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Unformatted text preview: T HE PLANT K INGDOM: SEEDLESS PLANTS (CHAPTER 27) cut a lot of chap 28 out-What are some environmental challenges of living on land?-How do plants adaptations meet these challenges?  Colonization of the land required anatomical, physiological and reproductive adaptations. Provide three adaptations of seedless plants that made colonization successful and discuss why they were important. • Colonization of land plants o Required anatomical, physiology and reproductive adaptations o Waxy cuticle Protects against water loss • Thinner for those in moister habitats Stomata (tiny pores) • For gas exchange needed for photosynthesis Multicelllular gamentangia and embryos  Based on molecular comparisons of DNA and RNA sequences; chloroplasts DNA, nuclear genes and rRNA sequence, plants probably arose from a group of green algae called the Charophytes. Bryophytes are nonvasculated, seedless plants that are the closest relatives to the charophytes. Name the three phyla that comprise the bryophytes and the representative plant groups in each. • Charophytes o Plants probably arose from charophytes A group of green algae o Based on molecular comparisons of DNA and RRNA sequences Close match between charophytes and plants Charophyst DNA…  With respect to the alternation of generations in the life cycle of plants, which generation gives rise to haploid gametes? Is this by mitosis or meiosis? (Fig. 27-2) Which generation involves the fusion of two haploid gametes, and the production of a diploid zygote? The diploid zygote produces haploid spores. Is this by meiosis or mitosis? Gametes (egg and sperm) are produced in a gametangium, surrounded by sterile non-reproductive protective cells. What are the male gametangia that produce the sperm cells called? What are the female gamentangia called? (Fig. 27-1) • Alternation of generations 1 o 2 parts of plant cycle Haploid (gametophyte generation) • Gives rise to haploid gametes by mitosis • Start of the sporophyte generation Diploid (sporophyte generation) • Two haploid gametes fusing, sporophyte produces haploid spores by meiosis that start of gametophyte generation • Alternation of Generation 2 o Gametophyte produces gametes by mitosis o Gametes (egg and sperm) in a gametangium are surrounded by layer of sterile non reproductive protective cells o Gametes fuse (fertilization) to form zygote First state of the sporophyte generation o Zygote developed into a multicellular embryo within a female gametangia • Alternation of Generation 3 o Zygote developed into multicellular embryo Protected and nourished by gametophyte o Mature sporophyte plant Developed from the embryo produced sporogengous cells (spore mother cells) o Sporogenous cells underfoot meiosis to form spores First stage in gametophyte generation • Gamentangia 1 o Most plants multicellular gamentangia...
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This note was uploaded on 02/28/2009 for the course BIOLOGY 101 taught by Professor Martin during the Fall '08 term at Rutgers.
- Fall '08