The Following Question Refers to the Figure

question 34

Multiple Choice

The following question refers to the figure.
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.

The cells in the 12 cell lines grown in low-glucose conditions showed the effects of which of the following processes?

• A) gene flow and genetic drift
• B) natural selection and mutation
• C) natural selection and gene flow
• D) conjugation and transformation

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Definitions:

Conditioned Stimulus

A previously neutral stimulus that, after becoming associated with the unconditioned stimulus, eventually comes to trigger a conditioned response.

Operant Conditioning

An educational method where the intensity of an action is altered by either reinforcement or punishment.

Observational Learning

The process by which individuals learn new behaviors or information by watching others, also known as modeling.

Situational Type Phobia

A type of anxiety disorder characterized by an irrational fear of specific situations, such as public speaking or flying.