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Kingdom plantae IGSCSE

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IGCSE 2016

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Kingdom plantae IGSCSE

  1. 1. Kingdom Plantae Extended
  2. 2. Divisions The plant Kingdom is divided into Divisions rather than Phyla We only need to know about: The Ferns and Angiosperms (flowering plants)
  3. 3. Mosses (for interest only)  Mosses are small plants that only grow in damp areas because they do not have a cuticle to stop them drying out  They so not have proper leaves, stems or roots
  4. 4. Ferns (Pteridophytes)– you need to know about these These plants dominated the world when dinosaurs were around but are not so common now
  5. 5. They have a cuticle so can grow in dryer areas They have true roots and stems with xylem and phloem to transport water and sugars They spread using rhizomes that grow away from the parent plant
  6. 6. The leaves are called fronds These grow by unfurling from fiddleheads
  7. 7. Fern life cycle - there are 2 stages
  8. 8. The plant we see is the sporophyte These have a full set of chromosomes in their cells We call this 2n chromosomes
  9. 9. On the back of the fronds we find sori
  10. 10. Spores are made in these by cell division called meiosis This gives the spores half the number of chromosomes or n
  11. 11. Spores are released and blown by the wind When they land in soil they can grow into a tiny microscopic pant called a prothallus This has only half a set of chromosomes
  12. 12. The prothallus is also called a gemetophyte because it makes gametes (sex cells) These are made by mitosis so they have half a set of chromosomes These are like roots This is a leaf-like structure but is very small
  13. 13. The male and female sex cells fuse to form a new plant with a full set of chromosomes It grows out of the gametophyte
  14. 14. And becomes an adult sporophyte
  15. 15. Because they are pretty ferns are popular house and garden plants
  16. 16. Gymnosperms (for interest only)  These are plants that reproduce using cones – like Pine Trees  The forests in North America and Europe are mostly coniferous  They have “soft wood” and grow quickly so are grown for paper and furniture
  17. 17. Angiosperms – flowering Plants you need to know this group Most of the plants we see are angiosperms They reproduce using flowers (sometimes the flowers are so small we can’t see them) The plants may be trees, shrubs, grasses, or herbs All of our important crops are angiosperms
  18. 18. There are two main groups: Monocotyledons and Dicotyledons The names of theses groups comes form the number of cotyledons in the seeds The Cotyledon is a food storage area: Dicotyledons have 2 and Monocotyledons have one Use this information to start filling in the table on
  19. 19. In fact these days scientists divide the groups by what the pollen looks like Monocotyledons have one furrow, Dicotyledons have two or more These pollen grains have been highly magnified by a scanning electron microscope
  20. 20. Roots Monocotyledon roots are fibrous – they branch out just below the soil This makes plants like grasses useful for holding soil in place and preventing erosion Dicotyledons tend to have tap roots – this is a long main root with side (lateral) roots coming off it Dicotyledon roots can go deep into the soil to find water
  21. 21. The next slide has some simple drawings for you to copy If we look at the roots in cross section we will see: Monocotyledons have a ring of xylem and phloem and a central pith – this is packing cells or a hollow region Dicotyledons have the xylem and phloem in the middle We will learn how xylem carries water and phloem carries sugar later this year
  22. 22. Monocotyledon root T/S Dicotyledon root T/S Epidermis Xylem and Phloem Pith Epidermis Cortex Xylem and Phloem
  23. 23. Stems Vascular bundles monocot Dicot Xylem and phloem are grouped together in stems to form vascular bundles In Monocotyledons the vascular bundles are scattered around In Dicotyledons they are neatly set in a ring near the edge
  24. 24. Monocotyledon Stem Dicotyledon Stem Epidermis Vascular bundles Epidermis Vascular bundles
  25. 25. leaves monocotyledon dicotyledon petiole One of the easiest ways to tell Monocotyledons from Dicotyledons is by the veins in their leaves. Veins are made of the xylem and phloem In Monocotyledons the veins are parallel and there is no petiole (stem) In Dicotyledons the veins are net-like and they have a petiole Can you work out the magnification of these leaves using the scale bar?
  26. 26. Flowers We will learn about flowers next year For now be aware that the flower parts (petals, anthers) come in 3’s in Monocotyledons, and in 4’s or usually 5’s in Dicotyledons Most monocotyledons are grasses and are wind pollinated so the flowers are really small and not brightly coloured
  27. 27. Check you have filled in the table completely in your notes

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