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Chapter 8 - Plants

Chapter 8 - Plants. Ms. Van Sciver’s Grade 7. Plants. Autotrophs – make their own food Multicellular Eukaryotes – have a nucleus Cells surrounded by cell walls. . Plant Origins. Land Adaptations. Support Rigid cell walls Vascular tissue Reproduction Gametophyte –

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Chapter 8 - Plants

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  1. Chapter 8 - Plants Ms. Van Sciver’s Grade 7

  2. Plants • Autotrophs – make their own food • Multicellular • Eukaryotes – have a nucleus • Cells surrounded by cell walls.

  3. Plant Origins

  4. Land Adaptations • Support • Rigid cell walls • Vascular tissue • Reproduction • Gametophyte – • Reproductive cells • Sporophyte – • Spores • Zygote – fertilized egg • Obtaining Water • Non vascular – must contact water • Vascular – tubes for water transport • Retaining Water • Cuticle • Transporting Materials • Non-vascular – diffusion/osmosis • Vascular – tubelike tissue

  5. Plant Life Cycle

  6. Seedless PlantsNon-Vascular - Bryophytes • Low Growing • Materials transport from cell to cell • Live in damp shady places • Thin cell walls

  7. Bryophyte Life Cycle

  8. Non-Vascular - Mosses More than 10,000 species Gametophyte – green- fuzzy appearing tiny leave like parts Root like structures – rhizoid Sporophyte stalk capsule contains spores

  9. Non-Vascular - Liverworts More than 8,000 species Found – moist rocks along streams Gametophyte – “liver” shaped Sporophytes – too small to see in umbrella shaped stalk

  10. Non-Vascular - Hornworts • Fewer than 100 species • Found in moist soil • Sporophytes – • slender, horn shaped

  11. Seedless Plants – Vascular • Ferns • Horsetails • Club Mosses • True Vascular Tissue • Release Spores • Need water for reproduction

  12. Ferns • More than 12,000 species • True Roots, stems, leaves • Sporophyte • Leaves – Fronds • Spore cases • Gametophytes • Tiny • Grow low to ground

  13. Fern Life Cycle

  14. Horsetails • Few Species alive now • Needle Like Branches • grow in circle around joints • Small leaves • grow flat against stem • Stem contains Silica

  15. Club Mosses • Only a few hundred species • Resembles branch of a pine tree • Ground pine • Grows in spiral around stem

  16. Seed Plants • Have Vascular Tissue • Xylem – carries water and minerals • Phloem – carries food (sugars) • Use Pollen and Seeds to reproduce • Pollen – male reproductive cell • Seeds – embryo, food supply, seed coat • Gymnosperms • Seeds not protected by fruit • Angiosperms • Produce Flowers • Seeds protected by fruit

  17. Seed Structure Monocot – one cotyledon (seed leaf) Dicot – 2 cotyledons

  18. Seed Dispersal • Seeds must be dispersed to prevent competition • Water • Sunlight • Minerals • Dispersed by • Wind • Water • Animals

  19. Germination • Needs- correct moisture, correct temperature, correct time – some seeds are dormant first

  20. Roots • Tip Covered by a root cap • Protects root during growth • New cells develop behind root cap • Root hairs • Tiny • Absorb water, minerals • Anchor plant in soil • Xylem • Phloem • Fibrous Roots - spreading • Taproot - deep

  21. Stems • Xylem – carries mineral, water • Phloem – carries food • Supporting Cells Woody Stems Outer bark – Cork Living Phloem Cambium Living Xylem Sapwood Hardwood Annual Rings Herbaceous Soft No wood

  22. Leaves • Conduct Photosynthesis • Lose water from stomatesduring transpiration • Guard cells control amount of water lost

  23. Gymnosperms Ginkgo • Seed Not Protected by a fruit • Needle like or scale like leaves • Deep roots system Cycad tropical Conifer Largest group Cone bearing Gnetophyte Deserts, tropical rain forests Can live 1,000 yrs.

  24. Gymnosperm Reproduction Pollination pollen - male parts Fertilization sperm reaches ovule Seed development Seed Dispersal

  25. Angiosperms • Produce Flowers • Seeds are protected by fruits Live almost everywhere

  26. Flower Parts

  27. Angiosperm Life Cycle

  28. Dicots vs. Monocots

  29. Tropisms • A plant grows toward a stimulus – positive • A plant grows away from a stimulus – negative • Touch – Thigmotropism • Light – Phototropism • Gravity – Gravitropism or • Geotropism • Hormones – Auxin – causes • cells to lengthen on side away • from light. • Plant bends toward light.

  30. Seasonal Changes • Photoperiodism – • response to length of day vs. night. • Critical Night Length • Short Day Plants – Bloom when daylight is shorter autumn • Long Day plants – Bloom when daylight is longer – spring and summer • Day Neutral – No effect

  31. Life Spans of Angiosperms • Annuals • Complete cycle in one growing season • herbaceous stems • Perennials • Flower every year • Most have woody steam • some have herbaceous stems • leaves and stems die each winter, but new are produced in spring. • Biennials • Year one – • stems, leaves • Year Two – • flowers, fruits, seeds

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