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37 Cards in this Set
- Front
- Back
What is a seed?
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consists of an embyo and its good supply, surrounded by a protective coat.
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Characteristics of Seed plants
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*seeds
*reduced gametophyte *heterospory *ovules *pollen |
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What is the advantage of seed adaptions?
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* resistant to desiccation
*resistant to UV exposure *reproduction away from moist conditions |
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What is the advantage of a reduced gametophyte?
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gametophyte can develop from spores retained within the sporangia of the parent sporophyte.
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what constructs an unfertilized ovule?
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the megasporangium(2n) containing the megaspore(n) (f gametophyte/egg) is surround by a tissue layer of integument(2n).
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Integument
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layer of sporophyte(2n) tissue around megasporangium(2n).
*Gymnosperms have 1 *angiosperms have 2 |
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Seed plant phylums
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Gymnosperm
Angiosperm |
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pollen grain
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male gametophyte (n) (sperm) enclosed within a pollen wall
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Pollination
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Transfer of pollen to the ovules. Not considered fertilization.
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Characteristics of Gymnpsperms
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*seeds not enclosed in ovaries
*seeds exposed on modified leaves (sporophylls) that usually form cones (strobili) |
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What was the transition from seedless to seed gymnosperms?
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Protgymnosperms
*woody stem with no seeds *gymnosperms dominated the Mesozoic |
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Phylum Cycadophyta
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*2nd largest group
*large cones and palm-like leaves |
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Phylum Ginkophyta
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Ginkgo biloba is the only surviving species
*tolerates air polllution *trees have different sexes |
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Phylum Gnetophyta
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*Gnetum, 35 spc
*Ephedra, 40 spc *Welwitchia1 spc *grouped based on molecular data |
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Phylum Coniferophyta
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*largest phylum
*600 spc *Doulas fir, European larch, Common Juniper, Wollemi pine (40 individuals left), Seqoia (largest organism), Bristlecone pine (oldest organism) |
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Megasporocyte ploidy level
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2n
within megasporangium |
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Megasporangium ploidy level
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2n
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megaspore ploidy level
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n
develops into female gametophyte and contains the archegonium/ia which will form the egg |
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Characteristics of Angiosperms
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Flowers and fruits (mature ovaries)
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Flower
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specialized structures for sexual reproduction
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Pollination Vectors
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Insects or other animals, wind dependent, water dependent
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Sepals
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modified leaves that enclose the bud
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petals
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brightly colored, aid in attracting pollinators
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Stamens
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Produce microspores that develop into pollen grains containing m gametophytes
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Parts of the stamen
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Filament= the stalk of the stamen
Anther = terminal sac where pollen is produced |
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Carples
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Produce megaspores (which produce female gametophytes)
Single or multiple carpels |
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Parts of the Carpel
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Stigma=sticky tip that receives pollen
Style= leads from the stigma to the ovary Ovary= contains 1+ ovules, when fertilized becomes a seed. |
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micropyle
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a pore that the pollen penetrates through to reach the ovule
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How many sperm are in a pollen grain
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two, one for the egg, one fuses with the two nuclei of the f gametophyte
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Double Fertilization
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Fertilization produces one Zygote, and a triploid cell
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cotyledons
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rudimentary seed leaves
either one or two |
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Endosperm
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what the triploid cell of f gamtetophyte develops into. Is rich in nourishment for the developing embryo.
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Archaefructus liaoningensis/ archefructus stnensis
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ancient sngiosperms
* has stamen and carpels but lacks petals and sepals * went back to aquatic enviro *spiral formation of leaves |
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Basal Anglosperms
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Oldest lineages
*Amborella (amborella trichopoda) lacks vessels *Water lily *star anise |
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Magnoliids
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spiral arrangement of pedals
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Monocots
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one cotyledon
parallel veins scattered vascular tissue fibrous root system one opening in pollen grain floral organs in m of 3 |
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Eudicot
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two cotyledons
net like veins ringed vascular tissue taproot three openings in pollen grain floral organs in m of 4 or 5 |