Experimental Approach
The long-term evolution experiment was intended to provide experimental evidence for several of the central questions of evolutionary biology: how rates of evolution vary over time; the extent to which evolutionary changes are repeatable in separate populations with identical environments; and the relationship between evolution at the phenotypic and genomic levels.
The use of E. coli as the experimental organism has allowed many generations and large populations to be studied in a relatively short period of time, and has made experimental procedures (refined over decades of E. coli use in molecular biology) fairly simple. The bacteria can also be frozen and preserved, creating what Lenski has described as a "frozen fossil record" that can be revived at any time (and can be used to restart recent populations in cases of contamination or other disruption of the experiment). Lenski chose an E. coli strain that reproduces only asexually, without bacterial conjugation; this limits the study to evolution based on new mutations and also allows genetic markers to persist without spreading except by common descent.
Read more about this topic: E. Coli Long-term Evolution Experiment
Famous quotes containing the words experimental and/or approach:
“If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning, concerning matter of fact and existence? No. Commit it then to flames: for it can contain nothing but sophistry and illusion.”
—David Hume (17111776)
“A lady with whom I was riding in the forest said to me that the woods always seemed to her to wait, as if the genii who inhabit them suspend their deeds until the wayfarer had passed onward; a thought which poetry has celebrated in the dance of the fairies, which breaks off on the approach of human feet.”
—Ralph Waldo Emerson (18031882)