Standards Alignment
- MS-LS1-6 primary
Construct a scientific explanation based on evidence for the role of photosynthesis in the cycling of matter and flow of energy into and out of organisms.
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Lesson Overview
This Grade 7 science lesson focuses on understanding how photosynthesis plays a critical role in the cycling of matter and the flow of energy into and out of living organisms. Students will construct scientific explanations based on evidence, analyzing how matter and energy move through organisms and ecosystems, grounded in NGSS standard MS-LS1-6.
Learning Objectives
- Explain how photosynthesis contributes to the cycling of matter in organisms and ecosystems.
- Describe how energy from sunlight flows into organisms through photosynthesis and flows out through other processes.
- Construct a scientific explanation using evidence to support the role of photosynthesis in matter and energy cycling.
Success Criteria
- Students can identify inputs and outputs of photosynthesis related to matter and energy.
- Students can trace the movement of matter (carbon, oxygen, water) through photosynthesis and cellular respiration.
- Students can construct explanations that connect photosynthesis to energy flow and matter cycling in organisms.
Prerequisite Knowledge
Students should understand basic concepts of matter and energy, including that matter is made of atoms and molecules and energy can be transferred or transformed. They should also be familiar with the idea that organisms need energy to live and grow.
Key Vocabulary
- Photosynthesis
- Matter cycling
- Energy flow
- Organisms
- Ecosystems
- Carbon dioxide
- Oxygen
- Glucose
- Sunlight
- Cellular respiration
Materials and Resources
- Diagrams or models of photosynthesis process
- Chart paper or whiteboard
- Markers
- Informational texts or videos about photosynthesis and energy flow
- Worksheets for evidence-based explanation construction
Teacher Preparation
- Prepare diagrams/models illustrating photosynthesis inputs and outputs.
- Gather or create informational resources on photosynthesis and energy flow.
- Prepare guiding questions to prompt student thinking about matter and energy movement.
- Set up materials for group discussions and explanation construction activities.
Detailed Lesson Notes
Photosynthesis and Matter Cycling
Photosynthesis is the process by which plants and some other organisms use sunlight to convert carbon dioxide and water into glucose (a sugar) and oxygen. This process cycles matter by taking in carbon dioxide (a matter form) from the air and water from the soil, and producing glucose and oxygen, which are matter forms used by organisms. The glucose contains carbon atoms that become part of the plant's structure or serve as energy sources for other organisms.
Energy Flow Through Photosynthesis
Energy from sunlight is captured by chlorophyll in plant cells during photosynthesis. This solar energy is transformed into chemical energy stored in glucose molecules. This energy flows into organisms when they consume plants or plant products. Energy then flows out of organisms through processes like cellular respiration, where glucose is broken down with oxygen to release energy for life functions, producing carbon dioxide and water as byproducts.
Constructing Scientific Explanations Based on Evidence
Students should learn to construct explanations that connect evidence about matter and energy movement. For example, evidence shows that plants take in carbon dioxide and release oxygen, which supports the explanation that photosynthesis cycles matter and flows energy into organisms. Scientific explanations must be supported by observations or data, such as gas exchange measurements or chemical composition of plant tissues.
Common Misconceptions to Address
A common misconception is that energy is created by plants during photosynthesis; instead, energy is transformed from sunlight into chemical energy. Another is that matter disappears during energy flow; matter is conserved and cycles through the ecosystem. Clarify that photosynthesis is not just about plants making food but about cycling matter and energy flow in ecosystems.
Connecting Photosynthesis to Ecosystem Dynamics
Photosynthesis is foundational to ecosystems because it provides the chemical energy and organic matter that support other organisms. The oxygen released supports respiration in animals and other organisms. Disruptions in photosynthesis affect matter cycling and energy flow, impacting ecosystem health and population dynamics.
Worked Examples
Worked Example 1
Scenario
Using the diagram of photosynthesis showing carbon dioxide and water entering a plant and glucose and oxygen leaving, explain how matter cycles through the plant.
Explanation
The diagram shows that carbon dioxide (matter) from the air and water (matter) from the soil enter the plant. Through photosynthesis, these are converted into glucose (matter) which the plant uses for energy and growth, and oxygen (matter) which is released back into the air. This shows matter cycling as atoms are rearranged but conserved.
Answer Guide
Carbon dioxide and water enter the plant and are converted into glucose and oxygen. The atoms in these molecules cycle through the plant, showing matter is reused and transformed.
Engage
Teacher Activity
Show students a diagram of a plant and ask them what they think plants need to live and grow. Prompt them to think about where plants get their energy and matter.
Student Activity
Students share ideas about plant needs and energy sources, discussing sunlight, water, and air.
