Phenomenon: In 1834 Charles Darwin studied birds on the Galapagos Islands. He observed that even though all the birds he saw were finches, the various species had different shaped beaks. He proposed that the finches all descended from a common ancestor, and the beak shapes changed as the birds adapted to eat different foods.

Variation in Populations The Galapagos Islands are located in the Pacific Ocean about 600 miles west of Ecuador (see picture below). At some point in the past, a small population of Finches (birds) were blown from South American to these islands. Each island has a slightly different ecosystem, and these finches adapted accordingly. This lead to significant variation in the shapes and sizes of their beaks. South American Finch

Variation in Populations Over time the finches developed different beak shapes and sizes in order to eat the local food (structural adaptations). Food Source Only Bugs Food Source Seeds & Bugs Food Source Only Seeds narrow-pointed beak for eating insects Moderately wide beak with a sharp point for cracking seeds and eating insects Very wide beak for only eating seeds

For this activity we will simulate the food with these 4 items. Let’s see how beak variations in a population of birds enables individuals to adapt to a specific environment. A bird species is brought to an island with just 4 food sources. For this activity we will simulate the food with these 4 items. Worms Bugs Toothpicks Rice Seeds Fruit Beans Marbles

Activity The genetic diversity resulting from sexual reproduction and/or mutations has led to four different beak types. For this activity we will simulate the beaks with these 4 items Large/wide Beak Medium Beak Plastic Spoons Clothespins Small Beak Large/thin beak Small Popsicle Sticks Large Popsicle Sticks

Activity You will be given simulated bird beaks and bird food. You will have only a brief amount of time to eat your food. You will record your data. Food Names Represented by Calories Worms toothpicks 5 Bugs rice 10 Seeds Beans 15 Fruit Marbles 20 Beak Type To Survive To Reproduce Large/wide beak (spoons) 60 100 Medium Beak (clothespins) Small Beak (small popsicle sticks) Large/thin beak (large popsicle sticks)

(Step by Step Instructions) Activity (Step by Step Instructions) Step 1: Select a “bird beak” type. Example: Large/wide beak Step 2: Scatter the assorted “food” type (example: worms (toothpicks) onto the grassy area. Step 3: Use your beak to “eat” for 30 seconds. ONE food item at a time in your beak—NO HANDS—and “swallow” the food by putting the food into your “stomach” (cup). No “flinging” or “dragging” food. If you drop the food, it returns to the environment—not your stomach! Step 4: Count or estimate the amount that you ate. Record data. Step 5: Use the provided chart to find the number of calories for your food type. Multiply to determine the total calories consumed. Record data. Step 6: Determine if your bird survived and/or reproduced.

One at a time, conduct timed trials (30 seconds each) with each beak type. Fill in the chart with your data. Large/thin beak Small Beak Large/wide Beak Medium Beak Food Names Amount Eaten Calories Consumed Survive (Yes or No) Reproduce Worms (toothpicks) Bugs (rice) Seeds (beans) Fruit (Marbles)

Make a chart, graph, or model to show your findings.