A Selection Pressure

Contributor
The Concord Consortium
Type Category
Instructional Materials
Types
Interactive Simulation , 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

A Selection Pressure is the first in a three lesson series from Innovative Technology in Science Inquiry, that leads students to make sense of evolution.  This lesson is introduced in the teacher guide (this is accessible once a login has been established) using a bug population and a set of questions as the phenomena.  Students then engage in discussion that leads them into gathering data on a population of sheep.  Students use an interactive simulation to gather data in order to create an explanation for evolution of  population growth through natural selection under different conditions.  This lesson is designed to be done individually, however could be done in groups depending on device availability.  The teacher has the ability to set up a class and assign the lesson through a portal on the ITSI website (requires teacher to sign up for the website for free).  Evolution Teacher Guide (accessible upon sign in)

https://guides.itsi.concord.org/evolution

 

Intended Audience

Learner
Educational Level
  • High School
  • Middle School
Language
English
Access Restrictions

Free access with user action - The right to view and/or download material without financial barriers but users are required to register or experience some other low-barrier to use.

Performance Expectations

HS-LS4-4 Construct an explanation based on evidence for how natural selection leads to adaptation of populations.

Clarification Statement: Emphasis is on using data to provide evidence for how specific biotic and abiotic differences in ecosystems (such as ranges of seasonal temperature, long-term climate change, acidity, light, geographic barriers, or evolution of other organisms) contribute to a change in gene frequency over time, leading to adaptation of populations.

Assessment Boundary: none

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

Comments about Including the Performance Expectation
The activity guides students through a series of simulations that allow students to experience the concept of adaptation through natural selection. This simulation uses a population of sheep with different quality of teeth to model what can happen to populations under different conditions. In these simulations student identify patterns in a sheep population when there is an environmental pressure to select for better teeth quality. The student activities model the concept of adaptation through natural selection and give students a solid visual on how this process could happen when there is selection pressure in order to create an explanation. During the lesson students are asked to investigate the change in a population due to an environmental change. A teacher could add a discussion about how other changes (disease, population, encroachment) can also causes populations to adapt. The peppered moth could be used as an example of how the industrial revolution (pollution) caused adaptation in a population.

HS-LS4-3 Apply concepts of statistics and probability to support explanations that organisms with an advantageous heritable trait tend to increase in proportion to organisms lacking this trait.

Clarification Statement: Emphasis is on analyzing shifts in numerical distribution of traits and using these shifts as evidence to support explanations.

Assessment Boundary: Assessment is limited to basic statistical and graphical analysis. Assessment does not include allele frequency calculations.

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

Comments about Including the Performance Expectation
The student activity addresses this performance expectation using computer simulations. Students run the simulations several times, both with the selection pressure and without. The simulations contain population numbers that students can use throughout the lesson in order to compare the populations. Students look for patterns in the data sets, compare their data to the rest of the class and use the information they gather to make predictions and create explanations. One suggestion for better incorporation of the PE would be to include a more explicit section on probability. A teacher could include other scenarios to incorporate more data or create their own simulations within the lesson in order to expand the use of statistics and probability.

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
Throughout the lesson students participate in a variety of simulations. Students run the simulations several times in order to collect data on the sheep population. As evidence is collected, students are required to save and analyze their data. This data is used to make predictions about future events and eventually used to create an explanation on how the populations changed over time. This lesson also includes an example using a different theory of evolution (Lamarck) in order to give students information on the different evolutionary theories and possible student alternative conceptions. The unit addresses the practice in full, however the teacher may want to expand on the different evolutionary theories, for example, how the simulations support or not support the theories of Darwin and Lamarck. By doing this the class would have another piece of evidence to consider as they construct their explanations.

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

Comments about Including the Science and Engineering Practice
This lesson supports the use of statistics and probability by having students run the simulations several times in order to look for patterns in the data. Students use their data to make predictions about the sheep population and compare their data to their peers. As they run their simulation they record their data in order to use it as evidence as they create their explanation. The element of the SEP referenced in the lesson fits the lesson, however it is a middle school element. Depending on the math level of the students the teacher may want to push their students by including the high school element which includes: determining function fits to data, slope, intercept and correlation coefficient for linear fits. This could be done by having students look at larger data set of populations.

Disciplinary Core Ideas

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

Comments about Including the Disciplinary Core Idea
All of the areas of this DCI are addressed in the lesson. The simulations help explain how populations could change over time due to a selection pressure resulting in a change among the sheep populations. This activity gives students a visual on how populations fluctuate under different conditions (limited grass) resulting in adaptation (better teeth). To expand this idea a suggestion would be to include an extension active based on the STEM career -Evolutionary Biologist by having students investigate the origins of different organisms in order to explain how they evolved over time using the fossil record.

