From Seed to Seed:
Plant Science for K-8 Educators

Activity 1: Life Cycles to Learn by

Grades: K-8

Associated Lesson Topics:

• Introduction to life cycles
• Germination
• Plant growth
• Photosynthesis
• Sexual reproduction/pollination
• Seed dispersal
• Nutrition
• Plant requirements

National Standards:

• SCIENCE: Standard A, Standard C
• LANGUAGE ARTS: Writing 1
• MATH: Measurement Standard

Planting the Seed...

What can you tell me about seeds? Do you think that all seeds look the same? After we plant a seed, what is the first thing you think we will see? What image does the word "plant" conjure up? How many different parts of the plant can you name? What do think each one of these parts does? How can we determine whether growth is taking place? Before you begin this activity, have students draw a picture of a generic plant. This picture will represent some of their current conceptions about plants. Comparing this drawing with those produced throughout this activity can provide an opportunity to address certain naive conceptions that students may have.

Teacher Information:

A great way to introduce the plant life cycle to your students is to frame your lessons around the developmental life stages (from seed to seed) of a plant you grow. When the seed germinates, germination is the lesson topic. When the seedling gets taller, the lesson topic is plant growth, and so on. Whether you are growing the plants in the classroom or in the garden, each student can have his or her own plant to adopt. Inside, students can label their pots and keep their plants at their desks for part of the day. Explain to your students that if they keep their plants at their desks all day, they will be depriving them of a necessary resource-light. Outside, students can place decorated popsicle sticks in the soil to identify their plants. Either way, students become attached to their plants and more interested in the plant's daily activities. In addition to learning about the life cycle, the students also learn about the needs of the plant. At the end of the life cycle unit, students can take their plants home. Alternatively, the plants or plant products can be sold to generate revenue for additional gardening activities or supplies.

Necessary Materials:

• Plant seeds: bean, sunflower, or pea seeds if you want visible fruits; Otherwise, marigold, nasturtium, or daisy seeds will work well.
• Planting materials.
• Garden: Popsicle sticks and paint.

Procedure:

Each week, students make observations of their plants. The observations can include drawings, measurements, or detailed notes. They can do this individually in their journals or as a class on a large piece of chart paper. The purpose of these observation periods is for students to record and understand the changes that are taking place in their plants over time.

If the above activity seems too time-consuming to fit into your schedule, try this alternative: Sow seeds at 2-week intervals over a period of 12 weeks and examine many, if not all, of the life cycles in a single lesson or week. Although we recommend introducing the stages of the life cycle over a longer period (as in the above activity), the same observations can be made in both activities.

Harvesting the Crop...

What does a plant need to grow? What is the effect on the plant if we alter certain growing conditions? Students can experiment with different growing conditions and investigate how these affect the plant during different life stages. For example,

What is the effect on growth when the plant is exposed to:

Overwatering vs. underwatering.
Plastic covering vs. no plastic covering.
Different light intensities.
Different temperatures.
Different types of soils.
Different sowing depths.

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