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Understanding Plants

Understanding Plants. Ms. Moore 8/30/12. What is a Plant?. Plants are: Multicellular Eukaryotes Photosynthesis using chlorophyll Most are autotrophs (some can be parasites or saprobes that live on decaying material) Fossil evidence: 470 million years ago . Typical Plant Cell.

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Understanding Plants

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  1. Understanding Plants Ms. Moore 8/30/12

  2. What is a Plant? • Plants are: • Multicellular • Eukaryotes • Photosynthesis using chlorophyll • Most are autotrophs (some can be parasites or saprobes that live on decaying material) • Fossil evidence: 470 million years ago

  3. Typical Plant Cell What is unique to a plant cell?

  4. Plant Life Cycle • 2 alternating phases • Sporophyte: spore-producing plant; occurs in diploid (2N) phase • Gametophyte: gamete-producing plant; occurs in haploid (N) phase

  5. Survival on Land • What do plants need to survive? • Sunlight • Water and Minerals • Gas Exchange (O2 and CO2) • Movement of Water and Nutrients • Evolved from an organism much like the multicellular green algae living today.

  6. Plant Kingdom • Botanists group based on 3 features: • Water-conducting tissues • Seeds • Flowers • Botanists have 4 groups: • Flowering plants: 235,000 species • Mosses and relatives: 15,600 species • Ferns and their relatives: 11,000 species • Cone-bearing plants: 760 species

  7. Bryophytes • Bryophytes: non-vascular plants • ex.: moss, liverworts, and hornworts • Life cycles depend on water for reproduction because they lack vascular tissue (use osmosis)

  8. Groups of Bryophytes • Mosses • Abundant in areas with water: swamps and bogs, near streams, and in rain forests • Rhizoids: long, thin cells that anchor them in the ground and absorb water (no roots) • Liverworts • Look like little green umbrellas • Can reproduce asexually with gemmae (smal multicellular reproductive structures; can form a cup) • Hornworts • Much like liverworts, except their sporophyte looks like a tiny green horn.

  9. Life Cycle of Bryophytes Gametophyte is the dominant stage. Dependence on water for fertilization to occur—sperm of bryophyte must swim to egg. Protonema: mass of tangled green filaments that forms rhizoids; from germinated sporophyte Antheridia: produces sperm Archegonia: produces egg

  10. Seedless Vascular Plants • Vascular Tissue: transport system for water and nutrients • Have true roots, leaves, and stems • 2 types vascular tissue: • Xylem: carries water upward from roots • Phloem: transports nutrients and carbs produced from photosynthesis • Examples: ferns, club moss, horsetails

  11. Ferns • Have characteristics of vascular plants: • RootsRhizomes • LeavesFronds • Life Cycle: • Diploid sporophyte is dominant stage. • Develop spores on underside of fronds in tiny containers: sporangia or groups called sori.

  12. Seed Plants • 2 groups: • Gymnosperms: bear seeds directly on the surfaces of cones • Angiosperms: flowering plants; bear their seeds within a layer of tissue that protects the seed • Pollination • transfer of pollen(male gametophyte) from male to female reproductive structure

  13. Characteristics of a Seed Seed: embryo of a plant that is encased in a protective covering and surrounded by a food supply Embryo: organism in early stage of development Seed Coat: surrounds and protects embryo

  14. Gymnosperms • Include: • Gnetophytes • Cycads • Ginkgoes • Conifers

  15. Angiosperms • Characteristics: • Develop flowers: unique reproductive organs; contain ovaries which protect seeds • Fruit: wall of tissue surrounding the seed (increases range of habitat)

  16. Two Types: Monocot & Dicot • Monocots: • Single cotyledon • Parallel veins • Floral: multiples of 3 • Vascular bundles throughout stem • Fibrous roots • Dicots: • Two cotyledons • Branched veins • Floral: multiples of 4/5 • Vascular bundles in ring • Taproot (carrot)

  17. Life Span • Annuals: complete one life cycle within one growing season • Ex: marigolds, petunias, pansies, wheat, cucumbers • Biennials: 2nd year produce flowers and seeds then die! • Ex: evening primrose, parsley, celery, foxglove • Perennials: live for more than 2 years • Herbacious: peonies, asparagus, grasses • Woody: palm trees, maple trees, honeysuckle

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