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15 Cards in this Set
- Front
- Back
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role of gametes
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pollen develop and disperse
pollen is dispersed by wind, pollinator truly terrestrial, no water needed for reproduction |
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advantages of the seed
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maintaining the female gametophyte as a dependent helps
seed is mechanism of dispersal |
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origin of angiosperms
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molecular clock set place the evolution of the angiosperms 145-208 mya
oldest unequivocal angiosperm fossils are pollen grains explosion of diversity many major lineages recognized by the end of Cretaceous 65-70 mya |
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orgin and evolution of the angiosperms
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most closely related land plants are "gymnosperms"
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how did angiosperms diversify so quickly
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efficient water transport vascular transpiration
efficient use of reproductive structures- no endosperm producer unless egg fertilized insect pollination: floral and extrafloral nectaries evolved anthers with excess pollen for insects to eat corolla tubes, clawed petals to make inscts more efficient pollinators |
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refined adaptations to life on land
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vascular tissue refinements for efficient transport
evolution of the flower |
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ABC homeobox genes
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developmental control genes
duplications/losses of these, or mutations |
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evolution of the flower
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funciton determines structure
primitive flowers have many spirally arranged unused whorls more derived flowers are variable- tends to exhibit fusion of parts |
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4 parts of a lower
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sepals
petals androcecium gynoecium |
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carpel
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modified leaf folded to enclose ovules
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pollination
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pollen from anther (usually of different plants) sticks to stigma (tip of carpel)
pollen grain germinates and sends tub down to ovule contained within the ovary |
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fertilization
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double fertilization: 2 sperms nuclei are deposited in female gametophyte
1 to fertilize the egg 1 to fertilize polar body |
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wind pollination
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flowers are small, non- descript
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animal pollination
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very showy
fragrant nectar or oils tons of pollen |
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