Environmental Change and Evolution: Which Mechanism of Microevolution Caused the Beak of the Medium Ground Finch Population on Daphne Major to Increase in Size from 1976 to 1978?

Contributor
National Science Teachers Association
Type Category
Instructional Materials
Types
Lesson/Lesson Plan
Note
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.

Reviews

Description

Lab 18:  Environmental Change and Evolution is one of a series of lab investigations for the middle school student from the book, “Argument-Driven Inquiry in Life Science:  Lab Investigations for Grades 6-8” by Patrick J. Enderle, Ruth Bickel, Leeanne Gleim, Ellen Granger, Jonathon Grooms, Melanie Hester, Ashley Murphey, Victor Sampson, Sherry A. Southerland.   Students use data on beak size of the medium ground finch that was collected by biologists Peter and Rosemary Grant who studied the finch population on Daphne Major Island in the Galapagos Islands. The average size of the beak of the finch population increased from 1976 to 1978 and students examine the characteristics of the medium ground finch and analyze data on beak size, amount of rainfall, and types of seeds available.  They then determine whether migration, natural selection or genetic drift caused the change.  Several questions are provided for the students to assess whether their argument is convincing, and students share their work with others in a round-robin format.  During the round-robin, one member of the group stays with the group’s work and explains it to others, as they visit.  The remaining group members go to other groups and listen and critique their arguments, resulting in a process during which every team evaluates each other’s work.

“Checkout Questions” are provided to facilitate student reflection on what was learned.  Students are assigned a short investigation report to finish processing their experience.  Significant background information is provided for teachers and to a lesser degree in the introduction section of the student handout. The standards addressed in the lesson are also included in the teacher’s notes.

Intended Audience

Educator and learner
Educational Level
  • Grade 8
  • Grade 7
  • Grade 6
  • Middle School
Language
English
Access Restrictions

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Performance Expectations

MS-LS4-4 Construct an explanation based on evidence that describes how genetic variations of traits in a population increase some individuals’ probability of surviving and reproducing in a specific environment.

Clarification Statement: Emphasis is on using simple probability statements and proportional reasoning to construct explanations.

Assessment Boundary: none

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
Students read about four different mechanisms of microevolution, mutation, migration, natural selection and genetic drift. They then analyze data of the beak size in the medium ground finch population on Daphne Major Island in the Galapagos Islands to determine whether the variation in beak size was responsible for the selection of some individuals to survive and reproduce more frequently than others. If they determine that this is the case, they may construct an explanation that natural selection is the mechanism of microevolution. If they do not think that survival and reproduction are factors in the change, they will choose migration or genetic drift as the cause of the change. An argument is written in the form of claim, evidence and justification of the evidence and then an argumentation session is held between groups in the class. There is now evidence about the gene that causes the genetic variation in beak sizes in finches, so that information could be introduced to students. See https://www.sciencedaily.com/releases/2015/02/150211153923.htm .

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
Students receive data that includes the number of medium ground finches on Daphne Major by month from 1976-1979, the number and physical characteristics of each medium ground finch on Daphne Major in November of 1976, the finch characteristics of each medium ground finch on Daphne Major in January of 1978, the rainfall by year and the seed type abundance. They then choose which data is needed to answer the question about the mechanism of microevolution and analyze it by finding the patterns in the data. If students have not previously worked with large data sets some guidance as to the types of questions that could be asked about each type of data would be useful.

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
This activity provides an opportunity for students to participate in argumentation. A simplified graphic organizer, “Argumentation Presentation on a Whiteboard” scaffolds students through the argumentation process. Students are given the chance to choose and develop their argument about which mechanism of microevolution caused the change in the average size of the beak in the population of medium ground finches. Several questions are provided for the students to assess whether their argument is convincing, and students share their work with others in a round-robin format. During the round-robin, one member of the group stays with the group’s work and explains it to others, as they visit. The remaining group members go to other groups and listen and critique their arguments, resulting in a process during which every team evaluates each other’s work.

