During my thesis I studied a fungus called Microbotryum violaceum. It is a parasite of plants (caryophyllacea) that replaces the pollen by spores in male plants and transforms the female structures in male like structures infected by spores. M. violaceum is actually a species complex and I investigated the genetic partition of this complex and the evolution of reproductive isolation.
Now I use E. coli as a model to understand the processes of diversification and maintenance of biological diversity. I work with one population of bacteria that diverged in 2 kinds of bacteria from one ancestral population in 1000 generations (150 days). The two evolved types of bacteria show specialization for different kind of carbon sources and I try to see what are the cellular modifications associated with this diversification (mainly comparing gene expressions)
I also work with another kind of E. coli to study the evolution of cooperation. I started an evolution experiment with bacteria cooperating to grow in one environment. Theoretically when there is a lot of cooperation going on (it is not only true for bacteria), a cheater that does not cooperate has an advantage (produces more offspring in my case) compared to the cooperators. Thus you expect the proportion of cheaters to increase. But when there is a lot of cheaters in your population, the cooperators produce more offspring. In my experiment, I want to verify this theory and see if 1. cheaters appear, 2. there is a dynamic in the system (proportion of cheaters and cooperators varying) (I simplified). You can imagine this kind of scenario in biology, economy, sociology...
Concerning observing speciation during a life time, it depends what you consider as a species. When you speak about species with sexual reproduction, you usually consider that you have two species when individuals from the two different groups cannot exchange genes, i.e. evolve independently (they cannot produce viable and fertile offsprings). In bacteria you do not have sex (or very few), so what you consider as species may vary from one peaple to another. I consider that the two types of bacteria I study are different species (they are adapted to different environmental conditions) and this occured in 150 days. The shorter example I know is 7 days... Even in sexual species you may have speciation very quickly....
I talked too much, sorry to bother the ones that are not interested...
Nina, What do you do with your soil microbes?