A comparison of the plant ecology of two fields

Students will apply random sampling techniques to do a plant population/community/ecosystem study to model how these things are interrelated.

A lesson plan for grades 8–12 Science

By Linda Sutton

Learn more

• Random Sampling Detailed information on random sampling
• How to use a dichotomous key A simple explanation of how to use a dichotomous key

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Related topics

• Learn more about biology, ecological relationships, ecosystems, field ecology, hands-on, labs, plants, science, and soil.

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Learning outcomes

• Students will gain experience using observation and classification skills.
• Students will compare interrelationships of organisms with their environment.
• Students will practice making and interpreting graphs.
• Students will learn the difference in populations and communities and their relationship to the ecosystem.

Teacher planning

Time required for lesson

3 hours

Materials/resources

• Two or more different lawns or fields
• Open square grids cut from paper, cardboard, etc.(any size as long as they are all the same size) (my class used 2ftx2ft cardboard squares with a one inch wide perimeter with an open center)
• Field notebooks and pencils
• Spade for digging or soil sampler
• Computer with software for graphing or graphing paper
• Soil color chart
• Soil pH kit
• Soil thermometer
• Soil moisture meter (optional)

Technology resources

Computer with software for graphing (optional)

Pre-activities

• Students must know how to use equipment.
• Students must know how to make bar and pie graphs.
• Students should know the definitions for “population”, “community” and “ecosystem.”
• Students should know how to use a dichotomous key.

Activities

1. In groups of two or three, students will sample a field for different plant types by tossing the grids randomly in a section of the field and then identifying, counting, and recording the different types of plants inside the grid.
2. Students will make three samples each at three different sampling sites within the field and average their findings for each plant type recorded for that field. The same procedure will be completed at the other field(s).
3. Visual observations will be recorded for each field area, (i.e. color of soil, surrounding buildings, types of water in the area). Soil temperature, pH, color, and moisture should be recorded from data collected from equipment for each site.
4. After data collection is complete, the plant count will be put into a computer program with spreadsheet and graphing capabilities or documented on paper by producing data charts and graphs comparing the plant populations of each field site. Either a double bar graph or two separate pie graphs should represent the plant type data collected. This data will be analyzed using the visual observations and/or the collection of environmental data to compare and contrast the two or more sites.
5. Discussion and/or a written report should follow determining why or why not differences of plant communities are found at each site.

Assessment

Assessments will be made by the quality of the graphs, written reports, correctness of data collected, and by the analysis students give for differences in the populations/communities. Graphs should be titled, correctly labeled, accurate and easy to read. The analysis should include good reasoning and explanations of the conclusions for the comparisons.

Supplemental information

North Carolina Trees and Wildflowers: An Introduction to Familiar Plants

Comments

• To get the most benefit from this study, it is best to choose two fields that obviously have different plant communities.
• Students should be guided to consider that the difference in the plant communities may be correlated to soil temperature, moisture, color, water availability, etc.
• To shorten the time for this lesson, the field data collection could be done in one block and the graphing and analysis could be assigned as homework.