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
After students analyze the data on finch beak size and determine which mechanism of microevolution is responsible for the change in the average size of beaks in the population, a scientific explanation is written based on the evidence. Students identify the guiding question, their claim, their evidence and their justification of the evidence. This is written on a whiteboard and used in the argumentation session of the activity. The protocol for writing an explanation is included in every activity in the book and is an excellent way to have students understand the process of how scientists report their findings after analyzing their data. The justification aspect, explaining why their evidence relates to the claim, is important for students to articulate their thinking.

Disciplinary Core Ideas

This resource appears to be designed to build towards this disciplinary core idea, though the resource developer has not explicitly stated so.

Comments about Including the Disciplinary Core Idea
Students should determine after analyzing the data that natural selection has happened in the finch population for beak size. Those with larger beaks in drought years where there are only hard seeds to eat have a selective advantage in surviving and reproducing. Over time, the large beak becomes more common in the population resulting in adaptation. Teachers will want to guide students to understand that something a living thing has or does that helps it survive is an adaptation.

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
The evidence from the change in beak size in the population and the type of seeds that were available from 1976-1978 due to the amount of rain that fell should help students to see that when there are Portulaca seeds which are small and soft, the smaller beaks survive. When there is a drought, the Portulaca seeds are all eaten and only the large, hard Tribulus seeds remain. Only finches with large beaks are able to crack the larger seeds, survive and pass on their genes. So natural selection leads to a predominance of larger beaked finches. Students are analyzing data to determine which mechanism of microevolution accounts best for the data. They determine what data they need to examine and how they will analyze it. This may be difficult for students if they have not had experience with this type of activity in the past. Scaffolding their understanding of how to work with data in spreadsheets such as is provided will need to happen before they can be successful in this activity. Teachers may want to start with abbreviated versions of the data first and then add more data as students become proficient in analyzing.

Crosscutting Concepts

This resource appears to be designed to build towards this crosscutting concept, though the resource developer has not explicitly stated so.

Comments about Including the Crosscutting Concept
The island of Daphne Major is a system and the Grants knew every bird that lived on the island as well as the quantity of each kind of seeds that was available. The boundaries of the system are well defined, but it was never labeled a system in the student reading. One suggestion is to make this explicit to students, asking them about the boundaries and what is included in the system in this investigation. An additional question in the Checkout Questions would be valuable. Students use the natural selection model in this activity to help them to understand the scenario. There could be a question added about what they would predict would happen if there was a large amount of rain.

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
Students read about the medium ground finch and examine a picture of their beak and also of the types of seeds that they eat. Students will need to determine the relationship between the structure of the beak and the type of seeds that they are able to eat to be able to construct an explanation that natural selection caused the change in beak size. If they do not realize this relationship they may choose genetic drift as the mechanism, but will not have as strong of an argument as those that see the relationship of the structure of the beak to the function of being able to crack open certain seeds. One suggestion is to have multiple pictures from online that show some variation in beak size instead of just the one picture that is in the student lab. An explicit discussion will need to take place in class about how the structure of beaks or other body parts are related to function.

Resource Quality

  • Alignment to the Dimensions of the NGSS: Students engage in three dimensional learning in this activity. The disciplinary core idea about natural selection is addressed through students analyzing data about finch beaks and constructing an explanation based on finding patterns in that evidence and then arguing their claim. The disciplinary core ideas, practices and crosscutting concepts are integrated in what the students do in this lab.

  • Instructional Supports: By having student analyze data, this activity provides an excellent, scientifically accurate context in which students can engage in three-dimensional learning. Several guiding questions are provided to facilitate students through the analysis as well as the argumentation session. Students have opportunities to build on feedback from other students as to whether their answer to the research question is the most valid and acceptable, and there is scaffolding in the form of a graphic organizer to support students.

  • Monitoring Student Progress: A “Checkout Questions” page is provided for a more immediate summative assessment (6 questions total). Students are also assigned a two-page “Investigative Report”. The report is divided into three sections and three major questions are provided for students to address in the report, which includes the results of their argumentation session. There is no rubric or sample answers provided.

  • Quality of Technological Interactivity: No technology is used in this activity except that there is a spreadsheet of data that needs to be downloaded and shared with students in digital or hard copy form.