What Darwin Never Saw
Lesson Introduction
Animal and plant species (definition) change over time to adapt to their environments. This is called evolution (definition). As seen in the What Darwin Never Saw video, different-shaped beaks allowed certain finches on the Galapagos Islands to live, while other finches perished.
In this lesson, students engage in a role-playing activity to get a first-hand look at how different-shaped beaks are suited for different purposes. By trying to fill their stomachs by picking up food with everyday tools, they learn that feeding habits of birds are very specialized. They conclude that diversity is important, for having a wide variety of animals feeding in the same area allows them all to survive.
Grade Level
2 through 6
Objectives
The students will:
1. participate in a role playing game about bird beaks and eating habits.
2. identify specific birds based on their beak shapes.
Time Allotment
one 40-minute session
Materials
large bird poster, or pictures of birds to pass around
paper cups to act as bird stomachs, one for each student bird
food: 50 marbles to act as beetles, 100 beans to act as flies, 100 toothpicks to act as worms
beaks: 10 spoons, 10 scissors, 10 tweezers, 10 clothespins
chalkboard
student journals
pencils or pens
video/video player
Books to Read
Birds, by Kathleen Daly, Racine, WI: Western Publishing, 1990.
Can Birds Get Lost? and Other Questions about Animals, by Jack Myers, Honesdale, PA: Bell Books, 1991.
Advanced Preparation and Teacher Notes
Find a spot in the classroom or outside to sit in a large circle.
Procedure
Tap Prior Knowledge
1. Look at the large bird poster or pictures of birds and ask students to note specific characteristics of the birds which help them to live in their habitats.
Share with Neighbor/Revise Ideas
2. Give students time to write down or draw a list of these important characteristics. Encourage them to share their lists and make revisions. Show the section of the What Darwin Never Saw video (from 44 10 to 48 00) which shows the different beaks of Darwin's finches. Share one of the biographies from our Career Connections with the students.
Engage Students in a Hands-on Activity
3. Invite the students to become birds for the rest of the class session. Distribute one paper cup to be a stomach for each student. Hand out one of the utensils to be a bird beak for each person. Engage the students in a discussion about picking up the food with the beak. Birds must pick up their food with their beaks. Remind them that they should not scoop up the food or use their fingers to pick it up. They should not use the stomach to pick it up either.
4. In a large circle in an open area of the room, invite the students shut their eyes and pretend they are asleep. Allow one student to lay one type of food out in the middle of the circle. Give the signal for the birds to wake up and begin feeding. Time them for one minute. Give the signal for the birds to stop feeding when the time is up. Turning on and off the lights makes a good signal.
5. Have all of the birds using similar beaks get together and total the amount of food they got to eat. For example, all of the spoons total together, and all of the tweezers total together, etc. Have the students record the results in their journals.
6. Do the same thing with the next two types of food. Remember to give students time to record results in their journals.
7. Finally, mix the three types of food together and let another student spread it in the area. When given the signal, the birds should make an effort to find the food. They will go after the kind of food that they find easiest to get. When finished, they switch to items which are harder for them to pick up.
Introduce the Scientific Principle/Concept
8. Plants and animals have features that help them live in different environments. Birds have different types of beaks which allow them to eat different types of food. Their beaks have adapted to match what is available and what they like. Many birds have beaks like tweezers. They can eat food near the surface, inside a tree, or in a flower. Other birds have a crusher beak, like a clothespin. They use their beaks to break open seeds. Some birds have beaks which are more like spoons, and they can scoop up fish or insects in the air. Instruct students to draw pictures of different-shaped beaks in their journals, along with a written description of the adaptation.
9. There is variation among individuals of one kind within a population. Since the birds eat different types of food, they can all live in the same area at the same time. On the Galapagos Islands, 13 distinct types of finches have evolved from the same species. Natural selection is the effect of the environment's interaction with each individual; it is directional because the environment will "favor" the survival of some individuals over other individuals. For example, if there is a gene that allows certain individuals to store fluids better, they will survive periods of drought better.
Lesson Assessment
10. Look at the students' journal entries. Each should have a description of the different beak shape and the kind of food it is adapted for. Younger students can draw pictures that correctly portray at least some of the features of the thing being described. If they are old enough, students can explain how the success of the feeding during the simulation changed for the type of beak and the type of food. What happened when they were well matched versus when they were not well matched?
Connect to Other Everyday Examples
11. Think about the many ways that we are adapted for the places where we live. Also, many people can live in the same area and take different things from it so that they all live in harmony.
12. Give students a chance to surf the World Wide Web for more examples of animal adaptations:
