chapter 29and 30 sum - Plant Diversity I. Characteristics...

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1 Plant Diversity I. Characteristics of Plants a. Plants are multicellular eukaryotes. b. They are photosynthetic and contain chlorophyll a , chlorophyll b , and carotenoids. c. Plants have cell walls made of cellulose, impregnated with pectins (primary cell walls) or lignin (secondary cell walls) d. Plants store food as starch. e. Plants are adapted to living on land: (Nearly all plants live on land.) 1) The sex organs have an outer layer of nonreproductive cells ( gametangia ) to keep gametes from drying out. These are called archegonia for the female gametes and antheridia for the male gametes. 2) Most plants have a cuticle (waxy coating) to prevent drying out. 3) Some plants have vascular tissue (phloem and xylem) to support and transport materials. Some plants have stomata (gas- exchange pores). What are the advantages to plants for living on land? What problems had to be solved for plants to live on land successfully? f. Plant Life Cycles All plants have an alternation of generations life cycle in which a haploid multicellular generation (gametophyte) alternates with a diploid multicellular generation (sporophyte).
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2 Note: Nonvascular plants have a dominant gametophyte generation. Nonvascular plants are homosporous; meaning that the spores all look the same. Vascular plants have a dominant sporophyte generation and most (but not all) are heterosporous, meaning that there are two types of spores: microspores that give rise to the male gametophytes and megaspores that give rise to the female gametophytes. II. Classification of Plants Plant biologists use the terms division (instead of phylum) for the major plant groups within the plant kingdom. A. Nonvascular Plants - Bryophytes Characteristics: - The gametophyte stage is dominant. The sporophyte is short- lived, smaller, and sometimes nutritionally dependent on the gametophyte. - Bryophytes grow only a few inches high. They lack vascular tissue for support and transport.
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3 - Nonvascular plants are thought to have evolved about 350 million years ago during the Carboniferous Period of the Paleozoic Era. They fill a niche that the vascular plants don't; they form part of the tundra ground cover in the Arctic. These plants cannot
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This note was uploaded on 11/29/2010 for the course BUSSINESS 221242 taught by Professor Michaeldouglas during the Spring '10 term at Georgia Perimeter.

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chapter 29and 30 sum - Plant Diversity I. Characteristics...

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