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Plants

Plants. Introducing…Plants. Earliest plants appeared around 500 million years ago Thought to have evolved from algal like ancestors. General Characteristics:. Eukaryotic, multicellular , photosynthetic Cellulose in cell wall Mostly terrestrial, variety of living conditions

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Plants

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  1. Plants

  2. Introducing…Plants • Earliest plants appeared around 500 million years ago • Thought to have evolved from algal like ancestors

  3. General Characteristics: • Eukaryotic, multicellular, photosynthetic • Cellulose in cell wall • Mostly terrestrial, variety of living conditions • Stationary (sessile)

  4. Alternation of Generations • Both diploid and haploid states • Diploid  spores • Haploid  gametes • Diploid (sporophyte) stage produces haploid cells through meiosis

  5. Haploid cells form asexual spores (gametophytes) • Gametophytes produce haploid sex cells (gametes) • Gametes produce diploid zygotes

  6. Adaptation for land... • Cuticle – waxy coating to prevent water loss • Stomata – open for gas exchange, close to prevent water loss

  7. Four major plant groups... • Bryophytes (mosses) • Lycophytes and Pterophytes (ferns) • Gymnosperms (conifers) • Angiosperms (flowering)

  8. Plant Evolution - Summary Mosses Ferns Conifers Flowering Plants Flowers Seeds Vascular tissue Multicellularity Common green algae ancestor

  9. Bryophytes (mosses) • Non-vascular • Plants lack true roots, stems and leaves • Grow in dense mats in moist environments • Sperm “swim” so water is needed

  10. Lycophytes and Pterophytes (ferns) • Vascular system(conducting tissues) • xylem and phloem - transport water and nutrients • Transport = taller growth!

  11. Seed Producing: • Extremely successful, great adapters due to specialized organs • Leaves • Stems • Roots • Reproduce sexually via pollination 2 Groups: • A) Gymnosperms (non-flowering) • B) Angiosperms (flowering)

  12. A) Gymnosperms • Specialized reproductive cones. • Pollen and egg cones (male and female) • Pollen grain produces embryo inside female cone

  13. B) Angiosperms • Flowering plants • Reproduce sexually by pollination • Can self pollinate or cross pollinate • Birds, bees, insects, wind, water

  14. Flowers produce both sperm and eggs • Eggs protected by ovary • Seeds form within ovary and ovary becomes fruit

  15. Homework! • Read Section 3.2 • Page 95 #1, 2, 3, 6

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