1. Unit 4- Plants M. Lauria

2. Background on Plants The Plant kingdom includes more than 270,000 species Believed to have evolved from green algae (chlorophyta). http://homepage.smc.edu/gallogly_ethan/travel _photos/misc/sean_mom_giant_redwood_tree.J PG

3. Adaptations to Land In order to prevent water loss on dry land, plants have a cuticle (waxy covering). Some have roots, stems and leaves to help obtain, transport, and use water and nutrients efficiently. Use spores and seeds to protect reproductive cells.

4. Adaptations to Land (cont.) Some plants have vascular tissues called xylem and phloem to help transport water and nutrients throughout the different parts of the plant. Some have stomates to prevent water loss and control gas exchange with the atmosphere.

5. Stomates Stomates are small openings along the surface of a leaf that control gas exchange. They close when the plant is beginning to lose to much water. They open when the plant needs CO2 www.emc.maric opa.edu/.../ BIOBK/BioBook PS.html

6. Cross- Section of a Leaf http://www.emc.maricopa.edu/faculty/farabee/BIOBK/leafst ru.gif

7. Xylem Conducts water Xylem cell is called a tracheid, its cell walls are impermeable to water Vessel elements are xylem cells found in angiosperms When these cells die, their cytoplasm disintegrates and they are able to conduct water.

8. Phloem Conducts a variety of plant nutrients and products Phloem cells are called sieve tube elements, are positioned end to end and have holes that connect their interiors. Companion cells are located next to sieve tubes and help to control them.

9. Cross Section of a Stem: Xylem and Phloem cd.ed.gov.hk/.../ Root/Ranuculus%2011.jpg

10. Classifying Plants From Modern Biology: Holt, Rinehart, and Winston

11. Non-vascular Plants Lack vascular tissue and do not form true roots, stems or leaves. Are seedless, and need water to reproduce sexually. Have an alternation of generations- sporophyte and gametophyte.

12. Seedless Vascular Plants Vascular plants can grow larger and live longer. Why? Include: Ferns, whisk ferns, club mosses, horsetails. http://www.ct-botanical- society.org/ferns/fernpics/phegopterishexa_frond.jpg

13. Alternation of Generations in a Fern staff.jccc.net/.../ celldivision/images/fern.gif

14. Vascular Seed Plants Plants with seeds have a greater chance at reproductive success than seedless plants. Why? Two main groups of seed-bearing plants: gymnosperms (“naked” seed) and angiosperms (seed protected in fruits).

15. Gymnosperms Have specialized male and female reproductive structures called scales. Larger structure is called a cone. http://www.pfc.forestry.ca/diseases/CTD/Group/Rust/lrg_ images/fig30b.gif

16. Gymnosperms Conifers (evergreens) include pines, spruce, fir, cedars, redwoods. Leaves are needle- shaped. Do not necessarily shed needles in the fall. Pollen from a pollen cone fertilizes egg within a seed cone. Seed within a seed cone is considered “naked.”

17. Angiosperms Flowering plants are most widespread of all plants? Why? Reproduce using pollination of flowers Seeds are contained within a protective fruit. Some flowers have both male parts (stamen- pollen producing) and female parts (ovary- egg producing)

18. Flower Parts www.ncsu.edu/project/ agronauts/images/flower.gif

19. Alternation of Generations In Vascular Seed Plants Sporophyte is the dominant form, and the gametophyte grows within the flowers or cones of the sporophyte. http://www.stevedibler.com/photos/N ature-Scenery/Dogwood_tree.jpg