Summary
Long-term laboratory studies, like Lenski's E. coli, that watch evolution happen in real time.
In depth
Richard Lenski's long-term E. coli experiment started in 1988 and has passed 75,000 generations. One population evolved to use citrate aerobically after about 31,500 generations. Replicated populations show the repeatability of adaptation and the role of chance.
Systems include bacteria (Lenski), yeast, Drosophila, bacteriophages, guppies in Trinidad introduced to predator-free or predator-rich streams, and digital organisms (Avida). Frozen samples of ancestors, a "frozen fossil record", allow direct comparison of ancestor and descendants.
In Lenski's experiment, all 12 lines showed rising fitness, with ever-slowing gains, and several evolved hypermutator phenotypes; the Cit+ trait required earlier potentiating mutations, showing historical contingency. Other work has shown repeated parallel changes at the molecular level, for example in yeast adapting to low glucose, showing that evolution can be somewhat predictable.
Frequently asked questions
What is Experimental Evolution?
Long-term laboratory studies, like Lenski's E. coli, that watch evolution happen in real time.
Which area of biology covers Experimental Evolution, and how advanced is it?
Experimental Evolution is one of the 53 topics in Evolution. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Evolution, Directional Selection, Cambrian Explosion.
Why does Experimental Evolution matter?
Experiments test evolutionary theory directly and inform drug resistance and cancer therapy.
Can you give an example of Experimental Evolution?
Yeast and virus experiments also show rapid adaptation.
What should I learn before Experimental Evolution?
Work through the Beginner topics in Evolution first, such as Evolution, Natural Selection, Charles Darwin, then return to Experimental Evolution. Advanced topics assume the Intermediate vocabulary.
What topics are related to Experimental Evolution?
The closest topics to Experimental Evolution are Evolution, Directional Selection, Cambrian Explosion, Natural Selection. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Experimental Evolution?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Experimental Evolution. To practise the whole of Evolution, use the Evolution quiz.
How is Experimental Evolution different from Evolution?
Experimental Evolution: Long-term laboratory studies, like Lenski's E. coli, that watch evolution happen in real time. Evolution: Change in the inherited characteristics of populations over successive generations. Read both side by side and note what each one explains.
How should I study Experimental Evolution step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Evolution and explain the difference aloud. Finally, take the Evolution quiz and come back to this page for any question you miss.