MS-LS4-6 | Modeling Natural Selection

Use mathematical representations to support explanations of how natural selection may lead to increases and decreases of specific traits in populations over time.

Clarification statement: Emphasis is on using mathematical models, probability statements, and proportional reasoning to support explanations of trends in changes to populations over time.

Assessment boundary: Assessment does not include Hardy Weinberg calculations.

Grade 8 Science Test Questions

Released New York State Grade 8 science test questions that assess MS-LS4-6 are listed here by test and question cluster. Each link opens the question with its answer key.

Exam	Cluster	Question
Spring 2025	Behavior and Evolution of Guppies	Question 49

Performance Level Descriptions

Every Grade 8 Science Test question on MS-LS4-6 is written to match one of the performance level descriptions (PLDs) below.

Level 1: Use a given mathematical representation to identify the evidence that supports the explanation, from those provided, that natural selection causes an increase or decrease in a specific trait in a population.

Level 2: Use a given mathematical representation to describe the evidence that supports the explanation that natural selection causes an increase and/or decrease in a specific trait in a population.

Level 3: Use mathematical representations to support explanations of how natural selection may lead to increases and decreases of specific traits in populations over time.

Level 4: Use mathematical representations and other empirical data to support explanations of how natural selection may lead to increases and decreases of specific traits in populations over time.

Resources

Examples and discussion of resources for the learning, teaching, and assessment of MS-LS4-6.

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NGSS Dimensions

Performance expectation MS-LS4-6 was developed using the following elements from the NRC document A Framework for K-12 Science Education:

Science and Engineering Practices

Using Mathematics and Computational Thinking
- Use mathematical representations to support scientific conclusions and design solutions.

Disciplinary Core Ideas

LS4.C: Adaptation
- Adaptation by natural selection acting over generations is one important process by which species change over time in response to changes in environmental conditions. Traits that support successful survival and reproduction in the new environment become more common.

Crosscutting Concepts

Cause and Effect
- Phenomena may have more than one cause, and some cause and effect relationships in systems can only be described using probability.

Page contributors: Caroline Leonard, Conrad Richman, Shirley Shameen

MS | MS. Natural Selection and Adaptations