Fern leaves are divided into many leaflets • Many lose their leaves at the end of the growing season • New leaves form in the spring • Named by the shapes of their leaves • Reproduce with spores • Found on the underside of the leaves • Brown/orange “spots”- spore cases: hold the spores

14. Vascular Plants • Fernscont. • Life cycle • Spore case opens • Carried by water or wind • If it lands in a moist place it grows into a small, flat, heart-shaped plant • Heart-shaped plant produces sperm cells and egg cells • Sperm swim through the water to fertilize the egg cell • Fertilized egg develops into a new fern

15. Vascular Plants Young root Embryo Stored food Young shoot Seed Coat • Seed: Part of a plant that contains an embryonic plant and stored food. • Embryo: an organism in it’s earliest stages of growth

16. Vascular Plants • Conifers: a type of seed plant that produces seeds in cones. • Most common land plants • Most do NOT lose their leaves • Found in the northern areas • Small needle-shaped leaves • Examples: • Evergreen Trees- sheds their leaves but not all at once • Pine, Spruce, & Fir • Loose their leaves each fall: • Larch, Dawn Redwood, & Bald Cypress

17. Vascular Plants • Conifers:

18. Vascular Plants • Conifers: • Life cycle of a pine tree: • Produce male and female cones • Small cones=male • *produce pollen: tiny grains of seed plants that develop sperm • *Found in early spring • *Wind is used to carry the pollen • Large cones=female • *contain egg cells • *when seeds are ripe the cones dry and the wood like scales open • **seeds fall to the ground • **if conditions are right the seeds grow into a new plant

19. Vascular Plants • Conifers:

20. Vascular Plants • Conifers: • Roots and Stems are woody • Xylem cells have thick cell walls • Leaves are tough and needle like • Some can be scale like • Can live in a variety of places • Wet areas, dry areas, high mountain slopes, close to sea etc. • Wood is mainly made of xylem cells\ • Paper, pencils, lumber, • Important shelter and food for animals • Bark, buds, and seeds are eaten by insects, birds, squirrels, rabbits, and more!

21. Vascular Plants • Flowering Plants: vascular plant that produces seeds inside a flower • Flower: the reproductive part of the plant • Male part: produces pollen • Sperm produced in the pollen • Must join with egg to reproduce • Carried by insects, wind, or other animals • Female part: produces eggs • Develops into a fruit that protects the seeds • More flowering plants than non • Better seed protection • Adaptive to many environments

22. Vascular Plants • Flowering Plants: • Examples: • Most broadleaved trees, vegetables, grasses, weeds, thorn bushes, and of course flowers like roses etc. • Only produce flowers at certain times during the year • Uses: • Decoration • Food source • Can you name some examples? • Which parts do you eat? (stems, leaves, fruit, or seed?) • Provides us with Oxygen • Removes carbon dioxide

23. Leaf Traits • Most are flat and green • Blade: thin, flat part of the leaf • Many different shapes: • Round, heart-shaped, long and narrow, short and broad • May not even look like a leaf • Example: needles • Stalk attaches the leaf to the stem • Many lengths and thicknesses • Example: celery stalk- the part you eat • Some plants do not have this • Examples: Grass & corn • Leaves NOT attached to the stem by stalks • Leaves directly attached to the stem • Contains xylem and phloem

24. Leaf Traits Stalk • Midrib: the main vein of the leaf • Continues off the stalk • Small veins branch off the midrib • Also contain xylem and phloem

25. Leaf Traits • Used to identify plants

26. Leaf Cells • Arranged in layers

27. Leaf Traits • Waxy layer: • Protects from water loss and from insects • Epidermis: outer layer of the cells of a plant • Only one cell thick • Palisade Layer: layer of long, green cells below the upper epidermis • Make most of the food for the plant • Contain many chloroplast • Chlorophyll green pigment

28. Leaf Traits • Spongy Layer: below the palisade layer, made of round green cells • Loosely arranged- in between filled with water and air • Also make food • Veins are found here

