BSC_2011Ch28Seedless

BSC_2011Ch28Seedless - BSC 2011 Dr. Presley Chapter 28...

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BSC 2011 Chapter 28 Dr. Presley Sadava9th Ch 28 1 of 13 Plants without seeds INTRODUCTION: 1859, Sir William Dawson discovered fossilized remains of what he named Psilophyton , meaning “naked plant.” It had branching stems that ended in spore cases; and appeared to lack roots and leaves. 1915, Robert Kidston and William Lang discovered fossils similar to Psilophyton near Rhynie, Scotland. Rhynia are examples of ancient terrestrial plants that lack seeds and other features of more modern plants. Seedless plants, such as mosses and ferns, are still abundant today. Fossilized remains of seedless plants are primarily found in coal deposits. WHAT IS A PLANT? See Fig 28.1, p. 590 - Plants are photosynthetic species including: glaucophytes (p. 579- first eukaryotic group after cyanobacteria, retain peptidoglycans in chloroplast), red algae , chlorophytes , charophyte s, and land plants . -“Plants” are embryophytes . This designation often used to include: land plants plus the streptophytes which are groups of green algae retaining egg in the parent - “ Green Plants ” designation includes: land plants, streptophytes and other green algae; all having chlorophyll b. CHARACTERISTICS OF ALL PLANTS : multicellular eukaryotes photosynthetic autotrophs, mainly terrestrial tissues well-developed (vascular tissues well-defined in tracheophytes ) photosynthetic with chlorophyll a , chlorophyll b , carotenoids ** chloroplasts with thylakoid membranes ** cell wall contain cellulose (20-26%) ** food reserve is the polysaccharide starch, stored in plastids microtubular spindle, cell plate cytokinesis, sperm structure, DNA ** **indicates probably evolution of plants from green algae Fig 28.2, p. 591 -possibly from stoneworts (charophyte genus Chara ) or from coleochaetales, - common characteristics : 1) plasmodesmata 2) branching and apical growth (Chara) like most plants ( Coleochaete- basal growth as in liverworts) 3) similar microtubular cell division and chloroplast structure - ancestral green algae lived at margins of ponds or marshes . From these marginal habitats, early plants made the move onto land. embryophyte with multicellular gametangia - zygote and embryo development is protected by tissues of parent body alternation of generations life cycle : two multicellular plant generations; gametophyte ( haploid ) produces gametes by mitosis , sporophyte ( diploid ) produces spores by meiosis **Compare dominance of generations of different plant groups Review this type of life cycle on page 592 ( and p. 222 from last semester)
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BSC 2011 Chapter 28 Dr. Presley Sadava9th Ch 28 2 of 13 Classification : Study Table 28.1 on page 590 (same for class and laboratory) Phylum is used to denote the same level of taxonomy as division. PLANT KINGDOM
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BSC_2011Ch28Seedless - BSC 2011 Dr. Presley Chapter 28...

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