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Leaf my plants alone

Leaf my plants alone. LEAF It; PLANT It; or DON’T TOUCH IT! . Our Agenda for the Next 2 Episodes: . 1.Land Plants evolved from green algae -question session 2.Mosses and other nonvascular plants have life cycles dominated by gametophytes - question session

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Leaf my plants alone

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  1. Leaf my plants alone LEAF It; PLANT It; or DON’T TOUCH IT!

  2. Our Agenda for the Next 2 Episodes: 1.Land Plants evolved from green algae -question session 2.Mosses and other nonvascular plants have life cycles dominated by gametophytes - question session 3.Ferns and other seedless vascular plants were the first plants to grow tall - question session

  3. But, First: What is a Plant? • Multicellular • Eukaryotic • Photosynthetic • Autotrophic • Cell walls made of cellulose • Chlorophylls a and b exist to help run photosynthesis

  4. Characteristics of Plants? • Plants dominate land and water • Have lots of diversity • Some less than 1 mm in length • Some more than 100 m tall • 12 phyla (divisions) have more than 290,000 known species • Some live a few weeks • Some live for thousands of years

  5. The history • Earth is approximately 4.5 billion years old • Only 1.2 billion years ago is there some evidence of cyanobacteria existence • Then, 500 million years ago small plants, fungi and animals started making thereway inland • Finally, 370 million years ago some plants appeared that could grow tall

  6. PROFESSOR KNOW-A-LOT

  7. A PLANT!!!

  8. ?

  9. Where did land plants evolve from? • Soil • Algae • Justin Bieber • God

  10. ALGAE

  11. Why move to Land? • Move to land from water provided many advantages: • More exposure to sunlight (photosynthesis) • Increased carbon dioxide levels • Larger supply of inorganic nutrients • Obtain direct sunlight by water and plankton • Also presented challenges: • Dying out due to evaporation

  12. Distant Relatives of Plants? • Most probably developed from aquatic algae called: Charophytes • Similarities between Charophytes and Land Plants: • Rosette-shaped cellulose-synthesizing complexes • Peroxisome enzymes • Structure of flagellated sperm • Formation of phargmoplast

  13. Difference between algae and a land plant 5 traits present in land plants, but absent to its ancestor, the algae: • Apical meristems • Alternations of generations • Multicellular embryo that is dependent on parent plant • Sporangia that walled spores • Gametangia that produce gametes

  14. Plants can be classified in three general ways: • This system classifies plants by whether or not they have vascular tissue • Nonvascular plants (Bryophytes) • Mosses • Liverworts • Hornworts • Seedless Vascular Plants • Lycophytes • Pterophytes • Seed plants • Gymnosperms (“naked seeds”) • Angiosperms (seeds develop in chambers) • 90% of all plant life are Angiosperms

  15. How did land plants survive in the Land environment? a)Rebecca Black nourished them with her sweet and angelic voice b)Adaptation c) God’s blessings d) With a pen.

  16. ADAPTION

  17. Adaptations needed to move onto Land • Early adaptation to land: • Cuticle – A waxy protective covering on plant surfaces that prevents water loss • Keeps water in plant • Keeps out carbon dioxide • Plants with stomata survived • Apical Meristems: Localized regions of cell division at tips of shoots and roots • Inhibit growth of cells which protects body and internal tissue

  18. Multi cellular; dependant embryos • “embryophytes” • Transfer of nutrients from parent • Alternation of generations • Sporophyte (diploid) and gametophyte (haploid) • Gametangia – gametes are produced within multi-cellular organ • Female – archegonia • Male – Antheridia • Vascular Tissue • Transport water and minerals

  19. egg sperm

  20. Commercial Break

  21. What are bryophytes? a) Ms.Kanisek’s hair products b)Non-vascular plants c)A fancy term that God made up d)Vascular Plants

  22. The Bryophytes • All non- vascular plants • 3 phyla • Mosses (Phylum Bryophyta) • Liverworts (Phylum Hepatophyta) • Hornworts (Phylum Anthocerophyta) • Botanists have identified 16,600 species • Don’t have vascular tissue • Do not form true roots, stems, leaves • Usually grow on land near streams and rivers

