Carlson5_Angiosperms1

Carlson5_Angiosperms1 - 1 Angiosperms #1 Bio 1B Fall ’07...

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Unformatted text preview: 1 Angiosperms #1 Bio 1B Fall ’07 Professor: Thomas Carlson 2 3 4 5 X X X Diploid Dominant X X Gametophyte dependent on sporophyte X animals & wind X mainly wind Pollination X X Gnetophytes Vessels X X X Tracheids X Double fertilization & Triploid Endosperm X X Antheridium X X X Archegonium X Flowers/Fruits X X Seeds X X Pollen X X X Aquatic ferns X Heterosporous X Independent sporophyte & gametophyte X X Water required for fertilization X Sporophyte dependent on gametophyte X Haploid Dominant X X X X Alternation of Generations Angiosperms Gymnosperms Pteridophytes Bryophytes [email protected] . edu 8/28/07 6 7 8 9 10 11 12 ANGIOSPERM LIFE CYCLE (Fig 30.10) Flowering Plant Flower Carpel (megasporophyll) Ovule (megasporangium) Megasporocyte = Mother cell = Diploid precursor cell Megaspore Megagametophyte (7 cells with 8 nuclei) Egg with 2 synergid cells near micropyle Two polar nuclei cell Egg (ovum) Flowering Plant Flower Stamen (microsporophyll) Anther with 4 chambers (4 microsporangia) Microsporocyte = Father cell = Diploid precursor cell Microspore Microgametophyte (2 celled pollen grain with 1 vegetative cell & 1 generative cell) Pollen tube develops from vegetative cell & 2 sperm develop from generative cell Sperm 13 Angiosperms (enclosed seed) • Pollen • Double fertilization • Triploid endosperm • Ovules in flowers enclosed by carpel • Seeds in fruits enclosed by carpel • Xylem contains vessel elements & fibers • Phloem contains companion cells • Complex leaves 14 Importance of Fowering plants • Most species rich group of plants ( at least 250,000 ) • Source of most human food • Rice, wheat, and corn are fruits of angiosperms 15 Diversity in angiosperms • Eucalyptus trees 100s of feet tall • Aquatic duckweed 1 mm in diameter • Epiphytes • Non-photosynthetic parasites • Insectivorous plants 16 Gymnosperm (naked seed) (Figs 30.3, 30.6) • Gymnosperm ovules are naked & exposed to air when the ovuliferous scales of conifers separate to let pollen in Angiosperms (enclosed seed) (Fig 30.10, 38.7, 38.8, 38.9) • Ovules surrounded by sporophytic tissues which create a barrier to outside world • Sperm reach eggs via pollen tubes growing through parental sporophyte tissue 17 Angiosperms Double fertilization (Fig 30.10, 38.6 Campbell) • One sperm fertilizes egg to form zygote • Other sperm joins with two nuclei in the megagametophyte to form triploid (3n) tissue called endosperm • The triploid endosperm becomes the source of nutrients for the developing embryo 18 19 Major Angiosperm Clades (Fig 30.12) (Judd et al., 2002) • Basal Families (pollen usually monocolpate) – usually have monocolpate pollen grains with single long grooved aperture – some lack vessels or have primitive vessels • Magnoliid Complex • Monocots (monocolpate pollen) • Eudicots (tricolpate pollen) (tricolpate pollen grains have 3 long grooved apertures, each with a central pore) 20 21 Primitive Angiosperm Clades (Fig 30.12) Basal Families = earliest flowering plants...
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This note was uploaded on 04/01/2008 for the course BIO 1B taught by Professor Carlson,mischel,power during the Fall '07 term at Berkeley.

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Carlson5_Angiosperms1 - 1 Angiosperms #1 Bio 1B Fall ’07...

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