Introduction to plants


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Introduction to plants

  1. 1. Introduction to Plants
  2. 2.  Plants have 4 Plant characteristics that they all share: Characteristics (1) Photosynthesis – Plants are green because they contain chlorophyll – Chlorophyll: green pigment that captures energy from sunlight, found in chloroplasts
  3. 3. – Plants use energy from sunlight to make food from carbon dioxide and water—this process is known as photosynthesis– Plants are producers—they make their own food
  4. 4.  (2) Cuticles – Plants don’t dry out because they are protected by a cuticle – Cuticle: a waxy layer that coats most of the surfaces of plants that are exposed to air
  5. 5.  (3) Cell Walls – Plants do not have a skeleton like animals – They stay upright and are protected because they are surrounded by a rigid cell wall – Cell wall is made of carbohydrates and proteins – Some plants form a secondary cell wall this stops them from growing larger
  6. 6.  (4) Reproduction – Plants have 2 stages in their life cycle: sporophyte stage and gametophyte stage – In the sporophyte stage plant makes spores – In suitable environment, spores grow & these new plants are called gametophytes
  7. 7. – During gametophyte stage, female gametophytes produce eggs and male gametophytes produce sperm.– Sex cells cannot grow directly into new plants—a sperm must fertilize an egg– The fertilized egg grows into a sporophyte, makes more spores, and the cycle starts again
  8. 8. Check for Understanding What are 4 characteristics that all plants share?Photosynthesis, cuticle, cell wall, and reproduction
  9. 9. 4 Main Groups of Plants First they can be classified as nonvascular plants and vascular plants Vascular plants are further divided into 3 groups: – (1) seedless plants – (2) nonflowering seed plants (gymnosperms) – (3) flowering seed plants (angiosperms )
  10. 10. Seedless Plants***2 groups of plants don’t make seeds: (1) Nonvascular Plants – Three groups of plants that lack specialized conducting tissues and true roots, stems, and leaves – Depend on diffusion to move materials from one part of plant to another – Most are small – Usually live in damp places – Don’t have true stems, roots, or leaves
  11. 11. – 3 groups of nonvascular plants are liverworts, hornworts, and mossesliverworts hornworts mosses
  12. 12. Mosses, Liverworts, and Hornworts– Have leafy stalks and rhizoids– Rhizoid: a rootlike structure in nonvascular plants that holds the plants in place and helps plants get water and nutrients– Have 2 stages to their life cycle
  13. 13. – Importance of Nonvascular Plants  Usually the first plants to live in a new environment, such as newly exposed rock  When they die, they form a thin layer of soil  Hold soil in place, reducing erosion  Some animals eat nonvascular plants  Other animals use them for nesting material  Peat mosses are important to humans because they can be dried out and burned as fuel
  14. 14.  (2) Seedless Vascular Plants – Ferns, horsetails, and club mosses are usually much smaller than in the past— some ferns grew 8 meters tall in ancient forests! – Because they have vascular tissues, they are often larger than nonvascular plants
  15. 15.  Ferns – Have a rhizome an underground stem from which leaves and roots grow – Fern leaves are called “fronds” – -The end of the fronds are called fiddle heads
  16. 16.  Club Mosses – Have vascular tissue, so not actually a moss Horsetails – Stems are hollow and contain silica—gives them gritty texture – Early Americans used horsetails to scrub pots and pans
  17. 17. – Importance of Seedless Vascular Plants  Help form soil & prevent erosion  Ferns add to soil depth, helping other plants to grow  Popular houseplants  Fiddleheads of ferns and some horsetails can be eaten  Horsetails are used in some dietary supplements, shampoos, and skin-care products  Remains of ancient ferns, horsetails, and club mosses form coal, which humans rely on for energy
  18. 18. Check for Understanding Name & describe the 4 main groups of plants 1)nonvascular: no specialized tissues 2) Seedless vascular: ferns, horsetails, club mosses 3) Gymnosperms: nonflowering seed 4) Angiosperm: flowering seed
  19. 19.  The Origin of Plants – Green algae may look like a plant, but it isn’t a plant – Scientists think that green algae and plants share a common ancestor because of the following similarities:  Both have the same kind of chlorophyll  Have similar cell walls  Both use photosynthesis to make own food  Both store energy in form of starch  Both have a two-stage life cycle
  20. 20. The similarities between a modern green algae(right) and plants, such as ferns (left), suggestthat both may have originated from an ancient species of green algae.
  21. 21. Check for Understanding  Explain the origin of plants-scientists think that green algae and plants share a common ancestor