Evolution is one of nature’s constants. It is a force that is always there, acting on all living creatures even though it has no predetermined end. However, over the past 25 years, scientist Richard Lenski believes he has found a model to predict the result of mutation evolution on living creatures over time. In the article “The Man Who Bottled Evolution,” Elizabeth Pennisi examines Lenski’s work and reports on his findings on the trends of mutation and evolution.
Since 1988, Richard Lenski has been conducting an experiment in which he monitors bacteria’s reaction to the introduction of harsh conditions. Lenski has been introducing stress factors like starvation to a population of bacteria, like E. coli. The bacteria would then be given two options: they would either have to adapt or die off. After about every 500 generations of bacteria, Lenski would freeze a sample in order to use in future research, where he would pit each of the generations against each other.
According to the article, Lenski compared each sample against each other and came to the conclusion that newer generations were more fit than their predecessors. However, even though all of the generations did evolve over time, Lenski noticed a trend: older generations evolved more than newer generations. Lenski explained that the evolution of the bacteria over time is eventually reaches a fitness peak where it has adapted to its environment and will only see minimal evolution.
Out of the original strains of bacteria, only half, or six out of twelve, experienced genetic mutation. Those that experienced genetic mutation while adapting to their environment saw their mutated genes result in an exponentially greater number of mutated genes, allowing them to survive. This experiment shows that evolution is reproducible and is evident in every living creature.
Pennisi made a strong case for the research that Lenski has conducted. By including specific numbers and results from the experiment, Pennisi appealed to logos. In doing so, he strengthened the claim Lenski was trying to make through the result of his experiment. Also, by writing for the respected science journal “Science,” published by the American Association for the Advancement of Science, she appealed to ethos.
Additionally, Lenski strengthens the research Pennisi reports on through the credibility he brings. As stated in the story, Lenski is a member of the National Academy of Sciences, where he has served on numerous committees. He has also been a MacArthur Fellow, which is an award granted for those that show the potential for creative work across all disciplines. Being a part of both of these prestigious institutions gives credibility to the data from the experiment that is presented.
Moreover, Pennisi included all the findings from the experiment. She did not pick and choose what she wanted to include in her article. Pennisi also kept her emotion and opinion out of the article. This led to a well-rounded and non-biased article.
Overall, Pennisi effectively presented the information and provided an interesting and factual article in doing so. Knowing that her intended audience would most likely be familiar with the concepts of evolution, she did a great job only including what was necessary. Additionally, his appeal to logos and ethos help reassure the reader that what they are reading is accurate.
Looking forward, we have to begin thinking about how this affects us in our everyday lives, especially when it comes to our health. Do you think that there will ever come a time when bacteria will not be able to “outevolve” the vaccines we use to fight them? If not, how will humans be able to defend themselves against disease without effective vaccines? Will our systems evolve over time where we come to a point that we are immune from new bacteria?
For a less science intensive read on the background of the experiment, read: http://arstechnica.com/science/2013/11/after-50000-generations-bacteria-are-still-evolving-greater-fitness/