Explanation
This activity activates prior knowledge and introduces the concept that plants obtain matter and energy from their environment, setting the stage for exploring photosynthesis.
Examples
- Students mention sunlight, water, air, soil nutrients as plant needs.
- Students recognize sunlight as an energy source.
- Students begin to connect matter intake (water, air) with plant growth.
Explore
Teacher Activity
Provide students with diagrams and informational texts about photosynthesis showing inputs (carbon dioxide, water, sunlight) and outputs (glucose, oxygen). Facilitate group discussions to analyze these materials.
Student Activity
Students work in groups to examine diagrams and texts, identifying the matter and energy inputs and outputs of photosynthesis.
Explanation
Students explore the process of photosynthesis by analyzing evidence and identifying how matter and energy move through the system.
Examples
- Students identify carbon dioxide, water, and sunlight as inputs.
- Students identify glucose and oxygen as outputs.
- Students recognize sunlight as energy input transformed into chemical energy.
Explain
Teacher Activity
Guide students to construct a scientific explanation using evidence from the exploration phase. Model how to connect matter cycling and energy flow in photosynthesis.
Student Activity
Students write or orally present explanations describing the role of photosynthesis in cycling matter and flowing energy into and out of organisms, citing evidence from diagrams and texts.
Explanation
This phase focuses on students articulating scientific explanations supported by evidence, fulfilling the NGSS standard MS-LS1-6.
Examples
- Students explain that carbon dioxide and water are converted into glucose and oxygen.
- Students describe energy from sunlight being stored in glucose.
- Students cite diagrams and texts as evidence.
Elaborate
Teacher Activity
Present scenarios or case studies showing how photosynthesis affects ecosystems, such as what happens if plants cannot photosynthesize.
Student Activity
Students analyze scenarios to explain how changes in photosynthesis impact matter cycling and energy flow in ecosystems.
Explanation
Students apply their understanding to broader ecological contexts, deepening comprehension of photosynthesis' role in ecosystems.
Examples
- Students explain that matter cycling and energy flow would be disrupted.
- Students recognize that other organisms depend on plants for energy and oxygen.
Evaluate
Teacher Activity
Assess students' ability to construct scientific explanations by reviewing their written or oral explanations and asking probing questions.
Student Activity
Students demonstrate their understanding by explaining photosynthesis' role in matter cycling and energy flow, responding to feedback.
Explanation
Evaluation focuses on students' ability to use evidence to explain scientific concepts, meeting the lesson's learning objectives.
Examples
- Students provide clear, evidence-based explanations.
- Students connect matter and energy movement accurately.
Classroom Activity
Students work in groups to examine diagrams and texts, identifying the matter and energy inputs and outputs of photosynthesis.
Guided Practice
Guided Practice 1
Prompt
What are the two main matter inputs plants need for photosynthesis?
Teacher Answer Guide
Carbon dioxide and water.
Guided Practice 2
Prompt
Describe how energy from sunlight is involved in photosynthesis.
Teacher Answer Guide
Energy from sunlight is captured by plants and transformed into chemical energy stored in glucose during photosynthesis.
Guided Practice 3
Prompt
Explain how photosynthesis contributes to the flow of energy into organisms.
Teacher Answer Guide
Photosynthesis captures sunlight energy and stores it in glucose molecules, which organisms use as a source of energy when they consume plants.
Guided Practice 4
Prompt
Analyze what would happen to the cycling of matter and energy flow if plants stopped photosynthesizing in an ecosystem.
Teacher Answer Guide
If plants stopped photosynthesizing, matter cycling would be disrupted because carbon dioxide would not be converted into glucose and oxygen. Energy flow would stop entering the ecosystem through plants, affecting all organisms that depend on them for food and oxygen.
Guided Practice 5
Prompt
Construct a scientific explanation using evidence to describe the role of photosynthesis in the cycling of matter and flow of energy into and out of organisms.
Teacher Answer Guide
Photosynthesis uses sunlight energy to convert carbon dioxide and water into glucose and oxygen. This process cycles matter by transforming atoms from carbon dioxide and water into organic molecules and oxygen, which organisms use. Energy flows into organisms as sunlight is stored in glucose and flows out when glucose is broken down during cellular respiration, releasing energy for life processes.
Independent Practice
- Foundational: What are the two main matter inputs plants need for photosynthesis?
- Developing: Describe how energy from sunlight is involved in photosynthesis.
- Application: Explain how photosynthesis contributes to the flow of energy into organisms.
- Analysis: Analyze what would happen to the cycling of matter and energy flow if plants stopped photosynthesizing in an ecosystem.
