Evolution can be defined as the change in the genetic composition of a population over time. According to a new study grazing pressure and pollination can also affect the genetic composition of plant populations. Researchers at Uppsala University and Stockholm University investigated these variables affect on two distinct morphs of Birds Eye Primrose population: a shorter plant with flowers produced close to the ground and a taller plant with flowers produced higher above the ground. The taller morph attracts pollinators with more ease than the shorter morph but at the cost of predation by grazers and seed predators. A field experiment showed that the pressures from either grazing or pollination determined which reproduced more successfully. Over an eight year span, results showed that changes in grazing pressures shifted the genetic frequency of the population with short plants having greater reproductive success than taller plants demonstrating that grazing pressure affects not only which plants occur more frequently but also the genetic composition of those populations.
http://www.sciencedaily.com/releases/2013/10/131021153210.htm
http://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs143_013583.pdf
It's remarkable to see that such a change in grazing could play a change in role for evolution in plant populations and pollinators. I am kind of left questioned as to why with such a quick transformation of grazing, why would it attract more pollinators rather then before. Maybe the taste for the livestock who are attracted to these plants has something to do with it. Therefore, does this lead to longevity in both pollinators and plants? What kind of evolutionary changes do we predict to see? If these changes serve as the newly foundation for evolution in plant populations and pollinators, what happens if we alter the affects around other species, will they react the same? This brilliant idea could then help lead to other traces such as extinction...endless possibilities!
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