Beaks As Tools: Selective Advantage in Changing Environments
This hands-on activity supports concepts covered in the short film The Beak of the Finch. Students collect and analyze data to learn why even slight variations in beak size can make the difference between life and death.
In their study of the medium ground finches, evolutionary biologists Peter and Rosemary Grant tracked the evolution of beak size twice in an amazingly short period of time due to two major droughts that occurred in the 1970s and 1980s. This activity simulates the food availability during these droughts and demonstrates how rapidly natural selection can act when the environment changes. Students use two different types of tools to represent different beak types to see which is best adapted to collect and “eat” seeds of different sizes. Students collect and analyze data and draw conclusions about traits that offer a selective advantage under different environmental conditions. They have the option of using an Excel spreadsheet to calculate different descriptive statistics and interpret graphs.
Student Learning Targets
Explain why even slight differences due to variations in beak size can have an impact on a bird’s ability to obtain food and survive.
Explain how changes in environmental conditions can result in strong selective pressures and cause adaptations to evolve in a relatively short period of time.
Follow an experimental protocol in collaboration with other students.
Make predictions based on observations and collect quantitative data to test their predictions.
Organize and analyze results by interpreting graphs and performing simple calculations.
Draw conclusions about traits that offer a selective advantage under different environmental conditions.
behavior, biodiversity, ecology, evolution, organismal biology, scientific methodology, scientific process, speciation
HS-LS2-1, HS-LS2-2, HS-LS4-2, HS-LS4-4, HS-LS4-5; SEP4, SEP6
EVO-1.D, EVO-1.E, EVO-1.J, SYI-3.D, EVO-1.M, EVO-1.O, EVO-3.A; SP1, SP5
Math.S-ID.3, S-IC.3; MP2, MP4
CC1, CC5; DP1