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LESSON 9

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LESSON 9

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  1. LESSON 9 SEXUAL REPRODUCTION IN FLOWERING PLANTS

  2. Concept #1 • TheFLOWERis the SEXUAL REPRODUCTIVE organ of a flowering plant.

  3. Concept #2 • PERFECTflowers-contain both male AND female reproductive structures. • IMPERFECTflowers- contain either the male OR the female reproductive structure

  4. Concept #3 • POLLINATION-is the transfer of pollen fromANTHERtoSTIGMA. • POLLEN GRAINSfrom different kinds of plants are very different inSIZEandSHAPE.

  5. Concept #4 • Some plants SELF-POLLINATE; others require CROSS-POLLINATION.

  6. Concept #5 • Pollen can be transported by WIND, WATER, GRAVITY, INSECTS, and HUMANS, among other things.

  7. Concept #6 • FERTILIZATION occurs when a SPERM NUCLEUS from a POLLEN GRAIN unites with the EGG NUCLEUS of an OVULE in an OVARY. • A SEEDbegins to form when fertilization occurs. The OVARY becomes the FRUIT.

  8. Types of Pollination • Self-Pollination • Cross-Pollination

  9. 1. Self - Pollination • When a plant pollinates itself (1 plant involved) • Genetically identical offspring • Occurs in different flowers on the same plant • ASEXUAL REPRODUCTION

  10. Self-pollination advantages • Makes sure plant does not go into extinction • If parent can survive in habitat, so can offspring

  11. Self-pollination disadvantages • No variation, so no evolution • Disease may spread easier among identical offspring

  12. 2. Cross Pollination • One plant pollinates another plant (2 plants involved) • Genetically different offspring • Different plant, different flowers (must be from same species) • SEXUAL REPRODUCTION

  13. Cross-pollination advantages • Evolution because offspring not identical to parent or other offspring • Disease will not affect all offspring at once because not genetically identical

  14. Cross-pollination disadvantages • Pollen might not reach stigma (must be compatible to work) • Two parent flowers, 2 different plants, same species (much more specific)