29. Leaf Traits • Another layer of epidermis with waxy layer, called lower epidermis • Stoma: small pore or opening in the epidermis (both lower and upper) of a leaf • Stomata=plural word for stoma • Allow gas exchange • Including water vapor • Open during the day lets in CO2 • Closed during the night • Guard Cells: green cells that change the size of the stoma in a leaf • Works by taking in or releasing water through osmosis

30. Water Loss • Transpiration: the process of water passing out through the stomata of the leaves • Plants may loose up to 90% of the water they take up through their roots each day • Wilting: when plant loses water faster than it can be replaced • Plant cells are mostly water • Water keeps the plant cells firm • Water loss is greater during warm days

31. Photosynthesis • Product: Sugar • Serves as food for the plant • 6CO2 + 6H2O Sunlight trapped by the chlorophyll C6H12O6 + 6O2

32. Photosynthesis Chlorophyll is used to trap the light energy Waste product: Oxygen

33. Sugar • Sugar made during photosynthesis: • Broken down and used to make other molecules used by the plant to grow • This releases energy

34. Plants for food • Leaves produce food for plants • Food produced for plants eaten by animals • Releases energy for animal to use

35. Plants for food • Animals that eat plants food source for animals that eat other animals

36. Uses of leaves • Leaves used for food • Animals, humans, insects etc. • Cattle, sheep, etc. eat leaves of grass • Examples: • Cabbage • Lettuce • Spinach • Onions • Leaves used for spices: sage, bay, parsley, etc • Tea • Peppermint • Spearmint • Used as medicine • Foxglove  contains chemical digitalis • Used in treating heart disease

37. Changes in leaves • Colored pigment • Green =chlorophyll • Forms only when light is present • Yellow & red also present • Chlorophyll covers up the effects of other pigments • Some plants are always colors other than green • Example: Coleus Plant • Some plants change color in the fall • Flow of sap slows • Temp drops • Less sunlight • Chlorophyll breaks down • Other colors show through

38. http://www.bio.umass.edu/biology/conn.river/liverwts.html liver warts slide 4 • http://www.irishviews.com/moss6.jpg Moss slide 4 • http://www.teara.govt.nz/en/mosses/1/2 life cycle of moss slide9 • http://www.warpedphotosblog.com/split-tip-fern-spores slide 12 • http://altoonsultan.blogspot.com/2010/08/walk-in-woods-fern-spores.html fern spores 2 slide 12 • http://www.teara.govt.nz/en/ferns-and-lycophytes/2/1 fern life cycle slide 14 • http://clara-hinton.blogspot.com/2010/05/inside-every-peanut-theres-man.html peanut slide 15 • http://www.onyxcollection.com/new/inlay_5a.html pine cone slide 17 • http://www.alaska-in-pictures.com/sitka-spruce-tree-cones-prince-william-sound-8874-pictures.htm Spruce Cones slide 17 • http://uacd.org/zones/Zone1/BoxElder/Tree%20Sale/EVERGREENS/Douglas_fir.htm Fir Cone slide 17 • http://biology.clc.uc.edu/courses/bio106/gymnospr.htm Male & female pine cones slide 19 • http://www.exploringnature.org/db/detail.php?dbID=32&detID=1895 life cycle of a conifer • http://www.my-photo-gallery.com/tag/vegetable-garden/ squash slide 22 • http://visual.merriam-webster.com/plants-gardening/plants/leaf/structure-leaf.php leaf structure slide 24 • http://en.wikipedia.org/wiki/Leaf leaves slide 25 • http://www.enchantedlearning.com/subjects/plants/leaf/ leaf layers slide 26 • http://www.phschool.com/science/biology_place/biocoach/photosynth/overview.html photosynthesis slide 31 • http://www.organicfertilizersources.com/blog/organic-fertilizer-beyond-the-crap/these-bugs-will-eat-your-plants insects eating leaves slide 34 • http://commons.wikimedia.org/wiki/File:Monarch_caterpillar_eating_swan_plant_leaf.jpg monarch caterpillar slide 34 • http://www.squidoo.com/coleus-plant?utm_source=google&utm_medium=imgres&utm_campaign=framebuster coleus plant slide 37