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

Comments about Including the Disciplinary Core Idea
All of the areas of the DCI are addressed in the unit. Students first run the simulation with the selection pressure off to see how the populations of sheep trend. They then run it again with the selection pressure (quality of teeth) on to see how those same populations trend. As they compare the two simulations they can observe that when there is no selection pressure the populations don’t change verses when there is selection pressure. In order to build in a local connection and a deeper understanding of selection pressure, a suggestion would be to include an investigation based on a local animal or plant population. This could be done in the ‘Concluding Career STEM Question’ included in the simulation and could provide an opportunity for students to work with local environmental professionals.

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
This lesson addresses cause and effect relationships, however they are not specifically called out. Cause and effect is studied across the lesson and students are asked to relate the cause/effect relationship after each simulation. The lesson uses cause and effect very effectively to model natural selection when there is and is not a selection pressure. One suggestion for improvement could be to make the use of the CCC more explicit. This insures the students understand that all of these different simulations illustrate cause and effect relationships, however some lead to a change in a population and some do not. Also note that the element of the CCC identified in the lesson is from the middle school grade band, however cause and effect relationships could be expanded to include the high school element.

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

Comments about Including the Crosscutting Concept
Throughout this lesson students identify patterns of natural selection in order to understand adaptation. Students are asked to look for patterns in the data they have gathered and compare it with their peers in order to build an explanation of adaptation. Although patterns are explicitly used in this lesson, they are not explicitly identified after each simulation. As students figure out how the population changes due to quality of teeth (macro), they also come to figure out that genes (micro) for teeth quality are passed from parent to offspring. A teacher using this lesson could identify the use of patterns in data analysis in order to make the CCC more explicit to the students. After each simulation, ask students to identify and discuss what they are seeing in their data. Identifying the use of patterns as they are used allows them continued practice in identifying patterns in different situations. Also note that the element identified in the lesson is from the middle school grade band, however could be expanded to include the high school element.

Resource Quality

  • Alignment to the Dimensions of the NGSS: This lesson introduces the concepts of natural selection and adaptation using the phenomena of a population change in bugs. Although the students do not go back to that phenomena the lesson does guide students in building an understanding about how natural selection occurs using the sheep simulations. Using the three-dimensions, students build an understanding of how adaptations occur within population of sheep using different mechanisms of natural selection. Although the lesson uses the three-dimensions, they are not used in concert with each other throughout the unit. The CCCs are not explicitly identified in the lesson, however they are explicitly identified in the lesson front matter. Students are asked to participate in a number of different science and engineering practices (using models, carrying out an investigation, analyzing and interpreting data) to identify patterns in cause and effect relationships in order to explain how natural selection leads to adaptations within populations. Tips for improvement could include: Make the CCCs explicit throughout the lesson by referring to them consistently in the questions. Go back to the anchoring phenomenon (the bug population) and revisit the initial questions to see if you still agree with your predictions.

  • Instructional Supports: This lesson does have some instructional supports including an optional activity that could expand on student understanding. The phenomena is relatable and it is built on accurate science. However, the opportunities for differentiation are not included. In order to make this lesson more accessible to a more diverse student population a suggestion would be to create differentiation options for English language learners, students with special needs, and other diverse learners. Tips for including instructional supports include: Scaffold in reading supports which could be a text to speech option on the computer or a print copy if students need additional one-to-one help. Use a voice to type program or scribe for students that have difficulty with writing or typing. Create a graphic organizer for students that need written language support.

  • Monitoring Student Progress: This computer based simulation unit has opportunities for monitoring student progress in several ways. The online version can be monitored by the teacher as students work their way through the lesson. If the print version is used the teacher can monitor progress while walking around the room. There are also natural breaks within the lesson to check for understanding. At the end of the simulations, when students need to share data and discuss their ideas with others, a teacher could use this as an opportunity to formatively assess students. There is a teacher guide included that contains front matter, guidance questions, and an answer key. Tips for progress monitoring include: Create a rubric designed to be used with the student explanation sections. Return to the anchoring phenomena (bugs) at the end of the lesson in order to have students revisit their answers. Were their predictions supported by the data? If not, how would they change them based on what they figured out from the lesson.

  • Quality of Technological Interactivity: This computer based simulation unit has opportunities for monitoring student progress in several ways. The online version can be monitored by the teacher as students work their way through the lesson. If the print version is used the teacher can monitor progress while walking around the room. There are also natural breaks within the lesson to check for understanding. At the end of the simulations, when students need to share data and discuss their ideas with others, a teacher could use this as an opportunity to formatively assess students. There is a teacher guide included that contains front matter, guidance questions, and an answer key. Tips for progress monitoring include: Create a rubric designed to be used with the student explanation sections. Return to the anchoring phenomena (bugs) at the end of the lesson in order to have students revisist their answers. Were their predictions supported by the data? If not, how would they change them based on what they figured out from the lesson?