1. 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.

2. 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

3. 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

4. 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

5. 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

6. 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)

7. (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.

8. 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)

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