Lect08S2011 - Pollination Pollination Mechanisms Fruit and...

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Unformatted text preview: Pollination Pollination Mechanisms Fruit and Seed Dispersal Variations in Floral Morphology Variations Flower used in floral structure lecture was: Complete Flower: Flower having all of the floral organs. Also Perfect flower: Flower having both stamen and carpels. Variations in Floral Morphology Variations Flower evolved many variations: Incomplete Flower: Flower lacking one or more of the four floral organs: Imperfect flower: Flower lacking either stamens or carpels, i.e. unisexual. May be: Monoecious: Male and female flowers on same plant. Dioecious: Male and female flowers on different plants. Variations in Floral Morphology Variations Some evolutionary trends observed in floral variations: Numerous few floral parts Floral parts all separate fused Flowers radially symmetrical or regular bilaterally symmetrical or irregular Variations in Floral Morphology Variations Numerous parts Few parts Variations in Floral Morphology Variations Separate Fused Variations in Floral Morphology Variations Radially symmetrical or regular Bilaterally symmetrical or irregular Variations in Floral Morphology Variations Radially symmetrical or regular Bilaterally symmetrical or irregular Variations in Floral Morphology Variations Perfect flower Imperfect flowers Variations in Floral Morphology Variations Silk=styles Silk=styles of carpels Tassel= stamens Corn female and male flowers, on same plant, i.e. monoecious Variations in Floral Morphology Variations Sagittaria flowers: Male flowers (left), Female flowers (right) on separate plants, i.e., dioecious Variations in Floral Morphology Why the Variation in Why Floral Morphology? Appearance of flowers evolved according to mechanism of pollination! More Floral Variations More Flowers variable in color and design: Note nectar guides. More Floral Variations More Flowers with fused petals: Note, again, nectar guides. More Floral Variations More Flower arrangement variation. The above is an example of a raceme. raceme More Floral Variations More Ray Floret Disk Floret “Sunflower” actually not a single flower, but a cluster of flowers arranged in a head. head L-Section of Sunflower L-Section Disk Floret Ray Floret More Floral Variations More Cadaverous Flower: Again, actually a cluster of flowers. Pollination Mechanism Pollination Categories Biotic pollination mechanisms: Examples of co-evolution: Evolution of two different species each one reciprocally influencing each other’s adaptations. Insects Animals Pollination Mechanism Pollination Categories Abiotic pollination mechanism Pollination not requiring the cooperation of another organisms: Wind Biotic Co-Evolution Biotic Scarab Beetle pollinating flower. Biotic Co-Evolution Biotic Beetle pollinating large flower. Biotic Co-Evolution Biotic Beetle pollinating clustered small flower. Biotic Co-Evolution Stamen and style curl upward Bee pollinating flower. Fused Petals forming landing platform Biotic Co-Evolution Bee flower. Large, radially symmetrical flowers. Smaller, bilaterally symmetrical flowers. Biotic Co-Evolution Bumble bee pollinating flower. Biotic Co-Evolution Bee pollinating flower: Bees can see in ultraviolet range. Biotic Co-Evolution Fly pollinating flower: Flies dull reddish brown, bad odor. Biotic Co-Evolution Fly pollinating flower: Flies dull reddish brown, bad odor. Raffesia sumatra can reach 3ft in diameter. Biotic Co-Evolution Fly pollinating flower: Flies dull reddish brown, bad odor. Amorphophallus titanum flowering stalk. Biotic Co-Evolution Biotic Butterfly pollinating flower. Biotic Co-Evolution Biotic Butterfly pollinating flower. Biotic Co-Evolution Biotic Moth pollinating flower. Biotic Co-Evolution Biotic Moth pollinating flower. Biotic Co-Evolution Biotic Moth pollinating flower. Biotic Co-Evolution Biotic Angraecum longicalcar has a nectar spur about 12”long. Darwin prediction in 1862. Biotic Co-Evolution Biotic Xanthopan morgani subspecies praedicta described in 1903. Biotic Co-Evolution Biotic Bat pollinating flower. Sausage Tree Sausage Example of a bat pollinated species. Biotic Co-Evolution Biotic Humming bird pollinating flower. Biotic Co-Evolution Biotic Mimicry: species mimic female bumble bee and wasp, respectively Biotic Co-Evolution Biotic Mimicry: Mimicry species mimics female fly species. Abiotic Pollination Abiotic Mechanism Corn “silk” (female) and “tassel” (male) flowers, respectively on same plant, i.e. monoecious Why So Many Mechanisms? After transition to terrestrial environment, evolution continued: The many variations on pollination mechanisms ensures reproduction & out breeding in flowering plants. Gymnosperms only had wind pollination. Random pollination. Fruits Fruits Categories of Fruits Categories In botanical sense, “a ripen ovary”. Definition broader than in common usage. Divided in categories of fruit types: Simple fruit Aggregate fruit Multiple fruit Categories of Fruits Categories Simple Fruit: Derived from a single flower with a single carpel. Categories of Fruits Categories Aggregate Fruit: Derived from a single flower with multiple, separate carpels. Multiple Carpels Single Carpel Categories of Fruits Categories Multiple Fruit: Derived from many flowers. Seed Dispersal Seed Evolution of fruits provided different mechanisms of seed dispersal: Fleshy fruits ripened when seeds mature. This signals animals that fruit is edible. Barb on fruit attaches onto fur of animals. AND more! Gymnosperms only has wind dispersal. Examples of Seed Dispersal Examples bird dispersal wind dispersal Examples of Seed Dispersal Examples Animal dispersal Examples of Seed Dispersal Examples Wind dispersal Examples of Seed Dispersal Examples animal dispersal Pollination and Dispersal Pollination Summary Evolution of variation in floral morphology occurred according to the mechanism of pollination. Pollination biotic or abiotic. Biotic pollinated flowers and pollinators co-evolved. Pollination and Dispersal Pollination Summary Variation of mechanisms of seed dispersal evolved. According to fruit types. Evolution in different mechanisms of pollination and seed dispersal led to success of flowering plants. ...
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Lect08S2011 - Pollination Pollination Mechanisms Fruit and...

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