Look Who's Coming for Dinner: Selection by Predation

In this activity, students formulate a hypothesis and collect and analyze real research data about how quickly natural selection can act on specific traits in a population as a result of predation. It is accompanied by a short video that describes the experiment this activity is based on.

Using measurements from a year-long field study on predation in which Dr. Jonathan Losos and colleagues introduced a large predator lizard to small islands that were inhabited by Anolis sagrei, this activity illustrates the role of predation as an agent of natural selection. It emphasizes that strong selective pressure can have measurable effects on trait variations in a population within a short time. After watching the short film The Origin of Species: Lizards in an Evolutionary Tree, students use a sample of research data from actual field experiments to work through this four-part activity:

• Part 1: Introduction of the field study and formulate a hypothesis.
• Part 2: State the hypothesis formulated by Losos and colleagues and how they tested it.
• Part 3: Collect data, perform simple calculations, and answer questions.
• Part 4: Watch a video on additional findings and answer discussion questions.

The quantitative analysis includes calculating and interpreting simple descriptive statistics and plotting the results as line graphs. The flow of this four-part activity is illustrated in Figure 1 on page 3 of the educator materials.

The “Resource Google Folder” link directs to a Google Drive folder of resource documents in the Google Docs format. Not all downloadable documents for the resource may be available in this format. The Google Drive folder is set as “View Only”; to save a copy of a document in this folder to your Google Drive, open that document, then select File → “Make a copy.” These documents can be copied, modified, and distributed online following the Terms of Use listed in the “Details” section below, including crediting BioInteractive.