I am very interested in the evolution of the evolution process itself. There are of course a lot of things that influence how evolution will work, but for this question, I am interested in things that are only related to the evolution process. Examples could be increase chance of mutations in newborns, change in reproduction age, and similar. I am specifically interested in observation where the evolution process itself has adapted to a change in the environment.
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Bacteria such as E. coli are known to increase their mutation rate (by switching to a more error prone polymerase among other things) when under stress. This can mean being placed in a medium where it's not adapted to grow (http://www.micab.umn.edu/courses/8002/Rosenberg.pdf) or when treated with antibiotics (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1088971/?tool=pmcentrez). |
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I think this falls into your criteria but correct me if i'm wrong :). The HIV reverse transcriptase protein has evolved to have relatively low fidelity (leading to a high mutation rate in replicated virus particles). Reverse transcriptase is also recombinogenic, ie. it can switch templates during replication leading to even more variability. Combined, these two properties lead to each individual having a large number of variant viral genomes, which leads to increased resistance to antiretroviral drugs etc. EDIT: I thought of influenza as a second example. The viral genome has evolved to be fragmented into 7-8 pieces of RNA, which can be swapped with other strains during co-infection of a single cell. This can lead to more virulent or transmissible strains of influenza; these can also be helpful to create new strains that influenza vaccines are no longer useful against. |
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Species have been observed in controlled experiments to use different sources of energy, for instance axenic E. coli cultures picking up citrate metabolism in Lenski's Lab at MSU. They have also shown that mutations to the mutator gene mutT can accelerate the process of evolution, though it's evolution directed by fitness in a very specific setting. |
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How about species actively changing the factors that play a role in the selection process? Humans are a species that have heavily modified this process. In the western world, we have gone away from selection by survival skills and genetic fitness to move to a social selection, where genome is secondary to social skills and adaptation to fashion, which are acquired skills. |
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If you look at the adaptive immune system, the process of B-cell recombination, clonal expansion and somatic hypermuation is, in essence, induced evolution. |
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