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Unformatted text preview: 1 Wednesday Feb 16, 2011 Finish Plant Reproduc;on Pollen and seed dispersal Plant responses to the environment 3 case studies 2 ~20% owering plants pollinated by wind most gymnosperms Pollen Dispersal How are the oral structures of wind dispersed species well suited to their mode of dispersal? Why do pines, oaks and grasses produce so much pollen? Grass owers Hazel staminate & carpellate owers 3 Pollen Dispersal 80% owering plants bio;cally (animal) pollinated, 65% by insects Bees Favor bright colored owers (yellow, blue) with sweet fragrance See UV radia;on nectar guides Reward? Feed on nectar and pollen Birds: Favor bright colored owers (red, yellow) with tube shape but no fragrance Reward? Feed on nectar Bats and moths: Favor Light colored owers (white, yellow) that are strongly aroma;c Reward? Feed on nectar and/or pollen 4 Pollen delivered to s;gmas 5 Darwins predicted moth? 1862, Darwin observed orchid from Madagascar that had nectaries ~12 long with nectar at bo[om. From the structure, he predicted the existence of an unknown moth with 12 probocis Check out youtube video at h[p://www.youtube.com/watch?v=OMVN1EWxfAU 6 Seed & Fruit Dispersal Wind Water Animals seeds hitch a ride oered as food Study ques=on: How does dispersal form (size, shape, number) match func=on (mode of dispersal)? 7 Diferent Fnch beaks adapted or diferent seed sizes What are the advantages and disadvantages for the plant having seeds dispersed? What are the advantages and disadvantages for the animal dispersers? 8 leshy ruit eaters/dispersers: Persimmon seeds in coyote scat Seedlings germina;ng rom cassowary scat 9 What exactly are ruits? For the plant, what is the advantage of producing a fruit? What is the disadvantage? ruit develops rom ovary in owering plants 10 ruit orm and seed arrangement variable: Fleshy fruits Dry fruits 11 Coordina7ng Plant Growth and Development, in Response to Environment Three case studies Phototropism and Auxin...
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