Bio171-F10-Lec 33 - Biology 171 Friday December 3 2010...

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Lecture 33: Fungal Diversity and Evolution Biology 171 Friday, December 3, 2010 Announcements Discussion Next Week: Selection on Human Populations Text Reading Lecture 33 : 4th: Chapter 31 (579-598) 3rd: Chapter 31 (664-677) Lecture 34 : 4th: Chapter 34 (668-673) 3rd: Chapter 34 (762-767) Angiosperms (concluded) The Origin of Fungi Fungal Phylogeny Fungal Structure and Reproduction Ecological Roles of Fungi: decomposers mutualists pathogens 1
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Pollination is the transfer of pollen grains from an anther (pollen producing organ) to a stigma (pollen receiving organ). Insect pollination is an important adaptation because it makes flowering plant sexual reproduction much more efficient. 20
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Petals are also arranged around the receptacle in a whorl. They are often brightly colored and advertise the flower to visually oriented animals such as bees, wasps, and hummingbirds. The nectary produces a sugar-rich fluid called nectar , which is harvested by many of the animals that visit the plant. The male reproductive structure of angiosperms is the stamen , which consists of a slender stalk called the filament and the pollen-producing organs called anthers . The female reproductive structure is the carpel . It consists of three regions: the stigma— the moist tip that receives pollen; a slender stalk called the style ; and the ovary at the base of the carpel. 21
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Many plants depend on animals to spread their pollen. This is a mutualistic relationship where the plant and the pollinator benefit each other. The plant expends less energy on pollen production and instead produces showy flowers, nectar, and/or odors. Some plants/flowers are more general, while others are more specific. Coevolution is often seen in a number of species of flowering plants that coevolved with specific pollinators. The pollinator gets a reward such as nectar for pollinating the plant. Coevolution is the the mutual evolutionary influence between two species. Each of the species involved exerts selective pressure on the other, so they evolve together. In many cases, coevolution results in mutualistic associations. plants increase fitness by enhanced: (a) female functions (e.g., produce more seeds) (b) male functions (e.g., reduce waste of pollen) Over 65% of Angiosperms are insect-pollinated and 20% of insects, at least at some stage of their life cycle, depend on flowers for their food. 22
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pollinated by insects has evolved to maximize its effectiveness at loading the foraging insect with pollen and subsequently depositing it on the stigma. Flower diversity reflects the diversity of pollinators they utilize. Passion-flower (Bottom Left) Sequential availability of anthers and stigmas ensures cross- pollination. 23
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This note was uploaded on 02/13/2012 for the course BIO 171 taught by Professor Josephinekurdziel during the Fall '08 term at University of Michigan.

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Bio171-F10-Lec 33 - Biology 171 Friday December 3 2010...

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