angiosperms.plant anatomy note guide.s2008

angiosperms.plant anatomy note guide.s2008 - General...

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General Biology 102 Lab Note Guide T.A.: K. Magee Angiosperms (Exercise 31) Phylum Anthophyta/flowering plants The most abundant, diverse, and widespread of all land plants. Their structural diversity, efficient vascular systems, mutualisms (esp. with fungi and insects), and short generation times have aided in their success. Range in size from 1 mm to over 100 m Large sporophyte that is independent of the microscopic gametophyte (same as in gymnosperms but opposite of bryophytes!); gametophyte totally dependent on sporophyte; the sporophyte is the large, mature organism with flowers that you easily recognize; the gametophyte within the flower is reduced to a pollen grain (produces a sperm nucleus) or an embryo sac (produces an egg) within an ovule *Sporophyte (2n) meiosis spores (n) gametophyte mitosis & cellular differentiation gametes Important to humans b/c our world economy is overwhelmingly based on them. We eat and use their vegetative structures (roots, stems, leaves) as well as reproductive structures (flowers, fruits, seeds). Flowers and fruit are 2 unique adaptations of angiosperm reproduction. Commonly divided into 2 classes: (table 31.1) 1. Monocots a. 1 cotyledon per embryo b. flower parts in sets of 3 c. parallel venation in leaves d. multiple rings of vascular bundles in stem e. lack a true vascular cambium (lateral meristem) 2. Dicots a. 2 cotyledons per embryo b. flower parts in sets of 4 or 5 c. reticulate (i.e. netted) venation in leaves d. one ring of vascular bundles or cylinder of vascular tissue in stem e. have a true vascular cambium (lateral meristem) Know flower parts (fig.31.3): a. receptacle- part of the flower stalk (peduncle) that bears the floral organs; located at the base of the flower; usually not large or noticeable b. sepals- lowermost or outermost whorls of structures, which are usually leaflike and protect the developing flower; collectively constitute the calyx c. petals- whorls of structures located inside and usually above the sepals; may be large and pigmented (in insect-pollinated flowers) or absent (in wind-pollinated plants); collectively constitute the corolla d. male portion of plant (androecium)- consists of stamens, each of which consists of a filament atop which is located an anther; inside the anthers are pollen grains, which produce the male gametes e. female portion of plant (gynoecium)- consists of 1 or more carpels, each made up of an ovary, style, and stigma; the ovary contains ovules that contain the female gametes; the term pistil is sometimes used to refer to an individual carpel or a group of fused carpels *During pollination, pollen grains are transferred to the stigma, where they germinate and grow a tube through the style to the ovary. Sporogenesis- production of microspores or megaspores via meiosis
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This note was uploaded on 04/07/2008 for the course BIOL 102 taught by Professor Gordon during the Spring '08 term at Howard.

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angiosperms.plant anatomy note guide.s2008 - General...

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