Typically, evolution is something abstract that we cannot observe. Sure we can look at a textbook and see what humans looked like a hundred million years ago, but humans have not evolved since we have been alive. Professor Richard Lenski has been running an experiment for more than 30 years observing evolution firsthand.
In 1988, Prof. Lenski put a small sample of E. Coli onto a Petri dish, allowing individual cells to form colonies. From these colonies, samples were taken to initiate 12 separate populations. The bacteria were placed in a controlled lab environment, devoid of other organisms, at a constant temperature of 37 degrees Celsius. They lived in a solution containing glucose, potassium phosphate, citrate, and other substances, with glucose being their sole carbon source.
Each day, the bacteria divided multiple times, increasing their numbers exponentially. The number of generations was not determined by time but by the available resources. This is because the main selection pressure was the bacteria’s ability to consume the limited glucose. The objective of the experiment was to observe if the 12 populations, which originated from individual cells, would independently develop similar traits due to unique mutations. This would indicate that the observed traits were not the result of starting with the same genetic variants but rather the outcome of independent mutations leading to advantageous traits.
The biggest breakthrough in the experiment came recently when one of the populations made a huge advancement. It evolved to use citrate as a second source of carbon. This gave that population a huge advantage over the others.
Overall, this experiment is conclusive tangible evidence of evolution for anyone that doubted it.
National Academy of Sciences – http://www.nasonline.org. “National Academy of Sciences.” Richard E. Lenski, http://www.nasonline.org/member-directory/members/7066.html. Accessed 20 July 2023.
“Richard E. Lenski.” RSS, http://www.macfound.org/fellows/class-of-1996/richard-e-lenski#searchresults. Accessed 20 July 2023.
Evolutionary Anthropology 