Plant Study Unit

Mysterious Mycorrhizae

This unit was designed to follow the steps of science inquiry from set up to conclusion. With the help of Bala Chaudhary our GK-12 Fellow and resident scientist, our class chose a question to investigate that related to her actual work in the field.

The purpose of this experiment was to determine if soil organisms affect plant growth.  We also tested to see if different plant species were affected by soil organisms differently.  Each pair of students worked on a single plant species and had both a pot with dead soil and a pot with live soil.  The whole class had about 10 students working on corn, 10 students working on marigold, and 10 students working on broccoli.

Concept or conceptual understanding:  Invisible soil fungi can strongly influence the growth of plants.

Corresponding chapters in text: Ecology Ch.1-3

Real world connections (Relevancy):  Students will learn how soil fungi can influence many aspects of their life including the production of food, medicine, and many crops.

AZ standards: Grade 7

Strand 1

PO 1. Formulate questions based on observations that lead to the development of a hypothesis.

PO 2. Select appropriate resources for background information related to a question, for use in the design of a controlled investigation.

PO 1. Demonstrate safe behavior and appropriate procedures (e.g., use and care of technology, materials, organisms) in all science inquiry.

PO 3. Conduct a controlled investigation, utilizing multiple trials, to test a hypothesis using scientific processes.

PO 4. Perform measurements using appropriate scientific tools (e.g., balances, microscopes, probes, micrometers).

PO 5. Keep a record of observations, notes, sketches, questions, and ideas using tools such as written and/or computer logs.

PO 1. Analyze data obtained in a scientific investigation to identify trends.

PO 3. Analyze results of data collection in order to accept or reject the hypothesis.

PO 4. Determine validity and reliability of results of an investigation.

PO 5. Formulate a conclusion based on data analysis.

PO 6. Refine hypotheses based on results from investigations.

PO 7. Formulate new questions based on the results of a previous investigation.

PO 1. Choose an appropriate graphic representation for collected data:

• line graph • double bar graph • stem and leaf plot • histogram

PO 2. Display data collected from a controlled investigation.

PO 3. Communicate the results of an investigation with appropriate use of qualitative and quantitative information.

PO 5. Communicate the results and conclusion of the investigation.

Strand 2

PO 3. Analyze the impact of a major scientific development occurring within the past decade.

PO 4. Analyze the use of technology in science-related careers.

PO 2. Describe how scientific knowledge is subject to change as new information and/or technology challenges prevailing theories.

PO 3. Apply the following scientific processes to other problem solving or decision making situations: • observing • questioning • communicating • comparing • measuring • classifying • predicting • organizing data • inferring • generating hypotheses • identifying variables

Strand 4

PO 2. Explain how organisms obtain and use resources to develop and thrive in: • niches • predator/prey relationships

PO 3. Analyze the interactions of living organisms with their ecosystems: • limiting factors • carrying capacity

PO 6. Create a model of the interactions of living organisms within an ecosystem.

Incorporation of inquiry: See strand 1 standards above

Behavior objectives:

• SWBAT set up a plant growth experiment
• SWBAT conduct plant growth measurements, collect data
• SWBAT represent data in the form of graphs
• SWBAT discuss the effects of invisible soil organisms on the growth of two different plant species.

Prior knowledge necessary: Plant morphology and photosynthesis, some background on limiting nutrients, definitions of mutualism symbiosis and parasite.

Identify possible student preconceptions:  Soil does not contain living things.  Plants only need water and light to grow, all fungi are bad.

Materials: plastic water bottles, corn/broccoli/marigold seeds, grow light, rulers, camera,

Lesson Description:  Students will initiate and monitor a plant growth experiment with two types of soil: living and dead.  They will collect soil from the school grounds and microwave half of it to create dead soil.  Two plant species will be grown in the two types of soil, one that benefits from soil organisms and another that is parasitized by soil organisms.  Students will track the growth of the two types of plants over about 9 weeks and compare their growth in live versus dead soil.  Students will graph their results and conduct quantitative analysis.

Assessment:

Lab write-up of entire experiment including: problem, hypotheses, methods, analyses, and conclusions.