In This Eight-Year Experiment, 12 Populations of E

Multiple Choice

In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population.
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Which term best describes what has occurred among the experimental populations of cells over this eight-year period?

A) microevolution
B) speciation
C) adaptive radiation
D) stabilising selection