BIOL 1902 Lecture 20: BIOL WEEK 20
13 Apr 2016
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Document Summary
Ultraviolet light allows pollinators to see colours that our eyes can"t: e. g. Cross-pollination (outbreeding) = better; greater genetic diversity. Flower w/ both sexual organs = hermaphroditic; perfect flowers. If pollen was up high & female flower is down low, pollen will fall to ground so better to have female flower on top. Which is why cones are at top of trees: spatial separation w/ each sex on separate plant (dioecious, white campion: either only male or female flowers on 1 plant. Spatial placement in same flower: e. g. bottle (closed) gentian attract bees. Temporal separation of the sexes: jeweled flowers start off as males, male part falls off & flower becomes female, temporal sex change = dichogany. Pink lady"s slippers employ placement strategy & also use deceit & trap: pouch-petal has slit opening, staminode = mixer of stamens & pistils put together, both partially blocked by staminode & sticky pollen masses.
