1. A Laboratory Activity for the Living Environment
Objective: Understand How Natural Selection Works
Key Words: adaptation, environment, struggle for survival, survival of fit, differential reproduction, accumulation of traits, natural selection
The Beaks of Finches
A Laboratory Activity for the Living Environment

2. Objective: Understand How Natural Selection Works
Key Words: adaptation, environment, struggle for survival, survival of fit, differential reproduction, accumulation of traits, natural selection
1. All 14 species of Darwin’s finches differ from each other in body size and/or beak size and shape
2. Different sizes and shapes differ in their efficiency at performing particular task
3. Not only do beaks vary in shape, but so do the muscles used to operate them

3. Objective: Understand How Natural Selection Works
Key Words: adaptation, environment, struggle for survival, survival of fit, differential reproduction, accumulation of traits, natural selection
Paper clip Clothespin Tweezer Tong Test tube holder Pliers
Examine the different tools (“beaks” and seeds provided. Predict with “beak” will be the most successful at picking up small seeds. Give the reason for you choice.
The tweezers,
because they are easy to handle, and the end is sharp and small
Predict which “beak” will be the least successful at picking up small seeds.
Give the reasons for your choice.
The test tube holder, because it has flat and thin end.

4. Objective: Understand How Natural Selection Works
Key Words: adaptation, environment, struggle for survival, survival of fit, differential reproduction, accumulation of traits, natural selection
Paper clip Clothespin Tweezer Tong Test tube holder Pliers
3. From this point on, you and your partner will model a finch feeding. The tool you were assigned will be your “beak”. Describe what characteristics it has that make it good for picking up small seeds. In the remaining space or on a separate sheet, draw an outline of your assigned “beak”.
The paper clip is good for picking up small seeds because it can be used as a bag to keep seeds inside.

5. Objective: Understand How Natural Selection Works
Key Words: adaptation, environment, struggle for survival, survival of fit, differential reproduction, accumulation of traits, natural selection

6. Objective: Understand How Natural Selection Works
Key Words: adaptation, environment, struggle for survival, survival of fit, differential reproduction, accumulation of traits, natural selection

7. Objective: Understand How Natural Selection Works
Key Words: adaptation, environment, struggle for survival, survival of fit, differential reproduction, accumulation of traits, natural selection
What characteristics of your “beak” interfered with feeding success on the original island?
The size, shape, type of edge, ability to handle it.
2. Name three traits other than beak characteristics that could contribute to the ability of a finch to compete successfully
Wing strength, distance from the feeding place to the nest, eye sight, sharp claws, etc…
3. Describe at least three beak variations that could randomly appear and further improve your species’ chances of survival when feeding on small seeds.
Medium size, sharp ends, solid and easy to handle
4. Why did some “beak” types survive on the new island (which large seeds) when they could not survive on the original island?
They are adapted to grip larger seeds better than small seeds

8. Objective: Understand How Natural Selection Works
Key Words: adaptation, environment, struggle for survival, survival of fit, differential reproduction, accumulation of traits, natural selection
6. Did those who were successful in Round One survive equally well when other were competing for food at the same dish during Round Two?
No. Fewer species survived when many species competed for food at the same dish.
7. Why were there fewer survivors at the end of Round Three
There were fewer survivors due to increased competition
8. At the end of Round Three, were the types of “beaks that were successful on the new island the same as the types of beaks that were successful on the original island?
No, some beaks were better adapted to pick up small seeds whereas other beaks did better job at picking up large seeds.

9. Objective: Understand How Natural Selection Works
Key Words: adaptation, environment, struggle for survival, survival of fit, differential reproduction, accumulation of traits, natural selection
9. Explain how this activity simulates each of the concepts listed below as they are involved in the process of natural selection.
*Environment:
*Variation
*Struggle for survival
*Competition
*Adaptation
*Selecting Agent
Students = birds, seeds = food, tools = beaks; tables = islands, cups = nests
Different types of beaks, and different sizes of seeds: large and small seeds
Each bird trying to get enough seeds to survive
More than one bird feeding at one bowl
Some beaks are better than others at picking up smalls seeds
Type of beak available for feeding &/or type of seed .

10. Objective: Understand How Natural Selection Works
Key Words: adaptation, environment, struggle for survival, survival of fit, differential reproduction, accumulation of traits, natural selection
10. Predict which species of finch would be most likely to survive if the weather on the Galapagos Islands gradually changed and the seeds available to the finches became larger with heavier coverings.
Large Ground Finches, because they have big, thick beaks to break the seed heavy coverings.

11. Objective: Understand How Natural Selection Works
Key Words: adaptation, environment, struggle for survival, survival of fit, differential reproduction, accumulation of traits, natural selection
11. One island is populated by two species Small Ground Finches and Small Tree Finches
What two types of food would you expect to be available on this island?
b. Would you expect the two species to compete for food on this island?
Animal food (such as insects) and
plant food (such as seeds)
No, they would not compete because they feed on different kind of food.
c. How might the two native finch populations be affected if several dozen Sharp-billed Ground Finches were to migrate to the island and survive?
The Small Ground Finches might have to compete with the new Sharp billed Ground Finches, since they have similar food preferences and beaks.
Therefore, Small Ground Finch population will decrease.

12. Objective: Understand How Natural Selection Works
Key Words: adaptation, environment, struggle for survival, survival of fit, differential reproduction, accumulation of traits, natural selection
12. a. Explain how an island could support large populations of both Large Ground Finches and Small Ground Finches
The island would need to have both large and small seeds available
b. How could you use the materials provided in this lab to test your explanation?
I would put many large and small seeds
in separate dishes.
Then, I would run trials using tools
from the “large-seed survivors”
and tools from the “small-seed
survivors” to compete for the
seeds in the dishes

13. Characteristics of Beaks
Beaks that were
# of beak types
Characteristics of Beaks
(Size and shape)
Present at the beginning of the activity
Successful at feeding in Round One on the original island – fed on small seeds, did not need to migrate
Not successful at feeding in Round One on the original island – fed on small seeds, had to migrate to the new island
Successful at feeding in Round Two on the original island- fed on small seeds
Successful at feeding in Round Two on the new island – fed on large seeds
Not successful at feeding in Round Two on either island – species dies out
Successful at feeding in Round Three on the original island – fed on small seeds
Successful at feeding in Round Three on the new island – fed on large seeds
Not successful at feeding in Round Three on either island – species eliminated

18. Objective: Understand How Natural Selection Works
Key Words: adaptation, environment, struggle for survival, survival of fit, differential reproduction, accumulation of traits, natural selection
9. Explain how this activity simulates each of the concepts listed below as they
are involved in the process of natural selection.
Variation
Competition
Struggle for survival
Adaptation
Environment
Selecting agent
Different types of beaks,
Different sizes of seeds: large and small seeds
More than one bird feeding at one bowl
Each bird trying to get enough seeds to survive
Some beaks are better than others at picking up smalls seeds
Students = birds, seeds = food, tools = beaks
tables = islands, cups = nests
The type of seed available in the environment