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Home → Teach Evolution → Lessons and Teaching Tools → Teaching Resources Database → Evolution and E. coli: Natural selection in a constant environment

Evolution and E. coli: Natural selection in a constant environment

Grade Level(s):

  • 9-12

Source:

  • BiteScis

Resource type:

  • Classroom activity

Time: Two to three 50-minute class periods

Overview

In this reading-, writing-, and discussion-based activity, students explore bacterial evolution occurring in a stable environment, which counters the intuitive misconception that environmental change is a necessary component to natural selection. A landmark study provides the backdrop against which students can challenge their thinking about what it means for a population to evolve.

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  • [Mechanisms of evolution: Grades 9-12] Evolution occurs through multiple mechanisms.
  • [Mechanisms of evolution: Grades 9-12] Evolution results from selection acting upon genetic variation within a population. (LS4.B)
  • [Mechanisms of evolution: Grades 9-12] There is variation within a population. (LS3.B)
  • [Mechanisms of evolution: Grades 9-12] Natural selection acts on the variation that exists in a population. (LS4.B, LS4.C)
  • [Mechanisms of evolution: Grades 9-12] Inherited characteristics affect the likelihood of an organism's survival and reproduction. (LS4.B, LS4.C)
  • [Mechanisms of evolution: Grades 9-12] Traits that confer an advantage may persist in the population and are called adaptations. (LS4.B, LS4.C)
  • [Mechanisms of evolution: Grades 9-12] Natural selection is dependent on environmental conditions.
  • [Mechanisms of evolution: Grades 9-12] Over time, the proportion of individuals with advantageous characteristics may increase due to their likelihood of surviving and reproducing. (LS4.B, LS4.C)
  • [Mechanisms of evolution: Grades 9-12] The number of offspring that survive to reproduce successfully is limited by environmental factors. (LS4.B, LS4.C)
  • [Mechanisms of evolution: Grades 9-12] Depending on environmental conditions, inherited characteristics may be advantageous, neutral, or detrimental.
  • [Mechanisms of evolution: Grades 9-12] Environmental changes may provide opportunities that can influence natural selection. (LS4.B, LS4.C)
  • [Mechanisms of evolution: Grades 9-12] Fitness is reproductive success — the number of viable offspring produced by an individual in comparison to other individuals in a population/species.
  • [Studying evolution: Grades 9-12] Scientists use experimental evidence to study evolutionary processes.
  • Disciplinary Core Idea LS3.B: Variation of Traits
  • Disciplinary Core Idea LS4.B: Natural Selection
  • Disciplinary Core Idea LS4.C: Adaptation

This lesson is meant to be used early in the evolution unit.