# Hands-on ActivityThe Benefits of Biodiversity

### Quick Look

Time Required: 30 minutes

Expendable Cost/Group: US \$0.00

Group Size: 2

Activity Dependency:

Subject Areas: Biology, Life Science

NGSS Performance Expectations:

### Summary

Students toss coins to determine what traits a set of mouse parents possess, such as fur color, body size, heat tolerance, and running speed. Then they use coin tossing to determine the traits a mouse pup born to these parents possesses. Then they compare these physical features to features that would be most adaptive in several different environmental conditions. Finally, students consider what would happen to the mouse offspring if those environmental conditions were to change: which mice would be most likely to survive and produce the next generation?
This engineering curriculum aligns to Next Generation Science Standards (NGSS).

### Engineering Connection

Probability and statistics are just a few of the tools used in engineering. This activity explores concepts studied by genetic scientists as well as biomedical and environmental engineers.

### Learning Objectives

After this activity, students should be able to:

• Using mice as an example, explain why not all of the offspring born to a population survive into adulthood.
• Explain why a diversity of characteristics within a population is beneficial to the population, even though not all of the individuals are well adapted to the environment at any given time.

### Educational Standards Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards. All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org). In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

###### NGSS: Next Generation Science Standards - Science
NGSS Performance Expectation

HS-LS3-3. Apply concepts of statistics and probability to explain the variation and distribution of expressed traits in a population. (Grades 9 - 12)

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This activity focuses on the following Three Dimensional Learning aspects of NGSS:
Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts
Apply concepts of statistics and probability (including determining function fits to data, slope, intercept, and correlation coefficient for linear fits) to scientific and engineering questions and problems, using digital tools when feasible.

Alignment agreement:

Environmental factors also affect expression of traits, and hence affect the probability of occurrences of traits in a population. Thus the variation and distribution of traits observed depends on both genetic and environmental factors.

Alignment agreement:

Algebraic thinking is used to examine scientific data and predict the effect of a change in one variable on another (e.g., linear growth vs. exponential growth).

Alignment agreement:

Technological advances have influenced the progress of science and science has influenced advances in technology.

Alignment agreement:

Science and engineering are influenced by society and society is influenced by science and engineering.

Alignment agreement:

###### Common Core State Standards - Math
• Find probabilities of compound events using organized lists, tables, tree diagrams, and simulation. (Grade 7) More Details

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• Develop a probability model and use it to find probabilities of events. Compare probabilities from a model to observed frequencies; if the agreement is not good, explain possible sources of the discrepancy. (Grade 7) More Details

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• Approximate the probability of a chance event by collecting data on the chance process that produces it and observing its long-run relative frequency, and predict the approximate relative frequency given the probability. (Grade 7) More Details

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• Recognize and explain the concepts of conditional probability and independence in everyday language and everyday situations. (Grades 9 - 12) More Details

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• Understand that two events A and B are independent if the probability of A and B occurring together is the product of their probabilities, and use this characterization to determine if they are independent. (Grades 9 - 12) More Details

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###### International Technology and Engineering Educators Association - Technology
• Brainstorming is a group problem-solving design process in which each person in the group presents his or her ideas in an open forum. (Grades 6 - 8) More Details

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###### North Carolina - Science
• Understand the relationship of the mechanisms of cellular reproduction, patterns of inheritance and external factors to potential variation among offspring. (Grade 7) More Details

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• Understand how the environment, and/or the interaction of alleles, influences the expression of genetic traits. (Grades 9 - 12) More Details

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• Explain how the environment can influence the expression of genetic traits. (Grades 9 - 12) More Details

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• Explain how traits are determined by the structure and function of DNA. (Grades 9 - 12) More Details

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### Materials List

Each group needs:

### Pre-Req Knowledge

• Students should be familiar with simple Mendelian genetics involving the inheritance of dominant and recessive traits.
• Students should be familiar with the characteristics of different biomes and habitats: temperate forest, tropical rain forest, temperate field, tropical grassland (savanna), swamp, tundra and desert.

### Introduction/Motivation

Tell students that they are each about to become the proud parents of — a baby mouse! Of course, before they can have a baby, they need to have a mate. These two statements will surely get their attention!

### Procedure

1. Let students choose their "mates," or choose student pairs to work together. Ideally, pair together a male and a female student, but this is not essential.
2. Distribute the handouts, ask students to read through them, and answer any questions about the instructions. Students will record the coin toss results on the data sheet.
3. Distribute the coins, one to each pair of students.
4. Give students time to work through the handouts. After determining the characteristics of both the parent mice and the pups, have students answer the bulleted questions.
5. When all students are finished, have students share their responses to the handout questions. Use the Investigating Questions to continue the discussion and make sure that students understand the main points of the activity.

### Vocabulary/Definitions

dominant gene: A gene for a visible or otherwise observable trait that can mask a recessive form of the same gene; for example, in humans the gene for long eyelashes is dominant over the gene for short eyelashes.

recessive gene: A gene for a trait that can be masked or hidden by a dominant form of the same gene; for example, the gene for attached (joined to the head) earlobes is recessive to the gene for detached (hanging free from the head) earlobes.

### Assessment

Questions: Ask students the following questions to gauge their understanding of the subject matter:

• How are adaptive features maintained in a population of organisms?
• Why is a diversity of characteristics within a population beneficial to the population, even though not all of the individuals will be well adapted to the environment at any given time?
• How does probability affect the genetic outcomes of offspring? (Answer: For some genes, the outcome is as simple as flipping a coin. In these cases, there is a 50% of one gene being expressed, or perhaps 25, 75, or even 100%! The outcome depends on the genetic make-up of the parents.)

### Investigating Questions

• In any one type of environment, why would you expect to find a variety of physical characteristics among the mouse population?
• Why do we call this activity the benefits of biodiversity?

### Activity Extensions

Have students research and learn about Darwin's observations of finches in the Galapagos Islands as a way to understand how new species can arise. Have them summarize their research by creating posters showing the different types of finches Darwin found and their corresponding food sources.

Have students research the simple genetic dominance relationships for attached and detached human earlobes. Which trait is dominant, which is recessive? Calculate the frequency of each earlobe type within the class or grade. Have students investigate within their own family. Start research with a description provided under "Earlobe" at Wikipedia.

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### Contributors

Mary R. Hebrank, project and lesson/activity consultant

### Supporting Program

Engineering K-PhD Program, Pratt School of Engineering, Duke University

### Acknowledgements

This content was developed by the MUSIC (Math Understanding through Science Integrated with Curriculum) Program in the Pratt School of Engineering at Duke University under National Science Foundation GK-12 grant no. DGE 0338262. However, these contents do not necessarily represent the policies of the NSF, and you should not assume endorsement by the federal government.