ALEX Lesson Plan


Density Independent and Dependent Factors Effects on Population

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  This lesson provided by:  
Author:Shaunna Aker
System: Cullman County
School: Cullman County Board Of Education
The event this resource created for:ASTA
  General Lesson Information  
Lesson Plan ID: 34527


Density Independent and Dependent Factors Effects on Population


Students will compare and give examples of density-independent and density-dependent factors and how they have an effect on the changing conditions on a lake. After establishing the difference between them, students will play a game where they change several factors and assess the effects of their changes to the environment.

This lesson results from a collaboration between the Alabama State Department of Education and ASTA.

 Associated Standards and Objectives 
Content Standard(s):
SC2015 (2015)
Grade: 9-12
10 ) Construct an explanation and design a real-world solution to address changing conditions and ecological succession caused by density-dependent and/or density-independent factors.*

Unpacked Content
Scientific And Engineering Practices:
Constructing Explanations and Designing Solutions
Crosscutting Concepts: Cause and Effect
Disciplinary Core Idea: Ecosystems: Interactions, Energy, and Dynamics
Evidence Of Student Attainment:
  • Analyze data on population growth to identify limiting factors, both abiotic and biotic.
  • Analyze data to find patterns that distinguish density-dependent from density-independent limiting factors.
  • Distinguish between primary and secondary ecological succession and show that an ecosystem responds to such a disturbance in a predictable manner. Analyze historical data to find patterns in an ecosystem's response to disturbance.
  • Design a solution to changing environmental conditions or ecological succession that accounts for density-dependent and independent factors.
  • Synthesize data and reasoning to evaluate potential solutions to an environmental problem.
  • Communicate proposed solution and support conclusions with evidence and reasoning.
Teacher Vocabulary:
  • Population density
  • Dispersion
  • Density-independent factor
  • Density-dependent factor
  • Population growth rate
  • Limiting factor
  • Ecological succession
  • Primary succession
  • Climax community
  • Secondary succession
  • Pioneer species
Students know:
  • Factors associated with population density are important regulators of population growth.
  • Density-independent factors that can impact population growth (e.g., flood, drought, extreme heat or cold, tornadoes, etc.).
  • Density-dependent factors that can impact population growth (e.g., predation, disease, parasites, competition).
  • The different types of ecological succession and their causes. Primary succession is the development of a community in an area of exposed rock that does not have any topsoil (e.g., hardened lava flow).
  • Secondary Succession is the change that takes place after a community of organisms have been removed but the topsoil remains intact (e.g., fire, flood, etc.).
  • Engineering design principles.
Students are able to:
  • Collect and organize population growth data compiled on population growth under varying conditions related to food availability, rainfall, predation, migration, and disease.
  • Analyze data to categorize factors, organize data and draw conclusions about a variety of limiting factors to classify each as density-dependent or independent.
  • Identify a problem, assess the data, determine if enough information is provided to make an informed decision, assess whether a solution is needed, and recommend what form that solution should take.
  • Apply engineering design principles to the development of a solution, identifying required inputs and expected outcomes and determine how the solution will be tested and refined.
Students understand that:
  • Ecosystems are constantly changing.
  • Changes in an ecosystem are the result of density-dependent or density-independent factors, sometimes including human activity.
  • By using the engineering design process, solutions to ecological problems can be developed, tested and refined.
AMSTI Resources:
ASIM Module:
Limiting Factors; Bead Bugs; Bluegill Limiting Factors; Bio-Assessment; Soil Profiles; Ecological Succession

Local/National Standards:


Primary Learning Objective(s):

  • Students will compare the difference between density-independent and density-dependent factors.
  • Students will predict examples of each type of factor for a reading article.
  • Students will explain how changing certain real-life factors will cause different effects to the overall system or environment.

Additional Learning Objective(s):

 Preparation Information 

Total Duration:

61 to 90 Minutes

Materials and Resources:

Fish Limiting Factors Board Game with die (Science in Motion Lab)

**Limiting Fish Factors Boardgame printout is available in the attachments if ASIM activity is not available**

Sticky Notepad

Science textbook or reference book

science notebook 

Technology Resources Needed:



  • Students compare the difference between abiotic and biotic factors.
  • Students will also need to have an understanding that all factors whether abiotic or biotic effect each other in some way.


First, the teacher will ask the students to make a list of all factors that can affect a large population of organisms in their notebook. Next, the teacher will write the words Abiotic and Biotic on the board and ask various students to write their examples on a sticky note and go up and stick under the appropriate category.

Next, students will look up the definition to Density-Independent and Density-Dependent Factors. Once they have read the definition, as a class, the students and teacher will create these two new categories on the board and place their examples under the correct category using participation from the class.


Next students will take 5 minutes to read the article named YELLOW PERCH IN LAKE WINNIPEG which is available in the attachments and through Alabama Science in Motion.

After reading the article, they are to assign each density-independent and density-dependent example under the right category. This activity is to be completed individually by each student. Once everyone is completed the activity, then the examples should be discussed as a whole class.


During the extend part of this lesson, students will get together in groups and play a board game (directions located in the attachments) that deals with the limiting factors on fish in a lake. They will roll a dice to determine how many spaces to move. And as they move, they will land on different limiting factors. They are to decide if that factor is a density-independent or dependent factor and why it would fall under that category. They will also discuss the effect that each factor has on the environmental system as a whole. These responses will be written in their science notebooks and then once everyone is finished they will be read out loud to the rest of the class.

There are also extending post lab questions that come with the Science In Motion lab sheet which is in the attachments.

**Some files will display in a new window. Others will prompt you to download.

Assessment Strategies

  • Formative Assessment will be used to assess student's responses during the Engage activity to compare the difference between density-independent and density-dependent factors.
  • The comparison chart that students use to compare factors will be assessed for correctness.
  • Group responses to the board game to explain how changing certain real-life factors will cause different effects to the overall system or environment.


Located in the attachments is a Limiting Factors Graphing Activity that can also be used as a way to pull in the mathematical and statistical effects of limiting factors on population growth and decline.


For remediation, students will be asked to visit a local pond and make a t-chart where they make a list of all dependent and independent factors affecting an animal population of their choice.

For example, what are the factors affecting a population of geese or fish within that area?

View the Special Education resources for instructional guidance in providing modifications and adaptations for students with significant cognitive disabilities who qualify for the Alabama Alternate Assessment.