- Challenge: Construct a scientific explanation using evidence to describe the role of photosynthesis in the cycling of matter and flow of energy into and out of organisms.
Independent Practice Teacher Answer Key
- 1. Carbon dioxide and water.
- 2. Energy from sunlight is captured by plants and transformed into chemical energy stored in glucose during photosynthesis.
- 3. Photosynthesis captures sunlight energy and stores it in glucose molecules, which organisms use as a source of energy when they consume plants.
- 4. If plants stopped photosynthesizing, matter cycling would be disrupted because carbon dioxide would not be converted into glucose and oxygen. Energy flow would stop entering the ecosystem through plants, affecting all organisms that depend on them for food and oxygen.
- 5. Photosynthesis uses sunlight energy to convert carbon dioxide and water into glucose and oxygen. This process cycles matter by transforming atoms from carbon dioxide and water into organic molecules and oxygen, which organisms use. Energy flows into organisms as sunlight is stored in glucose and flows out when glucose is broken down during cellular respiration, releasing energy for life processes.
Guiding Questions
- What matter and energy do plants take in and release?
- How does photosynthesis transform energy?
- Why is photosynthesis important for ecosystems?
- What evidence supports your explanation of photosynthesis?
- How would ecosystems change if photosynthesis stopped?
Common Misconceptions
- Energy is created by plants during photosynthesis rather than transformed from sunlight.
- Matter disappears during energy flow instead of cycling and being conserved.
- Photosynthesis only makes food and does not affect energy flow or matter cycling in ecosystems.
Differentiation
Support and Intervention
Provide sentence starters for constructing explanations. Use visual aids and diagrams to support understanding. Allow students to work in pairs for discussion and explanation construction.
English-Language Learner Support
Use clear, simple language and define key vocabulary. Provide bilingual glossaries for key terms like photosynthesis and energy. Use visuals and gestures to support comprehension.
Advanced and Extension
Challenge students to connect photosynthesis to cellular respiration and ecosystem dynamics. Encourage use of scientific texts to find additional evidence. Have students create models showing matter and energy flow in ecosystems.
Assessment
- Ask students to identify inputs and outputs of photosynthesis from diagrams.
- Have students explain energy transformation in photosynthesis orally.
- Review students' written explanations for evidence use and accuracy.
- Write a brief explanation of how photosynthesis cycles matter and flows energy into organisms.
- List two ways photosynthesis affects ecosystems.
- Create a detailed scientific explanation with evidence about photosynthesis' role in matter cycling and energy flow.
- Compare photosynthesis and cellular respiration in terms of matter and energy movement.
Answer Guide
- What are the two main matter inputs plants need for photosynthesis?
Answer: Carbon dioxide and water. - Describe how energy from sunlight is involved in photosynthesis.
Answer: Energy from sunlight is captured by plants and transformed into chemical energy stored in glucose during photosynthesis. - Explain how photosynthesis contributes to the flow of energy into organisms.
Answer: Photosynthesis captures sunlight energy and stores it in glucose molecules, which organisms use as a source of energy when they consume plants. - Analyze what would happen to the cycling of matter and energy flow if plants stopped photosynthesizing in an ecosystem.
Answer: If plants stopped photosynthesizing, matter cycling would be disrupted because carbon dioxide would not be converted into glucose and oxygen. Energy flow would stop entering the ecosystem through plants, affecting all organisms that depend on them for food and oxygen. - Construct a scientific explanation using evidence to describe the role of photosynthesis in the cycling of matter and flow of energy into and out of organisms.
Answer: Photosynthesis uses sunlight energy to convert carbon dioxide and water into glucose and oxygen. This process cycles matter by transforming atoms from carbon dioxide and water into organic molecules and oxygen, which organisms use. Energy flows into organisms as sunlight is stored in glucose and flows out when glucose is broken down during cellular respiration, releasing energy for life processes.
Real-Life Application
Encourage students to observe plants at home or in their neighborhood and discuss with family members how these plants get energy and matter to live and grow, connecting to photosynthesis concepts.
Homework or Home Connection
- Encourage students to observe plants at home or in their neighborhood and discuss with family members how these plants get energy and matter to live and grow, connecting to photosynthesis concepts.
Lesson Summary
Photosynthesis is a vital process that cycles matter by converting carbon dioxide and water into glucose and oxygen, and it flows energy by transforming sunlight into chemical energy stored in plants. This process supports life by providing energy and matter to organisms and maintaining ecosystem balance. Constructing scientific explanations with evidence helps us understand these essential biological and ecological processes.
Teacher Notes
Use the exact standards alignment and retrieved-source provenance stored with this enrichment.