Alpine Sky Pilots - measuring strength of selection

Alpine Sky Pilots - measuring strength of selection -...

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Darren Rothberg Biol 105 – Evolution Alpine Sky Pilot: Polemonium viscosum Rocky Mountain wildflower Near the timberline: pollinated by flies, small solitary bees and some bumblebees Higher tundra: bumblebees are only pollinators Flowers here are 12% larger than at timberline Large flowers attract more bumblebees The question: how long would it take to increase flower size 12% starting with the smaller-flowered timberline population? Measured flowers of 144 small-flowered timberline plants Germinated in lab and transplanted in parental habitat 7 years later had 58 blooming offspring
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Unformatted text preview: Heritability estimated as between 0.2 and 1.0 Measuring strength of selection differential Placed 98 Sky Pilots from a small-flowered timberline population in large screened cages that kept bumblebees and other pollinators out Measured flowers later and collected seeds Planted seedlings from these seeds in parental habitat Used the number of progeny from each plant flowering six years later to measure Plants with large corollas have greater fitness than those with smaller corollas Selection gradient = 0.13...
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