  23. What’s so special about bryophytes? • Ecological and economic benefits: • Absorb damaging levels of radiation from the sun • Can form extensive deposits of inorganic material (peat) • Carbon reservoirs, thus, balancing atmospheric carbon levels • Some used as natural antiseptic for wounds

  24. Classification of Bryophytes • Most primitive type of plants • Characteristics more closely related to plants than algae • Mostly terrestrial • Have alternation-of-generations life cycle • Seedless • Produce spores • No vascular tissue; so usually small (1-2 cm) • Bryophytes need water to reproduce sexually b/c sperm must swim to egg • In dry areas, reproduce sexually only when enough moisture is available • Asexual reproduction of haploid spores does not require water

  25. Phylum Bryophyta • Thick green carpet of moss you see is actually thousands of tiny moss gametophytes • Each gametophyte attached to soil by rootlike structures called rhizoids (RIE-zoidz) • Rhizoids don’t have vascular tissue • Filament of cells in mosses • Do function like roots by anchoring moss and absorbing water and inorganic nutrients • Gametophytes can be male / female or both

  26. Life Cycle of the Phylum Bryophyta

  27. Gametophyte Sporophyte Gametangia Protonemata (pre-gametophyte) Sporophyte Spores

  28. Phylum Hepatophyte • Includes liverworts • Grow in moist, shady areas • Most have thin, transparent leaflike structure arranged along stemlike axis

  29. Phylum Anthocerophyta • Includes hornworts • Look like liverworts • Also live in moist, shady areas • Share characteristic with algae: each cell has single large chloroplast instead of many small ones

  30. What are Vascular Plants? • Vascular plants have specialized conducting tissues (xylem and phloem) that transport water and substances • Can grow larger • Live in more environments than nonvascular plants • Strong stems allow them to grow tall • Rise above other plants – more sunlight

  31. Seedless Vascular Plants • Dominated earth until about 200 million years ago • 2 phyla • Lycophyta – Lycophytes • Pterophyta – ferns, whisk ferns, horsetails • Spores are mobile sexual reproductive parts of all seedless plants • Important for: REMOVE Carbon dioxide from atmopshere and become coal, which are used for fossil fuel

  32. How did Leaves Develop? • 2 Hypothesis for the development of Leaves: • Microphylls: originated from sprongia • Macrophylls / Megaphylls: branched vascular systems; may have evolved by fusion of branched stems

  33. Phylum Lycophyta • Club mosses • Look like miniature pine trees (also called ground pines) • They make strobilus (cone)  cluster of sporangia-bearing modified leaves • One member of Lycophyta is spike moss native to American Southwest • Turns brown and curls up into a ball at night • When moistened, it uncurls and turns

  34. Phylum Pterophyta • Diverse group of ferns • Some floating plant less than 1 cm across • Some reach 25 meters • Most have underground stem called rhizome • Some used as growing medium for orchids • Tightly coiled new leaves called fiddleheads • Fiddleheads uncoil to become fronds (leaves)

  35. IB Assessment Statements • 9.1.5 – Dicotyledonous plants have apical and lateral meristems • Apical meristems are sometimes reffered to as primary meristems and lateral meristems as cambium. Meristems generate new cells for growth of the plant.

  36. Bibliography • Allott, Andrew. Biology for the IB Diploma: standard and higher level. London: Oxford University Press, 2007. Print. • Damon, Alan, Randy McGonegal, Patricia Tosto, and William Ward. "9." Higher Level Biology. England: Pearson Baccalauraeate, 2007. 238-240. Print. • "Lands Plants, Diversity." Evolution of PLANTS. N.p., n.d. Web. 29 Sept. 2011. <home.earthlink.net/~cinidan/APBiology/PlantEvol.html>. • Reece, Jane B., and Neil A. Campbell. Campbell biology Jane B. Reece ... [et al.].. 8th ed. San Francisco: Benjamin Cummings :, 2009. Print.

  37. Define apical meristems • 2 marks

  38. -it is located in the apex of the root and stem • -growth in apical meristems allows roots and stems to elongate • -its shoot produces new leaves and flowers

  39. State the significance of the seedless vascular plants • 2 marks

  40. -growth helped produce the major global cooling-decaying remnants of the forests became coal, which are used for fossil fuel

  41. State the two types of phyla of bryophytes • 2 marks

  42. -liverworts-hornworts-mosses

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