Lecture 18 - BIO220

How does fertilization affect genetic diversity trend

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Unformatted text preview: fecting species richness Why do species diversity and genetic diversity respond in opposite directions? How does fertilization affect genetic diversity? -Trend is not dramatic, but it is real -Adding more nutrients = more (+) genetic diversity • Fertilizer eliminates a limiting resource of a competitively dominant species • Competitive dominants Measured w. molecular markers eliminate ‘weaker’ species • Elimination of ‘weaker’ competitors opens ‘niche space’ for more genotypes of the remaining species • Genotypes of A. odoratum: more dimensions of N, P, K, and Mg to specialize on when fewer species are present For a focal species, Anthoxanthum odoratum Silvertown et al. 2009, Ecology Letters 12: 165 170 28 Silvertown et al. 2009, Ecology Letters 12: 165 170 29 30 -Adding the resource: Limiting resources prevent 1 species from crowding out everyone out. Adding more N allows this one species to crowd everything out, if only it had more N. Adding more K allows another species to out compete etc. etc. -As these dominant species are having their ABIOTIC LIMITS REMOVED, they out-compete weaker species (------ species diversity) -When weaker species are out-competed, this means that there is more NICHE space PER G ENOTYPE of the remaining species (+++++++ genotype diversity) 5 -There are more resources available to be allocated to the thriving of weaker genotypes -There are more resources that the weaker genotypes can specialize on, once we have eliminated weaker species 19/03/2013 Summary: Ecological consequences of genetic variation Traditional View • Ecology Selection • Genetic variation in focal species Ecology Evolution evolutionary response Newer View Ideas above PLUS: -Genetic variation affects ecological processes • Genetic variation in focal species ecological processes • Genetic variation within species will affect almost all ecological processes: Genetics & Genomics – Distribution and abundance of other species – Disturbance recovery – Nutrient decomposition Bio 220 lives here 31 32 -"Look for parallels bet ween genetic/species diversity with Tilman example" -Compare this to areas where we are harvesting key individuals (e.g. in corn) p referentially -Where can we draw parallels bet ween these lectures? 6...
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