8. Bird Beak Buffet - Lesson Plan
Day 1 - Introduction
- Open class with a discussion of what human traits might help a person be more successful (Is it an advantage to be tall? Is it an advantage in America to be blond haired and blue eyed? How about in another country like Africa or Asia?) Leave the interpretation of “more successful” open and somewhat vague. If this seems to controversial for your group of students, then discuss variation in cat or dog traits and what might help a pet survive better (Is it an advantage for a cat to be shy? Is it an advantage for a dog to be friendly?).
- Lead the discussion towards thinking about what “more successful” really means. Does that mean being more popular or making more money or more likely to live happily ever after? In scientific terms, what matters in the long run is whether you survive, find a mate, and reproduce, passing on your genes to the next generation.
- Introduce the activity. Pass out the handout and describe the rules.
- Check that students understand that all the birds are of the same species but have different beak traits. Similarly, all the beans are of the same species but have different color traits.
- Check that students understand that the birds that eat the most food will have a baby with a similar beak and that the birds that eat the least will die. Similarly, surviving beans (those not eaten) will have one baby with the same color trait.
- Finally discuss the data collection that occurs after each round. Each student is responsible for counting the number of each type of bean they eat and entering their data on the bird population data clipboards. Once all the bird population data has been gathered, then a volunteer from each group will report their data on the bean population data clipboard.
- If data will also be collected in lab notebooks, have students copy or paste the data tables and graphs into their notebooks.
Day 2 – Bird Beak Buffet
- Distribute a cup to each student. Next, give each student a plastic utensil.
- Quickly go over the rules before heading out to the feeding ground. Make sure you bring clipboards, beans, a stopwatch, and a whistle.
- Place the 4 data clipboards in different locations near the feeding ground.
- Have students stand on the edge of the feeding ground. Sprinkle the mixed beans (100 of each type) into the feeding ground.
- Blow the whistle and give students 20 seconds to “eat” as many beans as possible. Look out for students that cheat (have cups touching the ground, interfere with other students, etc.) and dump out the contents of their cups or eliminate them from the game. Blow the whistle again to signal the end of the year.
- Each student should go to the clipboard for their beak type, count the number of beans of each type they ate, and enter that information in the data table.
- Each group should calculate the grand total number of beans of each type that were eaten by their group (the bottom row of the table).
- One volunteer from that group can bring that information to the bean population data clipboard and enter their groups’ information. The volunteers can then help to complete the bean data table and count out the proper number of beans to add to the feeding ground.
- While the volunteers are entering bean population data, the rest of the students should help to sort their beans by color and return them to the stockpiles.
- Finally, have students line up by the total number of beans they ate. Have the 5 students that ate the fewest beans act out a grisly death. (Acting out the deaths helps students realize that they are actually dying and entering the game as a new bird with new traits, not just trading in one tool for another.) Confiscate their utensils. Give them new beaks that match the beaks of the 5 students that ate the most beans.
- Have a student enter this information (the number of birds that died and number of babies born) on the bird population data clipboards.
- Repeat steps 5-11 for each of the next 3 years of the game for a total of 4 rounds.
- Collect the clipboards, cups and utensils. Sweep up any remaining beans.
Day 3 – Organize, graph and discuss data
- Create data tables on the board (or make and overhead copy) similar to the ones on the second page of the Bird Beak Student handouts.
- Use the information from the clipboards to fill in the summary table. Have students fill in their tables as well.
- Have students graph the data for each population (red beans, white beans, black beans, fork-bills, spoon-bills, blade-bills) with years 1-5 on the x axis and the number of organisms at the start of a year on the y axis. The graphing may be done:
- individually in their lab notebooks
- groups of 3 can each graph one bird and one bean and analyze graphs as a group
- a group of students can create large poster sized graph for one of the populations to display around the room.
- Discuss the graphs. Notice patterns such as one population going up while another goes down. See if the population is growing steadily or exponentially.
- Discuss the reasons why one population did well while another did poorly. Is there a different scenario in which a different bird or bean would do best?
- At this point it is possible to formally address some of the vocabulary.
- Discuss natural selection – the process by which organisms with traits that best suit the environment are most likely to survive, reproduce, and pass on their genes to the next generation. In this activity, the bean that had the best camouflage and that was the hardest to catch survived, reproduced, and passed on their genes.
- Discuss evolution – descent with modification, most often as the result of natural selection. In this activity, we started with the same number of beans of each type but ended up with the population skewed towards the beans with the best suited traits.
- Discuss adaptation – a trait that is very well suited to a given environment that has, through natural selection, increased in the population over many generations. In this case, a particular color of bean could be considered an adaptation since it increased in the population through natural selection.
- Describe Charles Darwin’s adventures on the Beagle and how his observations (particularly of the finches on the Galapagos Islands) led him to propose the idea of natural selection.
- Begin the process of busting the misconceptions that students have about evolution. See the Understanding Evolution website for a fabulous overview of the common misconceptions students have and responses to those misconceptions.
- Finally, return to the discussion you used to open this activity – what human traits might help someone be more successful – and revisit those issues in the light of what your students now know about natural selection and evolution. In particular, you can discuss whether and how natural selection has worked and is still working on the human species.
Submitted by irene on Sat, 2006-07-22 11:53