Plant Growth & Development
Lesson 2
What is Inside a Seed?
In Lesson 1, students looked at the outside of a lima bean seed. In this lesson, students will look inside to observe the internal structures. Brassica seeds are too small for this investigation: lima beans are bigger, which allows students to see the characteristics that most seeds share.
Objectives:
Students observe how the bean seed has changed after being soaked in water overnight. Students record their observations. Students open the bean and observe the inside. Students draw and label the parts of a bean seed.
4. Lesson set up and Management
GLE 1.1.7 Understand the characteristics of living organisms.
(Lessons 1-7, 9, 10, 16)
*Identify observable characteristics of living organisms (e.g., plants have roots, stems, leaves, seeds, flowers; bees have two antennae, compound eyes, six legs, two pairs of wings, a head, thorax, and abdomen).
GLE 1.2.1 Analyze how the parts of a system go together, and how these parts depend on each other.
(Lessons 1-14, 16)
*Identify the parts of a system (e.g., roots, stems, leaves, flowers, fruits, and seeds) and how the parts go together.
*Describe the function of a part of a system (e.g., leaves are the food factories of Wisconsin Fast Plants.)
*Explain how one part of a system depends upon other parts of the same system.
*Predict and explain how a system would work if one of its parts was missing or broken.
GLE 1.2.3 Know that substances are made of small particles.
(Lessons 1, 2, 6, 9 10, 11)
*Observe and describe that some particles can only be seen with magnification (e.g., parts of seeds, parts of flowers, parts of bees).
GLE 2.1.1 Understand how to ask a question about objects, organisms, and events in the environment.
(Lessons 1-16)
*Ask questions about objects, organisms, and events based on observations of the natural world.
GLE 2.1.2 Understand how to plan and conduct simple investigations following all safety rules.
(Lessons 1-16)
*Make predictions of the results of an investigation (e.g., growth rate of the Wisconsin Fast Plant during the growth spurt).
*
Generate a logical plan for, and conduct, a simple controlled investigation with the following attributes: 1) appropriate materials, tools, and available computer technology, 2) gather, record, and organize data using appropriate units, charts, and/or graphs
*Identify and use simple equipment and tools (such as magnifiers, rulers) to gather data and extend the senses.
*
Follow all safety rules during investigations.
GLE 2.1.5 Understand how to report investigations and explanations of objects, events, systems, and processes.
(Lessons 1-16)
*Report observations or data of simple investigations without making inferences.
*Summarize an investigation by describing:
- materials used in the investigation, -observations, data, results, -explanations and conclusions in written, mathematical, oral, and information technology presentation formats, -safety procedures used
GLE 2.2.1 Understand that all scientific observations are reported accurately and honestly even when the observations contradict expectations.
(Lessons 1-12, 15, 16)
*Explain why scientific observations are recorded accurately and honestly.
*Explain why scientific records of observations are not changed even when the records do not match initial expectations.
*Explain why honest acknowledgement of the contributions of others and information sources are necessary.
GLE 3.2.2 Understand that people have invented tools for everyday life and for scientific investigations.
(Lessons 1-12, 15, 16)
*Describe tools (technology) invented to advance scientific investigations (e.g., rulers, plant lights, automatic watering system, magnification devices, the development of Wisconsin Fast Plants by Dr. Paul Williams for classroom investigations).
- Many plants follow a life cycle that begins with growth from a seed and proceeds through the production of many new seeds.
- Plants have different stages in their life cycle.
All seeds have two main parts: the embryo, or baby plant, and the cotyledon, a thickened leaf that contains stored food for the seedling - oils, carbohydrates, and protein. Once the seedling produces true leaves, it has depleted the stored food in the cotyledon and begins producing its own food in its leaves through photosynthesis. The embryo is the tiny, undeveloped plant that includes all the parts of a mature plant. The outside of the seed, or the seed coat, protects these delicate internal structures.
4. Lesson set up and Management
Materials:
Students already have Activity Sheet 1, Recording Chart for Seed Observations from Lesson 1 so there is nothing for you to run off for this lesson.
Use overhead transparency (Figure 2-1) with overhead projector. If you have access to a video microscope and an LCD projector, that would be very helpful, but optional.
Distribution Center:
Students will each need to pick up:
- a dry bean seed,
- 2 or 3 soaked bean seeds (they break easily)
- 1 paper towel
- 1 hand lens for every 2 students
When a Materials Manager returns to the desk, the materials are placed in the Hands-Off Zone as they inventory what they should have picked up at the Distribution Center.
10X magnified view of the inside of a lima bean seed.
Student Management:
Students will have observed the dried seed the previous day, but have not had a chance to do a comparison with a soaked seed. Students will notice that the soaked seed will be larger because it has soaked up water and the seed coat will slip off easily compared to the seed coat of the dried seed. Also, the soaked seed will come apart easily and the dry seed will not. The soaked seed will also feel and smell different from the dried seed.
This is a good time to begin talking to students about seed dormancy. Seeds can remain dormant for a very long time, waiting for just the right conditions that would be ideal for the plant to survive. Most seeds need both warm temperatures and moisture to begin germination.
Stress the importance of having students draw and label the parts of their lima bean seed. This is a scientific skill that students will need to demonstrate on the science WASL. It is not the same as drawing a seed and listing the parts.
FINAL ACTIVITIES
Depending on the time of year when this unit is taught, the expectations you have for writing will need to be taken into account.
Show student work from your classroom if available.
NOTE: In the next lesson, your class will be planting the Brassica seeds. Try to recruit two or three parents to help. You can do Lesson 3 by yourself without additional help, but it will go a lot smoother with more adults available to assist students with disabilities and/or language barriers.
EXTENSIONS
This activity is listed as an extension, but it is critical that you present this opportunity to your students. Project the overhead transparency (Figure 2-2). Explain that it is an example of a scientific drawing. Ask students to point out features that make it a clear, complete, and accurate picture of a plant. Once they know and understand what good entries look like, they are better able to produce good entries for their own science notebooks.
EVALUATIONS
Make it very clear to your students that you are evaluating their science notebook entries for
- Clarity: descriptions are clear and precise
- Completeness: all parts of the seed are observed and described
- Accuracy: drawings should be as close as possible to the real thing
- Appropriate use of vocabulary: incorporate newly acquired words into written observations and label parts correctly
NOTE: Copy the glossary in the back of the teacher’s guide and have your students insert it into their science notebooks for reference during this unit.
Writing Support:
- Students draw and label the inside of their lima bean seed in their science notebooks.
- Have students also write the function of each labeled part of the seed.
Reading Support: Students use non-fiction reading skills.
- ScienceSaurus, A Student Handbook (use as a resource)
- How a Plant Grows
Have students partner-read and write interesting facts and questions they may have on sticky notes. Students leave their sticky notes on the pages of the book until they are ready to transfer their sticky notes into their student notebooks. Students will read this book cover to cover over the course of this science unit.